A 35-year-old male presents with weight gain, constipation, and depression. Blood tests show elevated cholesterol levels and a low free thyroxine (T4) level. What are the potential diagnoses and next steps?
The patient's symptoms of weight gain, constipation, and depression, along with elevated cholesterol and low free T4, are indicative of hypothyroidism. The most common cause is Hashimoto's thyroiditis, an autoimmune condition. The next steps would include testing for thyroid-stimulating hormone (TSH) levels and thyroid autoantibodies.