Hemolytic uremic syndrome (HUS) is characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury.
Most cases of HUS occur in children and are diarrhea-associated (D+ HUS). Diarrhea-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 diarrhea-associated HUS.
Adequate hydration is important to minimize renal damage in HUS associated with Shiga toxin-producing E coli infections. Avoidance of antibiotics, antimotility agents, and nonsteroidal 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.
Anemia 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.
Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Ninety percent of HUS cases occur in the pediatric 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
- diarrhea, especially bloody diarrhea
- 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 cyclosporine, 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 cyclosporine, 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
- Thrombotic thrombocytopenic purpura (TTP)
- Malignant hypertension
- Systemic lupus erythematosus (SLE)
- Guidelines on hemolytic uremic syndrome by Indian Society of Pediatric Nephrology: key messages
- Hemolytic uremic syndrome in a developing country: consensus guidelines
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