Neuroelectrophysiological evaluation of untreated hyperthyroid patients

Area of Science:

• Endocrinology
• Neurology
• Electrophysiology

Background:

• Hyperthyroidism commonly affects multiple organ systems, including the nervous system.
• Neurological symptoms like fatigue, muscle weakness, and paralysis are frequent in hyperthyroidism.
• Electromyography (EMG) is crucial for diagnosing muscle weakness and differentiating neuropathy from myopathy.

Purpose of the Study:

• To evaluate neurophysiological abnormalities in hyperthyroid patients.
• To assess the correlation between clinical status and electrophysiological findings.
• To determine the utility of electrophysiological studies in diagnosing subclinical neuropathy in hyperthyroidism.

Main Methods:

• Seventeen hyperthyroid patients underwent physical, neurological, and biochemical examinations.
• Electrophysiological tests included needle EMG, motor and sensory nerve conduction velocities, and somatosensory evoked potentials (SEPs).
• Disease activity was assessed using clinical status, neurological symptom/disability scores, and thyroid hormone levels (T3, T4, TSH).

Main Results:

• Significant differences were found in needle EMG, sensory conduction velocity, and SEP findings between patients and controls.
• Abnormalities in proximal muscles (80%) and polyphasic potentials (20%) were noted.
• Reduced sensory action potential amplitudes in median, ulnar, and sural nerves; decreased sural sensory nerve conduction velocity (35.5%); and prolonged Tibial SEPs (47%) were observed.

Conclusions:

• Electrophysiological studies demonstrate an initial axonal type of mild polyneuropathy in hyperthyroid patients.
• These tests are valuable for diagnosing asymptomatic polyneuropathy in this population.
• Findings highlight the subclinical neurological impact of hyperthyroidism.