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Diarrhoea

 

­­Differential diagnosis of diarrhoea

  • Infectious:
    • Viral
      • Norovirus; Rotavirus
    • Bacterial
      • E.coli; Salmonella; Shigella; Campylobacter
      • Vibrio cholerae
      • C. difficile
    • Protozoal/parasites
      • Giardia lamblia
      • Amoebic dysentery
  • Inflammatory bowel disease (IBD)
  • Irritable bowel syndrome (IBS)
  • Colorectal carcinoma
  • Coeliac disease
  • Drugs
    • Antibiotics; Cytotoxics; Laxatives; PPIs; Digoxin; NSAIDs; Propranolol
  • Thyrotoxicosis
  • Bacterial overgrowth
  • Pancreatic insufficiency
  • Short bowel syndrome
  • Ischaemic colitis

 

 History in diarrhoea

  • Presenting complaint
    • Increased stool frequency and volume
  • History of presenting complaint
    • Acute or chronic
    • Recent foods/contacts
    • Number of bowel motions/day
    • Incontinence and/or urgency
    • Tenesmus
    • Bloody diarrhoea
      • Shigella; Salmonella; Campylobacter; IBD; Colorectal carcinoma
    • Fresh PR bleeding
    • Mucus
    • Weight loss
    • Fevers
    • Fatigue
    • Steatorrhea
    • Joint pains/aches
    • Rashes
  • Past medical history
    • Previous bowel surgery
  • Medications
    • Antibiotics; Cytotoxics; Laxatives; PPIs; Digoxin; NSAIDs; Propranolol
  • Family history
    • Colorectal carcinoma
    • Autoimmune disease
    • IBD
  • Social history
    • Travel history
    • Alcohol consumption

 

 Examination in diarrhoea

  • Abdominal tenderness/masses
  • Anaemia
  • DRE – blood, masses
  • Lymphadenopathy
  • Goitre
  • Erythema nodosum
  • Cachexia
  • Abdominal scars

 

 Initial investigation and management of diarrhoea

  • Stool sample
    • Microscopy, sensitivities and culture
    • C. diff toxin
    • Ova, cysts and parasites
  • Blood tests
    • Full blood count
    • Inflammatory markers
    • Urea and electrolytes
    • Venous blood gas
    • Liver function tests
    • Thyroid function tests
    • Autoimmune screen
  • Abdominal X-ray
  • Fluid resuscitation
  • Antibiotics if not responding to fluid resuscitation or if suspecting an infectious exacerbation of IBD e.g. Metronidazole 400mg three times daily (check local guidelines)
  • If C. diff then give Metronidazole po 400mg three times daily and/or Vancomycin 500mg orally four times daily
    • See local guidelines for grading severity of C.Diff and subsequent treatment strategy

 

 Further management of diarrhoea

  • Flexible sigmoidoscopy  and/or Colonoscopy with biopsies
  • Abdominal ultrasound
  • CT abdomen/pelvis
  • Faecal elastase
  • TTG antibodies + OGD if suspecting coeliac disease
  • Loperamide 2-4mg up to four times daily if refractory diarrhoea with no treatable cause found – MUST exclude obstruction before prescribing.

 

Click here for medical student OSCE and PACES questions about diarrhoea

Common diarrhoea exam questions for medical students, finals, OSCEs and MRCP PACES

 

Click here to download free teaching notes on diarrhoea: Presentation-Diarrhoea

Perfect revision for medical students, finals, OSCEs and MRCP PACES