Case Presentation: A 65-year-old woman presented with acute bilateral hearing loss and pedal weakness and numbness. Vital signs were within normal limits. Physical exam was significant for 0/5 strength of dorsiflexion bilaterally and reduced touch sensation over the dorsal aspect of both feet; hearing was diminished, right greater than left. Initial labs were unremarkable. CT chest showed calcified granulomata of the left hilum, pleura, and spleen. The patient was diagnosed with Guillain-Barre Syndrome (GBS) per neurology, despite the absence of elevated protein on cerebrospinal fluid. Intravenous immunoglobulin and plasma exchange (PLEX) therapy were initiated. Despite completing 7 rounds of PLEX therapy, the patient developed progressive lower extremity weakness and sensory loss, worsening hearing loss, new onset hemoptysis, and acute renal failure complicated by hyperkalemia and volume overload requiring ICU transfer for continuous renal replacement therapy (CRRT). Further work up revealed an ANA of 1:40 and c-ANCA of 166.83. Subsequent kidney biopsy revealed severe necrotizing vasculitis and pauci-immune crescentic glomerulonephritis consistent with GPA. A biopsy of an incidental T4-9 paraspinal mass on MRI revealed granulomatous inflammation, further consistent with GPA. Rheumatology was consulted, and the patient was started on IV steroids, cyclophosphamide, and MESNA with plans to transition to Rituximab for maintenance therapy. At discharge, her hearing improved slightly, and although her sensorimotor deficits were still present they stopped progressing.
Discussion: Granulomatosis with Polyangiitis (GPA) is a small- and medium-vessel vasculitis that classically presents with pulmonary or kidney disease. In rare circumstances, patients may initially present with mononeuritis multiplex, a vasculitic peripheral neuropathy affecting two or more non-contiguous nerves. Nerves in the lower extremity are most often affected first, especially the peroneal nerve resulting in “foot drop,” as evident in our patient. Additionally, vasculitic neuropathy has been associated with worse outcomes, including corticosteroid failure, relapse of disease, and steroid dependence.
Conclusions: This case highlights a unique initial manifestation of GPA. In the absence of typical systemic GPA symptoms, progressive bilateral lower extremity motor and sensory loss initially led to an incorrect diagnosis of GBS. A wide differential diagnosis is important in unclear clinical cases, especially when initial treatment for a suspected diagnosis fails. Rheumatologic diseases can manifest in a variety of symptoms, and thus are important to consider in a differential. If an autoimmune process is suspected, it is important to consider a rheumatology consult early in the disease course.