Question 1

A 26-year-old woman comes to the physician to monitor her thyroid medication. She has a history of papillary thyroid cancer that was treated with a subtotal thyroidectomy and ablative radioiodine 3 years ago. The tumor was 2.1 cm in greatest dimension without lymph node involvement or distant metastasis. She currently takes 125 mcg of levothyroxine on an empty stomach every morning and has no current symptoms. Laboratory tests show undetectable thyroglobulin, undetectable anti-thyroglobulin antibodies, TSH of 4.8 μU/mL, and free T₄ of 1.3 ng/dL (normal 0.8-1.8 ng/dL). One year ago, her total body radioactive iodine scan and neck ultrasound were unremarkable. Which of the following is the most appropriate next step in management of this patient?

Accepted Answer

Explanation: 11ec2b69_bed9_6060_8f63_afa10ca032c0_MD0005_00 After treatment of thyroid cancer with surgery and ablative radioiodine therapy, patients frequently require thyroid replacement therapy due to loss of healthy thyroid tissue. In addition, high TSH levels stimulate the growth of residual thyroid cancer cells, and suppressing TSH with levothyroxine has been shown to decrease the risk of recurrent disease. However, suppressive doses of levothyroxine are associated with an increased risk of bone loss and atrial fibrillation. Therefore, the degree of TSH suppression will depend on the initial tumor stage and risk of recurrence. If the risk of recurrence is low, such as in this patient, levothyroxine supplementation should be provided to suppress TSH just below the normal range for the initial 6-12 months following thyroidectomy and radioactive iodine therapy. Then, if the patient is free of recurrence, the TSH levels should subsequently be maintained in the lower half of the normal range (Choice C). In patients with large, aggressive tumors, or distant metastasis, the TSH is typically kept below 0.1 µU/mL for several years after initial treatment (Choice E). (Choice A) Liothyronine (T₃) supplementation is not warranted for chronic treatment of hypothyroidism. T₃ can be used in place of levothyroxine for a short period to prevent symptoms of hypothyroidism in patients with thyroid cancer who are holding levothyroxine in preparation for radioactive iodine uptake and scan. (Choice B). Levothyroxine should be taken on an empty stomach, separately from other medications. Taking levothyroxine with meals or other medication can impair its absorption and make management erratic or unpredictable. Educational objective: TSH suppression with levothyroxine has been shown to decrease the risk of recurrence of differentiated epithelial thyroid cancers. The degree of TSH suppression depends on the initial stage of the cancer and risk of recurrence. References: Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer. (http://www.ncbi.nlm.nih.gov/pubmed/19860577)

Question 2

A 36-year-old woman comes to the physician due to low back pain.  The pain began 5 months ago and is getting progressively worse.  She describes it as aching, non-radiating, and without any aggravating or relieving factors.  The patient underwent Roux-en-Y gastric bypass surgery for morbid obesity 2 years ago, after which she lost about 45.4 kg (100 lb).  She takes a daily multivitamin containing calcium (1200 mg elemental calcium) and vitamin D (400 IU of cholecalciferol).  She eats a normal diet.  Spinal examination shows no focal tenderness.  Laboratory results are as follows:  Bone mineral density, performed using dual-energy x-ray absorptiometry, reveals a T-score of -2.0 at the lumbar spine and -1.5 at the hip.  Serum parathyroid hormone level is 955 pg/mL.  Which of the following is the best next step in management of this patient?

Accepted Answer

Explanation: 11ec2b69_bedd_7f19_8f63_21a28a5e4518_MD0005_00 This patient, with back pain, low phosphorus level, high alkaline phosphatase, and history of bariatric surgery, has likely vitamin D deficiency, with osteomalacia and secondary hyperparathyroidism. Hypophosphatemia is common and may be present in patients with normal calcium levels (increased production of parathyroid hormone causes increased renal excretion of phosphorus while maintaining calcium at normal levels). Serum 25-hydroxyvitamin D level is a very sensitive indicator for vitamin D stores and should be measured in patients suspected of vitamin D deficiency. A level <20 ng/mL is diagnostic. Gastric bypass surgery causes some degree of malabsorption in a majority of patients. To prevent the development of deficiencies following a bariatric procedure, all patients need lifelong supplementation of vitamins (eg, B1, B12, folic acid, vitamin D) and minerals eg, (iron, calcium, trace minerals). Patients should receive at least 2000-3000 units of cholecalciferol (vitamin D3) per day to maintain vitamin D levels of 30-50 ng/mL, and some may require even higher doses. This patient's current dose (400 IU per day) is insufficient to maintain vitamin D levels following Roux-en-Y gastric bypass. (Choice B) Testing for stool fat can assess malabsorption but would not confirm the diagnosis of vitamin D deficiency. Patients with gastric bypass surgery should receive vitamin D supplementation assuming malabsorption, regardless of stool fat content. (Choice C) Zoledronic acid is indicated for treatment of osteoporosis in men and postmenopausal women and for Paget's disease of bone. It should not be used in patients with vitamin D deficiency or malabsorption syndromes due to the risk of hypocalcemia. (Choice D) Ultrasound of the neck is useful to detect parathyroid adenomas, the most common cause of primary hyperparathyroidism. However, vitamin D deficiency causes secondary hyperparathyroidism and ultrasound is not helpful. (Choice E) Mild to moderate hypophosphatemia due to vitamin D deficiency will correct spontaneously with treatment of the underlying disorder. Supplementation of phosphorus is not necessary. Educational objective: Gastric bypass bariatric surgery causes malabsorption in a majority of patients. Patients will require at least 2000-3000 IU/day of cholecalciferol (vitamin D3) to maintain normal vitamin D levels. Other vitamins (eg, B1, B12, folic acid) and minerals (eg, iron, calcium, trace minerals) should be supplemented as well. References: Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient--2013 update: cosponsored by American Association of Clinical Endocrinologists, the Obesity Society, and American Society for Metabolic & Bariatric Surgery. (http://www.ncbi.nlm.nih.gov/pubmed/23529351) Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. (http://www.ncbi.nlm.nih.gov/pubmed/21646368)

