Paediatrics: Chronic diarrhoea

2021-03-04 12:00 AM

Nature and frequency of stool, presence of undigested food, relationship to diet changes (e.g. weaning) or travel, stool blood, or mucus, weight loss.

Chronic diarrhoea

Chronic diarrhoea

Defined as diarrhoea persisting for >14 days. Many of the diseases that cause acute diarrhoea can lead to chronic diarrhoea.

The pathophysiology may involve:

  • Reduced GI absorptive capacity, e.g. coeliac disease.
  • Osmotic diarrhoea, e.g. lactase deficiency.
  • The inflammatory, e.g. ulcerative colitis.
  • Secretory diarrhoea (rare), e.g. vasoactive intestinal peptide producing tumour.

Causes

Age 0–24mths

  • Malabsorption, e.g. post-infective gastroenteritis syndrome, lactose intolerance, cystic fibrosis, coeliac disease.
  • Food hypersensitivity, e.g. to cow’s milk protein.
  • Chronic non-specific diarrhoea (toddler diarrhoea); the child is usually thriving.
  • Excessive fluid intake.
  • Protracted infectious gastroenteritis.
  • Immuno-deficiencies, including HIV.
  • Hirschsprung’s disease.
  • Rarer causes (intractable diarrhoea) include congenital mucosal transport defects and autoimmune enteropathy.
  • Tumours (secretory diarrhoea).
  • Fabricated induced illness.

Older children

  • Inflammatory bowel disease (IBD).
  • Constipation (spurious diarrhoea).
  • Malabsorption—see Causes.
  • Irritable bowel syndrome (IBS).
  • Chronic infections, including giardiasis, bacterial overgrowth, and pseudomembranous colitis.
  • Laxative abuse.
  • Excessive fluid intake.
  • Fabricated induced illness.

History

Nature and frequency of stool, presence of undigested food, relationship to diet changes (e.g. weaning) or travel, stool blood, or mucus, weight loss.

Examination

  • Features of malnutrition or other illness, e.g. peri-anal disease in inflammatory bowel disease, or finger clubbing in cystic fibrosis.

Investigations

  • Stool: inspection; microscopy for bacteria or parasites, leucocytes,fat globules (pancreatic diseases), fatty acid crystals (diffuse mucosal defects); culture; pH (<5.5 = carbohydrate malabsorption); reducing substances (>0.5% = carbohydrate malabsorption); faecal occult blood (colitis); electrolytes (i Na+ and K+ = secretory diarrhoea; ‘rise’Cl = congenital chloridorrhoea).

Blood: U&E; FBC (d Hb = haematinic deficiency or blood loss; ‘rise’eosinophil = food hypersensitivity or parasites); ‘rise’CRP/ESR (inflammatory); blood gas; radioallergosorbent test (RAST) (food allergy); hormone level (vanillylmandelic acid (VMA), catecholamines, vasoactive intestinal polypeptide (VIP)) for secretory tumours.

Radiology: AXR, ultrasound, barium meal and follow-through.

Other: breath hydrogen test (lactose malabsorption or bacterial overgrowth); GI endoscopy biopsy (e.g. upper for coeliac disease, upper and lower for suspected IBD); sweat test/genetic testing (CF); rectal biopsy (Hirschsprung’s disease).

Treatment

  • Treat underlying cause.
  • Nutritional intervention if deficiencies are present.
  • Antibiotics are only useful if systemic illness or prolonged infection is present, e.g. SalmonellaCampylobacter, giardiasis, or amoebiasis.
  • Rarely, other drug treatments may be useful, e.g. loperamide or cholestyramine.

Chronic non-specific diarrhoea (toddler diarrhoea)

  • Occurs from 6mths to 5yrs.
  • Presents with colicky intestinal pain, ‘rise’flatus, abdominal distension, loose stools with undigested food (‘peas and carrots’ stools).
  • The child is otherwise well and thriving.
  • Examination and investigations are normal.

Treatment 

Reassurance; dietary (i fat intake; normalize fibre intake; ‘fall’ milk, fruit juice, and sugary drink intake); loperamide occasionally may be necessary.

Encopresis

  • Voluntary defaecation in unacceptable places, including the child’s pants in older children.
  • No organic abnormality is present; it is a symptom of an emotional disorder.
  • It is three times more common in boys.
  • Once an organic disease or spurious diarrhoea secondary to constipation with loading are excluded, consider behavioural problems and referral to a child and adolescent psychiatrist.