57.Small and Large Intestines

8/3/2019 57.Small and Large Intestines

1/33

57 The small and large intestinesNEIL J. McC. MORTENSEN

Abdominal pain

Abdominal pain arising from the alimentary canal is of two types.

1. Visceral pain. The alimentary tract is primarily a midline structure with a

bilateral nerve supply. Although rotation about the midline occurs during

development, nevertheless true visceral pain is referred to the midline as shown in

Fig. 57.1. It is dull and poorly localised. For example, an obstructing stenosis of the

terminal ileum, which is part of the midgut, would give rise to colicky periumbilical

pain.

2.Peritoneal pain is of the somatic type and is much more precise, more severe and

localised to the site of origin. These components account for the changes in character

and site of pain which occur in appendicitis. Once the full thickness of theappendicular wall becomes inflamed the overlying peritoneum becomes involved and

the patient has localised right iliac fossa pain (see Chapter 59).

Surgical anatomy

It is of great practical importance to be able to do the following:

1.distinguish various portions of the intestinal tract at sight;

2.know in which part of the abdomen the upper coils, as opposed to the lower coils, of

small intestine lie in relationship to the anterior abdominal wall;

3.be able to decide which is the proximal and which is the distal end of any coil under

consideration;

4.distinguish irrefutably large from small intestine.

The following are useful tips.

The mesentery of the jeiunum has only two series of arcades of blood vessels,

whereas the lower ileum has several series of arcades.

The mesenteric attachment runs from left to right. Provided that the gut is not

twisted, the proximal small bowel lies in the upper part of the abdomen and the lower

small bowel lies in the lower part of the abdomen.

The large intestine can be characterised by its taenia coli and appendices epiploicae.

Malformations and functional abnormalities

Congenital malformationsThese malformations are described in the following:

congenital atresia of the duodenum (see Chapter 58);

congenital atresia of the small intestine (see Chapter 58);

volvulus neonatorum (see Chapter 58);

vascular anomalies (angiodysplasia) (see below);

malrotation of the colon with failure of descent of the caecum which remains

under the right lobe of the liver. This is clearly very important should the patient

develop appendicitis (see Chapter 59).

Megacolon and nonmegacolon constipation

There is no single definition of constipation that can be described according to thecharacter of the stools, the frequency of evacuation and the ease of evacuation.


2/33

Generally speaking a bowel frequency of less than one every 3 days would be

considered abnormal. This group of conditions can be divided into:

1. megacolon:

(a) Hirschsprungs disease,

(b) non-Hirschsprungs megarectum and megacolon; 2. nonmegacolon:

(a) slow transit,(b) normal transit.

Hirschsprungs diseasePathology

The major feature of Hirschsprungs disease is an absence of ganglion cells in the

neural plexus of the intestinal wall, together with hypertrophy of the nerve trunks.

This is believed to result from a failure of migration of neuroblasts into the gut from

vagal nerve trunks at the end of the first trimester of foetal life.

The loss of ganglion cells extends for a variable distance above the anorectal junction.

In about two-thirds of patients the rectum and lower sigmoid colon are involved, butinvolvement of extremely short segments of the lower rectum or the whole intestinal

tract have been described.

The severity of symptoms is not always consistent with the length of the intestinal

segment involved and may be related to the number of acetylcholinesterase-positive

nerve fibres.

The absence of ganglion cells gives rise to a contracted nonperistaltic segment with a

dilated hypertrophied segment of normal colon above it (Fig. 57.2).

Clinical features

Hirschsprungs disease occurs in approximately one in 4500 live births. It shows a

familial tendency and is more common in males than in females. The clinical picture

varies from acute intestinal obstruction in neonates to chronic constipation in laterlife.

1. In neonates the delayed passage of meconium together with mild abdominal

distension should alert the paediatrician to the diagnosis of Hirschsprungs disease. It

is often complicated by enterocolitis which may result in perforation and septicaemia,

and there is still a high mortality from Hirschsprungs disease at this age.

2. Chronic constipation starting in the first few weeks of life. The classic picture of

gross abdominal distension, chronic constipation and failure to thrive should be rare

with a greater awareness of the diagnosis.

3. Severe constipation without soiling in otherwise healthy children and adults can he

caused by a short segment of Hirschsprungs disease. Faecal soiling is not usually a

feature of the condition.

Diagnosis

Rectal biopsy. Confirmation of the diagnosis depends on histological demonstration

of aganglionosis and hypertrophic nerve fibres in the nerve plexus. The pathologist

has to be able to see a representative area of at least one nerve plexus in the biopsy. In

children this can be obtained by a suction rectal biopsy or, in adults, by a formal strip,

full-thickness, rectal biopsy. Specimens are usually taken from just above the

anorectal junction. One is sent for biochemistry and one for histochemistry and

histopathology (Fig. 57.3).

Anorectal manometry. This is a useful screening test in the constipated young child or

adult who is otherwise fit. The rectosphincteric inhibitory reflex is absent. It shouldnot be carried out in ill neonates because of poor anal tone.


3/33

Radiology. Erect and supine abdominal radiographs are useful. If the large intestine is

obstructed, they will show distended loops of small and large intestine with fluid

levels consistent with a low intestinal obstruction. Intramural gas will indicate

enterocolitis, and free peritoneal gas, a perforation.

An enema using a water-soluble contrast medium will often confirm the diagnosis and

indicate the length and site of involved intestine. A rectal examination should not beperformed before radiology because it may dilate the abnormal segment and modify

the radiological features. The contrast is instilled through a fine 5 Fr catheter under

screening control with the patient in the lateral position. The coning down of the

transition zone, irregularity in the mucosa and abnormal contractions of the intestine

are important positive findings.

Treatment

This depends on the age of the patient, the length of the involved segment, the

severity of symptoms and the presence of enterocolitis.

In the neonate presenting with obstruction or any child or adult presenting with

enterocolitis, an initial colostomy is performed. The site of the colostomy should be as

low as possible in the ganglionated segment. A peroperative frozen section biopsy istaken to establish the presence of ganglia. This is important as the transition zone may

be difficult to locate precisely.

In the child or adult with constipation alone, the dilated intestine can be evacuated

with repeat rectal saline washouts and enemas as a first step. The choice of surgical

procedure to follow will depend on the length of the involved segment.

Short segment disease with minimal symptoms may respond to an extended

myectomy removing a strip of rectal wall up to the area where normal ganglion cells

start.

Long segment disease may be helped by one of the four operations shown below. The

definitive operation is preceded by a temporary colostomy for a few months which

allows the proximal distended colon to return to its normal calibre. If a neonate

requires a colostomy the definitive operation is delayed until the child weighs

approximately 10 kg when the pelvis is still shallow but wide enough to give good

access. The child will be between 10 months and 1 year of age and toilet training can

usually start soon after the operation.

In some older children it may be possible to clear the retained faeces with enemas and

laxatives; if so it may be possible to perform a one-stage operation.

Duhamel operation

The aganglionic segment is removed down to the level of the peritoneal reflection

over the rectum. The rectum is divided and dosed. The sacral hollow is opened and

the normal colon brought down to the posterior aspect of the rectal stump. With ananal retractor in place a transverse incision is made from the level in the posterior wall

just above the anal sphincter. The normal colon is then grasped and sewn to the

transverse incision in the rectum. The spur between the rectum and normal colon is

then divided with a stapler.

Swensons procedure

The rectum is mobilised from above taking care to dissect immediately outside the

fascia propia, preserving autonomic nerves to the bladder and seminal vesicles. The

intestine is transected proximally through normal colon, the presence of ganglion cells

having first been checked for by frozen section biopsy. The mobilised aganglionic

segment is then everted out through the anus, the everted rectal mucosa is cleaned,

and the anterior half of the junction between the top of the anal canal and the rectumis opened transversely. The proximal normal colon is then pulled through this opening


4/33

and an end-to-end anastomosis made between the colon and anal canal as the

aganglionic segment is excised. Once the anastomosis is complete it is reduced hack

into the anal canal.

Colo-anal anastomosis

This is usually reserved for older children, teenagers and adults. The rectum is

mobilised as before and transected just above the level of the pelvic floor. The normalcolon is then joined to the top of the anal canal either directly with a stapling

tecnhique or by a sleeve technique following a mucosectomy of the upper anal canal

and rectum, a procedure described by both Soave and Parks.

Restorative proctocolectomy

In cases of Hirichsprungs disease involving the entire colon, it is possible to

reconstruct with an ileoanal pouch procedure (see Chapter 60).

Idiopathic megarectum and megacolon

This is a rare condition and the cause is not known although in some it may result

from poor toilet training during infancy and in others by a congenital abnormality of

the intestinal myenteric plexus.

InvestigationOn clinical examination there may be a hard faecal mass arising out of the pelvis, and

on rectal examination there is a large faecaloma in the lumen. The anus is usually

patulous, perianal soiling is common, and sigmoidoscopy is usually impossible but

may show melanosis coli if the patient has been taking laxatives over many years.

