Chapter 30 - Appendix

7/30/2019 Chapter 30 - Appendix

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Anatomy and Function

The appendix begins to bud

off from the cecum at around

the 6th week of

embryological development. The base of the appendix

remains in a fixed position

with respect to the cecum,

whereas the tip can end upin various positions


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The appendix is composed of

the same layers as the colon

wall.

Mucosa, submucosa, inner circular

muscle, outer longitudinal muscle,serosa.

The 3 distinct bands of outer

longitudinal muscle, the taeniae

coli, converge on the appendix.

After you locate the cecum,

you can easily find the

appendix by ff the 3 taenia coli

until they converge at the base

of the appendix


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Although many have claimedthat the appendix is merely avestigial organ, it is actuallyan immunological organ and

secretes IgA. However, it isnot an essential organ andcan be removed withoutimmunological compromise.

length: 2 to 20 cm butaverages 69 cm.

Luminal capacity is < 1 mL.


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Incidence

Highest in early adulthood, at the peak of lymphoidtissue growth.

Second peak in the incidence of appendicitis occurs inthe elderly.

There is a higher incidence of appendicitis in males thanfemales (1.3:1), although females are more commonlymisdiagnosed with acute appendicitis than males.


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Pathophysiology

The probable sequence of events in acute appendicitis is:1. Luminal obstruction In young patients, more commonly by lymphoid tissue hyperplasia.

In older patients, fecalith is an increasingly common cause ofobstruction.

2. Distention and increased intraluminal pressure The appendiceal mucosa continues to secrete normally despite being

obstructed.

The resident bacteria multiply rapidly, further increasing intraluminalpressure.

3. Venous congestion The intraluminal pressure eventually exceeds capillary and venule pressures. Arteriolar blood continues to fl ow in, causing vascular congestion and

engorgement.

4. Impaired blood supply renders the mucosa ischemic andsusceptible to bacterial invasion.

5. Inflammation and ischemia progress to involve the serosalsurface of the appendix.


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Bacteriology

bacterial pop. of the normal appendix is similar to that of thenormal colon.

appendiceal flora remains constant throughout (exc.Porphyromonas gingivalis only in adults)

principal organisms: (acute & perforated appendicitis):

Escherichia coli and Bacteroides fragilis.


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Clinical Manifestations


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Symptoms

1. Abdominal pain- prime symptom initially diffusely centered in the lower epigastrium or umbilical area

moderately severe, steady, sometimes with intermittent crampingsuperimposed.

After 1-12 hours (usually 4-6hrs), pain localizes to the RLQ.

Variations in the anatomic location of the appendixaccount for many of the variations in the principal locusof the somatic phase of the pain.

2. Anorexia

3. Vomiting 75%

neither prominent nor prolonged

caused by both neural stimulation and presence of ileus


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Symptoms

4. constipation

beginning before the onset of abdominal pain

(many feel that defecation would relieve their abdominal pain)

5. Diarrhea particularly children

pattern of bowel function is of little differential diagnostic value.

The sequence of symptom appearance has greatsignificance for the DD.


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Signs

1. Vital signs are minimally changed by

uncomplicated appendicitis

temp elevation is rarely >1C (1.8F)

pulse rate is normal or slightly elevated

2. Patients with appendicitis usually prefer to lie

supine, with the thighs, particularly the R thigh,

drawn up, because any motion increases pain.

If asked to move, they do so slowly and with caution.


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Signs

3. The classic RLQ physical signs arepresent when the inflamedappendix lies in the anteriorposition.

max tenderness at or near the McBurney

point referred tenderness is felt maximally in

the RLQ localized peritoneal irritation

Rovsing signpain in the RLQ whenpalpatory pressure is exerted in the LLQ site of peritoneal irritation.

4. Cutaneous hyperesthesia (T10,T11, T12)

elicited either by needle prick or by gentlypicking up the skin between the forefingerand thumb.


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Signs

5. Muscular resistance to palpation of the abdominal

wall roughly parallels the severity of the

inflammatory process.

6. Anatomic variations in the position of the inflamedappendix lead to deviations in the usual physical

findings.

retrocecal appendix: less striking anterior abdominal findings

and flank tenderness inflamed appendix hangs into the pelvis: absent abdominal

findings and the dx may be missed unless the rectum is

examined.


