Oesophageal atresia

The commonest type is a blind-ended, upper oesophagus associated with a tracheo-oesophageal fistula involving the lower oesophagus (→ Fig. 20.1). Oesophageal atresia may occur alone or with a tracheo-oesophageal fistula. The incidence is approximately 1:3000 births. There may be co-existing anomalies of the heart, kidneys and intestines.

Figure 20.1 The commonest form of oesophageal atresia.

Duodenal atresia

This occurs in 1:6000 births. The common bile duct may open proximal or distal to an atresia. There is an association with Down’s syndrome and congenital heart disease.

Symptoms and signs

Associated with maternal polyhydramnios. Vomiting in first few hours of life usually bile-stained.

Investigations

• Antenatal diagnosis is possible with USS

• AXR shows ‘double bubble’ sign, i.e. gas bubble and fluid level on each side of upper abdomen owing to gas in stomach and proximal duodenum (→ Fig. 20.2).

Figure 20.2 Duodenal atresia. AXR with ‘double bubble’ gas sign and no gas pattern beyond the duodenum.

Treatment

Rehydration. Urgent surgery. Duodenoduodenostomy, i.e. a side-to-side anastomosis between proximal and distal duodenal segments.

Prognosis

Mortality depends on associated abnormalities and is high with Down’s syndrome and cardiac anomalies.

Small bowel atresia

The incidence is 1:20 000 births in the UK. It is somewhat more common in other parts of the world. It may occur at any level and may be multiple.

Malrotation (volvulus neonatorum)

In the first trimester, the midgut herniates outside the abdominal cavity but returns at the end of the 3rd month, rotating as it does so. Several rotational abnormalities may result. Obstruction may consequently result from a variety of causes from peritoneal bands to volvulus of the midgut. Failure of normal rotation invariably occurs in patients with exomphalos and diaphragmatic hernia.

Meconium ileus

This occurs in 15% of patients with cystic fibrosis. Meconium becomes inspissated in the terminal ileum with soft meconium above associated with distended proximal small bowel.

Anorectal abnormalities

These occur with an incidence of 1:5000 births. Management depends on accurate definition of the abnormality.

Necrotizing enterocolitis

This is an ischaemic disorder of the intestine of the newborn. The aetiology of the disease is unknown but bacterial infection, hypoxia and umbilical artery cannulation have been implicated. It is more common in premature infants and ‘epidemics’ have occurred on neonatal intensive therapy units, suggesting an infective aetiology.

Diaphragmatic hernia

This occurs with an incidence of 1:4000 births. A hernia may occur through the foramen of Bochdalek, i.e. a defect in the pleuroperitoneal canal; through the foramen of Morgagni, between the xiphoid and costal margin; through a deficiency in the central tendon; or through a congenitally large oesophageal hiatus. Herniae through the foramen of Bochdalek are most common. Normal development of the ipsilateral lung is impaired and that of the contralateral lung may also be impaired.

Symptoms and signs

May be diagnosed by prenatal USS. Presents with respiratory distress at birth. Apex beat displaced. Bowel sounds in chest. Scaphoid abdomen if the hernia is large and most of the bowel is in the chest.

Investigations

• CXR

• AXR: mediastinal shift, abdominal viscera in thorax; lack of intestinal gas pattern in abdomen (→ Fig. 20.3).

Figure 20.3 CXR of a neonate with a left diaphragmatic hernia. Note the hypoplastic lungs, mediastinal shift to the right, and gas in abdominal viscera in the left chest.

Treatment

Urgent respiratory assistance and maintenance of circulation. When ventilation is adequate and the patient is haemodynamically stable, closure of the defect is undertaken. May require prosthetic patch.

Prognosis

Mortality is high, especially with large defects, and is due to consequences of pulmonary hypoplasia.

Hirschsprung’s disease

This occurs in 1:5000 births. There is a defect in the parasympathetic ganglia in the submucosal and myenteric plexus of the bowel wall. The aganglionic segment is present for a varying distance upwards from the anus and always involves the rectum. Rarely it affects the whole colon and even more rarely, the small bowel. The peristaltic waves stop at the affected segment and the proximal bowel becomes dilated and hypertrophied. The aganglionic segment remains contracted. It is more common in males than females.

Gastroschisis

In this condition, there is a defect in the abdominal wall immediately adjacent to the umbilicus but the abdominal wall itself is completely formed. Coils of gut have no protective covering and are thick, oedematous and matted together. The diagnosis is obvious at birth.