Question 3

A 29-year-old man comes to the emergency department complaining of palpitations, sweating, and severe headache.  His symptoms resolve spontaneously by the time he is evaluated.  He has had at least 2 similar episodes during the past 2 months.  The patient's family history is unremarkable.  He does not use tobacco, alcohol, or illicit drugs.  His primary care provider saw him after the first episode and prescribed an anxiolytic medication.  However, the patient felt drowsy at his job and stopped the medication.  Physical examination shows a thin man who appears anxious and diaphoretic.  The thyroid is normal to palpation without any obvious nodules.  His temperature is 36.7 C (98 F), blood pressure is 126/84 mm Hg, pulse is 86/min, and respirations are 16/min.  During his prior emergency department visit for an identical episode, his blood pressure was 150/100 mm Hg and pulse was 120/min.  The laboratory results at that time showed normal thyroid function tests. 
Which of the following is the most appropriate next step in management?

Accepted Answer

Explanation: 11ec2b69_bed6_531b_8f63_a57134686e51_MD0005_00 This patient's episodic symptoms and hypertension are concerning for pheochromocytoma. The classic triad for pheochromocytoma includes episodic headache, sweating, and tachycardia. However, most patients may not have all 3 findings. Other findings can include orthostatic hypotension, blurry vision, and weight loss. Measurement of 24-hour fractionated urinary metanephrines and catecholamine levels is one of the preferred screening tests for the biochemical diagnosis of pheochromocytoma. Some experts prefer measuring plasma fractionated metanephrines as the initial screening test, which has high sensitivity but lower specificity than the 24-hour urine test. Urine levels of catecholamines, and metanephrines and plasma fractionated metanephrines can be affected by a number of drugs (eg, tricyclic antidepressants, over-the-counter decongestants), which should be stopped for 2 weeks before testing. Twenty-four-hour urinary vanillylmandelic acid excretion has a much lower sensitivity and specificity compared with 24-hour urinary fractionated metanephrine (Choice B). (Choice D) Beta-adrenergic receptor blockade before alpha-adrenergic receptor blockade may worsen hypertension in pheochromocytoma as unopposed alpha-adrenergic activity may cause vasoconstriction. (Choice E) Alpha blockers can falsely elevate catecholamine and metanephrines, which can interfere with correct interpretation of these test results. As a result, alpha blockers are started afterconfirming biochemical diagnosis of pheochromocytoma. Educational objective: Screening for pheochromocytoma should be considered in patients with episodic symptoms (headaches, diaphoresis, and tachycardia), early age-onset or refractory hypertension, and paroxysmal hypertension. A biochemical diagnosis of pheochromocytoma is typically made by measuring plasma free metanephrine levels or a 24-hour urine collection for measurement of catecholamine and metanephrine. References: Phaeochromocytoma. (http://www.ncbi.nlm.nih.gov/pubmed/16112304)

Question 4

A 29-year-old woman comes to the office for evaluation of hypercalcemia. Her serum calcium was 12.1 mg/dL on routine laboratory investigations performed for a life insurance application. The patient feels well and has had no excessive urination, bone pain, abdominal pain, headache, or constipation. Medical history is significant for upper gastrointestinal hemorrhage a year ago; the bleed was due to a large gastric ulcer, for which she is currently taking an oral proton pump inhibitor. She has a 10-pack-year smoking history but does not use alcohol or illicit drugs. The patient's menstrual cycles are regular; she has never been pregnant, is sexually active with one partner, and uses barrier contraception to prevent pregnancy. The patient's mother underwent parathyroid surgery for symptomatic hypercalcemia and takes a pill twice a week for an unspecified pituitary tumor. Blood pressure is 128/80 mm Hg and pulse is 78/min. BMI is 27 kg/m². Neck examination is unremarkable. A few small subcutaneous lipomas are present on the patient's back. The rest of her physical examination is unremarkable. Laboratory results are as follows: Bone mineral density by DXA is normal. Which of the following is the best next step in management of this patient?

Accepted Answer

Explanation: 11ec2b69_bed4_5748_8f63_07fe740fabff_MD0005_00 This patient has significant hypercalcemia with an elevated parathyroid hormone level consistent with primary hyperparathyroidism. In light of her young age, history of gastric ulcer, and family history of parathyroid and pituitary disease, this constellation of clinical features is highly suggestive of multiple endocrine neoplasia type 1 (MEN1). MEN1 is characterized by the "3 Ps": parathyroid adenomas or hyperplasia, pancreatic and gastrointestinal neuroendocrine tumors (eg, gastrinoma/Zollinger-Ellison syndrome), and pituitary adenomas (eg, prolactinoma). Additional findings (eg, multiple cutaneous lipomas) may also occur. Indications for parathyroidectomy in patients with MEN1, similar to those for sporadic primary hyperparathyroidism, include symptomatic hypercalcemia (or calcium >1 mg/dL above normal), end-organ complications (eg, osteoporosis, chronic kidney disease, nephrolithiasis), and increased risk for complications (eg, urinary calcium excretion >400 mg/day). Patients age <50 are likely to develop complications later in life and should also undergo parathyroidectomy; as patients with MEN1 typically present at a relatively young age, most should be offered surgery. Patients with MEN1 usually have multiple parathyroid adenomas and, therefore, require subtotal (>3½ glands) or total parathyroidectomy with autotransplant into a muscle pocket. (Choices B, C, and D) Calcitonin and metanephrine assays are used to screen for medullary thyroid cancer and pheochromocytoma, respectively. However, these tumors are components of MEN2, not MEN1, so testing is not required. MEN2 (Choice E) Zollinger-Ellison syndrome is characterized by an elevated serum gastrin level. However, gastrin can also be elevated due to hypercalcemia or use of proton pump inhibitors. Measurement of gastrin levels should be deferred until the patient is normocalcemic and has discontinued acid-reducing therapy for at least 2 weeks. Educational objective: Multiple endocrine neoplasia type 1 is composed of parathyroid adenomas or hyperplasia (primary hyperparathyroidism), pancreatic and gastrointestinal neuroendocrine tumors, and pituitary adenomas: the 3 Ps. Multiple parathyroid glands are usually involved; parathyroidectomy with autotransplant is necessary. References: Clinical practice guidelines for multiple endocrine neoplasia type 1 (MEN1). (http://www.ncbi.nlm.nih.gov/pubmed/22723327)

