Dorsal Midbrain Syndrome

Lesions of the dorsal midbrain produce a characteristic and highly localizing constellation of neuro-ophthalmic signs, which is known as the dorsal midbrain syndrome. In this chapter, we begin by summarizing the clinical features of the dorsal midbrain syndrome, which include supranuclear vertical gaze palsy, skew deviation, convergence insufficiency, convergence-retraction nystagmus, upper-eyelid retraction, and light-near dissociation of the pupils. We then list common causes of the dorsal midbrain syndrome, which include hydrocephalus, shunt malfunction, stroke, intrinsic brainstem tumors, and compression by extrinsic tumors, such as pineal and third ventricular tumors. Lastly, we discuss the neuro-ophthalmic features, diagnostic evaluation, and management of ventriculoperitoneal shunt malfunction.