Difficulty to Diagnosing Polyarteritis Nodosa in Children

Abstract

BACKGROUND Polyarteritis Nodosa is a necrotizing vasculitis that affects especially medium vessels. It can be a challenge in children due to atypical symptoms and long time up to diagnosis and treatment. CASE REPORT JSS, 11 years old girl, previously healthy, without familial history of autoimmune diseases, started one year ago daily fever around 39° for 6 months with no focus and spontaneous resolution. After 2 months of symptoms onset, she presented edema on the lower limbs with painful nodules and difficulty to step on the floor. She complained about weight loss (10 kilos in one year), anemia and high acute phase reactants. Initial infectious and oncologic work up was carried out and was negative. She presented all autoantibodies, including ANCA, negative, negative Mantoux test, normal dosage of muscle enzymes, and renal and hepatic function and normal echocardiogram. She presented anemia, discrete thrombocytosis and persistently elevated acute phase reactants. Ophthalmologic evaluation showed no alterations. MRI of the lower limbs was performed, with inflammatory perivascular signals on the fibular, soleal and tibial muscles with intraosseous nodulations. Biopsy on lower limb was requested and the results showed polyarteritis nodosa, with immunofluorescence negative. Immunosuppressive therapy with corticosteroids and azathioprine was started. CONCLUSION As presented in this case, PAN in children can take long time to diagnosis due to their varied clinical manifestation. The diagnosis is performed by clinical and histopathological findings