THE RADIOLOGY OF INTESTINAL OBSTRUCTION INCHILDREN AND INFANTS

BY

J. H. MIDDLEMISS, M.D., D.M.R.D.Assistant Radiologist, Royal Victoria Infirmary, Newcastle-on-Tyne

IntroductionOrganic intestinal obstruction is often late in

producing marked abdominal signs, and diagnosistends to be delayed. Although nothing can replacea careful record of the history and thorough clinicalexamination, any further- diagnostic aid which issafe, simple, and effective is welcome in doubtfulcases.-Flat x-ray investigation of the abdomen in cases

of suspected obstruction in adults and children hasbeen used for some years, but not as extensivelyas it might be. Every clinician is anxious to avoidperforming an unnecessary laparotomy, particularlyin an ill child. Consequently there is a tendency tokeep cases of suspected obstruction under clinicalobservation until a diagnosis can be made. Thismay mean that the child becomes acutely obstructed.If there is any investigation that will enable adiagnosis to be made at an earlier stage, that methodshould be adopted in all cases of doubt. Flatradiographs of the abdomen can give such informa-tion. There are, however, pitfalls in this form ofinvestigation, and it is thought that the publicationof some cases illustrating the scope and limitationsof the method, may be of some value to paedia-tricians.

Radiological Investigation in Intestinal ObstructionThe diagnosis rests on the interpretation of

abdominal gas shadows. Gas is normally presentin the large bowel, and in infants commonly in thesmall bowel too. Over the age of three years gas ispresent in the small bowel, but unless some disorderof motility intervenes, and that disorder may be ofa very minor nature, the gas is usually finely dividedand intermixed with the fluid contents of the smallbowel and rarely casts any shadow on a radiograph.Normally the contents of the small bowel arepropelled towards the large bowel, and stasis doesnot occur. Thus, if gas is present in the smallbowel, it will under normal conditions also bepresent in the large bowel. If gas is present in thesmall bowel and not in the large, if that part ofthe small bowel in which it is present is distended,

and if in addition the existence of stasis in the smallbowel can be demonstrated, then it can be deducedthat some form of mechanical obstruction ispreventing the onward passage ofthat gas. Obstruc-tion of the large bowel can be diagnosed in asimilar manner.One of the most frequent causes of obstruction

in infancy and early childhood is intussusception.Diagnosis is-often difficult, especially in those caseswhere blood in the stools is a late symptom.Hellmer (1943) published a series of 110 cases ofintussusception investigated and diagnosed by meansof a barium enema. However, in a shocked childbarium enema is not a procedure to be undertakenlightly; it will not improve the child's condition,and in any case is unlikely to demonstrate an ileo-ileal intussusception or a small-bowel obstructionfrom any other cause. Oral barium is to be avoided.The radiological procedure of taking straight filmsof the abdomen, however, is simple, in no wayupsets the child, and, in a case of obstruction,whatever the cause may be, gives positive evidencein most cases.

Radiologically the various parts of the small andlarge bowel can be recognized with relative certainty.The upper part of the small bowel lies mainly in theupper abdomen and to the left side, and showsthe mucosal folds or valvulae conniventes of thejejunum close together. The mid small bowel liesmainly in the umbilical region, and the mucosalfolds are rather more widely spaced. The lowerpart of the small bowel lies mainly in the right flankand pelvis and shows the smooth walls of the ileumdevoid ofmucosal folds. The caecum and ascendingcolon lie in the right flank, the transverse coloncrosses the upper abdomen, and the descendingcolon occupies the left flank; these parts of thecolon show the characteristic haustrations orsacculations of the large bowel. The sigmoid colonoccupies the pelvis and does not as a rule show thesame saccular appearance. Occasionally, there maybe some difficulty in differentiating the sigmoidcolon from the ileum, or the jejunum from thetransverse colon, but the difficulty can usually beovercome by taking a further radiograph with thepatient in a different position.The radiographic technique is to take two films

