Clinical features of microscopic polyangiitis associated with peripheral neuropathy

To analyze clinical features of patients with microscopic polyangiitis (MPA) associated with peripheral neuropathy (PN).The clinical data of 37 (44.6%) hospitalized MPA patients associated with PN in Peking Union Medical College Hospital from January 2008 to January 2014 was retrospectively analyzed, using the rest 46 hospitalized MPA patients without PN as control.(1) Out of the 37 MPA patients with PN, there were 15 men and 22 women, with the average age of (64 ± 9) years old and average time between the diagnosis and onset of the disease of 24.5 months. (2) Neurologic manifestations of these patients: mononeuritis multiplex (56.8%) and distal symmetrical polyneuropathy (43.2%) were the predominant peripheral nervous system manifestations. Lower limbs were more frequently affected, and mixed (sensory and motor) or sensory abnormalities were more commonly seen than single motor abnormalities. (3) Compared with MPA patients without PN, the incidence of myalgia and the count of platelet in peripheral blood, erythrocyte sedimentation rate (ESR) were statistically higher, while the serum level of albumin was statistically lower in MPA patients with PN. There were no statistical differences in age, sex, fever, rash, arthritis, interstitial lung disease, gastrointestinal lesions, renal and central nervous system involvement between two groups. (4) The multivariant Logistic regression analysis suggested that thrombocytosis was the risk factor for PN in MPA patients (OR = 1.005, P < 0.05).PN is common in MPA patients. Mononeuritis multiplex and distal symmetrical polyneuropathy, mixed neuropathy, and lower limbs involvement are predominant peripheral neurologic manifestations. Thrombocytosis may be one of the risk factors of PN in MPA patients, and PN may have minor effect on the prognosis of MPA.