Iatrogenic trigeminal sensorimotor neuropathy resulting from local anesthesia: a case report

Trigeminal neuropathy resulting from local anesthetic injection has not been reported in the literature. We present a 49-year-old man with 8 months of unilateral facial sensorimotor deficits in the distribution of the trigeminal nerve, following a local anesthetic injection. His medical history was significant for resection of an ipsilateral tongue carcinoma 4 years earlier with only postsurgical dysarthria and no other neurologic deficits. Magnetic resonance imaging of the head and face showed postsurgical changes and ipsilateral atrophic muscles of mastication without evidence of infection or tumor recurrence. Electrodiagnostic evaluation revealed prolonged ipsilateral R1, ipsilateral and contralateral R2 responses of the blink reflex, and neurogenic electromyographic changes in ipsilateral masseter and temporalis muscles, consistent with ipsilateral trigeminal nerve injury. Although trigeminal neuropathies from various etiologies have been reported, this unique case offers another etiology to consider: iatrogenic trigeminal neuropathy secondary to local anesthetic injection.