[Reversible posterior leukoencephalopathy syndrome in two patients with microscopic polyarteritis nodosa]

We report here two cases (72-year-old woman, 77-year-old-woman) with perinuclear anti-neutrophil antibody (P-ANCA) positive microscopic polyarteritis nodosa (mPN). Both patients presented with generalized convulsion, consciousness disturbance and severe hypertension several days after the administration of high dose methylpredonisolone followed by oral predonisolone. CT brain scan showed hypodensity area on bilateral posterior lobes. MRI T2 weighted image and FLAIR image showed increased signal intensity on the occipital gray and white matter. Although diffusion weighted MRI disclosed slightly high signal intensity, apparent diffusion coefficient (ADC) value at the occipital gray and white matter remained normal or even elevated. These findings, which were consistent with vasogenic edema, lead us to diagnose them as suffering from reversible posterior leukoencephalopathy syndrome (RPLS). After the second administration of high dose methylpredonisolone, their symptoms and signs, together with the MRI findings, gradually improved. To our knowledge, this is the first report concerning RPLS in a patient with mPN.