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Alvarado Scale

lists the 8 specific indicators identified. scores: 9-10: certain to have appendicitis

7-8: high likelihood of appendicitis

5-6: compatible with, but not diagnostic of, appendicitis (requires CT

scan)


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Signs

Clinical algorithm for suspected cases of acute appendicitis. If gynecologicdisease is suspected, a pelvic and endovaginal ultrasound examination isindicated


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Differential Diagnosis

Gastrointestinal Conditions Gastroenteritis

Mesenteric adenitis

Meckels diverticulum

Intussusception

Typhoid fever Primary peritonitis

Genitourinary Conditions Ectopic pregnancy

Pelvic infl ammatory disease Ovarian torsion/cyst/tumor

Urinary tract infection/

Ureteral stone


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Laboratory and

Diagnostic

Imaging


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Labs

Complete blood count:

Leukocytosis (> 10,000 in 90% of cases), usually with

concomitant left shift (polymorphonuclear neutrophil [PMN]

predominance).

Consider perforation or abscess if WBC > 18,000.

Urinalysis:

Helpful in ruling out genitourinary causes of symptoms.

RBCs and WBCs may be present secondary to extension of

appendiceal inflammation to the ureter.

Significant hematuria or pyuria, and bacteriuria from a

catheterized specimen should suggest underlying urinary tract

pathology.


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Diagnostic imaging

Abdominal x-ray: Not particularly useful in most cases.

May reveal appendicolith/fecalith (< 15% of cases).

Abdominal CT with contrast:

Very sensitive (9598%) and somewhat specific (8390%).

Useful in identifying several other inflammatory processes that may presentsimilarly to appendicitis.

Positive findings include: Dilatation of appendix to > 6 mm in diameter.

Thickening of appendiceal wall (representing edema).

Periappendiceal streaking (densities within perimesenteric fat).

Presence of appendicolith

Graded compression ultrasonography: Sensitivity of 85% and specifi city of 92% for diagnosing appendicitis.

Positive fi nding: Enlarged (> 6 mm), noncompressible appendix.

Especially useful in ruling out gynecologic pathology.


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Appendicial Rupture

Immediate appendectomy has long been the

recommended tx for acute appendicitis because of

the presumed risk of progression to rupture.

overall rate of perforated appendicitis: 25.8%. Highest rate of perforation:

65 years of age

delays in presentation are responsible for themajority of perforated appendices


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Appendicial Rupture

no accurate way of determining when and if an

appendix will rupture before resolution of the

inflammatory process.

occurs most frequently distal to the point of luminalobstruction along the antimesenteric border of the

appendix.

Rupture should be suspected in the presence of

fever (>39C) WBC count (>18,000 cells/mm3)


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ACUTE MESENTERIC ADENITIS

a disease most often confused with acute

appendicitis in children.

The pain usually is diffuse, and tenderness is not as

sharply localized as in appendicitis. Generalized lymphadenopathy may be noted.

Human infection with Yersinia enterocolitica or

Yersinia pseudotuberculosis, transmitted through

food contaminated by feces or urine, causesmesenteric adenitis as well as ileitis, colitis, and

acute appendicitis.

sensitive to tetracyclines, streptomycin, ampicillin, and

kanamycin.


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ACUTE MESENTERIC ADENITIS

A preoperative suspicion of the diagnosis should not

delay operative intervention, because appendicitis

caused by Yersinia cannot be clinically distinguished

from appendicitis due to other causes.

Salmonella typhimurium infection causes mesenteric

adenitis and paralytic ileus with symptoms similar to

those of appendicitis.


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GYNECOLOGIC DISORDERS

Pelvic Inflammatory Disease

an infection usually bilateral but, if confined to the R

tube, may mimic acute appendicitis.

S&s manifested Nausea and vomiting (50%)

Pain and tenderness are lower, and motion of the cervix is

painful.

Intracellular diplococci may be demonstrable onsmear of the purulent vaginal discharge.


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Ruptured Graafian Follicle Ovulation commonly results in the spillage of sufficient

amounts of blood and follicular fluid to produce brief, mildlower abdominal pain.

If the amount of fluid is unusually copious and is from the R

ovary, appendicitis may be simulated. Pain and tenderness are diffuse.

Leukocytosis and fever are minimal or absent.

Twisted Ovarian Cyst

When R-sided cysts rupture or undergo torsion, themanifestations are similar to those of appendicitis.

Patients develop RLQ pain, tenderness, rebound, fever, andleukocytosis.

If the mass is palpable on PE, the dx can be made easily.


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Ruptured Ectopic Pregnancy Blastocysts may implant in the fallopian tube (usually the

ampullary portion) and in the ovary.

Rupture of R tubal or ovarian pregnancies can mimic

appendicitis. The development of RLQ or pelvic pain may be the first symptom.

The dx of ruptured ectopic pregnancy should berelatively easy. presence of a pelvic mass and elevated levels of chorionic

gonadotropin. presence of blood and particularly decidual tissue is pathognomonic.

