A 37-year-old woman presents with several episodes of anxiety, sweating, and palpitations. She has a blood pressure of 170/110 mmHg and her pulse is 76 beats per minute. The patient recalls being told that she has a “persistently elevated calcium level.” Physical examination reveals a 3.5-cm nonmobile, hard, nontender thyroid nodule. Laboratory results are significant for elevated calcium and parathyroid hormone levels. A fine-needle aspiration biopsy of the thyroid nodule was performed and shows malignant cells.
Which of the following is most likely to be elevated in this patient?
Calcitonin. The patient in this question likely has multiple endocrine neoplasia (MEN) type 2A, also known as Sipple syndrome. The combination of parathyroid hyperplasia, symptoms consistent with pheochromocytoma, and a malignant thyroid nodule makes this the correct answer. The thyroid cancer found in MEN type 2A is medullary carcinoma, which produces calcitonin. (A) Thyroglobulin is used by the thyroid gland to produce T4 and T3. Thyroglobulin levels in the blood are also used as a tumor marker, particularly for papillary or follicular thyroid cancer. Thyroglobulin is not produced in anaplastic or medullary thyroid carcinoma. (C) Alkaline Phosphatase is elevated in several different clinical scenarios, including bile duct obstruction, osteoblastic activity resulting in active bone formation (Paget disease of the bone), and secondary hyperparathyroidism (often from decreased gut absorption of calcium from chronic renal disease). Although the patient in this question has parathyroid hyperplasia, her increased calcium levels would establish the diagnosis of primary hyperparathyroidism (rather than secondary hyperparathyroidism in which you would expect decreased calcium levels). (D) Erythrocyte sedimentation rate (ESR) is a nonspecific measurement of inflammation. Patients with subacute thyroiditis can have an elevated ESR, but you would expect an exquisitely tender thyroid.
A 21-year-old woman presents with fatigue that has been present for 6 months. History reveals a diagnosis of asthma and chronic rhinosinusitis that are well controlled with albuterol and fluticasone nasal spray. The patient denies drugs, alcohol, or sexual activity. She has a temperature of 37°C, blood pressure of 120/80 mmHg, heart rate of 75 beats per minute, respiratory rate of 16 breaths per minute, and oxygen saturation of 100% on room air. Physical examination reveals dental erosions and the patient refuses to take her hands out of her pockets. Laboratory studies reveal the following:
Based on these findings, what is the most likely diagnosis?
Surreptitious vomiting. The patient in this question has the diagnosis of surreptitious vomiting. The combination of dental erosions, metabolic alkalosis, and hypochloremia makes this the correct answer. The patient also has a low urine chloride concentration. (A) Diuretic abuse should definitely be considered in this clinical scenario as patients with diuretic abuse also present with hypokalemia and metabolic alkalosis; however, their urine chloride concentrations are usually high. (C) Diabetic ketoacidosis (DKA) results in metabolic acidosis (with anion gap), not metabolic alkalosis. (D) Primary hyperaldosteronism is caused by adrenal hyperplasia or by an aldosterone-secreting adrenal adenoma. This results in hypertension, hypokalemia, metabolic alkalosis, and low plasma renin. The patient in this question is normotensive, making this diagnosis unlikely.
A 74-year-old man with a history of New York Heart Association class III congestive heart failure presents with vague abdominal pain that has inconsistently responded to acetaminophen. He has a temperature of 37°C, blood pressure of 172/88 mmHg, heart rate of 75 beats per minute, respiratory rate of 18 breaths per minute, and oxygen saturation of 99% on room air. Physical examination reveals abdominal pain on deep palpation in all four quadrants. Laboratory studies reveal a serum sodium of 148 mEq/L, serum potassium of 2.8 mEq/L, and an increased plasma aldosterone to plasma renin activity ratio of 51 (normal range, 0.9 to 20). CT scan shows an incidental left adrenal mass. The patient is deemed a poor surgical candidate due to his cardiovascular state.
Which of the following is the next best step in management?
