DUPILUMAB INDUCED HYPEREOSINOPHILIC SYNDROME (HES)

Abstract

<h3>Introduction</h3> Hypereosinophilic syndrome (HES) is a rare disorder characterized by marked eosinophilia combined with organ system dysfunction. Hypereosinophilia has a wide differential diagnosis including allergy, medications, parasites, cancer, eosinophilic granulomatosis with polyangiitis (EGPA), and infection. Pulmonary, cutaneous, gastrointestinal, cardiac and neurologic systems are the most common sources of symptoms for those presenting with HES. We describe a case of HES manifesting with altered mental status two months after starting therapy with dupilumab. <h3>Case Description</h3> 77-year-old female admitted with altered mental status with past medical history notable for specific antibody deficiency (on Immunoglobulin replacement), asthma, and nasal polyps. She started dupilumab 3 months previously but complained of progressive confusion to the point of altered mental status requiring hospitalization. CBC on admission showed absolute eosinophil count of 30, 830 cells / uL. Inflammatory markers were elevated, Troponin was high. Cardiac MRI suggested eosinophilic myocarditis and MRI of brain showing numerous microinfarcts. No oncologic or infectious etiology was found. She was diagnosed with HES (vs EGPA given lack of vasculitis on biopsies) and managed with high dose steroids and mepolizumab resulting in significant clinical improvement. She remains flare free 12 months after starting mepolizumab. <h3>Discussion</h3> We present an interesting case of hypereosinophilic syndrome (and not EGPA) unmasked by treatment with dupilumab in a patient with nasal polyps. We believe this is the first case of such a scenario in the literature.