Dorsal Midbrain Syndrome

    • Impaired binocular upgaze and other neuro-ophthalmic deficits caused by dysfunction of the dorsal midbrain
    • Also known as Parinaud syndrome, pretectal syndrome, Sylvian aqueduct syndrome, and Koerber-Salus-Elschnig syndrome
    • Common causes: thalamic or midbrain stroke/hemorrhage, pineal region tumor, dorsal midbrain tumor, aqueductal stenosis, failed ventriculo-peritoneal shunt
    • Uncommon causes: demyelination, head trauma
    • Core clinical features
      • Reduced upgaze
      • Trap: reduced upgaze is often overlooked because it is mild or the patient avoids looking up
      • Convergence retraction of the eyes with attempted upgaze, especially in pursuing a downgoing optokinetic strip
      • Anisocoria with large pupils that have reduced constriction to light but intact constriction to a near target (“tectal light-near dissociation”)
      • Bilateral lid retraction (“Collier's sign”)
    • Possible accompanying neuro-ophthalmic features
      • Reduced downgaze
      • Downwardly deviated eyes (“sunset eyes”)
      • Exotropia, esotropia, or hypertropia
      • Torsional misalignment (fourth nerve palsy)
      • Torsional nystagmus
      • Skew deviation
      • Papilledema (if the Sylvian aqueduct is blocked)
    • Imaging features
      • MRI usually shows a lesion in or near the dorsal midbrain
        pineal tumor,
        thalamic infarct or hemorrhage,
        or obstructive hydrocephalus from aqueductal stenosis
    • Myasthenia gravis
    • Graves disease
    • Bilateral orbital trauma
    • Progressive supranuclear palsy
    • Whipple disease
    • Look for a constellation of features typical of dorsal midbrain syndrome, especially reduced upgaze
    • Tip: reduced upgaze is rarely an isolated abnormality in dorsal midbrain syndrome
    • Exclude shunt failure in patients with shunted hydrocephalus
    • Consider pineal and tectal midbrain tumor, aqueductal stenosis, and demyelination in children and young adults
    • Consider thalamic stroke, thalamic hemorrhage, and demyelination in older adults
    • Tip: remember that fourth nerve palsy (often bilateral) and dorsal midbrain syndrome are common in severe blunt head trauma because a moving midbrain smashes into the stationary sharp edge of the tentorium cerebelli
    • Order brain MRI
    • Clinical manifestations often lessen or disappear within weeks in mild stroke, demyelination, treated aqueductal stenosis and shunt malfunction, but…
    • Manifestations are often permanent following compressive pineal region lesions, stroke, and head trauma
    • Diplopia may be relieved with
      • Ground-in or press-on spectacle prisms
      • Eye patch
      • Spectacle occluder
      • Opaque contact lens
      • Extraocular muscle surgery

    Brainstem Ocular Motor Disorders

    Internuclear Ophthalmoplegia Skew Deviation Dorsal Midbrain Syndrome Thalamic or Tegmental Midbrain Syndrome Unilateral Pontine Syndrome Bilateral Pontine Syndrome Dorsolateral Medullary (Wallenberg) Syndrome Ototoxic Vestibulo-ocular Dysfunction Syndrome Acute Upgaze Deviation Acute Downgaze Deviation Acute Comitant Esotropia Omnidirectional Slow Saccades Omnidirectional Saccadic Pursuit