Which clinical manifestation is expected in a patient with hyperthyroidism?

In hyperthyroidism, one of the hallmark clinical manifestations is palpitations. This condition arises due to the increased levels of thyroid hormones, which stimulate the heart and often lead to an elevated heart rate. Patients may experience a sensation of their heart racing or irregular heartbeats as a result of heightened sympathetic nervous system activity that accompanies the excess thyroid hormone.

The other options, such as weight gain, slow speech, and fatigue, are more characteristic of hypothyroidism, where there is a deficiency of thyroid hormones leading to a decrease in metabolic processes, slower physical and cognitive functions, and weight accumulation. Therefore, palpitations distinctly reflect the increased metabolic state and excitability caused by hyperthyroidism, making it the expected clinical manifestation in such patients.