Trigeminal neuralgia triggered by auditory stimuli in multiple sclerosis.

OBJECTIVES To describe a patient with a demyelinating brainstem lesion who developed right-sided trigeminal neuralgia triggered by auditory stimuli and to discuss the pathophysiological mechanisms underlying this unusual phenomenon. DESIGN Case report. SETTING Referral center. PATIENT A 27-year-old man who presented with clinical signs of a brainstem lesion developed right-sided trigeminal neuralgia triggered by auditory stimuli to the right ear. Magnetic resonance imaging and electrophysiological studies demonstrated a demyelinating lesion in the pons affecting the right lateral lemniscus and the right trigeminal pathway. This phenomenon completely subsided within 4 days. After a relapse, the diagnosis of clinically definite multiple sclerosis was made. CONCLUSION Lateral spread of impulse activity within the demyelinating pontine lesion is the likely explanation for the unusual phenomenon of trigeminal neuralgia triggered by auditory stimuli.