Hemolytic uremic syndrome is formally characterized as a clinical syndrome marked by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury [1][2]. The disorder encompasses distinct pathogenic pathways, broadly stratified into Shiga toxin-associated variants resulting from specific bacterial gastrointestinal infections and atypical forms linked to genetic mutations or acquired autoantibodies targeting complement regulators [3][1]. Both etiologies ultimately converge on widespread endothelial injury and the formation of microvascular thrombi, leading to multi-organ system dysfunction [3][2].
Disease overview
BacterialHemolytic uremic syndrome
溶血性尿毒症综合征
Evidence-backed informationEN 3/7 applicable sections · ZH 3/7 applicable sectionsUpdated Sep 3, 2026
Hemolytic uremic syndrome represents a heterogeneous category of thrombotic microangiopathies clinically defined by concurrent microangiopathic hemolytic anemia, thrombocytopenia, and acute renal impairment [1][2]. These disorders encompass distinct etiologies, primarily driven by Shiga toxin-producing bacterial enteric infections or dysregulation of the complement alternative pathway [3][1]. Population-level data indicate an annual incidence of approximately 1.5 cases per 100,000 individuals, with pediatric cohorts bearing the highest disease burden while adult presentations frequently demonstrate more severe systemic involvement [1][2]. Despite generally favorable short-term survival rates exceeding 90%, the condition carries substantial long-term morbidity, including persistent renal dysfunction and progression to end-stage kidney disease in a notable subset of survivors [2].
Read the full clinical and epidemiological profile4
Initial manifestations typically commence with gastrointestinal distress, including bloody diarrhea, abdominal cramping, mild fever, and vomiting, which generally appear three to ten days following exposure to contaminated sources [2]. Renal compromise and cytopenias typically emerge five to ten days after symptom onset, coinciding with the natural resolution of the diarrheal illness [2]. While the syndrome predominantly affects children, older adults and elderly patients frequently experience more complex presentations involving neurological deficits, cardiovascular strain, and prolonged organ dysfunction [2]. Long-term sequelae can include persistent hypertension, seizure disorders, visual impairment, and chronic renal insufficiency in a subset of survivors [2].
The annual incidence of hemolytic uremic syndrome is estimated at approximately 1.5 cases per 100,000 individuals across affected populations [2]. Pediatric cohorts bear the highest disease burden, whereas adult presentations frequently demonstrate more severe systemic involvement [2]. Age significantly influences acute mortality, with fatality rates hovering around 3% in young children but rising to approximately 20% among middle-aged and older adults [2]. Longitudinal tracking indicates that roughly one-third of survivors may exhibit persistent renal abnormalities, while less than 10% progress to end-stage kidney disease requiring sustained dialysis [2].
- 1Boyer O et al. Hemolytic-Uremic Syndrome in Children. Pediatr Clin North Am. 2022 Dec. PMID: 36880929. doi: 10.1016/j.pcl.2022.07.006.PubMed: https://pubmed.ncbi.nlm.nih.gov/36880929/
- 2Wikipedia contributors. Hemolytic–uremic syndrome - Wikipedia [Internet]. Wikipedia. cited 2 Sept 2026.Available from: https://en.wikipedia.org/wiki/Hemolytic%E2%80%93uremic_syndrome
- 3Raina R et al. Atypical Hemolytic-Uremic Syndrome: An Update on Pathophysiology, Diagnosis, and Treatment. Ther Apher Dial. 2019 Feb. PMID: 30294946. doi: 10.1111/1744-9987.12763.PubMed: https://pubmed.ncbi.nlm.nih.gov/30294946/
- 4Abou-Ismail MY et al. Thrombotic microangiopathies: An illustrated review. Res Pract Thromb Haemost. 2022 Mar. PMID: 35615754. doi: 10.1002/rth2.12708.PubMed: https://pubmed.ncbi.nlm.nih.gov/35615754/
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