Case Presentation: An 88 year old female with no past medical history presented to the ED with low back pain, chronic cough and one episode of pinkish sputum.  Chest CT showed bilateral nodular lesions. Serological tests including ANCA were sent before her discharged home. Next day, she returned with acute right lower extremity weakness and difficult ambulation. Stroke workup was negative for any intracranial pathology. She was started on Aspirin and Statin.  MRI of the thoracic/lumbar spines was unremarkable.  She had worsening 3/5 ascending weakness of all extremities, acute encephalopathy, mild sensory loss, and areflexia.  Diagnosis of GBS was entertained, supported by cytoalbuminologic dissociation on lumbar puncture. She was started on IVIG and transferred to ICU. She developed acute respiratory failure with hypercapnic respiratory acidosis, and was intubated. Two days later, her clinical condition improved and was extubated. Serological tests came positive for p-ANCA, strongly positive proteinase 3, and positive myeloperoxidase.  Diagnosis of GPA was made. She was started on Methyl prednisolone 1mg/kg/day. GBS was the most likely diagnosis regardless of systemic vasculitis status. EMG/NCS was done and showed moderate subacute polyneuropathy with both axonal and demyelinating features. Patient was transferred to rehabilitation, with complete recovery. She was switched to azathioprine 100 mg daily and tapered oral prednisone.

Discussion: Granulomatosis with polyangiitis (GPA), known as Wegener, is a systemic necrotizing vasculitis, which affects small and medium sized blood vessels, with involvement of the upper and lower respiratory tract, kidneys, ear, nose and throat manifestations with recurrent sinusitis. The prevalence of neurological involvement is 22- 34%. Although Guillain Barre (GBS) with GPA is rarely reported, it was reported with Eosinophilic granulomatosis (EG) and Polyangiitis known as Churg-Strauss syndrome. Two phenotypes of GPA are recognized: a potential life threatening systemic form, and a more limited form. The presence of c-ANCA with PR3 ANCA specificity is observed in more than 90% of patients with GPA. Lung nodules are frequently seen, and are associated with rapidly progressive necrotizing glomerulonephritis and extra capillary crescents. The use of immunosuppressants and corticosteroids has converted this fatal illness into a disease with 80% remission rate, with 50% relapse at 5 years, but Maintenance therapy is required.

Conclusions: This is a rare presentation of GPA with nervous system involvement causing GBS with acute respiratory failure, requiring treatment with IVIG, immunosuppressant drugs and steroids. In our case immunological testing showed atypical rare findings with double positivity of both types of ANCA, with positive (peri)nuclear pattern of staining (P-ANCA) on indirect immunofluorescence, and highly positive antibodies to proteinase 3 and myeloperoxidase on ELISA. Nevertheless, the findings of PR3 ANCA or MPO strongly supported the diagnosis of vasculitis consistent with GPA.