Unique case of mononeuritis multiplex in a patient of Eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (formerly known as Churg Strauss syndrome) is a rare multisystem autoimmune disease. It is known to affect 1-3 adults/million population worldwide.

A 50-year-old woman presented to the emergency room with chief complaints of Cough with expectoration since last 7 days and right Lower limb pain and weakness since last 2 days followed by left upper limb pain and weakness since last 1 day. The diagnosis in this case was done based on a sural nerve biopsy done. Patient presented to us in her vasculitis phase with no evidence of eosinophilia however, previous lab reports show eosinophilia. She also has migratory pulmonary infiltration which we can notice when we compare an older CT scan to her most recent CT scan. Pulmonary infiltrates are seen frequently in EGPA. EGPA is an uncommon cause of migratory infiltrates. The patient also has mononeuritis multiplex with acute flares of disease in 2016, 2022 and 2024. Which is a common manifestation of EGPA often seen in 55-75% of patients.

This case could be an example of monteleukast induced EGPA, although it is difficult to establish an exact etiology. There have been numerous other cases of monteleukast induced EGPA, although the pathogenesis is unclear. EGPA continues to be an underdiagnosed condition with multiple cases being missed very year.