Exomphalos

In this condition, the opening is at the umbilicus. The umbilical cord coverings continue into a sac, which covers the visceral protrusion. Chromosomal abnormalities, heart defects and also genitourinary malformations frequently occur, e.g. ectopia vesica and cloacal abnormalities. The condition is obvious at birth.

Congenital hypertrophic pyloric stenosis

The aetiology of this condition is unknown. Progressive hypertrophy of the circular muscle of the pylorus occurs. The condition affects boys more than girls, being four times more common in boys, and occurs with an incidence of 1:4000 births. The first-born male child is most commonly affected. There is a familial tendency, especially on the maternal side.

Intussusception

This is the invagination of a portion of intestine into its lumen. It is commoner in children than adults. The peak incidence is between 6 and 9 months, although it may occur any time between 3 months and 2 years and occasionally in those younger and older than this age range. Most cases are ileocolic but ileo-ileal and ileo-ileocolic may occur. In most cases, the aetiology is unknown but hypertrophied Peyer’s patches, polyps, Meckel’s diverticulum or intramural haematomas (Henoch–Schönlein purpura) may be contributory. An intussusception is composed of three parts:

The outer tube is called the intussuscipiens: the inner and middle tubes are called the intussusceptum (→ Fig. 20.4).

Figure 20.4 An intussusception.

Symptoms and signs

An otherwise healthy child presents with colicky abdominal pain and vomiting. The child often screams, draws up its knees to its chest, and goes pale with an attack of colic. In between bouts of pain, the child appears normal. A first stool passed after onset of the pain may be normal but 30% of subsequent stools contain blood and mucus, the so-called ‘redcurrant jelly stool’. Palpation of the abdomen reveals a palpable sausage-shaped mass in the line of the colon. An empty RIF may be apparent on palpation as the swelling moves into the upper abdomen with peristalsis. PR examination may reveal blood or mucus. Occasionally, the apex of the intussusception may be palpable per rectum.

Investigations

• AXR may show typical gas distribution and may show small bowel obstruction

• USS or contrast enema (→ Fig. 20.5)

• Adequate resuscitation with i.v. fluids.

Figure 20.5 Barium enema showing the typical appearance of an ileocolic intussusception. The ileum (arrow) has progressed as far as the proximal transverse colon.

Treatment

At an early stage, the intussusception may be reduced by the pressure of either an air or fluid enema under ultrasound control. Operation is required in patients with peritonitis, radiological signs of perforation, or failure of hydrostatic reduction. At operation, the intussusceptum is reduced by gentle retrograde reduction, squeezing the apex out of its containing bowel. Traction should not be applied to the proximal bowel. If the bowel cannot be reduced or is gangrenous, resection is required.

Prognosis

Recurrence occurs in 1–2%. Mortality is very low if treatment occurs in the first 24 h but increases if resection is required.

Obstructed inguinal hernia

This is a common cause of surgical admission in boys under the age of 2 years. It may also occur in girls when bowel or ovary may become irreducible. It is associated with a patent processus vaginalis. There is a high incidence in premature babies. The condition is often bilateral.

Acute appendicitis

This is dealt with more fully in Chapter 14. Certain points, however, are relevant to appendicitis in children. The condition is rare under the age of 6 months. The stool is liquid and the appendiceal lumen relatively wide. Therefore, acute obstructive appendicitis is rare. It does, however, occur and may present with diarrhoea and vomiting and consequently be mistaken for gastroenteritis. Careful and repeated examination is therefore essential.

Mesenteric adenitis

This is enlargement of mesenteric lymph nodes caused by an adenovirus infection. Yersinia enterocolitica has also been implicated. It affects young children and adolescents. Usually there is a preceding history of URTI, with sore throat and cervical lymphadenitis. Essentially, mesenteric adenitis is inflammation of Peyer’s patches with secondary mesenteric lymphadenitis. The fever is usually higher than that of appendicitis, usually 38–39°C. The abdominal pain is more diffuse and examination reveals shifting tenderness rather than sharply localized tenderness in the RIF. Headache and mild photophobia may occur. These never occur in appendicitis. The WCC is usually raised but there is a relative lymphocytosis rather than neutrophil leukocytosis as seen in acute appendicitis. Treatment is symptomatic. If there is doubt over the diagnosis, appendicectomy is advisable.

Constipation

This is a common problem in children. The child is usually afebrile and relatively well, despite the abdominal pain.

