Diarrhoea questions

Diarrhoea is subjective, and can be defined as an increase in the volume, frequency or fluidity of stool relative to normal for the patient. Dysentery is diarrhoea with the presence of blood, mucous and protein in the stool, and often associated with signs and symptoms of systemic illness, e.g. fever, weight loss, anorexia, abdominal pain and dehydration.

Acute diarrhoea can be categorised into (a) osmotic; (b) secretory; (c) inflammatory and (d) dysmotility. With osmotic diarrhoea, fasting usually results in resolution of the diarrhoea, but with secretory diarrhoea fasting probably will make no difference.

  • Causes of osmotic –> laxatives, antacids, other drugs, congenital malabsorption
  • Causes of secretory –> bacteria, viruses, certain drugs. Faecal RBCs and WBCs uncommon; systemic symptoms uncommon
  • Causes of inflammatory –> invasive bacteria and parasites, inflammatory bowel disease, chemotherapy and radiotherapy. Faecal RBCs and WBCs common; systemic symptoms common

Questions to ask:

  • Volume, frequency and character of stools?
  • Blood/mucous in stool?
  • Onset and duration? Onset in relation to pain (which came first)? –> if diarrhoea first then pain, gastroenteritis likely
  • Does anything, e.g. eating/drinking, exacerbate/relieve diarrhoea?
  • Has the patient tried any medication for the diarrhoea? Has it worked?
  • Associated features? –> nausea, vomiting, fever, abdominal pain, constipation
  • Is diarrhoea the biggest problem, or are there other more pressing concerns?

  • HIV, transplants, malignancy, chemo/radiotherapy, abdominal surgery?
  • Past history/family history of diarrhoeal diseases?

  • Anyone else around you have diarrhoea? Are you associated with day care centres?
  • Recent dietary history à recent consumption of meats (cooked, uncooked), eggs, seafood, dairy foods and unusual foods
  • Recent travel to developing countries? Recent outdoor activities such as bushwalking? If so, what was the food + water situation?

A summary of epidemiologic questions:

  • Travel
  • ABx use
  • Institutionalised patients
  • Day care contact
  • Community outbreaks
  • HIV status
  • Raw seafood
  • Other food ingestions
  • Immunocompromised
  • Hospital associated

Questions to ask all the time:

· Smoker?

· Appetite?

· Weight loss?

· Any recent changes to medications?

· Allergies?

· Diabetic?

Non-infectious causes are responsible for about 15% of diarrhoea cases. They include:

  • Drugs
  • Fish and plant associated toxins
  • GI surgical pathology
    • IBD
    • Appendicitis
    • Bowel obstruction
    • Ischaemic bowel
    • Intussusception
    • Diverticulitis
    • Irritable bowel syndrome
    • Volvulus

Causes of infectious colitis:

(a) Campylobacter spp. Most common diagnosed cause of bacterial diarrhoea. Backpacker’s diarrhoea; contaminated food/water. Summer months. ~1wk duration. Very young children, and young adults. Prodrome of fever, headache, myalgia and abdominal cramps. Faecal WBCs and RBCs.

(b) Salmonella spp. Cafeteria/restaurant outbreaks, family gatherings. contaminated food/water (eggs/poultry). Summer months. Very young and very old. Prodrome of fever, headache, myalgia and abdominal cramps. Faecal WBCs (and RBCs, but not so much).

(c) Shigella spp. person to person spread; within families, day care. Sudden onset fever, headache, myalgia, abdominal pain. Faecal WBCs and RBCs

(d) Y. enterocolitica person to person and contaminated food/water. Fever, RLQ abdominal pain. Mimics appendicitis. Faecal WBCs and RBCs.

(e) V. parahaemolyticus raw/undercooked seafood. Sudden onset fever, headache and abdominal pain. Faecal WBCs and RBCs.

(f) EHEC 0157:H7 contaminated food/water, meat, outbreaks in institutions, day care. Fever, abdominal cramps, very bloody stools. Can be complicated by HUS and TTP. Faecal WBCs and RBCs.

(g) E.histolytica contaminated food/water, travel in developing countries. Sudden onset fever, abdominal cramps, bloody diarrhoea (amoebic dysentery). Faecal WBCs and RBCs.

(h) C. difficile after treatment with Abx (especially clindamycin) and antimotility agents, and especially in hospital setting. Fever, abdominal pain, bloody stools. Faecal WBCs and RBCs. Toxin destroys colonic mucosa.


  • Haemoccult and faecal cell count
  • C. difficile toxin
  • E. coli 0157:H7 toxin
  • Stool bacterial culture
  • Stool microscopy for ova and parasites