Posterior Interosseous Neuropathy with Peripheral Dystonia: A Case Report.

Background: Posterior interosseous neuropathy is an uncommon cause of peripheral dystonia.

Case report: A 62-year-old man awakened and noticed right finger drop. A neurological examination revealed posterior interosseous neuropathy with dystonia-like finger movements. Abnormal movements were predominantly observed in the right thumb, ring finger, and little finger. Within 2 weeks, the muscle weakness in the right fingers had completely improved. However, a brief abnormal posture of the right thumb was persistent.

Discussion: The residual abnormal posture of the right thumb may reflect pre-existing motor control abnormalities, which may have contributed to the onset of posterior interosseous neuropathy-associated peripheral dystonia.