Objective Peripheral nervous system involvement in eosinophilic granulomatosis with polyangiitis (EGPA) is well described. However, central nervous system involvement is uncommon. We describe a case of simultaneous central and peripheral nervous system involvement in EGPA. The diagnosis was confirmed on histopathology. A high index of suspicion is needed to initiate prompt treatment for this potentially life-threatening condition.

Report 85-year-old male presented with subacute generalised lower limb weakness on the background of known eosinophilic asthma treated with interleukin-5 inhibitor (mepolizumab) and prednisolone. During his admission, he developed transient aphasia, followed by mononeuritis multiplex involving the left median and femoral nerves and purpuric rash over few days. Laboratory investigations showed no peripheral eosinophilia. ANCA revealed a borderline elevated myeloperoxidase antigen (MPO) of 21 U/mL. MRI brain revealed multiple small foci of diffusion restriction within the basal ganglia bilaterally, as well as paranasal sinusitis. MRA/CT cerebral angiogram was unremarkable. Prolonged telemetry and TOE did not show any central embolic cause. Left lateral gastrocnemius muscle biopsy revealed fibrinoid necrosis associated with adjacent eosinophils. Induction with intravenous cyclophosphamide was commenced along with high dose corticosteroids. He has been neurologically stable since.

Conclusion Simultaneous peripheral nervous system involvement with multiterritory stroke should heighten the suspicion for systemic vasculitis. Cerebral arterial imaging may be normal in small to medium vessel vasculitis such as EGPA. .Pre-existing mepolizumab therapy may make diagnosis more challenging by normalising pathology results. Histopathology can be of value to confirm diagnosis.

References

1. Keogh KA, Specks U. Churg-Strauss syndrome: update on clinical, laboratory and therapeutic aspects. Sarcoidosis Vasc Diffuse Lung Dis 2006 Mar;23(1):3–12.

2. André R, Cottin V, Saraux JL, et al. Central nervous system involvement in eosinophilic granulomatosis with polyangiitis (Churg-Strauss): Report of 26 patients and review of the literature. Autoimmun Rev 2017;16(9):963–969.