Rinsho Shinkeigaku (Clinical Neurology)

Case Report

A case presenting with trochlear nerve palsy and segmental sensory disturbance due to circumscribed midbrain and upper pontine hemorrhage

Kenji Ishihara, M.D., Rikiya Furutani, M.D., Jun-ichi Shiota, M.D., Mitsuru Kawamura, M.D.

Department of Neurology, Ushioda General Hospital, *Department of Neurology, Showa University School of Medicine

We describe a patient presenting with trochlear nerve palsy and segmental sensory disturbance due to circumscribed mesencephalic hemorrhage. A 36-year-old man with no past illness visited our hospital complaining of sudden onset of diplopia, dysesthesia of the left face and upper extremity, and acuphenes of the left ear. Neurological examination revealed left trochlear nerve palsy and segmental sensory disturbance of the left side almost above T11 level. Pain and temperature sensation were disturbed, but vibration, joint position, graphesthesia, kinesthesia, and discrimination sensation were spared. Magnetic resonance imaging of the head, performed 7 days after onset, revealed acute to subacute phase hemorrhage at the right inferior colliculus. No abnormalities were identified on cerebral angiography. Symptoms gradually improved with conservative therapy. After about ten weeks, diplopia disappeared and area of sensory disturbance was reduced (disturbance of pain sensation reduced to about T4 level, temperature sensation to about T9).
Segmental sensory disturbance usually accompanies spinal cord lesion. However, several cases of similar symptoms following cerebrovascular disease of the brainstem have been reported. Conversely, some reports have indicated that trochlear nerve palsy due to midbrain hemorrhage accompanies sensory disturbance contralateral to the lesion. The nature of sensory disturbance is thus variable.
The present case suggests that segmental sensory disturbance might accompany trochlear nerve palsy caused by hemorrhage of the inferior colliculus, as intramedullary fibers of the trochlear nerve and spinothalamic tract are located nearby and somatotopy of the spinothalamic tract is preserved even at the level of the midbrain.

(CLINICA NEUROL, 43: 417|421, 2003)
key words: trochlear nerve palsy, segmental sensory disturbance, midbrain hemorrhage, spinothalamic tract

(Received: 3-Feb-03)