Urinary tract infections (UTIs)

There is abdominal pain and high pyrexia associated with dysuria, frequency and cloudy urine. Right pyelonephritis or cystitis may be mistaken for appendicitis. An FBC reveals neutrophil leukocytosis. An MSU and microscopy reveal cells and organisms. Beware the presence of cells alone. Pelvic appendicitis may irritate the bladder, producing frequency and pyuria but organisms will be absent on microscopy. Beware the presence of organisms alone as it may be due to contamination from the foreskin or vulva. Treatment of UTI is with appropriate antibiotics. Further investigation is with USS.

Lower lobar pneumonia

In this condition, pain may be referred via the thoracic nerves to the lower abdomen. Right lower lobar pneumonia may refer pain to the RIF and be mistaken for acute appendicitis. It is important to observe the breathing pattern and auscultate the chest. Anteroposterior and lateral CXR will confirm diagnosis.

Testicular torsion (→ Ch. 16)

Crohn’s disease

Acute regional ileitis may occur in children.

Gynaecological problems

Remember pregnancy may occur in very young girls. Onset of periods may be associated with acute lower abdominal pain. Torsion of ovarian cyst or ovarian dermoid may occur.

Biliary atresia

This occurs with an incidence of 1: 25 000 live births. The aetiology is unknown. It appears to develop after birth.

Choledochal cyst

Cystic dilatation of the bile ducts is usually extrahepatic involving the common bile duct. The aetiology is unknown.

Abdominal neuroblastoma

This is a highly malignant tumour arising from the neural crest. The commonest site is the adrenal gland. It occurs in children under the age of 5; 70% occur under 1 year. Metastases occur early.

Nephroblastoma (Wilms’ tumour)

This is an embryonic tumour of the kidney. The majority occur in the first 3 years of life. Less than 5% are bilateral. Metastases occur to the liver, lungs and regional nodes.

Signs and symptoms

Abdominal mass. Pain. Haematuria. Weight loss. Pyrexia. May be associated with abnormalities of the GU tract. Aniridia.

Investigations

• USS: solid tumour

• CT (→ Fig. 20.6): size, site, metastases.

Figure 20.6 An abdominal CT scan of a child with an abdominal mass. There is an extensive nephroblastoma (Wilms’ tumour) of the right kidney.

Treatment

Surgical excision. Chemotherapy with or without radiotherapy depending on the stage; 80–90% chance of cure. If the condition is bilateral dialysis will be required unless partial nephrectomy is possible. If there is no evidence of recurrence after 2 years, renal transplantation is indicated.

Fissure-in-ano

Constipation causes a split in the mucosa of the anal canal. It is usually painful on defaecation. A vicious circle occurs with worsening constipation owing to fear of defaecation. There is blood on the stool and toilet paper. The fissure is often in the midline, usually posteriorly. Treatment involves explanation of the condition to the parent. Lactulose helps to relieve constipation, and LA is applied locally before and after defaecation. Most cases settle on this regimen. Persistent fissures require exclusion of Crohn’s disease and TB.

Polyps

In addition to bleeding, they may prolapse on their stalk if they are low enough in the rectum. Occasionally they may twist and auto-amputate and are passed PR. Occasionally they may precipitate intussusception. Treatment is by excision. If they are in the rectum, this may be done under GA using a proctoscope, the stalk being cut with diathermy. Higher polyps can be snared at colonoscopy.

Rectal prolapse

This usually occurs around 2 years. Most cases settle spontaneously. Straining at stool precipitates the condition initially, which may then occur every time the child defaecates. There may be an underlying abnormality, e.g. spina bifida, previous anoplasty for imperforate anus or cystic fibrosis. Prolapse may involve the mucosa only or may involve the full thickness of the rectum.

Meckel’s diverticulum

This is a remnant of the vitellointestinal duct which was attached to the umbilicus and is found on the antimesenteric border of the terminal ileum about 60 cm from the ileocaecal valve in an adult and proportionately nearer in a child. Rarely, this may bleed if it contains gastric mucosa, which produces acid and ulcerates the adjacent small bowel mucosa. This may cause either bright red or dark red bleeding, depending upon the degree of haemorrhage. Abdominal pain is usually absent. The presence of gastric mucosa in a Meckel’s diverticulum may be demonstrated by a technetium scan. Treatment is by excision.

Intussusception

In this condition, rectal bleeding may occur and is classically the appearance of a redcurrant jelly stool associated with attacks of abdominal pain.