Sensory-Motor Polyneuropathy and Digital Ischemia: A Rare Presentation of Granulomatosis with Polyangiitis

Granulomatosis with polyangiitis (GPA) typically presents with upper or lower respiratory tract symptoms and/or with renal involvement. Although it can affect the peripheral nervous system frequently, with mononeuritis multiplex being the most common pattern, the occurrence of peripheral sensory-motor polyneuropathy as a presenting manifestation is distinctly rare. Prevalence of digital gangrene is also extremely rare in GPA. We describe a 46-year-old woman presenting with severe peripheral sensorimotor polyneuropathy affecting bilateral lower limbs preceded by a purpuric skin rash and multiple painful ulcers confined to the lower limbs. She had evidence of digital ischemia affecting multiple toes and dry gangrene of the left 4^th toe. Diagnosis of GPA was made based on skin biopsy, positive ANCA serology, and clinical criteria. She made a good recovery following aggressive immunosuppressive treatment with methylprednisolone and cyclophosphamide and was maintained on prednisolone and azathioprine. This case highlights the importance of suspecting GPA in a patient presenting with sensorimotor polyneuropathy and/or digital ischemia even in the absence of more classic presenting features and underlies the necessity of accurate differential diagnosis in evaluating a case of peripheral neuropathy.