Acute diarrhoea (≥3 loose stools/day for <14 days) ± vomiting, abdominal pain, fever; usually self-limited, viral.
History taking
- • Frequency, consistency, blood/mucus, vomiting, fever
- • Recent food (eating out, leftovers), water source, travel
- • Sick contacts, dehydration status (intake, urine output)
Examination
- • Assess dehydration: pulse, BP, postural drop, mucous membranes, skin turgor, capillary refill, urine output
- • Abdomen: tenderness, bowel sounds; rule out peritonitis
Red flags
- • Severe dehydration, hypotension, oliguria
- • Blood in stool with fever (dysentery)
- • Persistent vomiting, inability to tolerate orals
- • Elderly, immunocompromised, pregnant
Differential diagnosis
- • Viral (norovirus, rotavirus), bacterial (E. coli, Salmonella, Shigella, Campylobacter, Vibrio)
- • Parasitic (Giardia, Entamoeba)
- • C. difficile after antibiotics; food poisoning toxins
Recommended investigations
- • Usually clinical; no tests for mild self-limiting cases
- • Stool routine, occult blood, culture if dysentery or persistent
- • Stool C. difficile toxin if recent antibiotics
- • Electrolytes, RFT if dehydrated; CBC if febrile
Diagnosis
- • Clinical based on symptoms and exposure
Initial treatment / management
- • Oral rehydration is first-line (WHO ORS)
- • Zinc supplementation in children (10–14 d)
- • Antiemetic (ondansetron) for vomiting
- • Antibiotics only if dysentery, severe disease, immunocompromised — ciprofloxacin/azithromycin
- • Probiotics may reduce duration
Prescription examples
- • ORS sachets — 1 in 1 L water; 75 mL/kg over 4 h if dehydrated
- • Tab Ondansetron 4 mg PO TDS PRN
- • Tab Azithromycin 500 mg PO OD x 3 d (for dysentery)
- • Tab Zinc 20 mg PO OD x 14 d (children)
- • Avoid loperamide if dysentery or invasive infection
Follow-up advice
- • Review in 24–48 h if not improving
- • Persistent diarrhoea >14 d — investigate further
Patient counselling
- • Hand hygiene, safe water, food hygiene
- • Continue eating (BRAT diet); avoid dairy briefly
- • Return if blood in stool, fever, drowsiness, decreased urine output
Referral criteria
- • Severe dehydration needing IV fluids
- • Suspected cholera, dysentery, typhoid
- • Persistent diarrhoea, immunocompromised
Clinical pearls
- • Most cases viral and self-limiting — antibiotics not needed
- • Bloody diarrhoea without fever — think EHEC; avoid antibiotics (HUS risk)
- • Hypokalaemia and metabolic acidosis common in severe diarrhoea
References
- • WHO Diarrhoeal Disease Guidelines 2017
- • IDSA Infectious Diarrhea Guidelines 2017
Educational outpatient guide — verify against local guidelines before clinical use.
