Deciphering Thrombotic Microangiopathy: A Case-Based Exploration of Distinguishing Features Between Malignant Hypertension and Thrombotic Thrombocytopenic Purpura

Objective: Patients with severe hypertension can present with systemic signs of thrombotic microangiopathy (TMA), i.e., thrombocytopenia and microangiopathic hemolytic anemia (MAHA), and/or renal failure. Determining the underlying disease causing TMA is essential for selection of the optimal therapy. We aim to elucidate key factors for distinguishing TMA due to malignant hypertension from TMA due to thrombotic thrombocytopenic purpura (TTP). Design and method: We present here a case study focussing on a challenging clinical scenario involving TMA. Through detailed examination of the patient's presentation, laboratory findings, and response to treatment, the report takes you through a diagnostic journey emphasising the unique aspects of TMA in malignant hypertension as compared to TMA in TTP. Results: A 44 year old male was admitted with 2 weeks history of exertional breathlessness, orthopnea and severe headache with vomiting. On examination his BP was severely elevated at 253/150 mmHg and he had features of acute pulmonary edema (APO). Initial investigations Significant anemia (hemolytic picture with elevated LDH, low haptoglobin and Indirect hyperbilirubinemia) with thrombocytopenia. Peripheral blood film revealed fragmented RBCs(2-4/hpf), Severe renal failure Creatinine 757umol/L urea 30.9mmol/L Na 129mmol/L, K 2.6mmol/L. MRI Brain revealed features suggestive of Posterior reversible encephalopathy syndrome (PRES). He was diagnosed with hypertensive emergency complicated by APO, PRES and Acute kitney injury from MAHA. He was admitted to ICU and treated with IV GTN infusion, hydralazine and diuretics. He was also started on hemodialysis. Renal failure work-up-HbA1c 4.4, nonreactive viral markers, negative autoimmune serology (C3/C4 normal, Anti-dsDNA <25, ANA <80, ANCA negative). Secondary Hypertension work-up - negative for Renal artery stenosis, Conns, Cushings, Phaeochromocytoma and Thyroid disorders. ADAMTS-13 Activity: 28%, DCT Negative. He was closely monitored, continued on hemodialysis and his blood pressure well-controlled with consequent improvement in LDH, bilirubin, Hemoglobin, and thrombocytopenia. He did not require to be treated with plasma exchange. Conclusions: The report contributes valuable insights into the differentiation of these two related yet clinically distinct entities, providing guidance for clinicians to appropriately tailor the therapeutic interventions. Further research is essential for refining diagnostic criteria to enhancie the precision of therapeutic strategies in these complex medical scenarios.