Background
Both HUS and TTP involve acute episodes of non-immunological destruction of platelets due to the deposition of loose strands of platelets and fibrin in small vessels and thrombosis, leading to RBC and platelet destruction, a condition known as thrombotic microangiopathy (TMA).
- They present with similar blood profile and histological changes, microangiopathic anemia with red blood cell fragmentation, thrombocytopenia, and acute kidney injury.
- Although there's much overlap between the two, they are treated as distinct entities.
- TPP is caused by a deficient enzyme, while HUS is caused by shigatoxin and defective regulation of the alternative complement pathway.
- Fibrin predominates in HUS while platelets are more prominent in TTP.
- Neurological manifestations and multiorgan damage are more common in TTP.
Hemolytic uremic syndrome
There are several variants of hemolytic uremic syndrome (HUS), with the two most significant being the typical, diarrhea-associated HUS and the atypical HUS.
Pathomechanism
- Typical, diarrhea-associated HUS is triggered by the presence of shigatoxin (and