Radiology. As there is an enlarged rectum often with distention of the colon over a

variable length, a radiograph should he taken without prior bowel preparation using a

small quantity of water-soluble contrast to prevent barium impaction. There is usually

gross faecal loading of the enlarged rectum and colon and, when a contrast

examination is carried out, the width of the colon measured at the pelvic brim is

usually more than 6.5 cm (Fig. 57.4).

Anorectal physiology tests show abnormally large volumes inflated in the rectum to

induce a feeling of rectal fullness, and inhibition of the internal and external anal

sphincters is present but at much larger volumes than normal. Full-thickness rectal

biopsy shows normal ganglion cells which distinguishes this condition from

Hirschsprungs disease.

Medical treatment

This is directed at emptying the rectum and keeping it empty with enemas, washouts

and sometimes manual evacuation under anaesthesia. Thereafter the patient is

encouraged to develop a regular daily bowel habit with the use of laxatives and

repeated enemas as necessary.

Surgical treatmentSurgical treatment is necessary sometimes if medical therapy fails. Resection of the

dilated rectum and colon (Fig. 57.5)back to normal diameter colon with normal

ganglion cells confirmed by frozen section at the time of surgery is followed by

reconstruction with a colo-anal anastomosis.

Nonmegacolon constipation

Although constipation is often regarded as a trivial symptom some patients are greatly

disabled by abdominal pain, distension, reliance on laxatives and difficulty with

defecation. These are usually otherwise healthy individuals who seek help for

constipation but eat a normal diet and have a normal colon on endoscopy and barium

enema.

Investigation


5/33

Whole gut transit time can be measured by asking the patient to stop all laxatives and

take a capsule containing radio opaque markers (Fig. 57.6).Retention of more than 80

per cent of the shapes, 120 hours after ingestion, is abnormal.

Defecating proctography may be helpful if the main complaint is difficulty in passing

stools.

Idiopathic slow transit constipationThis disorder is usually seen in women and results from infrequent bowel actions

which may have been present since childhood or may suddenly follow abdominal or

pelvic surgery. They have delayed transit using marker studies and may or may not be

able to empty the rectum normally (Fig. 57.6).

This is a difficult condition to treat medically; dietary measures are usually

unsuccessful and surgical treatment is only justified after careful studies and when

medical treatment has been exhausted. Total colectomy and ileorectal anastomosis is

the preferred procedure but the results are unpredictable. One-third of patients

continues to have diarrhoea or constipation and two-thirds persisting abdominal pain.

It is essential to exclude underlying psychiatric or psychological problems.

Obstructed defecationSome patients complain of extreme difficulty in expelling stool. They may have

repeated attempts at rectal evacuation and their transit is often normal. The common

feature in these patients is weakness of the pelvic floor which descends on straining.

Patients may resort to digital evacuation or pressure on the perineum or within the

vagina to assist defecation. The cause is not known. It may arise from damage to

pelvic nerves caused by prolonged straining at stool or childbirth.

Defecation proctography will show abnormal evacuation. There may be an

intussusception with the upper rectum folding in to the lower rectum or an anterior

rectocele where the rectum bulges forward into the posterior wall of the vagina (Fig.

57.7).

Biofeedback training may be helpful in some patients; dietary therapy and laxatives

are usually unsuccessful. Surgery is a last resort, and either a defunctioning ileostomy

or a colostomy with colostomy irrigation is used in intractable cases.

Vascular anomalies (angiodysplasia)Capillary or cavernous haemangiomas are a cause of haemorrhage from the colon at

any age presenting with colonic bleeding. In the middle-aged or elderly patient it

needs to be distinguished from other causes of sudden massive haemorrhage, such as

diverticulitis, ulcerative colitis or ischaemic colitis.

Angiodysplasia is a vascular malformation associated with ageing. It has beenrecognised since the introduction of intestinal angiography and colonoscopy.

Angiodysplasiasoccur particularly in the ascending colon and caecum of elderly

patients over the age of 60 years and are not associated with cutaneous lesions. The

malformations consist of dilated tortuous submucosal veins and in severe cases the

mucosa is replaced by massive dilated deformed vessels. On histological

investigation, they are made up of dilated, distorted, thin-walled vessels with only a

scanty amount of muscle in their walls.

Inspection of the mucosa is often unremarkable. The lesions are only a few

millimetres in size and appear as reddish raised areas at endoscopy. Bleeding is

usually chronic and intermittent and can be severe. Many patients previously thought

to have bled from diverticular disease have probably been bleeding fromangiodysplasia in the caecum. There is an association with aortic stenosis.


6/33

Barium enema is usually unhelpful and should be avoided. Provided the bleeding is

not too brisk colonoscopy may show the characteristic lesion in the caecum or

ascending colon. Selective superior and inferior mesenteric angiography shows the

site and extent of the lesion by a blush. If this fails a radioactive test using

technetium-99m (9smTc)4abelled red cells may confirm and localise the source of

haemorrhage.Some angiodysplastic lesions can be treated by colonoscopic diathermy, but if

bleeding is brisk and the patient seriously ill emergency surgery will be necessary.

Here a catheter is placed in the appendix stump and the colon irrigated progradely

with saline or water. On-table colonoscopy is carried out and the site of the bleeding

can then be confirmed. Angiodysplastic lesions are sometimes demonstrated by

transillumination through the caecum (Fig. 57.8).If it is still not clear exactly which

segment of colon is involved then a total abdominal colectomy with ileorectal

anastomosis may be necessary.

Blind loop syndrome

It has been shown in dogs that, if a blind loop of the small intestine is made (Fig.

57.9),defects of absorption will appear. If this occurs in the upper intestine the defectis chiefly of fat absorption; if in the lower intestine there is vitamin B12 deficiency.

This has been found to occur in humans and is referred to as the blind loop syndrome.

Essentially, the stasis produces an abnormal bacterial flora, which prevents proper

breakdown of the food (especially fat) and mops up the vitamins that are present.

Sometimes the only manifestation is anaemia, resulting from vitamin B12 deficiency,

but if steatorrhoea appears, other serious malabsorption features follow. In general,

high loops produce steatorrhoea, whereas low loops tend to produce anaemia.

Temporary improvement will follow the use of antibiotics to destroy the bacteria

causing the trouble, but the main treatment is surgical extirpation of the cause of the

stasis where applicable.

Diverticular diseaseOne meaning of diverticulum is a wayside house of ill-fame; certainly these wayside

houses live up to their evil reputation. Diverticula can occur from the stomach to the

recto sigmoid. There are two varieties:

1. Congenital. All three coats of the bowel are present in the wall of the diverticulum,

e.g. Meckels.

2.Acquired. The wall of the diverticulum lacks a proper muscular coat. Most

alimentary diverticula are thought to be acquired.

Small intestine

Most of these diverticula arise from the mesenteric side of the bowel probably as theresult of mucosal herniation through the point of entry of blood vessels.

Duodenal diverticulum

There are two types:

1.Primary. Mostly in older patients on the inner wall of the second and third parts,

these diverticula are found incidentally on barium meal and usually do not cause

symptoms. They can cause problems locating the ampulla during endoscopic

retrograde cholangiopancreatography (ERCP) (Fig. 57.10).

2. Secondary. Diverticula of the duodenal cap resulting from long-standing duodenal

ulceration (Fig. 57.11).

Jejunal diverticula

These are usually of variable size and multiple (Fig. 57.12).Clinically they may (1)

be symptomless, (2) give rise to abdominal pain, flatulence and borborygmi, (3)


7/33

produce a malabsorption syndrome, or (4) present as an acute abdomen with acute

inflammation and occasionally rupture. They are more common in patients with

connective tissue disorders. In patients with major malabsorption problems giving rise

to anaemia, steatorrhoea, hypoproteinaemia or vitamin B1, deficiency; resection of

the affected segment with end-to-end anastomosis can be effective.

Meckels diverticulumMeckels diverticulum is present in 2 per cent of the population; it is situated on the

antimesenteric border of the small intestine, commonly 60 cm from the ileocaecal

valve, and is usually 35cm long. Many variations occur (2 per cent 2 feet 2

inches is a useful aidenldmoire) (Figs 57.13 and 57.14).

A Meckels diverticulum possesses all three coats of the intestinal wall and has its

own blood supply. It is therefore vulnerable to infection and obstruction in the same

way as the appendix. In 20 per cent of cases the mucosa contains heterotopic

epithelium, namely, gastric, colonic or sometimes pancreatic tissue. When present, the

abnormal mucosa lines the greater part of the proximal end of the pouch and extends

sometimes for a short distance into the nearby ileum.

Although Meckels diverticulum occurs with equal frequency in both sexes,symptoms usually resulting from the epithelium contained in the diverticulum

predominantly occur in males. In order of frequency,

these symptoms are as follows.

