An 85-year-old male has been losing mobility and gaining weight over the last two (2) months. The patient also has the heater running in his house 24 hours a day, even on warm days. Which of the following tests is most likely to be performed?
A. CBC (complete blood count)
B. ECG (electrocardiogram)
C. Thyroid function tests
D. CT scan
Correct Answer: C. Thyroid function tests
Weight gain and poor temperature tolerance indicate something may be wrong with the thyroid function. Thyroid function tests are designed to distinguish hyperthyroidism and hypothyroidism from the euthyroid state. To accomplish this task, direct measurements of the serum concentration of the two thyroid hormones—triiodothyronine (T3) and tetraiodothyronine (T4)—more commonly known as thyroxine, are extensively employed.
Option A: The complete blood count and metabolic profile may show abnormalities in patients with hypothyroidism. Thyroid dysfunction induces different effects on blood cells such as anemia, erythrocytosis, leukopenia, thrombocytopenia, and in rare cases causes’ pancytopenia.
Option B: Signs of hypothyroidism on ECG include sinus bradycardia, T-wave inversions (TWIs), QTc prolongation, and ventricular arrhythmias. Hypothyroidism can affect the cardiovascular system physiology and structure. These changes are often reflected on ECG.
Option D: Ultrasonography of the neck and thyroid can be used to detect nodules and infiltrative disease. High-resolution ultrasonography (USG) is the most sensitive imaging modality available for examination of the thyroid gland and associated abnormalities. Ultrasound scanning is non-invasive, widely available, less expensive, and does not use any ionizing radiation. Further, real-time ultrasound imaging helps to guide diagnostic and therapeutic interventional procedures in cases of thyroid disease.