Renal-Limited Thrombotic Microangiopathy Associated With a CD46 Variant: A Case Highlighting Multidisciplinary Diagnosis and Practice-Changing Insights

Thrombotic microangiopathy (TMA) encompasses disorders characterized by endothelial injury, microvascular thrombosis, and end organ injury. Although systemic TMA is typically identified through anemia, thrombocytopenia, elevated lactate dehydrogenase, suppressed haptoglobin and schistocytes, these markers lack sensitivity, particularly in renal-limited TMA. A patient presented with acute kidney injury requiring dialysis whose renal biopsy revealed extensive TMA despite the absence of schistocytes or other systemic features. Diagnosis and management required coordinated collaboration among nephrology, hematology, pathology, and pharmacy teams, enabling rapid interpretation of biopsy findings and timely initiation of complement component 5b inhibition. This multidisciplinary approach led to recovery of kidney function and discontinuation of dialysis. The case highlighted how team-based evaluation and shared decision-making improved diagnostic accuracy and treatment efficiency, ultimately elevating quality of care. It also reinforced the importance of early biopsy and reconsideration of TMA in patients without hematologic abnormalities. Recognition of renal-limited TMA and prompt initiation of complement-directed therapy are essential to prevent irreversible renal injury and optimize outcomes.