complement-mediated hemolytic uremic syndrome
Also written as: aHUS — Atypical Hemolytic Uremic Syndrome
Atypical form of HUS caused by dysregulation of the alternative complement pathway, often requiring specific targeted therapy.
Full Definition
Complement-mediated hemolytic uremic syndrome, also known as atypical HUS (aHUS), is a rare form of thrombotic microangiopathy caused by genetic mutations or acquired abnormalities in complement regulatory proteins. Unlike typical post-diarrheal HUS, aHUS is not associated with Shiga toxin-producing bacteria and has a more variable presentation and course. Mutations may affect complement factors H, I, B, C3, or membrane cofactor protein, leading to uncontrolled complement activation and endothelial damage. The condition often presents with recurrent episodes and can progress rapidly to end-stage renal disease without treatment. Management includes plasma exchange and complement C5 inhibition with eculizumab, which has dramatically improved outcomes in recent years.
Usage
Usage note: Often abbreviated as aHUS when referring to the atypical form; distinguish clearly from typical HUS.
In Context
- "Genetic testing revealed a complement factor H mutation confirming complement-mediated hemolytic uremic syndrome." — Pediatric nephrology genetics consultation
- "The patient responded well to eculizumab therapy for complement-mediated hemolytic uremic syndrome." — Specialized treatment center progress note