Clinical and pathological evaluation of hypertensive emergency-related nephropathy

The prognosis of patients with hypertensive emergencies has recently improved dramatically owing to the development of effective antihypertensive therapy. We examined the histological and clinical features of patients with hypertensive emergency-related nephropathy.

Twelve patients (11 men and one woman) were diagnosed as having hypertensive emergencies with acute renal failure according to the Joint National Committee-7 classification of blood pressure for adults and underwent renal biopsies at our hospital between 1995 and 2008. These patients were enrolled in this retrospective study.

The age of the subjects was 40.1±9.8 years. At presentation, the mean systolic/diastolic blood pressure was 232±32/146±12 mmHg and none of the patients were being treated with antihypertensive drugs, although 10 patients had histories of hypertension. The mean serum creatinine level was 6.1±4.7 mg/dL. All 12 patients showed left ventricular hypertrophy on echocardiography. On light microscopy of the renal biopsy specimens, all 12 patients showed onion skin patterns of the arterioles; however, no fibrinoid necrosis of the small arteries was found. Electron microscopy revealed electron-lucent widening of the subendothelial zone of the glomerular capillary walls in seven patients. One of the 12 patients did not respond to medical therapy and required regular dialysis. The other 11 patients responded to treatment.

An onion skin pattern of the arterioles is the most frequent histological finding in patients with hypertensive emergency-related nephropathy. Long-standing hypertension might contribute to this arteriolar change, since left ventricular hypertrophy was also seen in these patients. With strict control of hypertension using antihypertensive medications, the prognosis of patients with hypertensive emergency-related nephropathy can be improved.