M ethotrexate is widely used in the treatment of inflammatory arthritis and vasculitis. Paradoxically vasculitis is rarely an adverse reaction to methotrexate, with scant literature in the context of juvenile rheumatic disorders. We report a case of methotrexate-induced medium vessel vasculitis in a child with systemic juvenile idiopathic arthritis (sJIA).
CASE PRESENTATIONA previously healthy 10-year old boy was admitted to hospital with a 5-day history of fever, nausea, vomiting, abdominal pain, myalgia and headache. There was no diarrhoea, photophobia or rash. On examination he was alert, orientated and not distressed. His temperature was 39.4°C, pulse 131 bpm, blood pressure 105/66, weight 33 kg. He had hepatosplenomegaly, but no lymphadenopathy or neck stiffness. Examination of his skin, chest, and nervous system was otherwise normal.Initial treatment was with intravenous Cephtriaxone for 5 days. His fevers were noted to be quotidien, varying from 36.0°C to 39.4°C and a salmon-pink macular rash developed on his chest and upper thighs during the peak of the fevers. He developed knee pain and tender metatarsals, and after 10 days both ankle joints were swollen.His admission CRP was 416 mg/L, this fell to 254 mg/L the following day and then to 117 mg/L over the next 10 days. His platelets were initially low 49 and rose gradually to 404 over the same period. His haemoglobin varied between 10.9 and 8.6 (MCV 73) and white count between 5.5 (4.3 Neutrophils) and 8.0 (unremarkable film) during the same period. Other results: Ferritin 18 (12-300 ng/mL), LDH 526 (240-480 U/L), GGT 76 (5-50 U/L), Albumin 21 (7-35 IU/L), renal function, infection and malignancy including lumbar puncture, blood cultures, urinalysis and culture, CT chest abdomen and pelvis were normal. Echocardiogram and Aortic Arch Scan were normal.Further history was given of an episode of joint pain and swelling, aged 5 associated with diarrhoea and vomiting which resolved spontaneously after 7 days.
