• 9 SECTIONDisorders Gaze Cerebral

Acute Horizontal Gaze Deviation

Key Facts

•Sudden onset of sustained horizontal gaze deviation

•Caused by ipsilateral frontoparietal or contralateral pontine infarct or hemorrhage

•Frontoparietal lesion: patient has contralateral hemiparesis and does not attend to sensory stimuli in contralateral hemispace or on contralateral hemibody (hemispatial neglect syndrome)

•Pontine lesion: patient has ipsilateral hemiparesis and there is no neglect

•Distinguish from partial seizure, in which head and eyes are deviated contralateral to seizure focus, but this is usually an intermittent phenomenon

Clinical Findings

•Frontoparietal lesion:

• eyes deviated to side of lesion • no volitional gaze to side opposite lesion

•doll’s head maneuver (and caloric ear irrigation) elicits horizontal gaze to side opposite lesion • contralateral hemiparesis and hemispatial

neglect • patient initiates almost no activity, including speech, and appears passive (low tonic arousal state)

•Pontine lesion:

•eyes deviated to side opposite lesion • doll’s head maneuver fails to elicit horizontal gaze to side of lesion • may have hypertropia (skew deviation)

•may have internuclear ophthalmoplegia (one and a half syndrome) and exotropia (pontine exotropia)

•Focal seizure:

•eyes deviated to side opposite seizure focus • jerk nystagmus to side of gaze is common • doll’s head maneuver usually fails to elicit eye movement toward side of seizure focus • often accompanied to clonic movements of limbs, face ipsilateral to gaze deviation • consciousness may be impaired

•manifestations usually do not last beyond several minutes

Ancillary Testing

•Parietal or pontine lesion: brain imaging shows lesion

•Focal seizure: electroencephalography confirms diagnosis

Treatment

•Parietal or pontine lesion: supportive care

•Focal seizure: antiepileptics, treat underlying cause

Prognosis

•Parietal lesion:

•within days, volitional horizontal gaze to side opposite lesion begins to return but eyes remain deviated (gaze preference) • within weeks, eyes return to midposition and full volitional gaze is possible

•Pontine lesion:

•gaze deviation usually resolves but gaze abnormalities, skew deviation often persist

•Focal seizure:

•elimination of the epileptic discharge with medication stops manifestations

Fig. 9.4 Right horizontal gaze deviation. Eyes are deviated to the right in all positions of gaze.

A B

Fig. 9.5 Right parietal contusion. Postcontrast (A) coronal and (B) axial T1 MRIs show a low signal area (arrows) in the right parietal region from closed head injury. The patient’s eyes were deviated to the right. With encouragement, the patient could gaze to the left (gaze preference).

Deviation Gaze Horizontal Acute

• 9 SECTIONDisorders Gaze Cerebral

Spasm of the Near Reflex

Key Facts

•Triad of esotropia, miosis, and excessive accommodation (synkinetic near triad)

•Usually episodic but may be sustained

•Usually triggered by anxiety or malingering

•Patients complain of diplopia and blurred vision for distant objects and often headache

•Diagnosis based on finding at least two components of the triad and no other pertinent abnormalities

•Treatment options:

•monocular occlusion

•cycloplegia

•psychotherapy

•Avoid strabismus surgery because of high chance of secondary exotropia

Clinical Findings

•Diplopia and blurred vision for distant objects and often headache

•Comitant, usually fluctuating, esotropia with reduced abduction

• Eyes may be aligned with near fixation

•Fluctuating pupil size and accommodation

•Manifestations usually intermittent

Ancillary Testing

• Not necessary

Differential Diagnosis

•Acute convergence syndrome (see Acute convergence syndrome [acute comitant esotropia])

•Sixth cranial nerve palsy

•Thalamic infarct, hemorrhage, tumor (thalamic esotropia, pseudoabducens palsy)

Treatment

•Monocular occlusion, cycloplegia may break spasm

•Psychosocial counseling may interrupt impulse to converge

•Avoid eye muscle surgery (medial rectus recessions) because of high chance of causing secondary exotropia

Prognosis

• Treatments often ineffective but problem is usually self-limited