A Rare Geriatric Diagnosis of Eosinophilic Granulomatosis With Polyangiitis: A Case Report.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare form of systemic disease characterized by inflammation and necrotizing effects of the small and medium blood vessels. It is a vasculitis found in all age groups and both genders, although its etiology is unknown. The mean age at diagnosis is 40 years, consisting of an uncommon cause of vasculitis in people older than 65 years. It is the least common of the three antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (EGPA, granulomatosis with polyangiitis (GPA), and microscopic polyangiitis). The characteristic features of EGPA include extravascular eosinophilic granulomas, peripheral eosinophilia, and asthma, usually responsive to steroid treatment. In this article, we discuss a case of an 83-year-old male with a history of undetermined etiology of chronic kidney disease, chronic obstructive pulmonary disease (COPD), and severe chronic rhinosinusitis with nasal polyposis. First hospitalized with the suspicion of community-acquired pneumonia (CAP), based on worsening blood eosinophilia and unresolving respiratory symptoms, a suspicion for EGPA was raised. The development of an eosinophilic pleural effusion, later upon admission, was a predominant factor for its confirmation, as it constitutes a rare finding, only present in about 30% of patients. Laboratory tests showed elevated IgE, the presence of antineutrophil cytoplasmic antibodies directed against myeloperoxidase with a perinuclear staining pattern (ANCA-MPO), and the absence of antiproteinase 3 (anti-PR3) ANCA, which were consistent with the diagnosis. A pleural biopsy was then made, revealing fibrosis with the presence of eosinophils, although with no evidence of granulomas. According to the most recent and accepted classification criteria, the "2022 American College of Rheumatology and European Alliance of Associations for Rheumatology (ACR/EULAR) for EGPA," this patient presented with a score of 13 (a score greater than or equal to 6 is needed for the classification of EGPA). Hence, a diagnosis of EGPA was assumed, and the patient was initiated on corticosteroid therapy, with a favorable response. The aim of this article is to present a rare case of EGPA diagnosis made at the age of 83 years old, although there was evidence that could point to this disease years before the diagnosis was made. In the present case, it is important to point out the long diagnostic delay in a geriatric patient, much older than the median age of diagnosis for EGPA, culminating in a curious case of uncommon pleuroparenchymal involvement.