A patient presents with fatigue, dry skin, constipation, and unexplained weight gain. Which additional finding would support a diagnosis of hypothyroidism?

Hypothyroidism is a metabolic state resulting from deficient thyroxine (T4) and triiodothyronine (T3) production. It causes a generalized slowing of physiological processes, leading to myxedema and bradycardia. Clinical signs often include delayed relaxation of deep tendon reflexes and non-pitting edema. A. Exophthalmos: Bulging of the eyes is a classic sign of Graves' disease, which is the most common cause of hyperthyroidism. It is an infiltrative ophthalmopathy driven by autoimmune activity. It is not found in the hypometabolic state of hypothyroidism. B. Tachycardia: An increased heart rate is a hallmark of hyperthyroidism or thyrotoxicosis due to increased beta-adrenergic sensitivity. Hypothyroidism typically presents with bradycardia, reflecting the decreased metabolic demand on the cardiovascular system. C. Hyperreflexia: Overactive reflexes indicate a hypermetabolic state or upper motor neuron irritation. Hypothyroidism is associated with hyporeflexia and specifically a slow recovery phase in the Achilles reflex. Reflex activity is diminished, not increased, in thyroid deficiency. D. Velvet skin: While hypothyroid skin is typically described as dry, "velvet" or smooth, warm skin is actually more characteristic of hyperthyroidism. However, within the provided options for hypothyroidism, it is the only skin descriptor, though medical jargon usually favors "coarse" for this condition.