Rinsho Shinkeigaku (Clinical Neurology)

Case Report

Hypoalgesia and hypothermesthesia in a lower extremity due to compression of the medulla oblongata by an elongated vertebral artery

Yasushi Iwasaki, M.D.1)2), Tomohiko Nakamura, M.D.1)2) and Kensuke Hamada, M.D.1)2)

1)Department of Neurology, Meijo Hospital
2)Department of Neurology, Nagoya University Graduate School of Medicine

We describe the case of a 54-year-old man who presented with hypoalgesia and hypothermesthesia (pain and thermal numbness) in the left lower extremity. The patient first noticed a warm sensation in his left leg. By the time he first visited our neurological unit, the symptoms had been present for several weeks. His blood pressure was normal. Cranial nerve function and other neurological findings were normal except for hypoalgesia and hypothermesthesia in the left leg. Position and vibration senses were intact. Autonomic dysfunction was not found. Nerve conduction velocity and somatosensory evoked potentials were normal. Cranial MRI, MRA and 3D-CT showed an elongated and curved right vertebral artery that was normal in diameter but compressed to the lateral medullary zone. The artery was thought to compress the lateral spinothalamic tract. Cervical, thoracic and lumbo-sacral MRI findings were all normal. We believe that the patient's symptoms were provoked by the abnormal compression of the vertebral artery. The symptoms improved gradually within 2 month without operation therapy, but some hypoalgesia and hypothermesthesia are still present in the left leg.
Although several reports have described compression of the medulla oblongata by a vertebral artery, to the best of our knowledge, there have been no reports of hypoalgesia and hypothermesthesia due to vascular compression of the medulla oblongata.

(CLINICA NEUROL, 44: 176－181, 2004)
key words: vertebral artery, medulla oblongata, lateral spinothalamic tract, hypoalgesia and hypothermesthesia (pain and thermal numbness), MRI

(Received: 14-Jul-03)