Vaginal examination reveals cervical motion and adnexaltenderness, and a more definitive diagnosis can be established byculdocentesis.

tx: emergency surgery.


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OTHER INTESTINAL DISORDERS

Acute Gastroenteritis

can be easily distinguished from acute appendicitis.

characterized by profuse diarrhea, nausea, and

vomiting. Hyperperistaltic abdominal cramps precede the

watery stools.

abdomen is relaxed bw cramps, and there are no

localizing signs.


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Meckel's Diverticulitis

clinical picture is similar to that of acute appendicitis.

Meckel's diverticulum is located within the distal 2 ft

of the ileum. Meckel's diverticulitis is asso with the same

complications as appendicitis and requires the same

txprompt surgical intervention.


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Crohn's Enteritis

manifestations of acute regional enteritisfever,

RLQ pain and tenderness, and leukocytosisoften

simulate acute appendicitis.

(+) diarrhea and (-) anorexia, nausea, and vomiting favor a dx

of enteritis, but this is not sufficient to exclude acute

appendicitis.

In cases of an acutely inflamed distal ileum with no

cecal involvement and a normal appendix,

appendectomy is indicated.


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Colonic Lesions Diverticulitis or perforating carcinoma of the cecum,

or of that portion of the sigmoid that lies in the Rside, may be impossible to distinguish from

appendicitis. Symptoms may be minimal, or there may be

continuous abdominal pain in an area corres to thecontour of the colon

Pain shift is unusual pt does not look ill, nausea and vomiting are unusual, and

appetite generally is unaffected.

Localized tenderness over the site is usual and often is assowith rebound without rigidity.


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Colonic Lesions Diverticulitis or perforating carcinoma of the cecum,

or of that portion of the sigmoid that lies in the Rside, may be impossible to distinguish from

appendicitis. Symptoms may be minimal, or there may be

continuous abdominal pain in an area corres to thecontour of the colon

Pain shift is unusual pt does not look ill, nausea and vomiting are unusual, and

appetite generally is unaffected.

Localized tenderness over the site is usual and often is assowith rebound without rigidity.


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APPENDICITIS IN SPECIAL POPULATION


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Acute Appendicitis in the Young

dx is more difficult in young children than in the adult. Inability of young children to give accurate hx

diagnostic delays by both parents and physicians,

frequency of GI upset in children are all contributing factors.

PE (highest sensitivity for appendicitis)

maximal tenderness in the RLQ inability to walk or walking with a limp

pain with percussion, coughing, and hopping.

The incidence of major complications after appendectomy inchildren is correlated with appendiceal rupture.

tx regimen for perforated appendicitis: immediate appendectomy

irrigation of the peritoneal cavity.

Antibiotic coverage is limited to 24-48 hrs, IV usually are given until thewbc is normal and the patient is afebrile for 24 hours.


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Acute Appendicitis in the Elderly

Compared with younger patients, elderly patients aremore difficult to dx

Tend to present atypically, leading to delayed

diagnosis.

Present later in the course and with less pain, may present as

a small bowel obstruction.

Delayed leukocytosis.

Higher risk of perforation and higher mortality than in

younger patients.


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Acute Appendicitis during Pregnancy

Appendicitis is the mc surgical emergency inpregnant patients.

Fetal mortality increases 38% with appendicitis and

30% with perforation.

Difficult to diagnose

particularly true in the late 2nd - 3rd trimester, when many

abdominal symptoms may be considered pregnancy related.

Surgery is the standard tx, though 1015% ofwomen will experience premature labor.


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Appendicitis in Pts w/ AIDS or HIV Infection

The presentation of acute appendicitis in HIV-infected patients is similar to that in noninfected

patients.

fever, periumbilical pain radiating to the RLQ (91%), RLQ

tenderness (91%), and rebound tenderness (74%).

Although they may not have absolute leukocytosis,

compared to baseline WBC count, they will

demonstrate relative leukocytosis.

The Dd is expanded to include opportunistic

infections such as CMV-related bowel perforation

and neutropenic colitis.


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Treatment


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Once the decision to operate for presumed acuteappendicitis has been made, the patient should beprepared for the operating room.

Adequate hydration should be ensured, electrolyteabnormalities should be corrected, and pre-existing

cardiac, pulmonary, and renal conditions should beaddressed.

For intra-abdominal infxns of GI tract origin that are ofmild to moderate severity, the Surgical Infection Societyhas recommended single-agent therapy with cefoxitin,

cefotetan, or ticarcillin-clavulanic acid. For more severe infections, single-agent therapy with

carbapenems or combination therapy with a third-generation cephalosporin, monobactam, oraminoglycoside plus anaerobic coverage with

clindamycin or metronidazole is indicated.


