Haemolytic uraemic syndrome (HUS)
A rare but serious complication of diarrhoeal illness
What is haemolytic uraemic syndrome (HUS)?
Haemolytic uraemic syndrome (HUS) is a serious condition that can develop after certain gastrointestinal infections, most commonly Shiga-toxin producing Escherichia coli (STEC).
It is most often seen in children, older adults, and people with underlying health conditions. HUS is a medical emergency.
What causes HUS?
HUS usually follows infection with bacteria that produce Shiga toxin, particularly E. coli O157:H7 and related strains. The toxin damages blood vessels, especially in the kidneys.
What happens in HUS?
HUS is defined by three key features:
- Haemolysis — destruction of red blood cells
- Low platelets — increased bleeding risk
- Acute kidney injury — reduced urine output, rising creatinine, possible dialysis
Warning signs after diarrhoea
HUS typically develops several days after diarrhoea onset, often as bowel symptoms begin to improve.
- Reduced or absent urine output
- Dark or bloody urine
- Unusual bruising or bleeding
- Pallor and fatigue
- Swelling of the face or legs
- Confusion or drowsiness
These symptoms require urgent hospital assessment.
Why antibiotics and anti-diarrhoeal drugs can be dangerous
In suspected or confirmed STEC infection, antibiotics can increase toxin release and anti-diarrhoeal agents can prolong toxin exposure. Both may increase HUS risk.
How is HUS treated?
There is no specific cure. Treatment focuses on supportive care: fluids/electrolytes, transfusion if needed, dialysis if kidney failure develops.
Prognosis
Many recover fully with prompt care, but some develop long-term kidney problems. Rarely, HUS can be fatal.
Key takeaway: Bloody diarrhoea followed by reduced urine output is a medical emergency. Avoid antibiotics and anti-diarrhoeal drugs unless specifically advised.