Common peroneal and tibial nerve paralysis secondary to herpes zoster infection: a case report.

Background: The usual presentation of herpes zoster (HZ) is a self-limiting vesicular rash, often accompanied by post-herpetic neuralgia. However, HZ can give rise to other complications, that have unusual presentations and serious sequelae like segmental motor paralysis of the limbs that is a relatively rare complication.

Case: A 68-year-old man presented with foot drop on the right side had a history of HZ infection on and around the knee and the popliteal fossa. He was treated with acyclovir by a dermatologist and 10 days after the inital symptoms he developed weakness on the right ankle and on the muscles distal to the knee. In a few days foot drop has developed and he was unable to walk without help. Three months later he was admitted to the neurology out patient clinic. On his electrophysiological examination common peroneal nerve could not be stimulated on the right side. The distal latency of the tibial nerve has prolonged, CMAP amplitude has diminished and the nerve conduction velocity has slowed down. Latency of the sural nerve has prolonged with a small SNAP amplitude and a slow nerve conduction velocity on the right side. Electromyography revealed denervation on the muscles inervated by tibialis anterior and common peroneal nerves distal to the knee.

Conclusion: The double mononeuropathy of the tibial and common peroneal nerves secondary to HZ was not found in the published data. HZ should be considered as a possible cause of the paralysis of peripheral nerves and more attention should be paid to it.