1. Severe haemorrhage, caused by peptic ulceration. The blood is passed per rectum,

and is maroon in colour. Although the patient may vomit, the vomit does not contain

blood. There is rarely any pain and sometimes the bleeding precedes perforation. An

operation is required for serious progressive gastrointestinal bleeding. When no lesion

in the stomach or duodenum can be found the terminal 150 cm of ileum should be

carefully inspected.

2.Intussusception. In most cases, the apex of the intussusception is the swollen,

inflamed, heterotopic epithelium at the mouth of the divertictilum.

3. Meckels diverticulitis, with or without perforation, may result from obstruction by

food residue. The symptoms are those of acute appendicitis and, unless the appendix

has already been removed, the diagnosis is impossible before operation. When a

diverticulum perforates the symptoms may simulate those of a perforated duodenal

ulcer. Whether or not the diverticulum is perforated urgent surgery is required. In

nonperforated cases an inflamed diverticulum should be sought as soon as it has been

demonstrated that the appendix and Fallopian tubes are not at fault.

4. Chronic peptic ulceration. As the diverticulum is part of the midgut, the pain,

although related to meals, is felt around the umbilicus.

5. Intestinal obstruction. The presence of a hand between the apex of the diverticulumand the umbilicus may cause obstruction either by the band itself or by a volvulus

around it.

Radiology

Meckels diverticulum can he very difficult to demonstrate by contrast radiology;

small bowel enema would he the most accurate investigation.Technetium-99m

scanning

In cases of repeated gastrointestinal haemorrhage of unknown cause where a

Meckels diverticulum is suspected the abdomen is imaged with gamma camera after

the injection of 30100 mic Ci (111370 x 1010 Bq) of 99Tc-labelled

pertechnetate intravenously. This may localise heterotopic gastric mucosa revealing

the site of a Meckels diverticulum in 90 per cent of cases.Silent Meckels diverticulum


8/33

An aphorism attributed to Dr Charles Mayo is: a Meckels diverticulum is frequently

suspected, often sought for and seldom found. A Meckels diverticulum usually

remains symptomless throughout life and is found only at necropsy. When a silent

Meckels diverticulum is encountered in the course of an abdominal operation,

provided it is wide-mouthed and the wall of the diverticulum does not feel thickened,

it can he left. Where there is doubt and it can he removed without appreciableadditional risk it should he resected.

Exceptionally a Meckels diverticulum is found in an inguinal or a femoral hernia sac

Littres hernia.

Meckels diverticulectomy

A Meckels diverticulum which is broad based should not he amputated at its base

and invaginated in the same way as a vermiform appendix, because of the risk of

stricture. Furthermore this does not remove heterotopic epithelium where it is present.

The steps of diverticulectomy are shown in Fig. 57.15. Alternatively, a linear stapler

device maybe used. Where there is induration of the base of the diverticulum

extending into the adjacent ileum, it is advisable to resect a short segment of ileum

containing the diverticulum, restoring continuity with an end-to-end anastomosis.Colon

Diverticula of the colon are acquired herniations of colonic mucosa, protruding

through the circular muscle at the points where the blood vessels penetrate the colonic

wall. They tend to occur in rows between the strips of longitudinal muscle, sometimes

partly covered by appendices epiploicae. The condition is most commonly found in

the sigmoid colon but the caecum can also be involved and on occasion the entire

large bowel can be affected. The rectum with its complete muscle layers is not

affected. In 90 per cent of cases the sigmoid colon is involved and is almost always

the site of inflammation, i.e. diverticulitis. Some 5per cent of patients have associated

gallstones and hiatus hernia (Saints triad).

Diverticular disease is rare in Africans and Asians who eat a diet that contains natural

fibre. In Western countries, wherethe roughage has been removed from flour and

refined sugar forms a large part of the diet, diverticula are found in 25 per cent of

barium enemas of patients over the age of 40 and the incidence increases with age.

Diverticulosis

It is important to distinguish between diverticulosis and the presence of diverticula

which may be asymptomatic, and clinical diverticular disease where the diverticula

are causing symptoms. Diverticula probably arise as a result of muscular inco

ordination and spasm, resulting in increased segmentation and intraluminal pressures.

Excessive segmentation in response to food, prostigmine and morphine is found in

colonic motility studies, and this exaggerated response is more apparent insymptomatic than in asymptomatic individuals. On histological investigation the

diverticulum consists of a protrusion of mucous membranes covered with peritoneum.

There is thickening of the circular muscle fibres of the taeniae and the intestine

develops a concertina or sawtooth appearance on barium enema (Fig. 57.16). The

diverticula occur between the muscle clefts making the mucosal surface appear

trabeculated. The elastin content of the taenia coli is increased compared with

controls.

DiverticulitisDiverticulitis is the result of inflammation of one or more diverticula, usually with

some pericolitis. Episodes of diverticulitis may be followed by years free ofsymptoms, but the condition is essentially progressive the longer the duration the


9/33

worse the symptoms and the greater the risk of complications. Diverticulitis is not a

precancerous condition, but cancer may coexist.

The complications are the following:

1.recurrent periodic inflammation and pain in some

patients these episodes may be clinically silent;

2. perforation leading to general peritonitis or local(pericolic) abscess formation;

3. intestinal obstruction:

(a) in the sigmoid as a result of progressive fibrosis causing stenosis,

(b) in the small intestine caused by adherent loops of small

intestine on the pericolitis;

4. haemorrhage: diverticulitis may present with profuse

colonic haemorrhage in 17 per cent of cases, often

requiring blood transfusions;

5. fistula formation (vesicocolic, vaginocolic, enterocolic,

colocutaneous) occurs in 5 per cent of cases, vesicolic

being the most common.Clinical features

Diverticulosis may be asymptomatic, but the disordered colonic function may cause

symptoms of distension, flatulence and a sensation of heaviness in the lower

abdomen, all of which may be indistinguishable from the symptoms of irritable bowel

syndrome. Excessive colonic segmentation can cause severe pain in the left iliac

fossa, but this must be distinguished from episodes of often subclinical inflammation

in the sigmoid colon as a result of diverticulitis.

Diverticulitis. Persistent lower abdominal pain, usually in the left iliac fossa with or

without peritonitis in patients of either sex over the age of 40, could be caused by

diverticulitis. Fever, malaise and leucocytosis can differentiate diverticulitis from

painful diverticulosis. The patient may pass loose stools or may be constipated; the

lower abdomen is tender especially on the left but occasionally also in the right iliac

fossa if the sigmoid loop lies across the midline. The sigmoid colon is often palpable,

tender and thickened. Rectal examination may but does not usually reveal a tender

mass. The condition has been likened to left-sided appendicitis. Any urinary

symptoms may herald the formation of a vesicocolic fistula which leads to

pneumaturia (flatus in the urine) and even faeces in the urine.

Diagnosis

Radiology. Diverticulosis, as for the irritable bowel syndrome, is a diagnosis of

exclusion and symptoms should not be attributed to diverticulosis unless other

diseases have been excluded by barium enema, sigmoidoscopy or colonoscopy.Although the diagnosis of acute diverticulitis is made on clinical grounds it can be

confirmed during the acute phase by computerised tomography (CT). This will

demonstrate not only the diverticula but also any associated pericolicabscess (Fig.

57.17). Barium enemas and sigmoidoscopy are usually reserved for patients who have

recovered from an attack of acute diverticulitis for fear of causing perforation or

peritonitis. Water-soluble contrast enemas may, however, be helpful in sorting out

patients with large bowel obstruction. Barium radiology is carried out to exclude a

carcinoma and to assess the extent of the disease. Where the sigmoid colon is

thickened and narrowed, a saw-tooth appearance may be seen. Some strictures can

be very difficult to distinguish by radiology alone and in those circumstances

colonoscopy will be necessary to rule out a carcinoma.


10/33

Sigmoidoscopy. The mucosa may be normal and in acute attacks the sigmoidoscopy

will be painful and the mucosa inflamed. Colonoscopy or flexible sigmoidoscopy is

more helpful (Fig. 57.18). The necks of diverticula can be seen and the narrowed area

of diverticulitis can be entered, but on occasion not passed because of the severity of

disease. The differential diagnosis from a carcinoma can be impossible if a tight

stenosis prevents endoscopy.Management

Diverticulosis should be treated with a high-residue diet containing roughage in the

form of wholemeal bread, flour, fruit and vegetables. Bulk formers such as bran,

Celevac, Isogel and Fybogel may be given until the stools are soft. Painful

diverticular disease may require bed rest and antispasmodics.

Acute diverticulitis is treated by bed rest and intravenous antibiotics (usually

cefuroxime and metronidazole). After the acute attack has subsided and if the

diagnosis has not already been confirmed by CT, a barium enema should be carried

out.

Operative procedures for diverticular disease. Some 10 per cent of patients require an

operation either for recurrent attacks which make life a misery or for thecomplications of diverticulitis.

