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Hirschsprung’s disease. Dolychosigma. Dolychocolon

1. HIRSCHSPRUNG’S DISEASE

Etiology

  • Congenital condition in newborns due to absence of ganglion cells
    • Auerbach’s and Meissner’s plexus in the anorectum
  • It is due to a defect in migration of neural crest cells (precursor of ganglion cells) during gestation
  • Always involves the anus, internal sphincter and rectum – can extend proximally for part or full length of the colon

Associated conditions

  • Down syndrome
  • Waardenburg syndrome

Types

  • Ultrashort segment – only anal canal and terminal rectum is aganglionic
  • Short segment – anal canal and rectum is completely involved
  • Long segment – anal canal, rectum and part of colon is involved
  • Total colonic – anal canal, rectum and full length of the colon is involved

Pathophysiology

  • Absence of ganglion cells in Auberbach’s and Meissner’s plexuses
  • The aganglionic segment usually involves terminal colon (rectum/rectosigmoid)
  • The colon proximal to the aganglionic segment, in an effort to overcome the partial obstruction, becomes distended and the wall thickens due to muscular hypertrophy
Zones  
  • There is a narrow, spasmodic, non-relaxing pathological segment
  • Transitional zone proximal to it contains only few ganglion cells with formation of a cone
  • Proximally the colon is dilated enormously with hyperaemia, multiple ulcers and hypertrophied circular muscle fibres – causes neonatal intestinal obstruction

Clinical features

  • Small ribbon-like stool
  • Failure to mass meconium in first 24 hours of life
  • Toxic megacolon – fever, bile vomit, dehydration, abdominal distension, shock, explosive diarrhoea

Complications

  • Enterocolitis
  • Intestinal obstruction
  • Growth retardation
  • Constipation
  • Perforation
  • Peritonitis, septicaemia

Investigations

  • History of failure of passing meconium
  • Abdominal XR
  • Barium enema
  • Electromanometry – absence of recto-anal inhibitory reflex when rectum is distended
    • Not useful in neonates
  • Rectal biopsy – for definitive diagnosis
    • Shows absence of ganglion cells and nerve hypertrophy

Treatment

Initial management

  • Fluid resuscitation, nasogastric tube
  • Rectal tube irrigation

Multistep surgical management – definitive procedure

  • Colostomy in the newborn period
  • Definitive pull through procedure when the child is above 10kg – resection of the aganglionic segment and anastomosis of the ganglionated bowel to either the anus or a cuff of rectal mucosa
    • Three procedures  
      • Duhamel – the rectum is left in place and the ganglionic bowel is brought into the retrorectal space
      • Swenson – resection with end-to-end anastomosis, by exteriorising the bowel ends through anus
      • Soave – the mucosa and submucosa of the rectum are resected, and the ganglionic bowel is pulled through the aganglionic muscular cuff of the rectum

Complications of surgery

  • Anastomotic leak, stricture, faecal incontinence, persistent constipation

2. DOLICHOCOLON

  • Abnormally long intestine with loop formations
    • Should not be confused with abnormally large intestine, which is called megacolon
  • Can predispose to volvulus (abnormal intestinal rotation)
  • Dolichosigma is most common – lengthening of the sigmoid colon only
  • Possible cause – disturbance of the moto-evacuating function of the colon
    • Lengthening can also be associated with distension – megadolichocolon

Clinical features

  • Chronic constipation
  • Abdominal discomfort and cramping
  • Vague symptoms – indigestion, weight loss, insomnia

Investigations

  • Barium enema
  • Colonoscopy

Treatment

  • Diet high in fibre, increase water intake
  • Increase in physical activity
  • Laxatives
  • Surgery is only necessary if volvulus is present
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