Question 5

A 24-year-old woman has a 2.1-cm nodule in her right thyroid lobe.  She is otherwise healthy and takes no medications.  The patient has no past history of radiation exposure or family history of thyroid disease.  She does not experience pain, difficulty swallowing, or voice changes.  Physical examination is within normal limits.  Laboratory studies show normal T3, T4, and TSH levels.  An ultrasound of the thyroid gland reveals a solid nodule measuring 2.6 x 1.7 x 1.3 cm in the right lobe.  The left lobe appears to be normal in size and echotexture. 
Which of the following is the best next step in the management of this patient?

Accepted Answer

Explanation: 11ec2b69_beda_bff1_8f63_99a1a19abbb0_MD0005_00 Patients with thyroid nodules >1 cm should be evaluated based on their cancer risk factors (eg, family history, past radiation exposure, cervical lymphadenopathy), compressive symptoms (eg, hoarseness, difficulty swallowing), and thyroid functional status (ie, euthyroid, hyperthyroid, or hypothyroid). In general, an ultrasound of the thyroid should be obtained first. Patients with suspicious ultrasound findings (eg, hypoechoic, microcalcifications, internal vascularity) or cancer risk factors should undergo fine-needle aspiration (FNA). Measurement of serum TSH can further stratify the risk of malignancy in patients with a thyroid nodule. Patients with normal or elevated TSH levels have a higher risk of malignancy and should be evaluated with FNA. Patients with low TSH levels should be evaluated using thyroid scintigraphy, usually with iodine 123 (Choice B). A hyperfunctioning ("hot") nodule (increased isotope uptake in the nodule with decreased surrounding uptake) is rarely malignant and may be treated as benign hyperthyroidism. An indeterminate or hypofunctioning ("cold") nodule indicates a higher risk of cancer and requires further evaluation with FNA. This patient has a painless thyroid nodule without clinical risk factors for thyroid cancer, compressive symptoms, or features suggesting hyper- or hypothyroidism. However, due to the size of the nodule and normal TSH level, this patient should have FNA to rule out malignancy. (Choice C) Surgery referral following FNA is usually required when nodules are malignant or suspicious for malignancy. Surgery can also be considered for benign nodules if patients have significant associated compressive symptoms. (Choice D) Repeat ultrasound is recommended for follow-up of benign nodules after confirmation with FNA. Ultrasound can also be used to monitor nodules <1 cm that are not suspicious for malignancy. (Choice E) Benign nodules grow very slowly. Suppressive levothyroxine is usually not recommended as it does not effectively decrease nodule size. In addition, suppressive doses of levothyroxine can lead to adverse effects (eg, bone loss, atrial fibrillation). Educational objective: Thyroid nodules should be evaluated using TSH level and thyroid ultrasound. Patients with normal or high TSH and a confirmed nodule >1 cm in diameter on ultrasound should undergo fine-needle aspiration with nodule cytology. Patients with low TSH should have a radionuclide thyroid scan. References: Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer. (http://www.ncbi.nlm.nih.gov/pubmed/19860577) Evaluation of a thyroid nodule. (http://www.ncbi.nlm.nih.gov/pubmed/20510711)

Question 6

A 6-year-old girl is brought to the clinic for evaluation of acne.  Her parents first noticed mild acne on her forehead and nose 3 weeks ago as well as adult-type body odor that requires her to bathe more frequently.  The patient was born at 35 weeks gestation but has no ongoing medical conditions.  Blood pressure is normal.  Weight is at or above the 97th percentile and height is at the 97th percentile.  BMI is at or above the 97th percentile.  Comedonal acne is present on the forehead, cheeks, and nose but not on the back or chest.  Fundoscopic examination and pupillary reaction are normal bilaterally.  Cardiopulmonary examination is normal.  The areolae are enlarged, and breast tissue is palpable bilaterally.  The abdomen is soft and nontender with no palpable masses.  Coarse, dark pubic hair is noted.  Bone age is 9 years.  Laboratory results are as follows:  Which of the following is the most likely diagnosis in this patient?