1.The ideal operation carried out as an interval procedure after careful preparation of

the gut is a one-stage resection. This involves removal of the affected segment and

restoration of continuity by end-to-end anastomosis. At this operation the sigmoid

loop is often found adherent in the pouch of Douglas. Careful dissection will allow

eventual mobilisation of the recto sigmoid out of the pelvis exposing the normal

rectum, and greater mobility will allow an easier anastomosis.

2.If there is obstruction, inflammatory oedema and adhesions or the bowel is loaded

with faeces, a Hartmanns operation is the procedure of choice. The involved area is

resected. The rectum is closed at the penitoneal reflection, and the left colon brought

out as a left iliac fossa colostomy. The once popular staged procedures using a

preliminary transverse colostomy are now rarely used except by inexperienced

surgeons because of the high mortality associated with them. In selected obstructed

cases the bowel can be cleaned by on-table lavage, placing a urinarycatheter through

the appendix stump and washing the colon with physiological saline or water for

irrigation. This makes subsequent restoration and bowel continuity with an

anastomosis much safer (Fig. 57.19a, h).

3.In acute perforation, peritonitis soon becomes general and may be purulent, which

has a mortality rate of about 15 per cent. Gross faecal peritonitis carries more than a

50 per cent mortality rate and pneumoperitoneum is usually present; the diagnosis

may not be confirmed until emergency laparotomy. There is a choice of procedures:(a) primary resection and Hartmanns procedure (see above);

(b) primary resection and anastomosis after on-table lavage in selected cases;

(c) exteriorisation of the affected bowel which is then opened as a colostomy, now

rarely used;

(d) suture of the perforation with drainage with or without proximal defunction. In

selected cases with a small leak and minimal soiling.

4. Fistulae can only be cured by resection of the diseased bowel and closure of the

fistula. In the case of a colovesical fistula it is usually possible to pinch off the

affected bowel from the bladder, close it and then resect the sigmoid. In very difficult

cases a staged procedure with a preliminary defunctioning stoma may be necessary on

occasion.


11/33

5. Haemorrhage from diverticulitis must be distinguished from angiodysplasia. It

usually responds to conservative management and occasionally requires resection.

On-table lavage and colonoscopy may be necessary to localise the bleeding site.

Diverticular disease and carcinoma coexist in 12 per cent of cases. Exploration may

be necessary but, even then, differentiation may be difficult until histological

investigations are available (Table 57.1). Weight loss, falling haemoglobin andpersistently positive occult blood are sinister features.

Solitary diverticulum of the caecum and ascending colon is rare and is congenital, and

may present with symptoms and signs identical to those of acute appendicitis.

Extensive diverticular disease can sometimes affect the right colon. This, however, is

rare in the West hut more common in Eastern countries. In Japan, China, Malaysia

and Korea, right-sided disease is twice as common as left-sided disease.

Ulcerative colitis

Aetiology

The cause of ulcerative colitis is unknown; its prevalence among first-degree relatives

of patients is 15 times that of the general population but there is no clear Mendelian

pattern of inheritance. In spite of intensive bacteriological studies, no organisms orgroup of organisms can be incriminated. Relapse of colitis has, however, been

reported in association with bacterial dysenteries. Some cases are allergic to milk

protein. Smoking seems to have a protective effect and there have been anecdotal

reports of remission of the disease with smoking or the use of nicotine chewing gum.

Patients often comment that relapses are associated with periods of stress at home or

at work, but personality and psychiatric profiles are the same as the normal

population.

There remain three main hypotheses, none of which has been proved:

1. a mucosal immunological reaction;

2. a weakened mucous barrier;

3. defective mucosal metabolism of butyrates.

Epidemiology

There are 1015 new cases per 100 000 population a year in the UK. The disease has

been rare in Eastern populations hut is now being reported more commonly,

suggesting an environmental cause that has developed as a result of an increasing

westernisation of diet and/or social habits and better diagnostic facilities. The sex

ratio is equal; it is uncommon before the age of 10 and most patients are between the

ages of 20 and 40 at diagnosis.

Pathology

In 95 per cent of cases the disease starts in the rectum and spreads proximally. When

the ileocaecal valve is incompetent, retrograde (backwash) ileitis involving the last 30cm of the ileum is likely to occur. It is a nonspecific inflammatory disease, primarily

affecting the mucosa and superficial submucosa, and only in severe disease are the

deeper layers of the intestinal wall affected. There are multiple minute ulcers, and

microscopic evidence proves that the ulceration is almost always more severe and

extensive than the gross appearance indicates. When the disease is chronic,

inflammatory polyps (pseudopolyps) occur in up to 20 per cent of cases and may be

numerous. They result from previous episodes of ulceration heaving islands of spared

mucosa which will remain prominent when the adjacent mucosa heals. In severe

fulminant colitis a section of the colon, usually the transverse colon, may become

acutely dilated and the intestinal wall then becomes extremely thin and may perforate

(toxic megacolon). On microscopic investigation there is an increase ofinflammatory cells in the lamina propia, the walls of crypts are infiltrated by


12/33

inflammatory cells and there are crypt abscesses. There is depletion of goblet cell

mucin. The crypts are reduced in number and appear to be atrophic and irregularly

spaced. With time these changes become severe and precancerous changes can

develop (r~ severe dysplasia or carcinoma in situ).

Symptoms

The first symptom is watery or bloody diarrhoea; there may be a rectal discharge ofmucus which is either blood stained or purulent. Pain as an early symptom is unusual.

In most cases the disease is chronic and characterised by relapses and remissions. In

general, a bad prognosis is indicated by (1) a severe initial attack, (2) disease

involving the whole colon and (3) increasing age, especially after 60 years. If the

disease remains confined to the left colon the outlook is better.

Proctitis

Inflammation confined to the rectum accounts for about 25 per cent of all cases. As

most of the colon is healthy the stool is formed or semi-formed and the patient is often

severely troubled by tenesmus and urgency. The risk of cancer in these cases is low.

In 510 per cent there is spread to involve the rest of the colon.

Left-sided and total colitis (Fig. 57.20)Diarrhoea usually implies that there is active disease proximal to the rectum.

Approximately 15 per cent of patients have left-sided colitis, and 25 per cent have

total colitis extending beyond the midtransverse colon. The clinical pattern is one of

recurrent severe attacks of bloody diarrhoea up to 20 times a day, dehydration and

fluid electrolyte losses. Anaemia and hypoproteinaemia are common.

Disease severity

Disease severity can be graded as:

1.mild rectal bleeding or diarrhoea with four or fewer motions per day and the

absence of systemic signs of disease;

2. moderate more than four motions per day but no systemic signs of illness;

3. severe more than four motions a day together with one or more signs of

systemic illness: fever over 37.50C, tachycardia more than 90/minute,

hypoalbuminaemia less than 30 g/litre, weight loss more than 3 kg.

Complications of severe disease

Fulminating colitis and toxic dilatation (megacolon) (Fig. 57.21).

Patientswith severe disease should he admitted to hospital. Dilatation should he

suspected in patients with active colitis who develop severe abdominal pain. It is an

indication that inflammation has gone through all the muscle layers of the colon. The

diagnosis is confirmed by the presence on a plain abdominal radiograph of the colon

with a diameter more than 6 cm. The condition must be differentiated from dysentery,

typhoid and amoebic colitis. Plain abdominal radiographs should he obtained daily inpatients with severe colitis and a progressive increase in diameter in spite of medical

therapy is an indication for surgery (Fig. 57.22).

Perforation. Colonic perforation in ulcerative colitis is a gravecomplication with a

mortality rate of 50 per cent or more. Steroids may mask the physical signs.

Perforation can sometimes occur without toxic dilatation. Generally patients with

severe attacks should be managed so that they do not develop these complications.

Severe haemorrhage. Severe rectal bleeding is uncommon and may occasionally

require transfusion and rarely surgery.

Investigations

A plain abdominal film can often show the severity of disease. Faeces are only

present in parts of the colon that are normal or only mildly inflamed. Mucosal islands


13/33

can sometimes be seen and have been mentioned. Small bowel loops in the right

lower quadrant may be a sign of severe disease.

Barium enema

The principal signs are (Fig. 57.23):

loss of haustration, especially in the distal colon;

mucosal changes caused by granularity; pseudopolyps;

in chronic cases, a narrow contracted colon.

In some centres an instant enema is used with a water-soluble medium for contrast

instead of barium and no bowel preparation to avoid aggravating any underlying

colitis (Fig. 57.24).

Sigmoidoscopy

Sigmoidoscopy is essential for diagnosis of early cases and mild disease not showing

up on a barium enema. The initial findings are those of proctitis, the mucosa is

hyperaemic, bleeds on touch and there may be a pus-like exudate. Later tiny ulcers

may be seen and appear to coalesce. This is different from the picture of amoebic

dysentery where there are large deep ulcers with intervening normal mucosa.Colonoscopy and biopsy

This has an important place in management:

1. to establish the extent of inflammation;

2. to distinguish between ulcerative colitis and Crohns colitis;

3. to monitor response to treatment;

4. to assess long-standing cases for malignant change.

