Haemolytic uraemic syndrome (HUS) is characterised by the triad of microangiopathic haemolytic anaemia, thrombocytopenia, and acute kidney injury.
Most cases of HUS occur in children and are diarrhoea-associated (D+ HUS). Diarrhoea-associated HUS is usually caused by Shiga toxin-producing Escherichia coli.
Rarely other organisms, such as Shigella and Streptococcus pneumoniae, are implicated.
Acute kidney injury necessitating dialysis develops in approximately half of children with diarrhoea-associated HUS.
Adequate hydration is important to minimise renal damage in HUS associated with Shiga toxin-producing E coli infections. Avoidance of antibiotics, antimotility agents, and non-steroidal anti-inflammatory drugs is advised. Cautious use of opioids is advised; there are insufficient data on the effect of opioids on the course of HUS.
Anaemia can be treated with red cell transfusion. Platelet transfusions are generally avoided in the absence of active bleeding.
Atypical HUS can occur due to genetic or acquired abnormalities in the alternative complement regulatory pathway. HUS can also occur as a secondary phenomenon due to medications, cancer, and other systemic diseases.
Haemolytic uraemic syndrome (HUS) is characterised by microangiopathic haemolytic anaemia, thrombocytopenia, and acute kidney injury. Ninety percent of HUS cases occur in the paediatric population, due to Shiga toxin-producing Escherichia coli(STEC).
Atypical HUS occurs due to abnormalities in the alternative complement regulatory pathway, resulting in endothelial cell damage and causing microvascular thrombosis. Atypical HUS can occur in adults and children.
History and exam
Key diagnostic factors
- diarrhoea, especially bloody diarrhoea
- childhood, especially age <5 years
Other diagnostic factors
- known community outbreak of Shiga toxin-producing E coli
- history of ingestion of food that may have been contaminated with Shiga toxin-producing E coli
- unusual adverse effect following treatment with ciclosporin, some chemotherapy agents, targeted cancer agents, and quinine
- pregnancy or postpartum status
- unusual adverse effect following bone marrow transplant
- family history of possible HUS-like syndrome
- ingestion of contaminated food or water
- known community outbreak of toxicogenic E coli
- exposure to infected individuals in institutional settings
- genetic predisposition (atypical HUS)
- bone marrow transplant
- exposure to ciclosporin, some chemotherapy agents, targeted cancer agents, and quinine
- pregnancy- or postpartum-related
1st investigations to order
- peripheral blood smear
- renal function/creatinine
- serum electrolytes (sodium, potassium, chloride and bicarbonate, calcium and phosphorus)
- prothrombin time (PT), PTT
- stool culture on sorbitol-MacConkey agar to detect Shiga toxin-producing Escherichia coli
- polymerase chain reaction (PCR) to detect Shiga toxin 1/Shiga toxin 2
- proteins involved in complement regulation
Investigations to consider
- ADAMTS13 level
- serum amylase, lipase, glucose
Shiga toxin-producing Escherichia coli (STEC) HUS
secondary HUS: not due to Streptococcus pneumoniae
secondary HUS: due to S pneumoniae
Sharon Andreoli, MD
Byron P. and Francis D. Hollet Professor of Pediatrics, Pediatric Nephrology
Indiana University School of Medicine
SA owns stock in Merck and Pfizer, and has been a consultant for Reata Pharmaceuticals. SA is on the Editorial Board of Pediatric Nephrology and the Journal of Pediatrics.
Myda Khalid, MD
Associate Professor of Pediatric Nephrology
Indiana University School of Medicine
MK declares that she has no competing interests.
Dr Sharon Andreoli and Dr Myda Khalid would like to gratefully acknowledge Dr Ann Zimrin and Dr John Hess, previous contributors to this topic.
AZ and JH declare that they have no competing interests.
Rebecca Connor, MD
Section of Hematology and Oncology
Department of Internal Medicine
Wake Forest University Baptist Medical Center
RC declares that she has no competing interests.
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