[Long-lasting and isolated Uhthoff's phenomenon after effort preceding multiple sclerosis]

Area of Science:

• Neurology
• Ophthalmology

Background:

• Uhthoff's symptom, described in 1890, involves temporary vision impairment due to heat or exercise.
• It is a common symptom in patients diagnosed with multiple sclerosis.

Observation:

• Four cases presented isolated Uhthoff phenomenon years before multiple sclerosis diagnosis.
• Symptoms included transient visual, motor, or sensory disturbances triggered by intense physical activity.
• These symptoms manifested after a specific exertion threshold and resolved with rest.

Findings:

• Uhthoff's phenomenon results from conduction block due to axonal demyelination and temperature sensitivity.
• This phenomenon is strongly suggestive of multiple sclerosis, even when isolated.
• The cases indicate the possibility of "infraclinic multiple sclerosis".

Implications:

• Recognizing Uhthoff's phenomenon can aid in early multiple sclerosis detection.
• Understanding the pathophysiology provides insights into neurological conduction blocks.
• This symptom may serve as an early indicator for further neurological investigation.