1. Challenges in recognizing and diagnosing TA-TMA
TA-TMA is difficult to recognize as complex clinical picture post-HSCT
can mask or mimic TA-TMA, such as cytopenia due to marrow aplasia before
engraftment, drug-induced hypertension and immune-mediated hemolysis.
Besides, as not all features appear simultaneously and may evolve over
days to weeks, high index of suspicion is crucial to pick up subtle cues
of evolving TA-TMA such as persistent hypertension requiring multiple
anti-hypertensives, elevated LDH, or increased transfusion requirement
and platelet refractoriness. There has yet been a universally accepted
diagnostic criteria for TA-TMA. Histology is the most reliable modality
yet invasive and risky. Diagnostic triad of hypertension,
thrombocytopenia and elevated LDH proposed by Dvorak
(2) provides useful guidance in
recognizing TA-TMA, though proteinuria instead of thrombocytopenia is
the third universal feature in local cohort (Table 1b) .