Although it may occasionally be helpful, colonoscopy is not usually used in acute

cases for fear of aggravating the disease or perforation.

The cancer risk in colitis

Although this is an important complication the overall risk is only about 3.5 per cent.

It is much less in early cases but increases with duration of disease. Thus, after 20

years of colitis the risk may be as much as 12 per cent. Carcinoma is more likely to

occur where the whole colon is involved and where the disease started in early life

(Fig. 57.25). Carcinomatous change, often atypical and high grade, may occur at

many sites at once. The colon is involved rather than the rectum and the maximal

incidence is during the fourth decade.

The golden rule is that, when the disease has been present for 10 years or more,

regular colonoscopic checks must be carried out, even if the disease is clinically

quiescent. If on biopsy there is severe epithelial dysplasia, surgery is indicated.

Annual colonoscopy and biopsy is then part of cancer surveillance. In the rare cases

with a fibrous stricture these should be examined especially carefully for the presenceof an underlying carcinoma.

Extraintestinal manifestations

Arthritis occurs in around 15 per cent of patients and is of the large joint

polyarthropathy type, affecting knees, ankles, elbows and wrists. Sacroileitis and

ankylosing spondylitis are 20 times more common in patients with ulcerative colitis.

Skin lesions: erythema nodosum, pyoderma gangrenosum or aphthous ulceration.

Eye problems: iritis.

Liver disease: sclerosing cholangitis has been reported in up to 70 per cent of cases.

Diagnosis is by ERCP which demonstrates the characteristic alternating stricturing

and bleeding of the intrahepatic and extrahepatic ducts.

Bile duct cancer is a rare complication and colectomy does not appear to reduce therisk of subsequent bile duct cancer or sclerosing cholangitis.


14/33

Treatment

Medical treatment of an acute attack

Corticosteroids are the most useful drugs and can be given either locally for

inflammation of the rectum or systemically when the disease is more extensive.

Sulphasalazine and other 5-aminosalicylic acid (5-ASA) derivates, for example,

mesalazine and olsalazine, can be given both topically and systemically.Their main function is in maintaining remission rather than treating an acute attack.

Nonspecific antidiarrhoeal agents have no place in the routine management of

ulcerative colitis.

Mild attacks

Patients with a mild attack and limited disease will usually respond to rectally

administered steroids. In those with more extensive disease, oral prednisolone 2040

mg/day is given over a 34-week period. Sulphasalazine 1 g three times a day or one

of the newer 5-ASA compounds should be given concurrently.

Moderate attacks

These patients should be treated with oral prednisolone 40 mg/day, twice daily steroid

enemas and 5-ASA. Failure to achieve remission as an out-patient is an indication foradmission.

Severe attacks

These patients must be regarded as medical emergencies and require immediate

admission to hospital. Their appearance is often misleading, and they must be

examined at least twice a day with particular reference to the presence of signs of

peritonism. Their abdominal girth is measured and liver dullness should be percussed

regularly. A plain abdominal radiograph is taken daily and inspected for dilatation of

the transverse colon of more than 5.5 cm. The presence of mucosal islands on plain

radiographs (see Fig. 57.22), increasing colonic diameter or a sudden increase in pulse

and temperature may indicate a colonic perforation. A stool chart helps in the

assessment of response to therapy, and careful medical/surgical joint management is

essential. Fluid and electrolyte balance is maintained, anaemia is corrected and

adequate nutrition provided, sometimes in severe cases with intravenous nutrition.

The patient is maintained nil by mouth and treated with intravenous hydrocortisone

100200 mg four times daily. This can be supplemented with a rectal infusion of

prednisolone. There is no evidence that antibiotics modify the course of a severe

attack. Some patients are treated with azathioprine or cyclosporin A to induce

remission, If there is failure to gain an improvement within 57 days then surgery

must be seriously considered. Prolonged high-dose intravenous steroid therapy is

fraught with danger. Patients who have had weeks of treatment, during which the

colonic wall has become friable and disintegrates at laparotomy, are now fortunatelyrare.

Indications for surgery

The risk of colectomy is 20 per cent overall, ranging from 5 per cent in those patients

with proctitis to 50 per cent in those patients with a very severe attack:

severe or fulminating disease failing to respond to medical therapy;

chronic disease with anaemia, frequent stools, urgency and tenesmus;

steroid-dependent disease: here the disease is not severe but remission cannot be

maintained without substantial doses of steroids;

the risk of neoplastic change: patients who on review colonoscopy have severe

dysplasia;

extraintestinal manifestations; rarely, severe haemorrhage or stenosis causing obstruction.


15/33

Operations

I. In the emergency situation the first-aid procedure is a total abdominal colectomy

and ileostomy. The rectum can either he brought out at the lower end of the wound as

a mucous fistula or closed just beneath the skin. This has the advantage that the

patient recovers quickly, the histology of the resected colon can he checked, and

restorative surgery can be contemplated at a later date when the patient is no longeron steroids and in optimal nutritional condition. The alternative, division of the

rectum below the sacral promontory, can result in breakdown and pelvic abscess, and

makes subsequent identification of the stump more difficult.

2. Proctocolectomy and ileostomy: this is the procedure associated with the least

compilcation rate. The patient is left with a permanent ileostomy There is, however, a

20 per cent long-term risk of adhesion obstruction, and 510 per cent of the perineal

wounds are very slow to heal. The late result will be a chronic perineal sinus which

may require repeated currettage or excision. The obvious disadvantage is an ileostomy

and although many patients cope remarkably well there is a psychological and social

cost.

Rectal and anal dissection. Refinements of the procedure have included a close rectaldissection to minimise damage to the nervi erigentis and hence erectile dysfunction

which may occur in 0.52 per cent, and inter sphincteric excision of the anus which

results in a smaller perineal wound and fewer healing problems.

3. Restorative proctocolectomy with an ileoanal pouch (Parks). In this operation a

pouch or reservoir is made out of ileum (Fig. 57.26) as a substitute for the rectum and

sewn or stapled to the anal canal. Various pouch designs have been described, hut the

J is the most popular and the most easily made using staplers (Fig. 57.27). There is

some controversy over the correct technique for ileoanal anastomosis. In the earliest

operations, the mucosa from the dentate line up to midrectum was stripped off the

underlying muscle, but it is now known that a long muscle cuff is not needed. A

mucosectomv of the upper anal canal with an anastomosis at the dentate line is

claimed to remove all of the at risk mucosa and any problem of subsequent cancer. It

may also result in imperfect continence with nocturnal seepage. The alternative is a

double stapled anastomosis to the top of the anal canal preserving the upper anal canal

mucosa. Continence appears to be better, but the theoretical risk of leaving inflamed

mucosa remains.

The procedure can he carried out in one, two or three stages. In selected cases a

covering loop ileostomy is omitted hut is usually used. Complications include pelvic

sepsis usually resulting from a leak of the ileoanal anastomosis, small bowel

obstruction and pouch vaginal fistula. Frequency of evacuation is determined by

pouch volume, completeness of emptying, reservoir inflammation and intrinsic smallbowel motility, but can be between three and six evacuations daily. Although

associated with a higher complication rate, it is rapidly becoming the operation of

choice in younger patients, avoiding a permanent ileostomy. About 20 per cent of

patients have an episode of pouchitis, that is, inflammation of the reservoir, at some

time. It usually responds to treatment with metronidazole.

4. Colectomy and ileorectal anastomosis: if there is minimal rectal inflammation

this can occasionally he used; it has largely been superseded by restorative

proctocolectomy.

5. ileostomy with a continent intra-abdominal pouch (Kocks procedure). A

reservoir is made of ileum and just beyond this a spout is made by inverting the

efferent ileum into itself to give a continent valve just below skin level. The pouch isemptied by the patient inserting a catheter through the valve; now rarely used.


16/33

Ileostomy

End ileostomy (Brooke). In those patients with a permanent ileostomy there must be

scrupulous attention to detail during the operation to ensure that the patient has a good

functional result. The position of the ileostomy should be carefully chosen by the

patient with the help of a stoma care nursing specialist. The ileum is normally brought

through the lateral edge of the rectus abdominis muscle. The use of a spout (Fig.57.28) was originally described by Bryan Brooke and it should project some 4 cm

from the skin surface. A disposable appliance is placed over the ileostomy so that it is

a snug fit at skin level.

ileostomy care

During the first few postoperative days, fluid and electrolyte balance must he adjusted

with great care. There may he an ileostomy flux while the ileum adapts to the loss of

the colon, and the fluid losses can amount to 4 or 5litres/day. The stools thicken in a

few weeks and are semisolid in a few months. The help, skill and advice of the stoma

care nursing specialist are essential. Modern appliances have transformed stoma care

and skin problems are unusual (Fig. 57.29).

