Hyperreflexia on examination is most consistent with which condition?

• A. Hypothyroidism
• B. Hyperthyroidism
• C. Diabetes mellitus
• D. Addison's disease

Answer: (B)

Hyperreflexia signals increased neuromuscular excitability. When thyroid hormone is in excess, tissues become more responsive to catecholamines and metabolic rate rises, which raises the gain of the stretch reflex. This leads to brisk deep tendon reflexes on examination. In clinical practice, hyperthyroidism commonly presents with tremor, weight loss, heat intolerance, tachycardia, and hyperreflexia, making this finding most consistent with that condition.

Hypothyroidism usually shows the opposite—slower, diminished reflexes due to reduced metabolism. Diabetes mellitus, especially with peripheral neuropathy, tends to cause decreased or absent reflexes rather than brisk ones. Addison's disease does not typically feature hyperreflexia as a characteristic finding.