Synopsis
Recognise renal-predominant thrombotic microangiopathy, identify Shiga-toxin infection, distinguish complement-mediated disease and secondary mimics, and provide kidney support or urgent complement blockade safely.
- HUS is a thrombotic microangiopathy characterised by thrombocytopenia, microangiopathic haemolytic anaemia and acute kidney injury, with renal injury often dominating the presentation.
- Shiga-toxin-producing Escherichia coli HUS commonly follows abdominal pain and bloody diarrhoea, but diarrhoea may have resolved before kidney and platelet abnormalities appear.
- Send stool culture and Shiga-toxin PCR promptly and notify microbiology or UKHSA because infection-control and public-health actions extend beyond the individual patient.
- Supportive care with careful fluid assessment, electrolyte control, blood pressure management and dialysis when indicated is central to STEC-HUS.
- Avoid antimotility medicines in suspected STEC infection and seek microbiology advice before antibiotics because some antibiotic exposures may increase toxin release and HUS risk.
- Complement-mediated HUS results from dysregulated alternative complement and can be triggered by infection, pregnancy, surgery or transplantation in a genetically susceptible person.
- An ADAMTS13 activity above the severe TTP range makes TTP less likely but does not itself prove complement-mediated HUS; secondary TMAs must be excluded.
- Eculizumab or ravulizumab blocks terminal complement in eligible complement-mediated HUS and should be coordinated urgently through the specialist service with meningococcal protection.
- Complement levels can be normal during complement-mediated HUS, and genetic testing may be negative; diagnosis integrates phenotype, exclusions and expert complement assessment.
- Long-term follow-up after any HUS includes blood pressure, eGFR, proteinuria and recurrence or family counselling because apparently recovered kidney function may hide later CKD.
Key red flags
Refractory hyperkalaemia, pulmonary oedema, severe acidosis or uraemic complications requires urgent renal replacement assessment.
Investigation priorities
Establish evidence of thrombocytopenic microangiopathic haemolysis.
Management branches
Thrombocytopenia, schistocytes and haemolysis occur with acute kidney injury.
- Call nephrology and haematology, manage fluid, potassium, acidosis, blood pressure, seizures and pulmonary oedema and assess dialysis indications.
- Send stool STEC testing, pre-plasma ADAMTS13, coagulation and complement samples and review pregnancy, drugs, transplant, sepsis and hypertension.
- Treat high-probability TTP immediately with its exchange pathway and avoid prophylactic platelet transfusion while the mechanism remains thrombotic.
Key medicines
EculizumabThe specialised aHUS service gives the licensed intravenous weekly induction followed by weight-appropriate maintenance, with supplemental doses after specified plasma treatments.Meningococcal infection can be fulminant despite vaccination; provide prophylaxis and fever instructions and monitor infusion reaction, other Neisseria infection and pregnancy needs.
Antihypertensive therapyUse titratable intravenous treatment for a hypertensive emergency and kidney-appropriate oral agents for ongoing control, with targets set by critical care, renal and pregnancy context.Avoid precipitous pressure reduction that compromises organ perfusion; AKI, hyperkalaemia and pregnancy limit drug selection and require frequent review.