A 74 year old male with history of metastatic prostate adenocarcinoma presented with sudden onset vertigo and gait ataxia resulting in hospitalization. Evaluation included CT chest, abdomen and pelvis which revealed bony metastasis, enlarged para-aortic lymph nodes and right lower lobe pleural based nodule. MRI brain with and without contrast showed 3mm subtle enhancing lesion in the right periventricular white matter. Initial CSF studies showed elevated protein (125 mg/dL) and paraneoplastic CSF antibodies were positive for CRMP-5-IgG with a titer of 1:15360 and elevated P/Q type calcium channel antibodies (1.19 nmol/L). He underwent a 5 day course of IVIG. Repeat CSF studies after IVIG showed improved protein (95 mg/dL). He had clinical improvement in his vertigo and ataxia initially, however he declined over the following month with increased dizziness, persistent down beating nystagmus and dysmetria, and newly developed severe orthostatic hypotension.