A 36-year-old woman, gravida 0 para 0, comes to the office with frequent headaches and amenorrhea for the last 2 months. The patient has also had weight loss, intermittent palpitations, and vague visual disturbances. Her medical history is unremarkable, and she takes no medications. The patient experienced menarche at age 12 and has had normal menstrual cycles all her life. She does not smoke cigarettes or drink alcohol. Blood pressure is 130/60 mm Hg, and pulse is 103/min and regular. Weight is 69 kg (152 lb); a year ago it was 76 kg (168 lb). Examination shows a symmetrically enlarged, nontender thyroid gland. Auscultation of the chest shows tachycardia with regular heart rhythm. A fine hand tremor is noted. The remainder of the physical examination is unremarkable. Laboratory results are as follows: Which of the following is the most likely diagnosis for this patient?

Question

A 36-year-old woman, gravida 0 para 0, comes to the office with frequent headaches and amenorrhea for the last 2 months.  The patient has also had weight loss, intermittent palpitations, and vague visual disturbances.  Her medical history is unremarkable, and she takes no medications.  The patient experienced menarche at age 12 and has had normal menstrual cycles all her life.  She does not smoke cigarettes or drink alcohol.  Blood pressure is 130/60 mm Hg, and pulse is 103/min and regular.  Weight is 69 kg (152 lb); a year ago it was 76 kg (168 lb).  Examination shows a symmetrically enlarged, nontender thyroid gland.  Auscultation of the chest shows tachycardia with regular heart rhythm.  A fine hand tremor is noted.  The remainder of the physical examination is unremarkable.  Laboratory results are as follows: Which of the following is the most likely diagnosis for this patient?

Quizplus · Accepted Answer

11ec25c8_d3bb_cdcd_bc81_45117aa2e459_MD0003_00 This patient has clinical features of central hyperthyroidism (elevation of both TSH and thyroid hormones) associated with tumor mass effects (ie, headache, visual symptoms, impaired production of other pituitary hormones). Although uncommon, a TSH-producing pituitary adenoma is the likely cause of this patient's hyperthyroid state. Most TSH-secreting pituitary adenomas are macroadenomas. Patients with this condition typically have a goiter due to the effect of TSH on growth of the thyroid follicles. However, they do not have the extrathyroidal manifestations of Graves disease such as infiltrative ophthalmopathy or pretibial myxedema. Laboratory testing shows a high concentration of circulating thyroid hormone with an elevated or inappropriately normal TSH. By contrast, patients with non-TSH-dependent hyperthyroidism (much more common) will have a suppressed TSH. (Choice A) Resistance to thyroid hormone is an autosomal dominant condition due to mutations in the thyroid hormone receptor. Patients have elevated T3 and T4 and normal to elevated TSH levels, often with an associated goiter. However, these patients are clinically hypo-, not hyperthyroid. (Choices B and C) Graves disease is an autoimmune disorder associated with antibodies to the TSH receptor that stimulate release of thyroid hormone. Chronic lymphocytic (Hashimoto) thyroiditis is associated with thyroid peroxidase antibodies and can cause transient hyperthyroidism due to inflammatory destruction of thyroid follicles and release of thyroid hormone. The hyperthyroidism in both of these common disorders is TSH-independent, and TSH is suppressed. (Choice D) Normal pregnancy is associated with upregulation of thyroid hormone production due to increased thyroid-binding globulin and stimulation of TSH receptors by hCG. However, feedback inhibition of TSH secretion is intact, and pregnant women with clinical hyperthyroidism will have suppressed TSH. (Choice E) Surreptitious intake of thyroid hormone is occasionally seen in patients who are attempting to lose weight. In such cases, TSH is suppressed and the thyroid would not be enlarged. Educational objective: TSH-secreting pituitary adenomas cause hyperthyroidism with elevated thyroid hormone and elevated or inappropriately normal TSH levels. Most TSH-secreting tumors are macroadenomas and can be associated with mass effect symptoms including headache, visual field defects, and impaired function of surrounding pituitary tissue. References: Thyrotropin-secreting pituitary adenomas: epidemiology, diagnosis, and management. (http://www.ncbi.nlm.nih.gov/pubmed/26792794)

A 36-Year-Old Woman, Gravida 0 Para 0, Comes to the Office