Hirschsprung Disease

Question 1

Define Hirschsprung Disease.

Answer 1

Congenital disorder of the enteric nervous system, secondary to aganglionosis of the myenteric (Auerbach) and submucosal (Meissner) plexuses, resulting in a functional obstruction.

Question 2

Explain the general aetiology of Hirschrpung Disease.

Answer 2

Affects the anus and variable distance of bowel proximally. Classified according to the length of bowel affected (short segment, long segment, total colonic, total intestinal or ultra-short segment).

Question 3

Explain the embryology of Hirschsprung Disease.

Answer 3

Failure of neural crest-derived ganglion cells to migrate from proximal to distal bowel during development leading to the rectum / colon without parasympathetic nerve innervation. Affected bowel has only sympathetic nerve innervations -> hypertonicity and lack of appropriate relaxation in response to proximal distension -> narrow/contracted segment of bowel and stool stasis proximally.

Question 4

Explain the presentation of Hirschsprung Disease.

Answer 4

Absence of ganglion cells in the Auerbach and Meissner plexuses, increased amounts of acetylcholinesterase stained nerve endings, and hypertrophied nerve trunks in the lamina propria and muscularis propria.

Question 5

What is Hirschsprung Disease associated with?

Answer 5

Trisomy 21, Waardenburg syndrome, MEN2, FHx (long segment disease). Exclude other causes of neonatal abdominal distension (atresia, meconium ileus or plug syndrome).

Question 6

Summarise the epidemiology of Hirschsprung Disease?

Answer 6

1/5000 live births; accounts for 20% of all neonatal obstruction.M: F. 4 : 1. 90% of patients present in the neonatal period and 95% before the first year.

Question 7

What is the neonatal presentation of Hirschsprung Disease?

Answer 7

1. Failure to pass meconium in first 24–48 hours
2. Acute intestinal obstruction; abdominal distension, poor feeding, bilious vomiting
3. Severe life-threatening enterocolitis.

Question 8

What is the infantile presentation of Hirschsprung Disease?

Answer 8

1. Chronic obdurate constipation with abdominal distension without soiling
2. Intermittent abdominal pain and fever during episodes of retained faeces
3. Failure to thrive.

Question 9

What are the signs of Hirschsprung Disease?

Answer 9

Depends on the age of presentation. Typically abdominal distension with dilated loops of bowel. PR examination reveals a sudden explosive ‘gush’ of stool as the digital examination bypasses the aganglionic segment. Septic signs if associated enterocolitis.

Question 10

What are appropriate investigations for Hirschsprung Disease?

Answer 10

Bloods: Increased WCC/CRP with enterocolitis. Blood cultures and venous gas (acidosis).

Radiology: AXR – dilated bowel (important to exclude atresia as a differential diagnosis in the neonatal period). Gastrograffin enema – may demonstrate the transition zone.

Suction rectal biopsy: Three biopsies taken at 2, 3 and 4 cm from the anal margin above the dentate line. Full-thickness biopsy under aGA may be required if insufficient sample with SRB.

Anorectal manometry: Older children with chronic constipation

Question 11

What is the management for Hirschsprung Disease?

Answer 11

Initial: Neonates should be managed with broad spectrum IV antibiotics, NGT decompression, and rectal washouts (typically 15ml/kg TDS). If this fails (rare) then may require a colostomy to decompress the colon.

Surgical: Pull-through procedure performed (>3/12 of age)

Question 12

What are complications associated with Hirschsprung Disease?

Answer 12

Hirschsrpung enterocolitis, encoparesis, constipation, incontinence.

Question 13

What is the prognosis of Hirschsprung Disease?

Answer 13

Prognosis is poor with non-adequately treated enterocolitis (80% mortality). Postoperatively good outcome although majority will still have intestinal motility problems.