Accepted Answer

Explanation: 11ec2b69_bed8_c41f_8f63_3d6bad1a5870_MD0005_00 Precocious puberty is the premature development of secondary sexual characteristics (eg, breast development, pubic hair) in girls age <8 or boys age <9. Elevated estrogen stimulates breast development (thelarche), and elevated androgens account for adult-type body odor, acne, and axillary and pubic hair (pubarche). Both estrogen and androgens promote bone maturation, resulting in advanced bone age relative to chronologic age. Most children are also tall for age, as seen in this patient with height at the 97th percentile. Precocious puberty is subdivided into central and peripheral causes. Central precocious puberty is associated with early activation of the hypothalamic-pituitary-gonadal axis, resulting in increased LH and FSH levels. Most cases are idiopathic but pathologic causes include CNS tumors. Conversely, peripheral precocious puberty is caused by abnormal secretion of sex hormones from other organs (eg, adrenals, ovaries, testes) and results in suppression of the hypothalamic-pituitary-gonadal axis and decreased LH and FSH levels. This child has central precocious puberty as evidenced by advanced bone age in addition to elevated LH and FSH levels. Treatment for central precocious puberty is a gonadotropin-releasing hormone agonist that downregulates LH and FSH, thereby slowing the progression of pubertal development. (Choice B) Late-onset congenital adrenal hyperplasia may present with premature adrenarche and advanced bone age; however, premature thelarche is not typical due to normal estrogen levels. In addition, 17-hydroxyprogesterone is typically elevated, unlike in this patient. (Choice C) McCune-Albright syndrome is characterized by a triad of irregular café-au-lait spots, fibrous dysplasia of bone, and peripheral precocious puberty due to elevated estrogens produced by ovarian cysts. Although bone age is advanced, LH and FSH levels are suppressed, not elevated as in this patient. McCune-Albright syndrome (Choice D) Polycystic ovary syndrome (PCOS) presents in postmenarchal girls with menstrual irregularities (eg, oligomenorrhea) and signs of hyperandrogenism (eg, hirsutism). PCOS is not associated with precocious puberty. (Choice E) Premature adrenarche presents with early-onset pubic and axillary hair in addition to adult-type body odor due to mildly elevated serum androgens (eg, dehydroepiandrosterone sulfate). Bone age is typically normal, and additional signs of puberty, such as breast development, are not typically present due to normal estrogen levels. Educational objective: Central precocious puberty is the onset of secondary sexual characteristics in girls age <8 and boys age <9 with advanced bone age and elevated LH and FSH levels. References: Disorders of puberty: an approach to diagnosis and management. (http://www.ncbi.nlm.nih.gov/pubmed/29094880)

Question 7

A 53-year-old woman of white ethnicity comes to the office to discuss the results of her bone density test. She feels well but is very concerned about osteoporotic fractures as her mother passed away at age 81 after sustaining a hip fracture. The patient had menopause at age 50 and currently has no hot flashes or vaginal dryness. She eats a healthy diet and exercises at least 5 days a week with a combination of strength training and aerobic conditioning exercises. Medical history is unremarkable and her only medication is a daily over-the-counter vitamin D3 supplement (800 IU). She has never been married and has no history of pregnancy. The patient drinks a glass of wine every night and does not use tobacco or illicit drugs. In addition to osteoporosis, family history is positive for breast cancer in a maternal aunt. Vital signs are normal. BMI is 25 kg/m². Physical examination is unremarkable. Fasting laboratory and bone mineral density results are as follows: The 10-year probability of fracture calculated using the fracture assessment tool (FRAX) is 12% and 0.6% for a major osteoporotic fracture and a hip fracture, respectively. Mammogram a year ago was normal. Which of the following is the most appropriate next step in management of this patient's low bone density?

Accepted Answer

Explanation: 11ec2b69_bed5_1a9a_8f63_4167cee2fcaf_MD0005_00 Screening for osteoporosis by DXA is recommended for women age >65 and for postmenopausal women age <65 who have additional risk factors for osteoporosis (eg, low body weight, current smoking, family history of hip fracture, use of glucocorticoids). Postmenopausal women should also be counseled on preventive measures, including regular weight-bearing exercise and adequate intake of calcium and vitamin D. In addition to these general measures, bone-specific pharmacotherapy with bisphosphonates (eg, alendronate) is indicated for patients who have: Low bone mass with a history of fragility fracture Bone density criteria for osteoporosis (T-score <−2.5 on DXA) Osteopenia (T-score between −1 and −2.5) with a 10-year probability for major osteoporotic fracture >20% or hip fracture >3% based on the FRAX risk calculator This patient has osteopenia, but her fracture risk is much lower than the threshold to recommend bisphosphonate therapy (Choice C). However, most experts recommend periodic (eg, every 3-5 years) reassessment with DXA for postmenopausal women with osteopenia. (Choice B) Excessive alcohol intake (>3 drinks/day) is associated with increased fracture risk. However, this patient's moderate intake is not associated with an increased risk of fractures. (Choice D) Menopausal hormonal therapy (estrogen or combined estrogen/progestin therapy) is associated with a decreased risk of hip and vertebral fracture. However, it carries an increased risk for breast cancer, stroke, and venous thromboembolism and is generally advised only for women who have intolerable menopausal symptoms (eg, hot flashes). (Choice E) Selective estrogen receptor modulators (eg, raloxifene) can be considered as an alternate to bisphosphonates for treatment of osteoporosis in women who are at increased risk for breast cancer. However, this patient does not require additional therapy, and these medications are associated with an increased risk of venous thromboembolism. Educational objective: Bisphosphonate therapy is indicated for postmenopausal women with: Low bone mass with a history of fragility fracture Osteoporosis (T-score <−2.5 on DXA) Osteopenia (T-score between −1 and −2.5) and a 10-year probability for major osteoporotic fracture >20% or hip fracture >3% based on the fracture assessment tool (FRAX) risk calculator References: Evaluation and treatment of osteoporosis. (http://www.ncbi.nlm.nih.gov/pubmed/27235616) Clinical practice. Postmenopausal osteoporosis. (http://www.ncbi.nlm.nih.gov/pubmed/26789873)

Question 8

A 29-year-old man comes to the emergency department complaining of palpitations, sweating, and severe headache.  His symptoms resolve spontaneously by the time he is evaluated.  He has had at least 2 similar episodes during the past 2 months.  The patient's family history is unremarkable.  He does not use tobacco, alcohol, or illicit drugs.  His primary care provider saw him after the first episode and prescribed an anxiolytic medication.  However, the patient felt drowsy at his job and stopped the medication.  Physical examination shows a thin man who appears anxious and diaphoretic.  The thyroid is normal to palpation without any obvious nodules.  His temperature is 36.7 C (98 F), blood pressure is 126/84 mm Hg, pulse is 86/min, and respirations are 16/min.  During his prior emergency department visit for an identical episode, his blood pressure was 150/100 mm Hg and pulse was 120/min.  The laboratory results at that time showed normal thyroid function tests. The patient is placed on appropriate preoperative medications and is taken for surgical removal of the tumor.  During the procedure, he rapidly becomes hypotensive.  His blood pressure falls from 110/89 mm Hg to 80/50 mm Hg.  Which of the following is the most appropriate therapy for this patient's hypotension?

