Rinsho Shinkeigaku (Clinical Neurology)

Brief Clinical Note

Bilateral medial medullary infarction presented with monoplegia of the lower limb, followed by paraplegia and finally by tetraplegia

Zen Kobayashi, M.D., Taro Hino, M.D., Toshiro Kanazawa, M.D., Hiroaki Yokote, M.D., Takanori Yokota, M.D., Takashi Kanda, M.D. and Hidehiro Mizusawa, M.D.

Department of Neurology and Neurological Science Tokyo Medical and Dental University Graduate School of Medicine

A 69-year-old Japanese man suddenly developed monoplegia of left lower extremity, followed by paraplegia and finally by tetraplegia. MRI revealed an infarction in bilateral medial medulla extending from the cervicomedullary junction up to the upper limit of the medulla. Both hypoglossal nerve palsy and sensory disturbance were absent. At the pyramidal decussation, fibers to the lower extremities cross caudal to the fibers going to the upper extremities, therefore right below the decussation, fibers to the lower extremities run medial side of the fibers to the upper extremities, but later the former run lateral side of the latter. In this patient, the authors considered that the lesion initially damaged the pyramidal decussation at a slightly lower level, involving the tract to left lower extremity, and then extended to right lower extremitiy, to the left upper extremity, finally to the right upper extremity. Bilateral medial medullary infarction must be considered in the clinical course seen as in this patient.

(CLINICA NEUROL, 43: 195|198, 2003)
key words: bilateral medial medullary infarction, pyramidal decussation, pyramidal tract

(Received: 15-Jan-03)