A 34-year-old woman comes to the office due to fatigue. She feels excessively sleepy during the day and has dull, achy headaches almost every morning. The patient had papillary thyroid cancer 3 years ago, treated with thyroidectomy followed by postoperative radioactive iodine ablation. She has post-ablative hypothyroidism, but serum thyroglobulin, total body nuclear iodine scan, and ultrasound of the neck 6 months ago showed no evidence of residual thyroid cancer. Medical history is notable for vitamin D deficiency. Current medications include levothyroxine, vitamin D, calcium carbonate, and a combination estrogen/progestin oral contraceptive. The patient has gained 1.8 kg (4 lb) since starting the oral contraceptive 2 years ago for heavy, irregular periods. She has a sedentary lifestyle, and her diet consists mainly of frozen microwavable foods. She lives alone and has no children. The patient does not use tobacco, alcohol, or illicit drugs.
Blood pressure is 144/80 mm Hg and pulse is 76/min and regular. BMI is 34 kg/m². Neck examination shows no masses or lymphadenopathy. There is trace pitting ankle edema.
Laboratory results are as follows:
Which of the following is the best next step in management of this patient?

Question

A 34-year-old woman comes to the office due to fatigue. She feels excessively sleepy during the day and has dull, achy headaches almost every morning. The patient had papillary thyroid cancer 3 years ago, treated with thyroidectomy followed by postoperative radioactive iodine ablation. She has post-ablative hypothyroidism, but serum thyroglobulin, total body nuclear iodine scan, and ultrasound of the neck 6 months ago showed no evidence of residual thyroid cancer. Medical history is notable for vitamin D deficiency. Current medications include levothyroxine, vitamin D, calcium carbonate, and a combination estrogen/progestin oral contraceptive. The patient has gained 1.8 kg (4 lb) since starting the oral contraceptive 2 years ago for heavy, irregular periods. She has a sedentary lifestyle, and her diet consists mainly of frozen microwavable foods. She lives alone and has no children. The patient does not use tobacco, alcohol, or illicit drugs.
Blood pressure is 144/80 mm Hg and pulse is 76/min and regular. BMI is 34 kg/m². Neck examination shows no masses or lymphadenopathy. There is trace pitting ankle edema.
Laboratory results are as follows:

Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec193a_97c0_91a6_853d_4be7efb4e1fa_MD0002_00 This patient has fatigue, excessive daytime sleepiness, and morning headaches. She is also obese with mild hypertension, polycythemia, increased serum bicarbonate (likely due to hypercarbia from hypoventilation), and peripheral edema. These clinical features suggest obstructive sleep apnea (OSA), and the patient should undergo a sleep study (polysomnogram) to confirm the diagnosis. The prevalence of OSA is elevated in patients with hypothyroidism, although the pathophysiologic and epidemiologic links are debated. Other endocrine disorders associated with OSA include acromegaly, Cushing syndrome, and polycystic ovary syndrome. (Choice A) TSH stimulates epithelial thyroid cancer growth. Levothyroxine therapy is given after treatment of thyroid cancer to replace post-ablative thyroid function and reduce the risk of cancer recurrence; the target TSH level is determined by the risk of recurrence (low-normal for patients at low risk of recurrence, suppressed for patients at increased risk). This patient's elevated total T4 is explained by increased thyroxine-binding globulin levels due to estrogen in the oral contraceptive and does not indicate over-replacement. She is at low risk for cancer recurrence, her TSH is in the low-normal range, and her current dose should be maintained. (Choice B) Despite the popular belief that oral contraceptives cause weight gain, this has not been confirmed in randomized studies. Contraindications to oral contraceptives include include history of venous thromboembolism, migraine with aura, history of breast cancer, and tobacco use over age 35. (Choice D) Although this patient has some features to suggest Cushing syndrome (eg, hypertension, obesity, fatigue), her daytime sleepiness, polycythemia, and normal blood glucose make OSA more likely. (Choice E) This patient's mild hypertension is likely to respond to treatment of OSA. If OSA is ruled out and her blood pressure remains elevated, she should be counseled on lifestyle measures (eg, dietary modification, weight loss) before initiating antihypertensive medication. Educational objective: Clinical features that suggest obstructive sleep apnea (OSA) include obesity, fatigue, excessive daytime sleepiness, morning headaches, hypertension, and polycythemia. The diagnosis is established with polysomnography. The prevalence of OSA is increased in patients with hypothyroidism. __________ References: Obstructive sleep apnea in adults: epidemiology, clinical presentation, and treatment options. (http://www.ncbi.nlm.nih.gov/pubmed/22005188) Long-term follow-up of patients with papillary and follicular thyroid cancer: a prospective study on 715 patients. (http://www.ncbi.nlm.nih.gov/pubmed/21389143) Clinical guideline for the evaluation, management and long-term care of obstructive sleep apnea in adults (http://www.ncbi.nlm.nih.gov/pubmed/19960649)

A 34-Year-Old Woman Comes to the Office Due to Fatigue