Accepted Answer

Explanation: 11ec2b69_bed7_8b9d_8f63_1bf19168968f_MD0005_00 Even with adequate preoperative alpha blockade and adequate fluid replenishment, some patients with pheochromocytoma have intraoperative and postoperative complications. Hypotension is an important intraoperative complication due to decreased circulatory catecholamine levels following tumor removal. In addition, persistent preoperative alpha blockade results in decreased vascular tone. Intra- and postoperative hypotension usually responds well to normal saline bolus. Pressors may be required in patients who do not respond to intravenous fluids. Other complications include hypertensive crisis, hypoglycemia, and cardiac tachyarrhythmias. (Choices B and C) Dopamine and dobutamine are less effective in those with pheochromocytoma and intraoperative hypotension as the majority of these patients are on preoperative long-acting alpha blockade. As a result, the vascular response to vasoconstrictors is reduced. (Choice D) Studies have not shown that colloids are superior to crystalloid solution in the management of acute hypotension. In addition, colloids are more expensive than normal saline. (Choice E) Intravenous infusion of phentolamine or sodium nitroprusside is preferred for managing intraoperative severe hypertension. Educational objective: Intraoperative hypotension in patients with pheochromocytoma usually responds to an intravenous bolus of normal saline. Intravenous bolus of phentolamine is used for acute severe hypertension (not hypotension) during surgery for pheochromocytoma. References: Phaeochromocytoma. (http://www.ncbi.nlm.nih.gov/pubmed/16112304) Laparoscopic adrenalectomy for pheochromocytoma: a literature review. (http://www.ncbi.nlm.nih.gov/pubmed/12487269)

Question 9

A 41-year-old woman comes to the physician with an 8-month history of amenorrhea.  Multiple home pregnancy tests during this time have been consistently negative.  She has mild dyspareunia and blurred vision but no headaches, galactorrhea, hot flashes, or weight change.  The patient's past medical and family histories are unremarkable.  She takes no medications, including over-the-counter drugs.  She does not use alcohol, tobacco, or intravenous drugs.  Physical examination is unremarkable.  Basic metabolic panel and complete blood count are within normal limits.  Her hormone profile shows a prolactin level of 50 ng/mL (normal 5-20 ng/mL).   Serum luteinizing hormone level is undetectable, follicle-stimulating hormone is low normal, and the α-subunit is markedly increased.  Serum thyroid-stimulating hormone, testosterone, and insulin-like growth factor 1 are normal.  Magnetic resonance imaging of the pituitary shows a 2-cm pituitary tumor with suprasellar extension.  What is the most appropriate next step in management of this patient?

Accepted Answer

Explanation: This patient has amenorrhea and hypogonadism with suppressed luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels but increased α-subunits. This is strongly suggestive of a nonfunctioning pituitary adenoma, which usually arises from the gonadotropin-secreting cells (gonadotrophs) in the pituitary gland. Normal gonadotrophs secrete LH and FSH (which are dimeric hormones consisting of a common α-subunit and a different β-subunit), but the dysfunctional cells in most gonadotroph adenomas secrete primarily just the common α-subunit. The clinical symptoms of α-subunit overproduction are usually minimal ("nonfunctioning" adenoma), and the diagnosis is not apparent until the adenoma is large enough to cause headaches or visual disturbances due to mass effect. The preferred therapy for most nonfunctioning pituitary adenomas is trans-sphenoidal surgery, which can provide rapid relief of the associated neurologic symptoms. Patients may also regain their normal gonadal function after resection. Radiation (field therapy or stereotactic radiation) may be used as adjuvant therapy in patients with incompletely resected adenomas. However, radiation is not first-line therapy as its onset of action is too slow, it can damage surrounding neurologic tissues, and it can lead to delayed hypopituitarism in many cases (Choice D). (Choice A) Dopaminergic medications such as cabergoline are the preferred treatment for prolactin-secreting adenomas (prolactinomas), but they have no significant effect on gonadotropin-secreting adenomas. Large nonfunctioning pituitary adenomas that compress the pituitary stalk may block the normal hypothalamic inhibition of prolactin secretion, leading to a mild increase in prolactin levels. This does not indicate the presence of a prolactinoma, which usually is associated with a much larger increase in prolactin levels (>200 ng/mL). (Choice B) Patients with amenorrhea due to a pituitary adenoma may be treated with estrogen and progesterone to restore menses and relieve hypogonadal symptoms. These would not address the underlying tumor, however, and would not relieve symptoms related to mass effect. (Choice C) Octreotide, a somatostatin analogue, acts on somatostatin receptors in the pituitary to inhibit release of growth hormone. It is sometimes used in growth hormone-producing adenomas (acromegaly) but has minimal benefits in nonfunctioning adenomas. Educational objective: Nonfunctioning pituitary adenomas generally arise from gonadotropin-secreting cells of the pituitary gland. Patients usually present with hypogonadism and low gonadotropin levels; serum α-subunit levels are characteristically increased. Large tumors may cause symptoms directly through mass effect on local tissues. The primary treatment modality is trans-sphenoidal surgery. References: Non-functioning pituitary adenomas. (http://www.ncbi.nlm.nih.gov/pubmed/19945027)

