Eosinophilic Granulomatosis With Polyangiitis Presenting With Rare Neurological Manifestations

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare disease characterized by inflammation of small and medium-sized blood vessels, leading to damage in various organs. It is classically associated with asthma, eosinophilia, and multisystem involvement, including frequent peripheral nervous system manifestations. We report the case of a 72-year-old woman with a history of asthma, rhinitis, and strokes, who presented with progressive muscle weakness, myalgia, and distal sensory deficits. Neurological examination revealed proximal muscle weakness and a length-dependent sensory loss. Laboratory investigations demonstrated marked eosinophilia, elevated creatine kinase, and positive antimyeloperoxidase antibodies with an atypical cytoplasmic ANCA pattern. Imaging showed diffuse muscular hypermetabolism on positron emission tomography, while electromyography and nerve conduction studies revealed a length-dependent axonal polyneuropathy with mild myopathic features. Muscle biopsy demonstrated mild nonspecific myopathic changes without definite evidence of vasculitis or eosinophilic infiltrates. Based on the 2022 American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria, a diagnosis of EGPA with neurological involvement was established. The patient was treated with high-dose corticosteroids and rituximab, resulting in significant clinical and biochemical improvement at 3 months. This case illustrates the coexistence of atypical neurological manifestations of EGPA, including prominent myopathy, length-dependent polyneuropathy, and retrospectively suspected central nervous system vasculitic involvement, emphasizing the importance of early recognition and multidisciplinary management.