Complications of an ileostomy include prolapse, retraction, stenosis, bleeding andparaileostomy hernia.Loop ileostomy. This is often used to defunction a pouch

ileoanal procedure or even a low anterior resection. A knuckle of ileum is pulled out

through a skin trephine in the right iliac fossa. An incision is made in the distal part of

the knuckle and this is then pulled over the top of the more proximal part to create a

spout on the proximal side of the loop with a flush distal side still in continuity. This

allows near-perfect defunction, but also the possibility of restoration of continuity by

taking down the spout and reanastomosing the partially divided ileum.

Crohns disease (regional enteritis)

Crohns disease became widely recognised following the report in 1932 by Crohn,

Ginzburg and Oppenheimer describing young adults with a chronic inflammatory

disease of the ileum. It can affect any part of the gastrointestinal tract from the lips to

the anal margin, but ileocolonic disease is the most common presentation.

Epidemiology

It is most common in North America and northern Europe. Prevalence rates as high as

56 per 100 000 have been reported in the UK. Over the last four decades there seems

to have been a rise in the incidence which cannot be accounted for by increased

diagnosis. It is slightly more common in females than in males but is most commonly

diagnosed in young patients between the ages of 25 and 40. There does, however,

seem to be a second peak of incidence around the age of 17.Aetiology

Although Crohns disease has some features suggesting chronic infection, no

causative organism has ever been found; similarities between Crohns disease and

tuberculosis have focused attention on mycobacteria. Focal ischaemia has also been

postulated as a causative factor, possibly originating from a vasculitis arising through

an immunological process. A wide variety of foods has now been implicated but none

conclusively. Smoking increases the risk threefold.

About 10 per cent of patients have a first-degree relative with the disease and there is

an association with ankylosing spondylitis. Cell-mediated immune function may be

defective in patients with Crohns disease but it is not known whether this is a

consequence of the disease itself or the effects of malnutrition and medical therapy.As with ulcerative colitis it is now believed that Crohns disease can predispose to


17/33

cancer, although the incidence of malignant change is not nearly as high as in

ulcerative colitis and is most manifest in the ileum.

Pathology

Ileal disease is the most common accounting for 60 per cent of cases; 30 per cent of

cases are limited to the large intestine and the remainder consists of patients with ileal

disease alone or more proximal small bowel involvement. Anal lesions are common.Crohns disease of the mouth, oesophagus, and stomach and duodenum are

uncommon. Resection specimens show a fibrotic thickening of the intestinal wall with

a narrow lumen (Fig. 57.30). There is usually dilated gut just proximal to the stricture

and, in the strictured area, there are deep mucosal ulcerations with linear or snake-like

patterns. Oedema in the mucosa between the ulcers gives rise to a cobblestone

appearance. The transmural inflammation leads to adhesions, inflammatory masses

with mesenteric abscesses and fistulae into adjacent organs. The serosa is usually

opaque, there is thickening in the mesentery and mesenteric lymph nodes are

enlarged. The condition is discontinuous with inflamed areas separated from normal

intestine; these are sometimes called skip lesions. Under the microscope there are

focal areas of chronic inflammation involving all layers of the intestinal wall. Thereare noncaseating giant cell granulomas but these are only found in 60 per cent of

patients. They are most common in anorectal disease. The earliest mucosal lesions are

discrete aphthous ulcers. Recent studies have also shown multifocal arterial

occlusions in the muscularis propia.

Clinical features

Presentation depends upon the area of involvement.

Acute Crohns disease

Acute Crohns disease occurs in only 5 per cent of cases. Symptoms and signs

resemble those of acute appendicitis but there is usually diarrhoea preceding the

attack. Rarely there could be a free perforation of the small intestine, resulting in a

local or diffuse peritonitis. Acute colitis with or without toxic megacolon can occur in

Crohns disease but is less common than in ulcerative colitis.

Chronic Crohns disease

There is often a history of mild diarrhoea extending over many months occurring in

bouts accompanied by intestinal colic. Patients may complain of pain, particularly in

the right iliac fossa, and there may be a tender mass palpable. Intermittent fevers,

secondary anaemia and weight loss are common. A perianal abscess or fissure may be

the first presenting feature of Crohns disease; the cause is often an infected anal crypt

associated with concomitant diarrhoea, but as the disease becomes chronic specific

fistulae resulting from the Crohns disease itself can develop.

After months of repeated attacks with acute inflammation the affected area ofintestine begins to narrow with fibrosis causing abdominal pain on eating, giving rise

to what has been described as food fear. Children developing the illness before

puberty may have retarded growth and sexual development.

With progression of the disease adhesions and transmural fissuring, intra-abdominal

abscesses and fistula tracts can develop.

1.Entero-enteric fistulae can occur into adjacent small bowel loops or the pelvic colon

and entero-vesical fistulae may cause repeated urinary tract infections and

pneumaturia.

2. Entero-cutaneous fistulae rarely occur spontaneously and usually follow previous

surgery.

Anal disease (see Chapter 58)


18/33

In the presence of active disease, the penianal skin appears bluish. Three or more

oedematous pinky-blue fleshy tags protrude from the anal margin; they may have

superficial ulceration on the inner surface extending into the anal canal. Superficial

ulcers with undermined edges are relatively painless and can heal with bridging of

epithelium. Deep cavitating ulcers are usually found in the upper anal canal; they can

be painful and cause perianal abscesses and fistulae, discharging around the anus andsometimes forwards into the genitalia.

The most distressing feature of anal disease is sepsis from secondary abscesses and

perianal fistulae. Remarkably the rectal mucosa is often spared and may feel normal

on rectal examination. If it is involved, however, it will feel thickened, nodular and

irregular.

Investigation

Sigmoidoscopic examination

Sigmoidoscopic examination may be normal or show minimal involvement.

Ulceration in the anal canal will, however, be readily seen.

Colonoscopy

As a result of the discontinuous nature of Crohns disease there will be areas ofnormal colon or rectum. In between these there are areas of inflamed mucosa which

are irregular, ulcerated with a mucopurulent exudate. The earliest appearances are

aphthoid-like ulcers surrounded by a rim of erythematous mucosa. These become

larger and deeper with increasing severity of disease. In colonic Crohns disease there

may be stricturing and it is important to exclude malignancy in these sites (Fig.

57.31). At the ileo-colic anastomosis of a patient having had previous ileocaecal

resection, recurrent disease is usually seen on the ileal side of the anastomosis.

Radiology

Barium enema will show similar features to those of colonoscopy in the colon. The

best investigation of the small intestine is small bowel enema (Fig. 57.32). This will

show up areas of delay and dilatation characterising partial obstruction. The involved

areas tend to be narrowed, irregular and sometimes, when a length of terminal ileum

is involved, there may be the string sign of Kantor. Sinograms are useful in patients

with entero-cutaneous fistulae. CT scans are used in patients with fistulae and those

with intra-abdominal abscesses and complex involvement. Magnetic resonance

imaging (MRI) has been shown to be useful in assessing perianal disease.

Treatment

Medical therapy

Steroids are the mainstay of treatment. Patients with a relapse of their Crohns disease

are treated with up to 40 mg prednisolone orally, daily supplemented by 5-ASA corn-

pounds in those patients with colonic involvement, although there is some evidencethat this may help small bowel disease as well. Those who have symptoms and signs

of a mass or an abscess are also treated with antibiotics. Azathioprine is used for its

additive and steroid-sparing effect. Nutritional support is essential. Severely

malnourished people may require intravenous feeding or nasoenteric feeding

regimens. Anaemia, hypoproteinaemia, electrolyte, vitamin and metabolic bone

problems must all be addressed.

Indications for surgery

Surgical resection will not cure Crohns disease. Surgery is therefore focused on

complications of the disease. As many of these indications for surgery may be

relative, joint management by an aggressive physician arid a conservative surgeon is

thought to be ideal. These complications include:recurrent intestinal obstruction;


19/33

bleeding;

perforation;

failure of medical therapy;

intestinal fistula;

fulminant colitis;

malignant change;perianal disease.

Surgery

To preserve functional gut length, resection is kept to a minimum so as to deal with

the local problem. The whole of the gastrointestinal tract has to be examined carefully

at the time of laparotomy. If on occasion Crohns disease is diagnosed during the

course of an operation for suspected appendicitis, the appendix should be removed. If

the ileum is thick, rigid and pipe-like, senior help should be sought so that an

ileocaecal resection can be carried out.

The course of the disease after surgery is unpredictable but recurrence is common. It

does not seem to be related to the presence of disease at the resection line. Recurrence

rates vary from site to site hut the cumulative probability of recurrence requiringsurgery for ileal disease is of the order of 20, 40, 60 and 80 per cent at 5, 10, 15 and

20 years, respectively, after previous resection. Restorative operations have a higher

incidence of recurrence than, for example, proctocolectomy and ileostomy.

1. Ileocaecal resection is the usual procedure for ileocaecal disease with a primary

anastomosis between the ileum and the transverse colon.

2. Segmental resection: short segments of small or large bowel involvement can he

treated by segmental resection.

