Glazed (Vision) and Confused

A 60-year-old man presented with vitritis and optic neuropathy in the setting of headaches and behavioral changes. MRI brain revealed bilateral temporal lobe inflammation consistent with limbic encephalitis. He was subsequently diagnosed with small cell lung cancer with a paraneoplastic syndrome characterized by CRMP5 IgG as a cause of his symptoms. His visual symptoms improved markedly after anti-inflammatory therapy and his cognitive symptoms were mildly better following systemic chemotherapy. The clinical presentation, pathophysiology, and therapy of CRMP5 associated paraneoplastic syndromes are discussed.