Dorsal Midbrain Syndrome (Parinaud's Syndrome) with Bilateral Superior Oblique Palsy:

43-year-old male referred for evaluation of binocular diplopia

Dorsal Midbrain Syndrome (Parinaud's Syndrome) with Bilateral Superior Oblique Palsy:

43-year-old male referred for evaluation of binocular diplopia

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Chief Complaint: 43-year-old male referred for evaluation of binocular diplopia.

History of Present Illness: Patient had a sudden onset of binocular, vertical and torsional, diplopia subsequent to a CVA 2 years prior to presentation. He noticed some improvement over the initial 6 months but the diplopia had been constant since then. He also complained about oscillopsia that was more pronounced in upgaze. The family members noticed an anomalous chin up position subsequent to the CVA.

PMH/FH/POH: Patient was comatose after a sudden onset of intracranial bleed 2 years prior to presentation, and he underwent bilateral ventriculostomy followed by ventriculoperitoneal shunt for acute hydrocephalus. Developed pulmonary embolism 1 month after the bleed. Developed lower limb deep venous thrombosis 6 months prior to presentation. FH significant for blood coagulopathies in multiple family members.

EXAM

SYSTEMIC: Ataxia, sluggish speech, tremors of the right hand and weakness of lower extremities. OCULAR:

• Best corrected visual acuities: 20/25 OD and 20/25 OS.
• Anomalous head posture: 20 degree chin-up and 10 degree left head tilt
• Pupils: 3mm OU, Light near dissociation present, No RAPD
• EOM: ‘V’ pattern esotropia with underelevation on both adduction and abduction in both eyes. Alternating hypertropia in side gazes (see photos). Vertical saccades were hypometric (upward > downward). Convergence retraction nystagmus noticed in upgaze.
• Double-Maddox Rod: 30 degree excyclotorsion OS (primary gaze). 42 degree excyclotorsion OS (downgaze)
• IOP: 16 mm of Hg OD & OS.
• SLE: normal anterior segment.
• Fundus: Excyclotorsion OU. Rest normal.

Figure 1: EOM. Nine cardinal positions of gaze showing diffuse underelevation in both eyes. A ‘V’ pattern esotropia is seen. Alternating hypertropia is seen in the horizontal side gazes. There is also underdepression on adduction in both eyes.

Figure 2: MRI scans of head.

Saggital T1 MRI scan of the head without contrast. Evidence of prior brainstem hemorrhage (arrowheads) extending vertically from posterior pontomesencephalic junction into the cerebral peduncle with hemosiderin staining of superior cerebellar peduncle.	Axial T1 MRI scan of head with contrast. Following administration of contrast, there was enhancement along the margins of the hemorrhagic cleft which could be an underlying occult vascular malformation/sequelae from prior hemorrhage.

Discussion

Parinaud’s Syndrome (Dorsal Midbrain Syndrome) with bilateral Superior Oblique Palsy

The cause of diplopia, oscillopsia, and anomalous head posture in this patient was a combination of dorsal midbrain syndrome and bilateral superior oblique palsy. This patient developed an idiopathic brainstem hemorrhage that extended from the ponto-mesencephalic junction upto the cerebral peduncles involving the rostral midbrain. Subsequent angiography was inconclusive for arteriovenous malformation. The signs of dorsal midbrain syndrome seen in this patient were light near dissociation, convergence retraction nystagmus, and vertical gaze palsy. The signs of bilateral superior oblique palsy seen in this patient were chin-up position, ‘V’ pattern esotropia, alternating hypertropia, bilateral superior oblique underaction and significant excyclotorsion.

The supranulcear vertical gaze limitation in this syndrome results from involvement of the posterior commissure, interstitial nucleus of Cajal, or rostral interstitial nucleus of the medial longitudinal fasciculus.

Considering the amount of torsion, head posture, and significant ‘V’ pattern, we performed a bilateral superior oblique tucking (15 mm OD and 11 mm OS) along with a bilateral recession of medial recti by about 4.5 mm with half-tendon-width infraplacement of the medial rectus tendons. Postoperatively the torsion was significantly corrected, and the patient had a moderate residual esotropia in primary gaze.

Diagnosis: Parinaud's Syndrome (Dorsal Midbrain Syndrome)

EPIDEMIOLOGY Sporadic Causes: obstructive hydrocephalus, mesencephalic hemorrhage, multiple sclerosis, A/V malformation, trauma, compression from tumor (pineal tumors)	SIGNS MAJOR COMPONENTS Vertical gaze disturbance Convergence retraction nystagmus Light near dissociation of the pupils Lid retraction (Collier’s sign) MINOR COMPONENTS Spasm/paresis of convergence Spasm/paresis of accomodation Pseudoabducens palsy (thalamic esotropia) Associated Ocular Motility Deficits Skew deviation Third nerve palsy Internuclear ophthalmoplegia See-saw nystagmus
SYMPTOMS Difficulty looking up Diplopia Blurred vision at near Oscillopsia Accompanying neurological symptoms	TREATMENT Treatment is primarily directed towards the etiology of dorsal midbrain syndrome. A thorough work up including neuroimaging is essential to rule out the various causes of dorsal midbrain syndrome.

Differential Diagnoses for Dorsal Midbrain Syndrome

Light-near dissociation

• Argyll Robertson pupils
• Aberrant regeneration of the third nerve
• Diabetes
• Tonic pupil
• Deafferention

Vertical Gaze Palsy

• Limited upgaze in elderly patients
• Progressive supranuclear palsy
• Niemann-pick disease
• Whipple’s disease