A Shearing Sensation: An Uncommon Cause of Thrombotic Microangiopathy

Introduction: Malignant Hypertension (MH) defined as a type of hypertensive emergency with severe increase in blood pressure often >200/120 mm Hg, hypertensive retinopathy (flame hemorrhages, cotton wool spots, papilledema) and renal damage (6). Thrombotic microangiopathy (TMA) is a coagulation system disorder resulting in extensive clot formation within small blood vessels. MH has a low prevalence and incident rate of 5/100,000 within the Caucasian population (7) & a prevalence of about 3.2% in the African American (AA) population (8). There is a paucity of reported cases of biopsy proven MH-TMA. Publications have reported a prevalence of up 25%, but variations exist due to results based on lab tests without confirmatory renal biopsy (7). Case Description: A 43 y/o AA male with medical history of Tobacco Abuse, EtoH abuse & HTN presented with 1 week of abdominal discomfort & BP of 232/118mmhg. Notable initial findings & management found in figure 1. Extensive workup confirmed presence of TMA with renal biopsy findings showed inter- lobular artery “onion skin” thickening with a narrowing lumen, intimal fibrosis, ischemic glomerulus and thrombi within glomerular arteriole with features of chronic tubulointerstitial nephropathy. Discussion: Microangiopathic hemolytic anemia (MAHA) defined as an intrinsic mechanical destruction of erythrocytes; underlying etiologies are grouped into primary TMA (TTP,HUS,aHUS) & secondary TMA (MH,DIC,Drug induced). The exact mechanism MH-TMA is unclear but the proposed theory consists of hypertension induced shearing & endothelial damage of arterioles and glomerular capillaries which advances to TMA (3). The challenge to swiftly identify MAHA is due to overlapping symptomatic presentations of TTP, HUS, atypical HUS/CM-TMA & MH-TMA. Ultimately, when presenting symptoms consist of severe hypertension, anemia, thrombocytopenia and progressive renal dysfunction should raise suspicion for MH induced TMA. Renal biopsy is the gold standard to assist in diagnostic confirmation of MH induced TMA & management entails aggressive blood pressure control.