3. Colectomy and ileorectal anastomosis. In patients with widespread colonic disease

with rectal sparing and a normal anus this can be a useful option.

4. Temporary loop ileostomy. This can be used either in patients with acute distal

Crohns disease allowing remission and later restoration of continuity or in patients

with severe penianal or rectal disease.

5.Proctocolectomy. Patients with colonic and anal disease failing to respond to

medical treatment or defunction will eventually require a permanent ileostomy.

6.Strictureplasty. Multiple strictured areas of Crohns disease (Fig. 57.33) can be

treated by a local widening procedure, strictureplasty, to avoid excessive small bowel

resection (Fig. 57.34) (Lee).

7. Anal disease is usually treated conservatively by simple drainage of abscesses,

placing setons around any fistulae, and occasionally in patients with inactive disease

primary repair of a recto-vaginal or high fistula in ano could be attempted.

InfectionsIntestinal amoebiasis. Amoebiasis is an infestation with Entamoeba histolytica. This

parasite has a world-wide distribution.

Life history of the parasite. The active form of the parasite or trophozoite lives in the

intestinal mucous membrane where it ingests red blood corpuscles and other cells and

multiples by mitosis. Should the parasite become pathogenic, it makes its way into the

follicles ofLieberkuhn and, by dissolving into glandular tissue via the cytolysins,

submucous loculi are produced. Some of these burst through the mucous membrane to

become amoebic ulcers. While the trophozoites continue their activities in the base of

the ulcer, others cease to feed, migrate towards the surface and become transformed

into cysts which pass into the outer world with the faeces. Amoebiasis is transmitted

mainly in contaminated drinking water.


20/33

Pathology.The ulcers, which have been described as bottlenecked because of their

considerably undermined edges, have a yellow necrotic floor, from which blood and

pus exude. Although on rare occasions the ulcers are scattered throughout the large

intestine, in 75 per cent they are confined to the lower sigmoid and upper rectum.

Biopsy.Endoscopic biopsies or fresh hot stools are examined carefully to look for the

presence of amoebae. It is important to emphasise, however, that the presence of theparasite does not indicate that it is pathogenic (Fig. 57.35).

Clinical features. Dysentery is the principal manifestation of the disease but it may

come in various other guises.

Appendicitis or amoebic caecal mass. In tropical countries where amoebiasis is

endemic, this is a constantly recurring problem. To operate on a patient with amoebic

dysentery without the precautions subsequently described is to invite an exacerbation

of amoebiasis which may prove fatal. The bowel is friable and satisfactory closure of

the appendix stump becomes difficult or impossible, especially in cases where a

palpable mass is present. When there is an amoebic mass there tends to be tenderness

on deep palpation over the caecum and the sigmoid.

Perforation.The most common sites are the caecum and recto-sigmoid; usuallyperforation occurs into a confined space where adhesions have previously formed and

a pericolic abscess results which eventually needs draining. When there is sudden

faecal flooding in the general peritoneal cavity, drainage of the region of the

perforation, gastrointestinal aspiration, intravenous fluid, antibiotics and a full course

of emetine are sometimes successful.

Severe rectal haemorrhage as a result of separation of the slough is liable to occur.

Granuloma.Progressive amoebic invasion of the wall of the rectum or colon, with

secondary inflammation, can produce a granulomatous mass indistinguishable from a

carcinoma.

Fibrous stricture may follow the healing of extensive amoebic ulcers.

Intestinal obstruction is a common complication of amoebiasis, and the obstruction is

the result of adhesions associated with pericolitis and large granuloma.

Paracolic abscess, ischiorectal abscess and fistula occur from perforation by amoebae

of the intestinal wall followed by secondary infection.

Ulcerative colitis. A search for amoebae should always be made in the stools of

patients believed to have ulcerative colitis.

Treatment.High-dose intravenous steroids in this situation can he catastrophic.

Metronidazole (Flagyl) is the first-line drug, 800 mg three times daily for 710 days.

Diloxanide furoate is best for chronic infections associated with the passage of cysts

in stools. Intestinal antibiotics improve the results of the chronic stages, probably by

coping with superadded infection.Typhoid and paratyphoid. Surgical complications. Paralytic ileus is the most common

complication of typhoid.

Intestinal haemorrhage may be the leading symptom.

Perforation.Perforation of a typhoid ulcer usually occurs during the third week and is

occasionally the first sign of the disease. The ulcer is parallel to the long axis of the

gut and is usually situated in the lower ileum.

Paratyphoid B. Perforation of the large intestine sometimes occurs. Vigorous

intravenous antibiotic therapy is given; occasionally surgery is required to defunction

the colon or in late cases remove the colon as for ulcerative colitis.

Cholecystitis.Acute typhoid cholecystitis is not uncommon and perforation can occur;

gallstones occasionally contain typhoid bacilli and some patients may become typhoidcarriers.


21/33

Phlebitis.Venous thrombosis, particularly of the left common iliac vein, is an

occasional complication of typhoid fever.

Genitourinary complications. Typhoid cystitis, pyelitis and epididymo-orchitis may

all occur.

Joints.All degrees of arthritis, from a mild effusion to suppuration, occur as a

complication of this disease.Bone.Typhoid osteomyelitis and typhoid of the spine occur.

Tuberculosis of the intestine. Tuberculosis can affect any part of the gastrointestinal

tract from the mouth to the anus. The sites affected most often are the ileum, proximal

colon and peritoneum. There are two principal types.

Ulcerative tuberculosis is secondary to pulmonary tuberculosis and arises as a result

of swallowing tubercle bacilli. There are multiple ulcers in the terminal ileum, lying

transversely, and the overlying serosa is thickened, reddened and covered in tubercles.

Clinical features. Diarrhoea and weight loss are the predominant symptoms and

usually the patient will be receiving treatment for pulmonary tuberculosis.

Radiology.A barium meal and follow-through or small bowel enema will show the

absence of filling of the lower ileum, caecum and most of the ascending colon as aresult of narrowing and hypermotility of the ulcerated segment (Fig. 57.36).

Treatment.A course of chemotherapy is given. Healing often occurs provided the

pulmonary tuberculosis is adequately treated. An operation is only required in the rare

event of a perforation or intestinal obstruction.

Hyperplastic tuberculosis. This usually occurs in the ileocaecal region although

solitary and multiple lesions in the lower ileum are sometimes seen. This is caused by

the ingestion of Mycobacterium tuberculosis by patients with a high resistance to the

organism. The infection establishes itself in lymphoid follicles, and the resulting

chronic inflammation causes thickening of the intestinal wall and narrowing of the

lumen. There is early involvement of the regional lymph nodes which may caseate.

Unlike Crohns disease, with which it shares many similarities, abscess and fistula

formation is rare.

Untreated, sooner or later subacute intestinal obstruction will supervene often together

with the impaction of an enterolith in the narrowed lumen.

Clinical features. Attacks of abdominal pain with intermittent diarrhoea are the usual

symptoms. The ileum above the partial obstruction is distended, and the stasis and

consequent infection lead to steatorrhoea, anaemia and loss of weight. Sometimes the

presenting picture is of a mass in the right iliac fossa in a patent with vague ill health.

The differential diagnosis is that of an appendix mass, carcinoma of the caecum,

Crohns disease, tuberculosis or actinomycosis of the caecum.

Radiology.A barium follow-through or small bowel enema will show a long narrowfilling defect in the terminal ileum.

Treatment.When the diagnosis is certain and the patient has not yet developed

obstructive symptoms, treatment with chemotherapy is advised and may cure the

condition. Where obstruction is present, operative treatment is required and ileocaecal

resection is best.

Actinomycosis of the ileocaecal region. Abdominal actinomycosis is rare. Unlike

intestinal tuberculosis, narrowing of the lumen of the intestine does not occur and

mesenteric nodes do not become involved. A local abscess, however, spreads to the

retroperitoneal tissues and the adjacent abdominal wall, becoming the seat of multiple

indurated discharging sinuses. The liver may become involved via the portal vein.

Clinical features. The usual history is that appendicectomy has been carried out for anappendicitis. Some 3 weeks after surgery a mass is palpable in the right iliac fossa and


22/33

soon afterwards the wound begins to discharge. At first this is thin and watery, and

then later it becomes thicker and malodorous. Other sinuses may form and a

secondary faecal fistula develop. Pus should be sent for bacteriological examination

where the characteristic sulphur granules can be seen.

Treatment.Penicillin or cotrimoxazole has to be prolonged and high dosage.

Tumours of small intestineCompared with the large intestine, the small intestine is rarely the seat of a neoplasm

and these become progressively less common from the duodenum to the terminal

ileum.

Benign. Adenoma, submucous lipoma and leiomyoma occur from time to time, and

sometimes reveal themselves by causing an intussusception.

The second most common complication is intestinal bleeding from an adenoma in

which event the diagnosis is frequently long delayed because the tumour is

overlooked at barium radiology, endoscopy and even surgery.

