Haemolytic Uraemic Syndrome

Haemolytic uraemic syndrome is characterized by the triad of microangiopathic haemolytic anaemia, thrombocytopenia and acute kidney injury.

The commonest form in children follows infection with Shiga toxin producing Escherichia coli, often after a prodrome of abdominal pain and bloody diarrhoea.

Endothelial injury causes platelet activation and microvascular thrombosis, particularly within the renal circulation.

Several days after diarrhoeal illness, the child may develop:

• Pallor
• Fatigue
• Oliguria or anuria
• Oedema
• Hypertension
• Petechiae or bruising
• Irritability
• Reduced consciousness or seizures in severe disease

Typical findings include:

• Falling haemoglobin
• Thrombocytopenia
• Schistocytes on peripheral blood film
• Elevated LDH
• Reduced haptoglobin
• Elevated creatinine and urea
• Haematuria and proteinuria

Send stool testing for Shiga toxin or STEC where available.

Coagulation tests are usually relatively preserved, helping distinguish HUS from disseminated intravascular coagulation.

Management is predominantly supportive.

• Carefully manage fluid and electrolyte balance.

• Avoid fluid overload once renal failure is established.

• Packed red cell transfusion may be required for symptomatic or severe anaemia.

• Platelet transfusion is generally avoided unless significant active bleeding or an invasive procedure requires it.

• Monitor potassium closely.

Dialysis is required for standard AKI indications including refractory hyperkalaemia, severe acidosis, pulmonary oedema, significant uraemia or prolonged severe oliguria.

Antibiotics and antimotility agents are generally avoided in suspected STEC diarrhoea, because they may increase toxin exposure or HUS risk.