Review Question - QID 217642

This patient with upgaze palsy, light-near dissociation (decreased reaction to light with intact reaction to accommodation), lid retractions, and convergence-retraction nystagmus (retraction of the globe, involuntary convergence, and nystagmus with attempted upgaze) most likely has Parinaud syndrome (dorsal midbrain syndrome). Common causes of Parinaud syndrome include obstructive hydrocephalus, stroke, and pineal tumors such as pineocytomas.

Parinaud syndrome is a constellation of neuro-ophthalmologic findings present in patients with lesions of the pretectal region of the midbrain. Common etiologies of Parinaud syndrome include pineal region tumors such as pineocytoma and germinoma, brainstem hemorrhage, and ischemic infarction. Lesions to the dorsal midbrain lead to damage of the vertical gaze center (rostral interstitial nucleus of the medial longitudinal fasciculus and the interstitial nucleus of Cajal), midbrain supranuclear fibers, and Edinger-Westphal nuclei. These lesions lead to upgaze palsy, convergence retraction nystagmus, and light-near dissociation, respectively. Downgaze is relatively preserved until late in the disease course due to bilateral innervation, compared to unilateral innervation for upgaze. Diagnostic evaluation should include a complete eye exam and magnetic resonance imaging (MRI) of the brain. Treatment involves addressing the underlying condition; for patients with pineocytomas, this would involve tumor resection. Persistent symptoms after tumor resection are common and can be treated with visual tracking exercises, spectacle and prism correction, or strabismus surgery.

Hoehn et al. reviewed the ophthalmic outcomes of 35 pediatric patients with pineal tumors. The authors found that half of these patients had Parinaud syndrome, of which only 12% experienced complete resolution of symptoms after appropriate treatment of the underlying tumor. They recommended that long-term ophthalmologic care be provided for these children who have residual deficits.

Incorrect Answers:
Answer 1: Craniopharyngiomas are benign tumors that develop near the pituitary gland. Ophthalmic manifestations of craniopharyngiomas include diplopia and bitemporal hemianopsia due to compression of the optic chiasm. Craniopharyngioma is less likely in this patient with vertical gaze palsy and full visual fields.

Answer 2: Lateral pontine stroke can present with contralateral loss of pain and temperature sensation, ipsilateral facial nerve palsy, facial hemianesthesia, ipsilateral limb ataxia, ipsilateral central deafness, nystagmus and vertigo, and ipsilateral Horner’s syndrome (ptosis, miosis, and anhidrosis). Although this patient has nystagmus, it is only in the setting of upgaze, which is more suggestive of convergence-retraction nystagmus. In addition, this patient has lid retractions and not ptosis.

Answer 3: Myasthenia gravis can initially present with isolated ocular symptoms of ptosis and/or diplopia in more than half of cases. Although myasthenia gravis can cause either horizontal or vertical binocular diplopia and mimic vertical gaze paresis, myasthenia gravis always spares the pupils. In this patient with light-near dissociation, Parinaud syndrome is more likely than myasthenia gravis.

Answer 4: Optic neuritis is common in patients with multiple sclerosis. It presents with transient monocular visual disturbance and eye pain exacerbated by eye movement. This very young patient with painless upgaze palsy without loss of distance vision is unlikely to have optic neuritis.

Bullet Summary:
Parinaud syndrome presents with light-near dissociation, convergence retraction nystagmus, and upgaze palsy and can be caused by compression of the pretectal area of the midbrain from a pineal tumor.