Hyperthyroidism: The Daily PANCE Blueprint

The answer is D, TSH

• The serum TSH level is used to measure and to detect hyperthyroidism and hypothyroidism. The sine qua non of hyperthyroidism is a low serum TSH level, and it is the screening test that should be used. The serum free T4 should be measured after hyperthyroidism is confirmed by TSH. If the free T4 is normal, then a serum T3 should be ordered; 10% of the cases of hyperthyroidism are actually the result of a T3 toxicosis rather than a T4 problem. Radioactive iodine uptake will show hyperthyroidism in this case, but it is not the most appropriate initial test. Its use will be discussed later in the chapter. Thyroid antibodies will be present in Graves disease and can help confirm your suspicions, but they are not used to diagnose hyperthyroidism.

Pearls

Hyperthyroidism is the production of too much thyroxine hormone

• Symptoms include unexpected weight loss, rapid or irregular heartbeat, sweating, and irritability, although the elderly often experience no symptoms.
• Physical exam findings will include fine, thin, moist skin, prominent eyes with lid retraction (proptosis, or exophthalmos), startled expression, hyperreflexia, and goiter (enlarged thyroid gland)
• EKG changes such as PVCs
• The patient will complain of heat intolerance, palpitations, weight loss, tachycardia, and anxiety
• Labs will show low TSH and high free T4
• Most commonly caused by Graves disease (autoimmune against TSH receptor)
• Treatment is methimazole or PTU
• Thyroid storm is an acute form of hyperthyroidism that results from untreated or inadequately treated severe hyperthyroidism.

Diagnosis

Diagnosis: Low TSH, with high T3 and T4 confirms hyperthyroidism – with Graves’ disease usually only the T3 is elevated

• ↓ TSH
• ↑ Free T4, plus either free T3 or total T3
• Sometimes radioactive iodine uptake
• Antibodies:
• Graves: Anti-thyrotropin antibodies

Treatment

The cardiac symptoms of Graves’ disease can be treated with β-Blockers

• Most often atenolol 25-50 mg PO QD is the starting dose, and it can be increased up to 200 mg PO QD if the blood pressure tolerates.

To treat Graves disease antithyroid drugs (methimazole or PTU), radioactive iodine, and surgery (thyroidectomy) are all used depending on the patient

• Methimazole may be given; starting dose for mild hyperthyroidism is 10 mg PO QD
• Propylthiouracil (PTU) P for pregnant (during first trimester)
• Complications: dysrhythmias, osteoporosis, thyroid storm, CHF, pregnancy issues including miscarriage, injury to the recurrent laryngeal nerve during surgical repair