Eosinophilic Granulomatosis with Polyangiitis in a Twelve-Year-Old BoyReceiving Montelukast: A Case Report

Introduction: Eosinophilic granulomatosis with polyangiitis (EGPA) is a multisystem disorder characterized by asthma, prominent peripheral blood eosinophilia, and small-vessel vasculitis. We report a case of EGPA in an adolescent with uncontrolled asthma who was receiving montelukast. Case: A 12-year-old boy who is known to have asthma and allergic rhinitis which were previously controlled on ICS, intranasal steroids, and prolonged use of montelukast for 4 years. He presented with cough and nasal blockage for 2 months. He also reported an increase in the frequency of asthma attacks and received multiple courses of systemic steroids. Subsequently, his asthma controller medications were upgraded to ICS/LABA few weeks prior to admission. His symptoms were also associated with weight loss, diarrhoea and haematochezia. He was vitally stable and maintained oxygen saturation on room air. Physical examination revealed nasal polyps, purple skin flat lesions on palms and feet (Figure1), and bilateral crackles on chest auscultation. His blood investigations were significant for leukocytosis with marked eosinophilia (11x103/uL, (51%)), high inflammatory markers and total-IgE (1975 kU/L). Initial chest XR showed bilateral interstitial thickening and small pleural effusions (Figure2). Chest CT showed centrilobular nodules and peripheral ground-glass opacities, tree-in-bud appearance with no peripheral sparing in addition to moderate pericardial effusion and bilateral mild pleural effusion (Figure3). Sinus CT showed extensive sino-nasal polyposis with pansinusitis (Figure4). Initial echocardiography showed moderate pericardial effusion with normal biventricular function. Patient was started on IV furosemide. During his hospitalization, patient developed chest pain. His serial troponin was rising and LV contractility was depressed. ECG showed ST-segment depression. Therefore, EGPA with cardiac involvement was suspected. Cardiac MR showed features of a peri-myocarditis. IVIG was commenced for suspicion of coronary artery involvement, which was later disputed by cardiac cath. He was also started on IV pulse steroids at a dose of 30 mg/kg for 3 days which resulted in dramatic decrease in troponin level, eosinophil count and CRP. Skin biopsy, which was later performed after administration of steroids, showed perivascular non-necrotizing granulomas. His ANA, ANCA and COVID-19 PCR came negative. Serum chemistries and urine microscopy were unremarkable. Patient was later started on Rituximab with significant clinical, serological and radiological (Figure5,6) improvement after 10-months of follow-up. Discussion: EGPA is rare but should be considered in children with uncontrolled asthma, eosinophilia and rhino-sinusitis. This case shows the importance of being aware that montelukast could cause EGPA, in spite of the uncertainty about its mechanism. (Figure Presented).