USMLE (United States Medical Licensing Examination) Step 1 Practice Exam

What are common features of thyrotoxicosis? Select the correct set of symptoms from the list below:

1. Decreased reflexes, weight gain, cold intolerance

2. Heat intolerance, weight loss, anxiety

3. Muscle weakness, constipation, low heart rate

4. Anemia, high blood pressure, hair loss

The correct answer is: Heat intolerance, weight loss, anxiety

Thyrotoxicosis, also known as hyperthyroidism, is characterized by an excess of thyroid hormones in the body, leading to a variety of clinical manifestations. Among the common features, heat intolerance, weight loss, and anxiety are prominent symptoms. Heat intolerance occurs because increased levels of thyroid hormones stimulate metabolism, causing the body to generate more heat and resulting in a feeling of being overly warm. Weight loss is another key feature, despite increased appetite. The elevated metabolic rate leads to a breakdown of muscle and fat reserves, contributing to weight loss. Anxiety is linked to the impact of excess thyroid hormone on the nervous system. It can manifest as irritability, mood swings, and restlessness, which are common in individuals experiencing thyrotoxicosis. Overall, these symptoms arise due to the metabolic boost driven by excess thyroid hormones, which affects multiple systems in the body. This set of symptoms is characteristic of hyperthyroid states, distinguishing them from other clinical scenarios where symptoms would manifest differently.