Bilateral Trochlear Nerve Palsy as a Consequence of Cerebellar Medulloblastoma: Clinical and Pathological Findings in a Calf.

Abstract

1-month old female Holstein calf had not been able to stand since birth. Delivery was uncomplicated and no treatment had been administered before admission. On physical examination, the calf had slightly decreased body condition, but was bright and alert. The calf was in lateral recumbency with spastic extension of all four limbs and opisthotonus. If positioned in left lateral recumbency, the calf raised its head, which fell immediately to the ground after rotation of the neck. The calf made no attempt to raise its head when lying in right lateral recumbency. Attempts to passively position the calf in a quadrupedal stance or in sternal recumbency were unsuccessful. Despite the lateral recumbency, the calf was able to suckle. A thorough neurologic examination was carried out. Mental status and consciousness were considered normal. Because of recumbency, postural reactions could not be tested. The menace response was absent in the right eye and present in the left eye. In both eyes, the medial end of the pupil was rotated dorsally. This dorsomedial rotation of the eyes was not affected by changes in the position of the head. Moreover, incomitant strabismus (i.e., degree of misalignment of the eyes varying with the position of