Question 10

A 30-year-old woman comes to the office due to tingling and numbness in both of her distal lower extremities for the last 3 months. Her symptoms are gradually worsening. She also has had intense fatigue. She has not had any weight change, constipation, skin dryness, headaches, or visual changes. The patient was diagnosed with primary hypothyroidism secondary to Hashimoto thyroiditis when she was 10 years old. She is currently on 100 mcg per day of levothyroxine orally. Her mother also has hypothyroidism. The patient does not use tobacco, alcohol, or recreational drugs. Her menstrual cycles have been irregular for the last 6 months. Her last menstrual period was 2 months ago. She is sexually active with one partner. Blood pressure is 114/78 mm Hg and pulse is 72/min. She weighs 69 kg (152 lbs) and is 163 cm (5'4") tall. Her thyroid is nonpalpable. Her mucous membranes are moist and pale. Her tongue appears to be bald. She does not have any scleral icterus. Vibration and proprioception are decreased in both of her lower extremities distally. Pain and temperature sensations appear normal. Her ankle jerks are absent, but other reflexes are brisk. Babinski is present, and Romberg signs is positive. The rest of the physical examination is unremarkable. Stool obtained from the rectal examination is negative for occult blood. Laboratory results reveal a hemoglobin of 8 g/dL and hematocrit of 24%. Her total leukocyte count is 3,200/mm³. Her platelet count is 300,000/mm³. Basic serum chemistries are within normal limits. Her total T4 level is 8.2 mcg/dL (normal 4-12 mcg/dL) and TSH level is 2.4 micro IU/mL. What is the next best step in the management of this patient?

Accepted Answer

Explanation: The patient's primary hypothyroidism predisposed her to other autoimmune disorders such as pernicious anemia. Involvement of the posterior column (loss of proprioception), lateral column (brisk reflexes), and peripheral nerves (loss of ankle jerks) indicate neurologic involvement due to vitamin B12 deficiency, which resulted from atrophic gastritis (pernicious anemia). Dietary vitamin B12 binds to intrinsic factor secreted by the parietal cells in the gastric mucosa. The intrinsic factor-vitamin B12 complex is then carried to the terminal ileum for receptor-mediated absorption. Pernicious anemia results from the autoimmune destruction of parietal cells, leading to achlorhydria and decreased production of the intrinsic factor. The lack of intrinsic factor leads to vitamin B12 deficiency. The red blood cells are macrocytic due to ineffective erythropoiesis due to defective nucleic acid synthesis. Neurologic involvement is characterized by involvement of posterior and lateral columns in the spinal cord ("subacute combined degeneration") and leads to ataxia, loss of proprioceptive, and vibratory sensations. Severe spasticity, weakness, and peripheral nerve involvement can occur. Symptoms and signs are more prominent in the lower than the upper extremities. (Choice A) Increasing the levothyroxine dose is not the appropriate choice for this patient because her thyroid function tests are within normal limits. The fatigue in this patient is most likely due to anemia. (Choice B) Although neurologic involvement can indicate cord compression, the history and other features of this patient suggest otherwise; therefore, MRI is unnecessary. (Choice C) Endocrinopathy with polyneuropathy can be seen with POEMS(polyneuropathy, organomegaly, endocrinopathy, M-proteins and skin changes) syndrome. SPEP is done to look for an M-spike. This patient does not have organomegaly or skin changes. (Choice E) Folate levels may be obtained to determine the cause of macrocytic anemia; however, the patient's history of autoimmune hypothyroidism and characteristic neurological picture is more suggestive of vitamin B12 deficiency. Educational objective: Patients with primary hypothyroidism are predisposed to get other autoimmune diseases such as pernicious anemia. Vitamin B12 deficiency in pernicious anemia is due to a deficiency of intrinsic factor secreted by the stomach. Neurologic involvement in Vitamin B12 deficiency is characterized by subacute combined degeneration of the spinal cord and peripheral neuropathy.

Question 11

A 26-year-old woman comes to the office due to fever, sweating, heat intolerance, and shortness of breath.  Her symptoms began a week ago and have become progressively worse.  The patient has also had severe pain in the anterior neck, which radiates to the angle of the jaw and ears and is worse when she turns her head.  She adds that she has "been under a lot of stress lately since I was laid off from my job.  I have been babysitting to make some extra money, but I think one of the kids gave me 'the flu.'  I had a runny nose, cough, and fever a few weeks ago."  Medical history is unremarkable, and the patient takes no medications.  She has smoked a pack of cigarettes a day for the last 7 years, and smoked marijuana for a few months as a teenager.  The patient is not sexually active and has never been pregnant.  Her last menstrual period was 2 weeks ago.  She is adopted, and her family history is unknown.  Temperature is 38.3 C (100.9 F), blood pressure is 156/60 mm Hg, pulse is 110/min, and respirations are 22/min.  The thyroid gland is diffusely enlarged, firm, and very tender.  The extremities are warm and moist.  Eye examination shows lid lag but no proptosis.  The remainder of the examination is unremarkable.  Laboratory results are as follows:

A radioactive iodine uptake with scintigraphy in this patient is mostly likely to show which of the following?

