RADIOLOGICAL FEATURES

At least 2 radiographs should be obtained, including a supine abdominal radiograph and either an erect chest image and or a left lateral decubitus image. A common sign is a collection of gas in theright upper quadrant adjacent to the liver, lying mainly inthe subhepatic space and the hepatorenal fossa, which is visibleas an oval or triangular gas shadow not obviously in continuity with the rest of the bowel. Clear visualization ofthe outer as well as the inner wall of a bowel loop—Rigler’ssign—is a valuable indication of a pneumoperitoneum.

The falciform ligament in particular, and occasionallythe umbilical ligaments and urachus, may be visualized by free gas when it lies on either side. Relatively large amounts of gas may accumulate as with gastric or colonic perforation andshow up beneath the diaphragm (cupola sign) or on the upperpart of the abdomen in a decubitus lateralfilm.

Management: depends on the cause of the pneumoperitoneum and the general condition of the baby. For babies on ventilation, the management is directed towards the cause of the pneumoperitoneum. When pneumoperitoneum results due to necrotizing enterocolitis, peritoneal drainage is recommended. For other gut perforations, depending upon the general condition laparotomy is performed.

Figs 5.17A and B: Pneumoperitoneum (A) 3 days pretern neonate presented with refusal to feed and abdominal distension. (B) X-ray Chest and abdoment in erect position reveals gas under diaphragm depicting hollow viscous perforation

A B

PROGNOSIS

This is again dependant upon the etiology and the general condition of the baby.

INTUSSUSCEPTION (Figs 5.18A to C) DEFINITION

Telescoping of a portion of intestine into itself is called intussusception and is the commonest cause of intestinal obstruction in infants. Usually the proximal intestine telescopes into the distal and in the process the mesentery is also dragged along with it.

• Usually occurs in the age of 3 months to 1 year. These are often well-nourished healthy children.

CLINICAL FEATURES

Clinically there is a triad of colicky abdominal pain, a sausage like mass, and red currant jelly stool.

DIAGNOSIS

 Barium enema- confirms the diagnosis, which will show either a filling defect or a spring coil appearance. This procedure helps in both diagnosis and therapy. Successful reduction occurs in 50 to 75 percent in early cases.

TREATMENT

 The non-operative treatment is hydrostatic reduction done either by barium enema (fluoroscopy-guided) or normal saline (ultrasound guided). It should be attempted only on cases less than 24 hours old that do not have significant abdominal distension. Rapid rehydration and intravenous antibiotic administration should be done beforehand. The procedure should be done using a steady hydrostatic pressure under the supervision of a pediatric surgeon, keeping the theatre ready for a laparotomy, should the reduction fail.

Figs 5.18A to C: (A and B) Red currant jelly stool (C) Barium enema showing “spring coil” appearance

B C

A

 The operative treatment is either reduction or resection and anastomosis depending on viability of the gut.

PROGNOSIS

There is 5-10 percent chance of recurrence after barium reduction. This occurs within first 48 hours after reduction. The rate of recurrence after surgical reduction is about 1 percent to 5 percent.

HIRSCHSPRUNG’S DISEASE (HD) (Figs 5.19A and B)

PATHOLOGY

Hirschsprung’s disease is characterized by a congenital absence of ganglion cells in the distal colon and rectum. This results in an inability of the distal bowel to relax in response to a peristaltic wave causing a functional obstruction. The proximal bowel dilates producing a megacolon. Aganglionosis begins with the anus, which is always involved, and continues proximally for a variable distance. It typically extends to the rectosigmoid junction in about 80 percent cases. It is continuous and uninterrupted till the proximal ganglionated segment is reached. Both the myenteric (Auerbach) and submucosal (Meissner) plexus are absent, resulting in reduced bowel peristalsis and function.

FREQUENCY

HD occurs once in every 5,000 live births. It may affect more than one family member in 4 to 8 percent cases. The longer the length of the affected segments of the bowel, the higher the rate of familial incidence.

Figs 5.19A and B: Hirschsprung’s disease. (A) Operative photograph of a case of Hirschsprung’s disease showing the narrow and the dilated colon and transitional zone. (B) Barium enema showing transition zone (a funnel shaped area between the normal distended colon and aganglionic segment)

A B

EMBRYOLOGY

Ganglion cells, which are derived from the neural crest, migrate caudally with the vagal nerve fibers along the intestine. These ganglion cells arrive in the proximal colon by 8 weeks of gestational age and in the rectum by 12 weeks of gestational age. Arrest in migration leads to an aganglionic segment. This is believed to result in clinical HD.

ASSOCIATED PROBLEMS

HD can be associated with Down’s syndrome in 5 to 15 percent cases. Atresia of both small and large bowel and imperforate anus can be associated. Various neurocristopathies such as MEN type 2A, Waardenburg syndrome and Smith-Lemli-Opitz syndrome have been described with HD.

DIAGNOSIS

HD should be considered in any child who has a history of constipation dating back to newborn period. The usual presentation in the newborn consists of non-passage of meconium within first 24 hours after birth, delayed passage or prolonged passage of meconium. However this history may be absent in 6 to 42 percent of patients. Other presenting symptoms are poor feeding, constipation, persistent distension of abdomen, and emesis. Any form of small or large bowel perforation in a newborn should raise the suspicion of HD.

Patients with HD are prone to developing enterocolitis, which is the major cause of mortality and morbidity. The entity manifests clinically with explosive diarrhea, abdominal distension and fever. In patients with Down’s syndrome having HD, the incidence of enterocolitis is very high.

On physical examination, there is distension of abdomen. The perineal examination is important so that an anterior anus is not mistaken for an HD. Rectal examination is classically said to reveal an empty anus and rectum that grips the finger and the explosive passage of feces and gas when the finger is withdrawn. However, rectal examination (or any rectal manipulation, e.g. insertion of thermometer) should be avoided as it may alter the findings of barium enema.