Reversible facial pain due to hydrocephalus with trigeminal somatosensory evoked response changes. Case report.

A patient with hydrocephalus due to aqueductal stenosis suffered facial pain which was relieved after the insertion of a ventriculoperitoneal shunt. The trigeminal somatosensory evoked response (TSER) of the affected side showed lower amplitudes and longer latencies as compared to the unaffected side. Following surgery, the waves regained higher amplitudes and shorter latencies. An episode of shunt malfunction was accompanied by recurrent facial pain and impairment of the TSER. Both improved after revision of the shunt. The possible etiology of facial pain in patients with hydrocephalus is discussed.