Accepted Answer

Explanation: 11ec2b69_bedb_aa55_8f63_2932d1c11500_MD0005_00 This patient has primary hyperthyroidism (elevated T4, suppressed TSH). In light of her fever, neck pain, tender goiter, and elevated erythrocyte sedimentation rate, this is most likely due to subacute thyroiditis. Subacute (de Quervain, subacute granulomatous) thyroiditis (ST) is often preceded by an upper respiratory illness and is thought to be due to a postviral inflammatory process. Thyrotoxicosis in ST is caused by release of stored thyroid hormone due to follicular injury. Other possible findings include leukocytosis, mild anemia, and mild elevation of liver enzymes, as seen in this patient. Due to suppression of TSH, patients with ST have decreased organification of iodine and thyroid hormone synthesis. As a result, they will typically have a very low radioiodine uptake on thyroid scintigraphy. Decreased uptake is also seen in silent (painless) thyroiditis, postpartum thyroiditis, surreptitious thyroid hormone abuse, and iodine-induced thyroiditis. (Choices B and D) Focal radioiodine uptake (ie, a "hot" nodule in a "cold" thyroid background) suggests a hyperfunctioning adenoma. Patchy uptake is seen in toxic multinodular goiter. These patients may have symptomatic hyperthyroidism but are less likely to have fever or thyroid tenderness and usually have nodular rather than diffuse enlargement. In addition, the incidence of toxic nodular disease increases with age and is uncommon in young patients. (Choice C) Diffusely increased uptake is seen in Graves disease, which is due to thyrotropin receptor autoantibodies that stimulate iodine uptake and thyroid hormone synthesis. In Graves disease, goiter is less likely to be tender than in ST. Educational objective: Subacute thyroiditis is characterized by fever and a painful, diffusely enlarged thyroid, often associated with thyrotoxicosis. It is due to acute inflammation of the thyroid and release of stored thyroid hormone, leading to suppressed TSH and decreased radioactive iodine uptake. References: Subacute, silent, and postpartum thyroiditis. (http://www.ncbi.nlm.nih.gov/pubmed/22443972)

Question 12

A 46-year-old man with type 2 diabetes mellitus is scheduled for cardiac catheterization in 2 days for undiagnosed, episodic chest pain. For 15 days, the patient has had retrosternal chest pain radiating to his arm, and it is becoming more frequent. He went to the emergency department 7 days ago due to chest pain. The patient was admitted for overnight observation but left against medical advice. Three sets of cardiac enzymes tests were negative, and his ECG showed nonspecific ST-T changes. He has a history of hypertension, a 6-year history of diabetes mellitus, and does not check his blood glucose levels regularly. Medications include metformin and lisinopril. At his last emergency department visit, laboratory results (chemistry profile and complete blood count) were normal, and he was started on low-dose aspirin. He has a long smoking history, and uses alcohol occasionally. The patient has a strong family history of premature coronary artery disease. Today, blood pressure is 127/70 mm Hg and pulse is 66/min. BMI is 30 kg/m². The remainder of the examination is within normal limits. Which of the following is the best next step in management of this patient?

Accepted Answer

Explanation: Metformin's major side effects include gastrointestinal upset (eg, nausea, abdominal pain, diarrhea), decreased intestinal vitamin B12 absorption, and lactic acidosis. Lactic acidosis occurs rarely but can be fatal. Patients with normal renal and hepatic function can rarely develop lactic acidosis, but the incidence appears to be higher in those with abnormal renal function (eg, contraindicated for estimated glomerular filtration rate <30 mL/min/1.73 m²) or hepatic dysfunction. Other contraindications include active alcohol use, sepsis, and congestive heart failure (although many patients with well-compensated heart failure and normal renal function can tolerate metformin). Metformin given with large-dose intravenous iodine contrast (eg, cardiac catheterization) can increase the risk for lactic acidosis (given the potential for contrast-induced renal failure). As a result, most clinicians discontinue metformin on the day of intravenous iodine contrast exposure (regardless of baseline creatinine) and restart the drug at least 48 hours later after documenting stable renal function (Choice A). Because this patient's procedure is in 2 days, he can continue the metformin until then. (Choice B) Aspirin can cause platelet dysfunction for ≥1 week and so is usually discontinued at least 7 days before procedures with increased bleeding risk. However, aspirin can be continued safely during cardiac catheterization, and discontinuing aspirin can increase this patient's risk for myocardial infarction. (Choice C) ACE inhibitors (eg, lisinopril) have not been proven to cause increased risk for contrast-induced nephropathy. In fact, some studies have shown that ACE inhibitors may protect against contrast-induced nephropathy by blocking renal vasoconstriction. They are sometimes held on the day of the procedure only (ie, not 2 days before) to avoid potential prolonged hypotension. (Choice E) This patient is at goal blood pressure according to current guidelines and does not require additional antihypertensive therapy. Calcium channel blockers (eg, amlodipine) or thiazide diuretics can be added if this patient's blood pressure is not controlled. Educational objective: Metformin is contraindicated for patients with renal insufficiency, hepatic dysfunction, alcohol abuse, sepsis, or congestive heart failure (especially with estimated glomerular filtration rate <30 mL/min/1.73 m²). It can increase the risk for lactic acidosis when combined with large-dose intravenous iodine contrast (eg, during coronary angiography). Metformin is usually held on the day contrast is given and restarted at least 48 hours later after documenting stable renal function. References: Five things to know about...metformin and intravenous contrast. (http://www.ncbi.nlm.nih.gov/pubmed/23048079)

Question 13

A 32-year-old female comes to the physician's office for a follow-up visit.  She was recently brought to the emergency department due to head trauma, and the head CT scan performed at that time revealed an abnormal sella.  She does not have any significant medical problems.  She is currently not on any medications.  Her menstrual cycles are regular.  She is sexually active with one partner.  She does not have any children.  Her family history is insignificant.  She does not smoke cigarettes or drink alcohol.  Her physical examination is unremarkable.  Prolactin, IGF-1, LH, FSH, TSH, and free T4 are within normal limits.  Her plasma cortisol is normally suppressed after the administration of 1 mg of dexamethasone.  MRI of the pituitary region shows a 5-mm hypo-intense lesion within the pituitary gland, whose architecture is not distorted.  The rest of the brain appears normal.  What is the next best step in the management of this patient?

