45-year-old, 1 day of profuse watery diarrhoea ("rice-water"), vomiting, leg cramps; very dry, BP 86/50, not passing urine (or bloody diarrhoea with fever and tenesmus)
Red flags
Shock
Bloody diarrhoea + AKI (HUS)
Severe abdominal pain/distension
Age >65 or immunocompromised
Differential diagnosis
Viral gastroenteritis
C. difficile
IBD flare
Ischaemic colitis
Typhoid (fever > diarrhoea)
Sepsis from another source
When to admit, call ICU or discharge
Admit: Severe dehydration, unable to keep ORS down, AKI, bloody diarrhoea with sepsis, elderly/immunocompromised
ICU: Shock refractory to fluids, HUS with complications, fulminant C. difficile
Dialysis: AKI with refractory K⁺, acidosis or overload (HUS)
Key points
ORS saves most lives — IV only for severe dehydration or inability to drink.
Cholera: rice-water stools, rapid shock — a single dose of doxycycline or azithromycin shortens illness.
Notifiable diseases (cholera, typhoid) → public health; food-handler exclusion.
Never
Give antimotility drugs in bloody or febrile diarrhoea
Give antibiotics for suspected STEC (E. coli O157)
Use empirical fluoroquinolones for dysentery in India (high resistance)
Under-replace fluids in cholera — losses can exceed 1 L/h
Common mistakes
Antibiotics in STEC
Antimotility in dysentery
FQ for Shigella
Missing C. difficile after antibiotics
Disposition and follow-up
Ward for rehydration; ICU for refractory shock or HUS. Public health for notifiable pathogens.
ICU Decoded — original critical-care and internal-medicine pathways by
Dr Javed Akhtar, each cited to a current guideline. For education and quick
reference; verify every dose against local protocols before prescribing.