of the abdomen of the child, one an antero-posterior247

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ARCHIVES OF DISEASE IN CHILDHOODprojection with the child supine, the other a postero-anterior projection with the child either standingor suspended erect. The postero-anterior projectionis used for the erect radiograph in order to produceless radiographic distortion of bowel shadows, andso to give a truer indication of the -degree ofdistension.As pointed out earlier, the physiological process

is for the small bowel contents, both fluid andgaseous, to pass through the small bowel and oninto the large bowel, a dynamic process. In -theerect film, fluid levels indicate stasis at that site atthe time that the exposure was made. The corre-sponding supine film will show in which parts of thebowel the gas is present, and if a mechanical blockexists the most distal part of recognizable distendedbowel will be in the region just proximal to theblock. It should be remembered that in intus-susception the obstruction is almost invariably atthe proximal end of the process and so is in mostcases a small-bowel obstruction.Thus the radiological signs of mechanical obstruc-

tion in the small bowel are stasis in the small bowel,gaseous distension of the small bowel, and acomplete absence of gas shadows from the largebowel. In some cases where obstruction is onlypartial, some gas bubbles may be present in collapsedbowel beyond the site of the obstruction. All gasshadows in the abdomen must be carefully studied;by identifying all the distended bowel, a relativelyaccurate localization of the site of the obstructioncan be effected. By the same prodess a diagnosisof large-bowel obstruction can be established andlocalized. -In a mixed series of over two hundredcases, adults and children, no case of large-bowelobstruction in a child was encountered other thanthose due to congenital anomalies such as animperforate anus; in a previous paper the appear-ances of large-bowel obstructions in adults havebeen described (Middlemiss, 1948).By this means obstruction can be demonstrated

early, and elsewhere the author has published acase of intussusception in an infant diagnosed bystraight radiography within twenty-four hours of theonset ofsymptoms (Middlemiss, 1948). The follow-ing cases have been selected to illustrate the pointsalready mentioned.

Case 1. V.B., a girl aged 9 months, had afour-day history of vomiting and diarrhoea. Duringthe last twenty-four hours the motions containedblood and mucus. On admission the baby wasextremely ill and dehydrated. The abdomen wasflabby and distended, but there was no palpablemass. Survey films (figs. 1 and 2) showed consider-able distension of the small bowel (mostly thejejunum, but some ileum was recognizable), completeabsence of gas shadows from the large bowel, andfluid levels present in the small bowel. This wasregarded as evidence of a complete small-bowelobstruction in the mid or low small bowel. Atoperation an irreducible ileo-ileal intussusception

was found; resection was perfomned, but the childdied.

Case 2. K.A., a boy aged 5 months, had a coldand bronchitis fourteen days before admission.Thirty-six hours before admission he vomited andhad obvious spasms of abdominal pain. Bowelaction was normal at that time. The following dayhe started to vomit, passed blood in the motion, andwas admitted to hospital. On examination he didnot appear to be having much abdominal painthough he was obviously a poorly baby. There wasno palpable tumour, and shortly after admission hepassed a watery brown stool. He was thought tobe suffering from gastro-enteritis. He took feedsfor the next twelve hours without vomiting, andthen passed another stool containing blood andstarted to vomit again. Survey films of the abdomen(figs. 3 and 4) showed very marked distention of aconsiderable length of small bowel, no gas in thelarge bowel, and, in the erect film, fluid levels inthe small bowel. This was regarded as a completeintestinal obstruction occurring low in the smallbowel. At operation an ileo-colic intussusception,the head of which had reached the hepatic flexure,was found and reduced. The patient made a goodrecovery.

