Synopsis
Recognise thrombotic microangiopathy after bloody diarrhoea, confirm haemolysis, thrombocytopenia and kidney injury, avoid harmful antimicrobials and antimotility drugs in suspected STEC, and escalate early for renal and neurological support.
- HUS is the triad of microangiopathic haemolytic anaemia, thrombocytopenia and acute kidney injury; the components may evolve sequentially rather than appear together.
- Most childhood UK cases follow Shiga toxin-producing E. coli gastroenteritis, often abdominal pain and diarrhoea that becomes bloody several days before pallor and oliguria.
- Send stool or, if unavailable, a rectal swab labelled suspected STEC or HUS for culture and toxin/PCR testing; a negative late sample does not exclude the syndrome.
- First-line blood tests are FBC with serial platelets, blood film for schistocytes, reticulocytes, bilirubin, LDH, haptoglobin, creatinine, electrolytes, bicarbonate, glucose and coagulation screen.
- A direct antiglobulin test is usually negative in microangiopathic haemolysis and helps distinguish immune haemolytic anaemia when the picture is uncertain.
- Do not give antibiotics for suspected STEC gastroenteritis unless infection specialists identify a separate compelling indication; UKHSA warns they may increase HUS risk.
- Do not use loperamide or other antimotility agents in suspected STEC or bloody diarrhoea because toxin and organism retention may worsen disease.
- First-line treatment is meticulous supportive care: careful volume assessment, measured isotonic replacement before oliguria when depleted, then input matched to losses once AKI develops.
- Do not transfuse platelets solely for a low count; reserve them for clinically important bleeding or an invasive procedure after specialist discussion because platelet consumption is ongoing.
- Transfuse red cells for clinically significant or symptomatic anaemia using the paediatric transfusion plan, with close attention to potassium and fluid volume.
- Dialysis is used for refractory hyperkalaemia, acidosis, pulmonary oedema, uraemic complications or uncontrolled fluid overload; the decision is not based on urea or creatinine alone.
- Notify suspected HUS to the local health protection team on clinical suspicion, apply enteric infection control, and obtain exposure history including farms, animals, food, water, nursery and household cases.
Key red flags
Reduced urine, rising weight, oedema, hypertension or breathlessness after bloody diarrhoea suggests evolving AKI and fluid overload.
Marked pallor, jaundice, petechiae or bruising with falling haemoglobin and platelets indicates active microangiopathic haemolysis.
Irritability, confusion, seizure, focal deficit or reduced consciousness indicates central nervous system involvement and requires intensive monitoring.
Potassium elevation, severe acidosis, pulmonary oedema, uraemic symptoms or anuria requires immediate nephrology and critical-care assessment for kidney replacement therapy.
HUS without preceding diarrhoea, recurrent episodes, family history, very early onset or persistent complement abnormality raises concern for complement-mediated atypical HUS.
Fever with neurological signs, profound coagulopathy or shock requires simultaneous assessment for sepsis, meningitis and disseminated intravascular coagulation.
Investigation priorities
Detect anaemia, thrombocytopenia and fragmented red cells as the triad evolves.
Management branches
A child has severe or bloody diarrhoea, especially under age 5 years.
- Send stool or rectal swab explicitly labelled suspected STEC and assess hydration, blood pressure, weight and urine output.
- Obtain baseline FBC, film and renal profile when admitted, systemically unwell or clinically concerning, then arrange serial review.
- Avoid antibiotics and antimotility medicines unless a separate specialist-defined indication overrides the STEC risk.