PeutzJeghers syndrome consists of:

familial intestinal hamartomatous polyposis affecting the jejunum, where it is a

cause of haemorrhage, and often intussusception; melanosis of the oral mucous membrane and the lips.

The melanosis takes the form of melanin spots sometimes present on the digits and

the perianal skin, but the pigmentation of the lips is the sine qua non (Fig. 57.37).

Histology.The polyps can be likened to trees. The trunk and branches are smooth

muscle fibres and the foliage is virtually normal mucosa.

Treatment.As malignant change rarely occurs, resection is necessary only for serious

bleeding or intussusception. Large single polyps can be removed by enterotomy or

short lengths of heavily involved intestine can be resected. Those lesions within reach

can be snared by colonoscopy.

Malignant. Lymphoma. There are three main types as follows.

1.Western type lymphoma. These are annular ulcerating lesions, which are sometimes

multiple. They are now thought to he non-Hodgkins B-cell lymphoma in origin.

They may present with obstruction and bleeding, perforation, anorexia and weight

loss.

2. Primary lymphoma associated with coeliac disease. There is an increased incidence

of lymphoma in patients with coeliac disease; this is now regarded as a T-cell

lymphoma. Worsening of the patients diarrhoea, with pyrexia of unknown - origin

together with local obstructive symptoms, is the usual feature.

3.Mediterranean lymphoma. This is found mostly in North Africa and the Middle East

and is associated with alpha-chain disease.

Unless there are particular surgical complications these conditions are usually treatedwith chemotherapy.

Carcinoma.As with other small bowel tumours these can present with obstruction,

bleeding or diarrhoea. Complete resection offers the only hope of cure (Fig. 57.38).

Carcinoid tumour. These tumours occur throughout the gastrointestinal tract, most

commonly in the appendix, ileum and rectum in decreasing order of frequency. They

arise from neuroendocrine cells at the base of intestinal crypts. The primary is usually

small but when they metastasise, the liver is usually involved with numerous

secondaries, which are larger and more yellow than the primary, and when this has

occurred the carcinoid syndrome will become evident. The tumours can produce a

number of vasoactive peptides, most commonly 5-hydrox-ytryptamine (serotonin),

which may be present as 5-hydroxyindoleacetic acid in the urine during attacks.


23/33

The clinical syndrome itself consists of reddish-blue cyanosis, flushing attacks,

diarrhoea, borborygmi, asthmatic attacks and, eventually, sometimes pulmonary and

tricuspid stenosis. Classically the flushing attacks are induced by alcohol.

Treatment.Most patients with gastrointestinal carcinoids do not have carcinoid

syndrome. Surgical resection is usually sufficient. In the cases found incidentally at

appendicectomy nothing further is required. In patients with metastatic disease,multiple enucleations of hepatic metastases or even partial hepatectomy can he carried

out. The treatment has been transformed by the use of octreotide (a somatostatin

analogue) which reduces both flushing and diarrhoea, and octreotide cover is usually

used in patients with a carcinoid syndrome who have surgery to prevent a carcinoid

crisis. Carcinoid tumours generally grow more slowly than most metastatic

malignancies; the patients may live with the syndrome of metatastic disease for many

years.

Tumours of the large intestine

BenignThe term polyp is a clinical description of any elevated tumour. It covers a variety of

histologically different tumours shown in Table 57.2.

Polyps can occur either singly, synchronously in small numbers or as part of a

polyposis syndrome. In familial adenomatous polyposis, more than 100 adenomas are

present. It is important to be sure of the histological diagnosis because adenomas have

significant malignant potential.

Adenomatous polyps

Adenomatous polyps vary from a tubular adenoma (Fig. 57.39), rather like a

raspberry on a stalk, to the villous adenoma, a flat spreading lesion. Solitary

adenomas are usually found during the investigation of colonic bleeding or sometimes

fortuitously. Villous tumours more usually give symptoms of diarrhoea, mucus

discharge and occasionally hypokalaemia. The risk of malignancy developing in an

adenoma increases with increasing size of tumour, for example, in 1-cm diameter

tubular adenomas there is a 10 per cent risk of cancer, whereas in villous adenomas

over 2 cm in diameter there may be a 15 per cent chance of carcinoma. Adenomas

larger than 5mm in diameter are usually treated because of their malignant potential.

Colonoscopic snare polypectomy or diathermy obliteration with hot biopsy forceps

can be used. Huge villous adenomas of the rectum can be difficult to remove even

with techniques per anus and occasionally proctectomy is required; the anal sphincter

can usually be preserved.

Hamartomatous polypsPeutzJeghers polyps may occur in the colon as either solitary or multiple lesions.

Juvenile polyps may occur as multiple lesions in the colon often associated with a

congenital defect such as a malrotation or Meckels diverticulum. They have minimal

malignant potential and ate only removed if they are causing troublesome pain,

bleeding or hypoproteinaemia.

Haemangioma

A localised submucous telangiectasis is often the cause of bleeding which may be

profuse. If bleeding is continuing, both angiography and colonoscopy can help to

localise the source. If found by colonoscopy the lesion can be removed

endoscopically, whereas arteriographic detection can be followed by the use of

vasopressin or microspheres to stop the haemorrhage. Often the only method ofdetecting it is to operate while the bleeding is in progress. The distribution of blood


24/33

within the intestine is noted; scrutiny of the blood-containing portion of the colon may

reveal the lesion but on-table colonoscopy could be necessary. The tumour is resected

once located.

Lipoma

Lipoma is less frequently encountered in the large than in the small intestine. In the

large intestine it is almost always confined to the caecum. The tumour is submucousand in more than half the cases it is the cause of an intussusception. On occasion a

lipoma at the ileocaecal valve can be confused with a caecal cancer.

Familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is a general neoplastic disorder of the

intestine. Although the large bowel is mainly affected polyps can occur in the

stomach, duodenum and small intestine. The main risk is large bowel cancer, but

duodenal and ampullary tumours have been reported. It is inherited as a Mendelian

dominant and the gene responsible (APC gene) has now been identified on the short

arm of chromosome 5 (Bodmer). Males and females are equally affected. It can also

occur sporadically without any previous sign or history, presumably by new

mutations. There is often, in these cases, a history of large bowel cancer occurring inyoung adulthood or middle age suggesting preexisting adenomatosis.

FAP can be associated with benign mesodermal tumours such as desmoid tumours

and osteomas. Epidermoid cysts can also occur (Gardners syndrome); desmoid

tumours in the abdomen invade locally to involve the intestinal mesentery and

although nonmetastasising they can become unresectable.

Clinical features. Polyps are usually visible on sigmoidoscopy by the age of 15 years

and will almost always be visible by the age of 30. Carcinoma of the large bowel

occurs 1020 years after the onset of the polyposis. One or more cancers will already

be present in two-thirds of those patients presenting with symptoms.

Symptomatic patients. These are either new proposition or those from an affected

family who have not been screened. They may have loose stools, lower abdominal

pain, weight loss, diarrhoea and the passage of blood and mucus. Polyps are seen on

sigmoidoscopy, and the number and distribution of polyps, and usually cancers if they

ate symptomatic, are shown on a double-contrast barium enema. If in doubt

colonoscopy is performed with biopsies to establish the number and histological type

of polyps. If over 100 adenomas (Fig. 57.40) ate present the diagnosis can be made

confidently but it is important not to confuse this with nonneoplastic forms of

polyposis.

Asymptomatic patients. Usually members of affected families attend for screening. As

yet there is no reliable means of knowing whether an individual is affected unless

adenomas develop. If there are no adenomas by the age of 30, FAP is unlikely.Pigmented spots in the retina (CHIRPES) and deoxyribonucleic acid (DNA) tests for

the FAP gene should make screening mote reliable in the future.

If the diagnosis is made during adolescence, operation is deferred usually to the age of

17 or 18.

Screening policy.

1. All members of the family should be examined at the age of 1012 years,

repeated every 12 years.

2. Most of those who are going to get polyps will have them at 20 and these

requite operation.

3. If there are no polyps at 20, continue with 5-yearly examination until age 50; if

there are still no polyps there is probably no inherited gene. Carcinomatous changemay exceptionally occur before the age of 20. Examination of blood relatives,


25/33

including cousins, nephews and nieces, is essential and a family tree should be

constructed and a register of affected families maintained.

Treatment. Colectomy with ileorectal anastomosis has in the past been the usual

operation because it avoids an ileostomy in a young patient. The rectum is

subsequently cleared of polyps by snaring or fulguration. The patients ate examined

by flexible sigmoidoscopy at 6-monthly intervals thereafter. In spite of this, aproportion of patients develops carcinoma in the rectal stump. The risk of carcinoma

in the St Marks series was 10 per cent over a period of 30 years.

The alternative and now more common operation is a restorative proctocolectomy

with an ileoanal anastomosi

57.Small and Large Intestines

Documents

Transcript of 57.Small and Large Intestines