An elderly woman notes the gradual onset of fatigue and feeling tired. She has gained a significant amount of weight over the last year. She complains frequently that the house is too cold and is turning up the thermostat. Constipation has become a problem.
Which of the following is true of this primary condition?
Correct Answer E:
Hypothyroidism is thyroid hormone deficiency. It is diagnosed by clinical features such as a typical facies, hoarse slow speech, and dry skin, and by low levels of thyroid hormones. Symptoms may include cold intolerance, constipation, forgetfulness, fatigue, personality changes and weight gain.
Serum TSH is the most sensitive test. In primary hypothyroidism, there is no feedback inhibition of the intact pituitary, and serum TSH is always elevated, whereas serum free T4 is low. In secondary hypothyroidism, free T4 and serum TSH are low.
A 42-year-old woman has recently experienced fatigue, sleepiness, dry skin, constipation, and a 4.5 kg weight gain. Her thyroid is firm and twice the normal size.
Which one of the following is the most sensitive laboratory test that will be used to diagnose this patient's condition?
Correct Answer D:
Hypothyroidism is thyroid hormone deficiency. It is diagnosed by clinical features such as a typical facies, hoarse slow speech, and dry skin, and by low levels of thyroid hormones.
Serum TSH is the most sensitive test. In primary hypothyroidism, there is no feedback inhibition of the intact pituitary, and serum TSH is always elevated, whereas serum free T4 is low. In secondary hypothyroidism, free T4 and serum TSH are low (sometimes TSH is normal but with decreased bioactivity). Management includes treatment of the underlying cause and administration of thyroxine.
A 28-year-old woman presents with a three month history of fatigue, weight gain, menstrual irregularity and declining memory.
Which of the following laboratory results is likely in the diagnosis of the underlying problem?
Correct Answer C:
Hypothyroidism is common, especially among older people, particularly women; it affects about 10% of older women. It can, however, occur at any age.
Insufficient thyroid hormone causes body functions to slow. Symptoms are subtle and develop gradually. They may be mistaken for depression, especially among older people. Facial expressions become dull, the voice is hoarse and speech is slow, eyelids droop, and the eyes and face become puffy. Many people with hypothyroidism gain weight, become constipated, and are unable to tolerate cold. The hair becomes sparse, coarse, and dry, and the skin becomes coarse, dry, scaly, and thick.
Usually hypothyroidism can be diagnosed with one simple blood test: the measurement of thyroid-stimulating hormone, which will be high due to a lack of negative feedback. A second blood test is needed to measure the level of the thyroid hormone T4 that is not bound by protein (free). A low level confirms the diagnosis of hypothyroidism.
A 35-year-old woman comes to the physician because of palpitations, restlessness, sweating, weight loss, and a tremor for the past 6 weeks. Examination shows a fine tremor, lid lag and stare, and pretibial myxedema. The thyroid gland is diffusely enlarged, asymmetric, and lobular. A bruit is present over the gland. Laboratory studies show an undetectable level of thyroid-stimulating hormone, an increased level of thyroid hormones, and an increased radioactive iodine uptake. The diagnosis of Graves' disease is made and the treatment options are discussed. The patient selects radioactive iodine therapy.
This patient is at greatest risk for which of the following conditions?
Correct Answer B:
Hypothyroidism is the main complication of radioactive iodine therapy, affecting up to 70% of patients in 10 years. Radioactive iodine therapy is a safe and effective treatment for Graves' disease because it can provide the same ablative effects of surgery without the surgical complications. There is no evidence that this treatment increases the risk for carcinoma.
A 58-year-old woman is scheduled for an abdominal operation. She has hypothyroidism that is controlled with thyroid replacement medication and will be unable to eat or drink for 4 days following the procedure. She is concerned about receiving her thyroid medication.
She should be advised of which of the following?
Thyroxine is the hormone of choice for replacement therapy. It has a half-life of seven days, and any alteration in dose is not reflected for four to six weeks. Therefore, it is very unlikely that she will develop signs and symptoms of hypothyroidism. She will not be given the medication either through the nasogastric tube or intravenously, nor does she require a preoperative loading dose.
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