What is conjugate gaze palsy?

Conjugate Gaze Palsy: Definition and Clinical Significance

Conjugate gaze palsy is a neurological condition characterized by the inability to move both eyes together in the same direction, resulting from damage to the supranuclear pathways that coordinate horizontal or vertical eye movements. This condition indicates significant neurological dysfunction and often requires urgent evaluation.

Anatomical Basis and Types

Conjugate gaze palsy occurs when there is damage to the neural pathways responsible for coordinating eye movements, specifically:

• Horizontal gaze palsy: Results from damage to:

  • Frontal eye fields (cortical lesions)
  • Paramedian pontine reticular formation (PPRF) in the brainstem
  • Connections between these structures

• Vertical gaze palsy: Results from damage to:

  • Rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF)
  • Posterior commissure
  • Pretectal area in the midbrain

Clinical Presentation

Patients with conjugate gaze palsy typically present with:

• Inability to move both eyes in the same direction (horizontally or vertically)
• Eyes may be deviated toward the side of the lesion in cortical lesions (looking toward the lesion)
• Eyes may be deviated away from the side of the lesion in pontine lesions (looking away from the lesion)
• Diplopia (double vision)
• Abnormal head positioning to compensate for gaze limitations
• Associated neurological deficits depending on the location of the lesion

Diagnostic Evaluation

When evaluating a patient with suspected conjugate gaze palsy:

1. Clinical examination:

   • Test versions and ductions
   • Document limitations in eye movements
   • Assess for overactions or incomitance
   • Test oculocephalic reflexes (doll's eye maneuver) 1

2. Neuroimaging:

   • MRI brain with and without contrast is the preferred imaging modality
   • CT head may be used in acute settings
   • MRA/CTA for suspected vascular causes 2

Common Causes

Conjugate gaze palsy can result from various pathologies:

• Stroke: Most common cause, particularly in the territory of the middle cerebral artery or brainstem 3, 4
• Multiple sclerosis: Especially with internuclear ophthalmoplegia 1
• Brain tumors: Affecting the brainstem or cortical eye fields
• Traumatic brain injury
• Demyelinating diseases
• Neurodegenerative disorders (e.g., progressive supranuclear palsy)

Clinical Significance and Prognosis

Conjugate gaze palsy has significant clinical implications:

• Associated with higher stroke severity and larger infarct volumes 4
• More frequent in right hemispheric strokes (44.6% vs 23% in left hemispheric strokes) 4
• Indicates higher mortality and severe neurological impairment 3
• May be more severe and long-lasting in patients with right-sided brain damage 3

Differential Diagnosis

Important conditions to distinguish from conjugate gaze palsy:

• Internuclear ophthalmoplegia: Impaired adduction of the ipsilateral eye with abducting nystagmus of the contralateral eye
• Skew deviation: Vertical misalignment of the eyes due to vestibular pathway dysfunction 2
• Individual cranial nerve palsies: Affecting CN III, IV, or VI
• Myasthenia gravis: Fluctuating weakness with fatigue
• Orbital disease: Mechanical restriction of eye movements

Management Approach

Management should focus on:

1. Urgent evaluation for underlying causes, particularly stroke

2. Neuroimaging to identify the lesion location and extent

3. Treatment of the underlying cause:

   • Thrombolysis for acute ischemic stroke if eligible
   • Steroids for demyelinating disease
   • Surgical intervention for tumors if appropriate

4. Symptomatic management:

   • Prism glasses for persistent diplopia
   • Eye patching for intractable diplopia
   • Vision therapy and rehabilitation

Key Points to Remember

• Conjugate gaze palsy is a neurological emergency that often indicates significant brain pathology
• The pattern of eye movement limitation helps localize the lesion
• Right hemispheric lesions are more likely to cause conjugate gaze palsy than left hemispheric lesions
• Urgent neuroimaging is essential for diagnosis and management
• Prognosis depends on the underlying cause and extent of neurological damage

In rare cases, complete bilateral horizontal gaze paralysis ("one and one syndrome") can occur, typically as a manifestation of multiple sclerosis 5.