Which of the following are signs and symptoms of hyperthyroidism? Select all that apply. (Select All that Apply.)

Hyperthyroidism is a hypermetabolic clinical state resulting from excessive circulating triiodothyronine and thyroxine levels, which upregulate beta-adrenergic receptor sensitivity. This state drives systemic hyper-reactivity, manifesting as tachycardia, heat intolerance, significant weight loss, and neuromuscular excitability. In Graves' disease, autoimmune orbital fibroblasts trigger exophthalmos via deposition of extracellular glycosaminoglycans. A. Highly excitable and overactive: Excess circulating thyroid hormones accelerate cortical and peripheral nervous system activity, precipitating profound psychomotor agitation, restlessness, and anxiety. This hyper-adrenergic state causes severe emotional lability and persistent sleep disturbances. The central nervous system remains in a state of continuous overstimulation. B. Exophthalmos (bulging eyes): Autoantibodies target the thyroid-stimulating hormone receptors behind the eyes, provoking retro-orbital inflammation, fat hypertrophy, and extraocular muscle edema. This tissue expansion forces the globes anteriorly through the orbital rims, impairing eyelid closure. It represents a specific infiltrative feature of autoimmune thyrotoxicosis. C. Tremors: Upregulated peripheral beta-adrenergic receptors enhance neuromuscular sensitivity, producing a characteristic fine, involuntary rhythmic oscillation of the outstretched hands. This hyperkinetic manifestation reflects the systemic hyper-responsiveness to endogenous catecholamines. It serves as a classic objective sign of accelerated metabolic activity. D. Chronic neck ache: While thyrotoxicosis can feature a localized goiter, chronic cervical pain is not a diagnostic or systemic manifestation of thyroid hormone excess. Neck discomfort points toward musculoskeletal strain or acute thyroiditis rather than generalized hypermetabolism. It lacks specificity for hyperthyroid-induced physiological states. E. Mask-like expressions: Diminished facial animation and rigid expressions characterize the hypokinetic state of Parkinson's disease due to central dopamine depletion. Hyperthyroidism causes the opposite effect, producing an anxious, wide-eyed stare with hyper-reactive facial expressions. This feature is inconsistent with an overactive metabolic state.