[Beware, polyarteritis nodosa still exists in nephrology!].

Renal involvement of systemic vasculitides is an emergency in nephrology. Although it has become very rare, the diagnosis of polyarteritis nodosa must be considered in some patients. A 70-year-old patient, previously healthy, presented with acute renal failure and malignant hypertension and abundant albuminuria. Subcutaneous nodule, orchitis and mononeuritis appeared subsequently. The search for auto-immunity or viral infection was negative. Markers of thrombotic microangiopathy, present initially, resolved after blood pressure control. After a renal computed tomography with contrast medium injection was considered normal, without any micro-aneurysm, a renal biopsy was performed. It showed vascular lesions and glomerular ischemia. It was complicated by hemorragic shock after 36hours. The diagnosis of periarteritis nodosa was finally made after arterial angiography showed millimetric renal micro-aneurysms. In case of systemic vasculitis with renal involvement, periarteritis nodosa must be part of differential diagnosis, especially in case of malignant hypertension, subcutaneous nodosa and orchitis, and despite albuminuria. This implies the search for micro-aneurysms with arterial angiography, and the contraindication of renal biopsy, associated with a high risk of severe hemorrhage. Periarteritis nodosa still exists in nephrology, even without hepatitis B infection. The association of acute renal failure with medium vessel vasculitis, with negative ANCA, must alert the nephrologist and lead to arterial angiography not to renal biopsy.