Snapshot A 39-year-old woman is brought to the ED by her husband who says she has been acting strange for the last few hours. Workup reveals pallor, fever, and epistaxis. On physical exam, you see an enlarged spleen and a blood pressure of 220/130 (normally 140/95). Labs are remarkable for a significant thrombocyopenia and an elevated indirect bilirubin. A biopsy of her kidney is shown. Introduction Rapid ↑ in blood pressure due to vascular damage to renal vessels secondary to benign nephrosclerosis (most common cause) thrombotic thrombocytopenic purpura hemolytic-uremic syndrome Presentation Symptoms oliguria due to acute renal failure Physical exam BP > 210/120 mmHg hypertensive encephalopathy (see topic) Studies Pathology gross appearance hemorrhages on surface of the kidney - "flea bitten" histology hyperplastic arteriolosclerosis Treatment Pharmacologic nitroprusside ↑ cGMP via direct release of NO results in ↓ TPR in venules and arterioles cyanide toxicity treated with nitrites + sodium thiosulfate fenoldopam dopamine D1 receptor agonist preferentially ↑ flow in renal vasculature preserves blood supply of kidney note: fenolDOPAm diazoxide K+ channel opener results in hyperpolarization of arteriolar smooth muscle ↓ TPR ↓ insulin secretion resulting in hyperglycemia