Case 3. J.C., a boy aged 8 months, yomitedintermittently for three days before admission.During this time he took some feeds but returnedmost of them. He had passed three stools a day,and for the last two days they had been hard butcontained no blood. He had had no obviousattacks of abdominal pain. On admission he wasan ill, dehydrated baby; the abdomen was a littledistended, and it was considered that there waspossibly a tumour in the right flank. It was nottender and nothing abnormal was detected perrectum. Survey films were taken, and the erectfilm (fig. 5) showed distension of the small bowel,mostly the ileum, containing fluid levels, and acomplete absence of gas shadows from the largebowel; over' the right ilium a single loop of ileumcontaining gas but collapsed and of normal lumenwas demonstrated. It was considered that this wasevidence of a partial low small-bowel obstruction.At operation the lower part of the ileum was foundbound down to the posterior abdominal wall andobstructed by two enlarged lymph glands, and smalltubercles were studded throughout the mesenteryand generally throughout the abdomen. Theobstruction was relieved, and the child recoveredfrom the operation. When seen four months laterthe child was taking feeds nornally.

Case 4. G.S., a boy aged 14 months, had beena healthy infant until three days before admission,when he was noticed to be pale and unhappy. Herefused all food at that time and vomited, andsubsequently continued to vomit frequently. Hewas completely constipated during the three days.

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RADIOLOGY OF INTESTINAL OBSTRUCTION

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FIG. I.-Case 1: erect film showing distension and fluiid levels in small bowel.

FIG. 2.-Case 1: showing distended bowel to be mainly jejunum with some ileumand confirming complete absence of gas from large bowel (supine film).

..:.. .!..

FIG. 3.-Case 2: erect film showing many distended loops of small bowel containingfluid levels.

FIG. 4.-Case 2: supine film showing that the distension involves a considerablelength of small bowel, mainly ileum, and confirming complete absence of gasfrom large bowel.

PLATE I.4A

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ARCHIVES OF DISEASE IN CHILDHOOD

FiG. 5.-Case 3: erect film showing distension of loops of ileum containing fluidlevels. There is no gas demoistrated in large bowel, but there is gas in aloop of ikum of normal lumen over the right ilium.

FiG. 6.-Case 4: taken during barium enema showing complete filling of largebowel.

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FiG. 7.-Case 4: erect film showing distension ofloops ofjejunum and ileum containingfluid levels, and complete absence of gas shadows from large bowel. Traces ofbarium remaining from the barium enema adminstered some hours earlier can beseen.

FK;. 8.-Cse 5: erect film showing fluid levels in small bowel but in addition markeddistension of large bowel.

PLATE II.

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RADIOLOGY OF INTESTINAL OBSTRUCTION

9 -FIG. 9.-Case 6: erect film showing marked distension of many loops of bowel, some of

them contaiing fluid levels. The length of bowel running along the left flank is shownnot to have a fluid level at its lower end.

FIG. IO.-Case 6: supine film. Comparison with the erect film shows the fluid levels to bein small bowel and the ascending colon. Gaseous distension, however, extends as faras the distal end of the descending colon.

FiG. 11 -Case 7: erect film of a case of coeliac dises showing fluid levels in small andlarge bowel.

FIG. 12.-Case 8: supine film of an eight-year-old boy seven days after appendicectomy,showing distended loops of small and large bowel scattered throughout the abdomen.

PLATE III.

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ARCHIVES OF DISEASE IN CHILDHOODOn admission to hospital he was a miserable, illbaby and appeared to be in pain. An enemaremoved a quantity of hard faeces from the rectum;there was no occult blood in the excreta. Intus-susception being suspected, a barium enemainvestigation was carried out under screen controLbut the large bowel was seen to fill completely(fig. 6). The infant retured to the ward, appearedto be improved, and took a feed; however, somehours later, as his condition again appeared to bedeteriorating and vomiting had . recomm-enced, asurvey film of the abdomen was taken (fig. 7).This showed distended loops of small bowel,jejunum, and ileum, with evidence of stasis of bowelcontents and no evidence of any gas in the largebowel; thus there was conclusive evidence of a lowsmall-bowel obstruction, probably complete. Atoperation a loop of ileum was found bound downto a Meckel's diverticulum by an adhesion, and thebowel immediately proximal to this was twistedabout the adhesion. The obstion was complete.The adhesion was severed, the obstruction relieved,and the child made a good recovery.