Spironolactone. The patient in question has primary hyperaldosteronism, as evidenced by hypertension, hypokalemia, and an adrenal mass on CT scan. Although this patient has a unilateral adrenal adenoma, patients with primary hyperaldosteronism can also have bilateral adrenal hyperplasia. Clues to diagnosis include an elevated plasma aldosterone to plasma renin activity ratio (>20). The increased aldosterone levels act via negative inhibition to decrease renin levels. CT scan can distinguish a unilateral adenoma from bilateral adrenal hyperplasia. Although surgery is preferred for patients with a unilateral adrenal adenoma, medical therapy is the preferred route for patients with bilateral adrenal hyperplasia or those with unilateral adrenal adenoma who are poor surgical candidates. Spironolactone is an aldosterone antagonist that also acts as an androgen receptor antagonist. Side effects include gynecomastia in men and menstrual irregularities in women among others. If side effects are a concern for the patient, eplerenone is an alternative treatment. Eplerenone is a selective mineralocorticoid antagonist, but with low affinity for androgen receptors. (A) Hydrochlorothiazide is indeed recommended for blood pressure control in primary hyperaldosteronism if aldosterone antagonist therapy is insufficient. However, it is not the first drug that should be administered. (B) Phenoxybenzamine is a nonspecific and irreversible α-blocker used in the medical management of pheochromocytoma. (D) Verapamil is another antihypertensive used in some patients, but is not first-line medical therapy in a patient with primary hyperaldosteronism.
A 36-year-old woman with a history of Graves disease presents with perioral numbness and muscle cramps for the last 2 weeks. She underwent a thyroidectomy 2 months ago for a large goiter that was beginning to compress her trachea. She has never had these symptoms before and her family history is insignificant. Physical examination is unremarkable and laboratory studies reveal the following:
Which of the following is associated with her condition?
Prolongation of the QT interval on ECG. The patient in this question presents with signs and symptoms of hypocalcemia (perioral numbness and muscle cramps). Other signs of hypocalcemia include tetany, carpopedal spasms, and neuromuscular irritability. The patient has primary hypoparathyroidism as evidenced by low serum calcium levels and elevated phosphorus levels. Chronic renal failure can also produce low serum calcium levels and elevated phosphorus levels, but this patient has normal BUN and creatinine levels, so she does not show signs of kidney failure. On ECG, hypocalcemia presents as a prolongation of the QT interval. (A) Peaked T waves on ECG are seen with hyperkalemia. (B) Widening of the QRS complex is also seen with hyperkalemia, but can be seen with bundle branch block as well. (D) Shortened QT interval on ECG is seen with hypercalcemia.
An obese 32-year-old woman with a history of gastroesophageal reflux disease (GERD) presents with amenorrhea for the past year. Review of systems is unremarkable. She has 3 children and denies tobacco, alcohol, or drug use. She has a temperature of 37°C, blood pressure of 120/80 mmHg, heart rate of 75 beats per minute, respiratory rate of 16 breaths per minute, and oxygen saturation of 100% on room air. Visual field testing reveals no abnormality and her pregnancy test is negative. Laboratory studies reveal a serum prolactin level of 108 ng/mL. MRI of the pituitary gland confirms a 5.5-mm pituitary adenoma.
Treatment with bromocriptine. The patient in this question presents with symptoms and laboratory values consistent with a prolactinoma. The presence of amenorrhea and galactorrhea in females and hypogonadism in males are classic symptoms for a prolactinoma. An adenoma of the pituitary gland less than 10 mm is called a microadenoma, which does not usually have a mass effect that would affect other pituitary hormones. The first-line treatment for all prolactinomas remains dopamine agonists such as bromocriptine and cabergoline. These agents often decrease prolactin levels to the normal range and shrink the tumor. Dopamine agonists inhibit secretion of prolactin from the anterior lobe of the pituitary gland. (B) Estrogen replacement therapy is often given to patients who experience intolerable side effects from the use of dopamine agonists, but is not first-line treatment. (C) Surgery is often indicated for those patients with prolactinoma who have visual field defects that do not improve quickly after medical treatment with dopamine agonists. Surgery is also an option for those patients who do not respond to dopamine agonists. (D) Serial prolactin levels and close observation remain an option for asymptomatic patients with prolactinoma given the slow growth (however, this patient presents with amenorrhea).
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