9: The infant with chronic diarrhoea



Information: Defining the type of diarrhoea helps direct the assessment of cases



  • Osmotic diarrhoea:

    • Stops on fasting within 24 hours
    • Stool pH usually <5 (acid from fermented malabsorbed sugars)
    • Low stool sodium (<70 mmol/l)
    • High measured osmolality (often >400)

  • Secretorydiarrhoea:
  • Continues despite fasting

    • Fasting stool pH usually >6
    • High stool sodium (>70 mmol/L)
    • High measured osmolality (often 280–320 mOsmol/L)

  • Osmolar gap: measured osmolality minus calculated osmolality ([Na] + [K]) × 2
  • Protein-losing enteropathy: steatorrhoea, hypoalbuminaemia, raised stool alpha-1-antitrypsin levels, lymphopoenia and hypogammaglobulinaemia






Differential diagnosis (see Algorithm 9.1)



  • Common:

    • Non-specific (functional diarrhoea), e.g. toddler diarrhoea
    • Post-infectious (transient) lactase deficiency
    • Cow’s milk/soya protein intolerance
    • Coeliac disease (see Chapter 12)
    • Cystic fibrosis
    • Short bowel syndrome
    • Motility disorder, e.g. after gastroschisis repair
    • Infectious, e.g. Cryptosporidium, Giardia, Entamoeba
    • After chemotherapy or radiotherapy
    • Graft-versus-host disease
    • Drug side-effects

  • Rare:

    • Primary or acquired immune deficiency: recurrent infection, skin rashes
    • Sucrase–isomaltase deficiency: watery diarrhoea onset at weaning
    • Infant-onset inflammatory bowel disease, e.g. interleukin (IL)-10 receptor deficiency
    • Secretory tumours, e.g. VIPoma: abdominal mass, abnormal gut hormone profile
    • Lymphangectasia: raised stool alpha-1-antitrypsin
    • Pancreatic insufficiency, e.g. Schwachmann syndrome (neutropoenia and skeletal abnormalities)
    • Autoimmune enteropathy: antienterocyte antibody
    • Abetalipoproteinaemia: acanthocytes on blood film
    • Chlylomicron retention disease (Anderson’s disease): typical small bowel histology
    • Zinc deficiency: perianal and perioral skin rash
    • Eosinophilic gastroenteritis: typical small bowel histology
    • Intractable diarrhoea syndromes:

      • Congenital chloride diarrhoea
      • Congenital sodium diarrhoea
      • Glucose–galactose malabsorption
      • Microvillous inclusion disease
      • Tufting enteropathy
      • Trichohepatoenteric syndrome (phenotypic diarrhoea of infancy)





Algorithm 9.1 Biochemical assessment of chronic diarrhoea in infants


c9-fig-5002




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May 31, 2016 | Posted by in GASTROENTEROLOGY | Comments Off on 9: The infant with chronic diarrhoea

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