Lateral tegmental brainstem hemorrhages.

Hypertension intracerebral hemorrhages are caused by leakage from small penetrating branches of larger cerebral vessels. In the brainstem, these vessels penetrate in a median, paramedian, and more lateral orientation. As illustrated by three patients reported here, hemorrhage from the lateral vessels may be limited to the lateral tegmentum, or spread to the dorsal basis pontis. The syndrome is relatively consistent and includes (1) ipsilateral conjugate gaze palsy, (2) ipsilateral internuclear ophthalmoplegia, (3) small reactive pupils with a smaller pupil ipsilateral to the lesion, (4) limb ataxia of the cerebellar type (often greater ipsilaterally), (5) contralateral hemiplegia, and (6) contralateral severe hemisensory loss. Patients frequently survive after lateral tegmental hemorrhages, which can be diagnosed by CT.