What causes recurrent forceful eye closure with a metallic taste?

Localization of Recurrent Forceful Eye Closure Preceded by a Sense of Metallic Taste

Recurrent forceful eye closure preceded by a metallic taste is most likely a manifestation of a focal seizure, specifically a simple partial seizure with sensory (gustatory) and motor components, and warrants neurological evaluation and neuroimaging.

Clinical Presentation and Localization

The combination of a metallic taste followed by forceful eye closure suggests a specific pattern of neurological activity:

1. Metallic taste sensation:

   • Represents a gustatory aura, typically originating from the insula or operculo-insular cortex
   • Can be the first manifestation of a simple partial seizure
   • Metallic taste is a well-documented sensory phenomenon that can precede other seizure manifestations 1

2. Forceful eye closure:

   • Represents a motor component following the sensory aura
   • Eye closure-triggered paroxysmal activity has been documented in epilepsy cases 1
   • May involve frontal lobe regions, particularly Brodmann areas 8 and 9, which show changes in neural activity during eye closure 2

Differential Diagnosis

1. Focal seizure disorder (most likely):

   • Simple partial seizures with sensory (gustatory) and motor components
   • May progress to complex partial seizures if consciousness becomes impaired

2. Blepharospasm with sensory trigger:

   • A form of focal dystonia affecting the eyelid muscles
   • Can sometimes be preceded by sensory symptoms
   • However, metallic taste is not a typical trigger 3

3. Medication-induced phenomenon:

   • Certain medications can cause dysgeusia (taste disturbances)
   • Botulinum toxin has been reported to cause metallic taste in some cases 4
   • However, the combination with eye closure is not typical

4. Angle-closure glaucoma (less likely):

   • Can present with eye pain and visual disturbances
   • May cause forceful eye closure due to pain
   • However, metallic taste is not a typical symptom of angle-closure glaucoma 3, 5

Diagnostic Approach

1. Neurological evaluation:

   • Detailed history focusing on:
     • Duration and frequency of episodes
     • Associated symptoms (headache, altered consciousness, other motor symptoms)
     • Precipitating factors
     • Family history of seizure disorders

2. Neuroimaging:

   • MRI brain with contrast to evaluate for structural abnormalities
   • Focus on temporal lobe, insular cortex, and frontal regions

3. Electroencephalography (EEG):

   • Standard EEG with eye closure protocol
   • Consider prolonged video-EEG monitoring if standard EEG is negative but clinical suspicion remains high
   • Eye closure can trigger specific EEG patterns in susceptible individuals 1, 2

4. Ophthalmological examination:

   • To rule out angle-closure glaucoma or other ocular pathology
   • Dark-room gonioscopy to assess anterior chamber angle 3

Management Recommendations

1. For suspected seizure disorder:

   • Referral to neurology for comprehensive evaluation
   • Consider antiepileptic medication if diagnosis is confirmed
   • Monitor for cognitive changes, as eye-closure-triggered epileptic activity has been associated with cognitive impairment over time 1

2. If angle-closure glaucoma is suspected:

   • Urgent ophthalmology referral
   • Intraocular pressure measurement
   • Consider laser peripheral iridotomy if appropriate 3, 5

Key Considerations

• The combination of metallic taste and forceful eye closure is unusual and warrants thorough neurological evaluation
• Metallic taste perception involves complex neural pathways and can be a manifestation of focal seizure activity 6, 7
• Eye closure can trigger specific patterns of neural activity across multiple brain regions, not limited to visual cortex 2
• Long-term monitoring may be necessary as recurrent epileptic activity triggered by eye closure has been associated with cognitive deterioration over time 1

Red Flags Requiring Urgent Evaluation

• Progressive increase in frequency or severity of episodes
• Development of altered consciousness during episodes
• Associated headache, nausea, or vomiting
• Visual disturbances beyond the episodes of eye closure