Acute upward gaze palsy: Not always Parinaud syndrome.

INTRODUCTION: Parinaud syndrome, caused by midbrain infarction, usually manifests as an ocular conjugate upgaze palsy. However, this sign should not point out straightforwardly to Parinaud syndrome, as other lesions in the central nervous system could cause it.

CASE DESCRIPTION: The case of a 47-year-old woman showing acute onset of diplopia with bilateral upward gaze palsy is described. Parinaud syndrome was suspected on clinical grounds. However, brain magnetic resonance imaging displayed an acute ischemic lesion in the right anteromedial thalamus.

CONCLUSIONS: Bilateral upward gaze palsy may be caused by unilateral thalamic infarction. The mechanism by which a unilateral thalamic lesion causes bilateral gaze palsy is discussed.