Paraneoplastic autonomic neuropathy is a rare condition where there is sympathetic and/or parasympathetic nervous system dysfunction related to an underlying cancer. Symptoms may begin before or after the diagnosis of cancer and progress over weeks to months. It can occur in many cancers, but small cell lung carcinoma is the most common. Other commonly associated cancers include carcinoma of the thyroid, pancreas, and colon, carcinoid tumors, and Hodgkin lymphoma. It often occurs in conjunction with other paraneoplastic syndromes such as encephalomyelitis.

Signs and symptoms include orthostatic hypotension, constipation, urinary incontinence, erectile dysfunction, dry eyes, and/or dry mouth. There may also be an associated sensory or motor neuropathy. Treatment is focused on treating the underlying malignancy. Prognosis is usually poor, and symptoms often do not improve.