Simultaneous bilateral ulnar neuropathy: an unusual complication caused by neuroleptic treatment-induced tardive dyskinesia: A Case Report.

Rationale: In the past decade, only a few studies have focused on simultaneous bilateral ulnar neuropathy.

Patient Concerns: A 54-year-old Asian male who has suffered from paranoid schizophrenia for 2 years. He reported that flexion contracture occurring over his fourth and fifth fingers on both hands appeared since six months after he started taking the antipsychotic drug. The electromyogram revealed bilateral ulnar neuropathy with chronic axonal degeneration at the elbow level. McGowan classification was performed to evaluate the severity of the ulnar nerve injury, and the patient was diagnosed with a grade 3 injury on his left hand and a grade 2 injury on his right hand.

Diagnosis: Simultaneous bilateral ulnar neuropathy at the elbow, a complication caused by tardive dyskinesia in a patient under the high-dose, first-generation, antipsychotic drug.

Interventions: We consulted a psychiatrist to assist in adjusting the patient's kind of the antipsychotic drug and performed the anterior transposition of ulnar nerve to avoid nerve entrapment caused by tardive dyskinesia.

Outcomes: Numbness of the palms continued to regress over the following 6 months after the anterior transposition of the ulnar nerve. Regression of the involuntary movements, including repeated bending of the elbows, and shaking of both feet, was noted from the patient but was incomplete.

Lessons: Two literatures concluded that parkinsonian rigidity is the main cause of simultaneous bilateral ulnar neuropathy by Sampath et al and Kurlan et al. Unlike the cases of stereotyped posture-caused neural compression reported previously, we inferred that repeated involuntary motion caused by first-generation antipsychotic drug might have been one of the causes of the patient's nerve compression.