It is obvious that the survey would have beencarried out more profitably as a prelimnaryinvestigation.

Differential DgnosisThe demonstration of fluid levels in bowel is not

an indication of intestinal obstruction; that is apoint which cannot be too strongly emphasized.Fhlid levels merely indicate that at the time ofexposure the contents in that part of the bowel inwhich the fluid levels exist are static. It is essentialto analyse all gas shadows, to determine the siteand distribution of the fluid levels, to assess thedegree of distension of the bowel, and to establishthe fact that gas does not exist in any quantity in thebowel beyond that part in which the fluid levels arepresent. In other words the state of affairs mustbe seen as a whole, and one isolated sign must notbe fastened on and misinterpreted.

Case 5. Fig. 8 is the erect film of a boy of6 months who presented with a history of threedays' diarrhoea with green offensive motions, andobvious spasms of abdominal pain; ten hoursbefore admission he passed dark red blood perrectum and began to vomit. After admission nostool was passed but vomiting continued. The babywas pale and dehydrated. No abdominal tumourwas palpable, but he was considered possibly to haveintussusception. The film showed fluid levels in thesmall bowel with some distension of the small bowel;but, in addition there was very considerable gaseousdistension of the large bowel, in which no fluidlevels could be detected. With such distension ofthe large bowel there obviously could not be asmall-bowel obstruction. In fact after administra-tion of sulphamezathine the child recovered rapidlyfrom what had been a severe gastro-intestinal upset

of an indeterminate nature. It should be noted thatin the earlier stages the radiological investigtion,though presenting certain features which might havebeen misinterpreted to indicate an obstructive lesion,in fact provided evidence to the contrary.

Case 6. Figs. 9 and 10 are the erect and supinefilms respectively, of a boy aged 4 years. He wasadmitted to hospital as a case of intestinal obstruc-tion, acute abdominal pain. having started aboutmidday the same day. He was a flushed child,crying continuously, retching occasionally, but notactualW vomiting. Tbere was generalized abdominaldistension with resistance on palpation but noobvious rigidity or tenderness. There were markedborborygmi. The x-ray investigation was carriedout at 3.0 a.m., and the clinicians did not call inthe radiologist on duty. On their own interpreta-tion of the filns, backed by the clinical signs andsymptoms, they decided that the child was obstrcedand they carried out an exploratory laparotomy.No obsruction was found. The filns showdistension of the small bowel and of the large bowelas far as the sigmoid colon; there are fluid levelsin the small bowel and in the right half of the largebowel. This shows quite clearly that there is someintestinal disorder, but it equally clearly rules outthe possibility of obstruction. The child sub-sequently developed left-sided pneumonia witheffusion, and made a normal recovery.

This case shows the value of x-ray investigationin such disorders, and also the necessity for havinga radiological opinion.

Case7. Fig. I is the erect film of a child aged4 years who had coeliac disease. A routine bariumfollow-through investigation was carried out, andscout films of the abdomen were taken beforehand.Clinically there is little likelihood of a case ofcoeliac disease being investigated for potentialintestinal obstuction. It is of interest, however,to demonstrate the existence of fluid levels in sucha case: the author has consistently shown this insuch cases. Analysis of the gas shadows in thesupine film of this case showed that the distributionwas such that it could not under any circusutancesbe due to a mechanical obstruction.

