Clinical Characteristics and Outcomes of Mexican Patients With Polyarteritis Nodosa: A Single-Center Study Over 40 Years

The aim was to describe the clinical characteristics and outcomes of Mexican patients with polyarteritis nodosa (PAN) from a single center. METHODS We conducted a medical records review study (1975-2018) that included patients with childhood- and adult-onset PAN. Demographics, organ involvement, phenotype, treatment, and outcomes were assessed and compared against previously published cohorts. RESULTS Thirty-one patients were included, 20 (64.5%) female, with a median age at diagnosis of 28 years (interquartile range [IQR], 16-42). Seven (23%) were classified as cutaneous; 23 (74%), systemic; and 1 (3%), progressive systemic phenotype. Eleven patients (35%) had childhood-onset PAN. Most common manifestations were musculoskeletal (71%), cutaneous (68%), constitutional (61%), peripheral neuropathy (39%), and gastrointestinal (29%). The median Birmingham Vasculitis Activity Score and Five-Factor Score at diagnosis were 9 (IQR, 4-13) and 1 (IQR, 0-1), respectively. Most patients were treated with glucocorticoids (94%). Twenty-four (80%) achieved complete and 6 (20%) partial remission at a median follow-up time of 30 months (8-192 months). The median Vasculitis Damage Index at last follow-up was 1 (IQR, 0-1). Nineteen (66%) experienced relapses. Patients with childhood-onset PAN more frequently had central nervous system and gastrointestinal involvement (36% vs 5%, p = 0.04 and 64% vs 10%, p = 0.003, respectively), microaneurysms (100% vs 38%, p = 0.02), and lower levels of C-reactive protein (0.3 vs 15.4 mg/dL, p = 0.03), compared with adult-onset PAN patients. CONCLUSIONS Our cohort of PAN patients showed predominantly a systemic phenotype. Outcomes were generally good, with most patients achieving complete remission. Childhood-onset differed from adult-onset PAN in terms of clinical and serological characteristics, whereas clinical manifestations and outcomes may be different than the ones reported in other cohorts.