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Surgical Procedures


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Open appendectomy

most surgeons use either a McBurney(oblique) or Rocky-Davis (transverse)

RLQ muscle-splitting incision in

patients with suspected appendicitis.

incision should be centered over either thepoint of maximal tenderness or a palpable

mass.

If an abscess is suspected

laterally placed incision (allows

retroperitoneal drainage and avoid generalizedcontamination of the peritoneal cavity)

If the diagnosis is in doubt

lower midline incision (allows more

extensive examination of the peritoneal cavity)


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Open appendectomy

Several techniques can be used to locate the appendix since cecum is visible within the incision, the convergence of the

taeniae can be followed to the base of the appendix.

limited mobilization of the cecum is needed to aid in adequatevisualization.

Once identified, the appendix is mobilized by dividing themesoappendix, with care taken to ligate the appendicealartery securely.

The appendiceal stump can be managed by simple

ligation or by ligation and inversion with either a purse-string or Z stitch.

The mucosa is frequently obliterated to avoid thedevelopment of mucocele.

The peritoneal cavity is irrigated and the wound closed inlayers.


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Open appendectomy

If appendicitis is not found, a methodical searchmust be made for an alternative diagnosis.

cecum and mesentery is inspected.

Next, small bowel is examined in a retrograde fashion

beginning at the ileocecal valve and extending at least 2 ft.

If purulent fluid is encountered, it is imperative that

the source be identified.

medial extension of the incision (Fowler-Weir), with

division of the A and P rectus sheath for further

evaluation of abdomen


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Laparoscopic Appendectomy

performed under general anesthesia. nasogastric tube and a urinary catheter are placed

before obtaining a pneumoperitoneum.

requires the use of three ports. surgeon stands to patient's L. One assistant is required to operate

the camera. 1st trocar placed in the umbilicus (10 mm)

2nd trocar is placed in the suprapubic position.

3rd trocar (5 mm) is variable and usually either in LLQ, epigastrium,or RUQ.

Initially, the abdomen is thoroughly explored to excludeother pathology.

The appendix is identified by following the anteriortaeniae to its base.


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Dissection at the base of theappendix enables the surgeon tocreate a window between themesentery and the base of theappendix (A)

mesentery and base of theappendix are then secured anddivided separately.

When the mesoappendix is involvedwith the inflammatory process, it is

often best to divide the appendixfirst with a linear stapler and then todivide the mesoappendiximmediately adjacent to theappendix with clips, electrocautery,

Harmonic Scalpel, or staples (B,C)


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A principal proposed benefit of laparoscopicappendectomy has been decreased postoperative pain.

Hospital length of stay also is statistically significantlyless after laparoscopic appendectomy.

In nearly all studies, laparoscopic appendectomy isassociated with a shorter period before return to normalactivity, return to work, and return to sports.

Laparoscopic appendectomy may be beneficial in obesepatients, in whom it may be difficult to gain adequate

access through a small RLQ incision. Fertile women with presumed appendicitis constitute the

group of patients most likely to benefit from diagnosticlaparoscopy.

Natural Orifice Transluminal Endoscopic


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Natural Orifice Transluminal Endoscopic

Surgery (NOTES)

Still experimental In this procedure the appendix is removed via upper

gastrointestinal endoscopy with the surgeon

operating through the gastric wall and ultimately

removing the appendix through the mouth without

any external scar.

The gastrotomy is closed from within the stomach.


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Interval Appendectomy

The accepted approach for the tx of appendicitisassociated with a palpable or radiographically

documented mass (abscess or phlegmon) is

conservative therapy with interval appendectomy 6-

10 weeks later.

initial tx consists of IV antibiotics and bowel rest.


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Prognosis

Principal factors influencing mortality rupture occurs before surgical tx

the age of the patient

overall mortality rate in acute appendicitis w/ rupture

is approx 1%.

mortality rate of appendicitis w/ rupture (elderly) is

approx 5%

Death is usually attributable to uncontrolled sepsisperitonitis, intra-abdominal abscesses, or gram-

negative septicemia.


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Chronic appendicitis

Characteristically, the pain lasts longer and is lessintense than that of acute appendicitis but is in the

same location.

lower incidence of vomiting, but anorexia and

occasionally nausea, pain with motion, and malaise

are characteristic.

Leukocyte counts are normal and CT scans are

nondiagnostic. Laparoscopy can be used effectively in the

management of this clinical entity.

Appendectomy is curative.


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Appendceal Neoplasms

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