These three cases serve to show that fluid levelsmay occur in bowel under many other conditionsthan those produced by mechanical obstnrtion.There is, however, one important class of cases inwhich they may occur and which it is important todifferentiate from mecanical obstructions, that is,postoperative distensions. A postoperative dis-tension may be traumatic, that is, a result of thehandling of bowel during a laparotomy, or infective,for example, due to peritonitis. In most cases theprocess is a temporary or transitory one lasting froma few hours to three or four days. It may resolve,or it may become generalized, the so-called

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RADIOLOGY OF INTFSTINAL OBSTRUCTION 253' paralytic ieus.' Whatever the stage of the con-dition, it is primarily the inhibitory result of activesmulation of the sympathetic nerve supply tobowel-wall muscle. The radiological appearancesshow either a segmental or a general distribution;if segmental, the small and large bowel in oneparticular region in the abdomen are involved;ifgeneral, then the small and large bowel throughoutthe whole abdomen are involved. This involvementshows a distension of bowel by gas; the distensionmay vary from the size of the normal lumen ofbowel to a very marked dilatation. In an erect filmof the condition there may be fluid levels, and if sothey are scattered throughout both the small andlarge boweL showing no tendency to be restrictedto the proximal end of the alimentary canal, as theyare in mechanical obstrction.

Case 8.. Fig. 12 is the supine film of such a caseof inhibition ileus of infective origin. It is of a boyaged 8 years on whom seven days previouslyappendicectomy with drainge had been performed;peritonitis had ensed, with considerable abdominaldistension. Subsequently a pelvic abscess wasdrained. The film shows generalized distension ofthe small and large bowel with some 'layering 'between the loops of bowel probably due to theperitoneal effusion. The erect film (unsuitable forreproduction) showed fluid levels with a similardistribution. The distribution of the gas shadowsexcludes the possibility of a anical obstnxtion.

It is of the utmost importance in such cases ofpostoperative distension to be able to differentiatebetween an inhibition ileus and a manicalobstrcion. In the event of a m nical obtion (due, for example, to adhesions) developing asa postoperative complication, its early diagnsis anddifferentiation from a simple postoperative disten-sion may save life. This radiological investigation,while not necessarily infallible, is often a means ofdemonstating earlier than by clinical observationthe fact that a mechanical obstruction is developingor has developed. It is that surveyfilms of the abdomen be taken in all cases ofabdominal distension persisting or developing afterthe fifth postoperative day. In doubtful cases thisinvestigation should be repeated at intervals oftwenty-four hours.

1. The appearances of m ical obstuctionofthe bowel are: (a) stasis, as shown by the presenceof fluid levels; (b) distension of bowel by gas; and(c) absenc of gas shadows, or the demonstrationof collapsed bowel distal to the obstuction. Thesite of the obstrction can be llizad just distal tothe most distal part of distended bowel

2. Fluid levels may occur in bowel due to otherconditions. Of these the most important isinhibition ileus occurrig as a postoperative com-plication. In this, the small and large bowel areinvolved, either in one segment of the abdomen orthrougbout the whole abdomen, and the distensionand fluid levels are not restricted to the proximalside of a block as in ical obsuction, but aredistibuted through the whole alimentary canal.

3. In a paeiatric department, or indeed in anyhospital, the contributions which this technicalprocedure has to make as an aid to clinical diagnismay be listed as follows:

(a) it is estially a time-saving factor, oftenenabling the establishment of earlier diagnosis andso providing for earlier surgical ttment beforeacute obstrucion develops;

(b) it may provide a diais in many cases inwhich the history and clinical signs and observationhave failed to do so; this appLies partlarly toinfants, and in many instan it may be the meansof etablishig a diagnosis when the alternative maybe the spending of a further valuable twenty-fourhours in clinical observation, whih in turn mayonly lead to a delayed exploratory aparotomy;

(c) it is espeially helpful in the obsrvation ofpostoperative distsion, paricularly after the fifthday, when the clinician is on the look-out for thepossible development of mehanical obstruton asa postoperative complication.

REFERENMAscroft, P. B., and Samuel, E. (1941). Brit. J. Radio!.,

14, 11.Biggs, A. D., and Pontius, G. V. (1947). J. Pedia.,

30, 306.Helir, H. (1943). Acta radiol. Stockh., 24. 235.Middlemiss, J. H. (1948). Brit. J. Radiol. (In the

press.)

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