Accepted Answer

Explanation: The vignette describes the classic presentation of pituitary incidentaloma. Incidental pituitary tumors are very common and are usually innocuous. Majority of these tumors tend to remain very small. This patient has a small tumor and does not have clinical or laboratory evidence of any pituitary abnormalities or dysfunction. She can be safely followed with periodic assessment of the pituitary gland with MRI. (Choice A)Cosyntropin test is usually used in the evaluation of patients with adrenal insufficiency. (Choice C)Plasma ACTH levels are measured when the screening test for Cushing's syndrome (overnight dexamethasone suppression test) is positive. This patient has normal overnight dexamethasone suppression test. ACTH levels are always interpreted with simultaneous measurements of plasma cortisol. (Choice D)This patient does not require transphenoidal resection of the pituitary adenoma because she does not have any clinical features of hormonal dysfunction or any compressive symptoms. (Choice E)This patient clinically appears to be eucortisolemic. She does not need therapy with hydrocortisone. Educational Objective: Incidentally discovered small lesions in the sellar region are very common. Patients with a small mass or lesion without any hormonal dysfunction can be safely followed by periodic assessment of the pituitary gland with MRI.

Question 14

A 60-year-old Caucasian male complains of difficulty swallowing which has rapidly worsened within the last two weeks.  The patient noticed a swelling on the front of his neck that started growing for the past month.  He was otherwise in his normal state of health.  He also complains of fevers, night sweats, and weight loss.  He denies cough, dyspnea, chest pain, headache, abdominal pain, skin rashes, and urinary symptoms.  His past medical history is significant for mild hypertension treated with hydrochlorothiazide, as well as a small goiter for the past 10 years.  He states that his blood tests for thyroid hormone levels were normal, and he has never taken thyroid hormone preparations in the past.  His family history is positive for a mother and several other family members with hypothyroidism.  He has a smoking history of 15-pack-years but quit 25 years ago.  He does not drink alcohol.  Physical examination reveals a large, irregular, non-tender swelling over the inferior aspect of his neck.  The lower margin of this swelling can not be palpated.  He develops facial plethora and venous engorgement of the neck veins after raising his arms above the shoulder for 20 seconds.  CBC and basic chemistries are normal.  TSH is 26.0 μU/ml (normal 0.35-5.0 μU/ml) and free T4 is 0.2 μg/dl (normal 0.8 to 1.8 μg/dl).  Antithyroid peroxidase antibodies are detected in very high titers.  What is the most likely diagnosis in this patient?

Accepted Answer

Explanation: This patient describes a prior history of a mild goiter; however, there has been a recent rapid increase in the size of his thyroid gland which is likely the cause of his difficulty swallowing. Pemberton's test consists of having the patient raise his arms over his head for up to 60 seconds. The presence of facial plethora or engorgement of neck veins is strongly suggestive that the thyroid is the source of the patient's obstructive symptoms. Inability to palpate the inferior edge of the thyroid is also suggestive that there is substernal extension. This patient's laboratory tests consisting of elevated TSH and low T4 confirm that he is hypothyroid. The positive antithyroid peroxidase antibodies make Hashimoto's thyroiditis the most likely cause of this patient's hypothyroidism. Patients with Hashimoto's often have a mildly enlarged thyroid gland. This may have been the cause of the patient's mild goiter over the past 10 years, but would not explain the rapid growth of the patient's thyroid gland over the past several weeks. The most likely diagnosis in this case is thyroid lymphoma. The primary risk factor for the development of thyroid lymphoma is preexisting Hashimoto's thyroiditis in which there is chronic lymphocytic infiltration of the thyroid gland. Thyroid lymphoma should be suspected in patients with a history of Hashimoto's who have a rapidly enlarging thyroid gland and subsequent obstructive symptoms. (Choice A) Colloid goiter is a cause of thyroid enlargement in adolescent girls who have normal thyroid function tests and negative antithyroid antibodies. (Choice B) Follicular thyroid cancer may present as a palpable nodule but should not be this rapidly progressive. (Choice C) Medullary thyroid cancer usually presents as a thyroid nodule, sometimes in the presence of Multiple Endocrine Neoplasm. It is a neoplasm of the thyroid gland C cells and typically has an elevated calcitonin level. (Choice D) Papillary thyroid cancer also usually presents as a palpable nodule but should not progress this rapidly. Educational objective: Thyroid lymphoma usually presents as rapid enlargement of the thyroid gland in patients with Hashimoto's thyroiditis. Pemberton's sign is the presence of facial plethora or neck vein distention when the arms are raised and confirms an enlarged thyroid gland as the cause of esophageal obstructive symptoms.

Question 15

A 26-year-old white woman who is a long distance runner comes to your office.  She trains daily and participates frequently in marathons and other long-distance competitive events all around the country.  She denies smoking or alcohol drinking, and says that she follows a healthy, low-fat diet.  Her last menstrual period was three years ago, but this is not a problem for her as she does not want to get pregnant "at least in the next five years."  After an extensive work-up, her amenorrhea was attributed to exercise.  She is 168 cm (5'6'') tall and weighs 50 kg (110 lbs).  Her blood pressure is 100/60 mmHg, pulse is 58/min, and respirations are 14/min.  Physical examination shows no abnormality.  You alert the patient that her amenorrhea poses the risk of another condition.  Which of the following conditions are you referring to?

Accepted Answer

Explanation: Females who maintain a lower weight or body mass index (BMI) due to the sport or activity that they regularly engage in (e.g. ballet dancers, gymnasts, and runners) may become hypoestrogenic and present with exercise-induced amenorrhea. They are at special risk of developing osteopenia, and even osteoporosis. Spontaneous fractures have been reported in these types of patients, with osteoporosis or osteopenia confirmed through bone densitometry. Treatment consists of improving caloric intake; if this is not possible, patients are started on hormonal replacement with oral contraceptives and supplementation with calcium and vitamin D. (Choice E)Paradoxically, there is a tendency toward hypercholesterolemia, not the opposite. (Choice C)There is no risk of early menopause, but exercise-induced amenorrhea can mimic early menopause because of estrogen deficiency. (Choices A and B)Exercise-induced amenorrhea is a diagnosis of exclusion. Thyroid hormone and prolactin level determinations are necessary in the evaluation of this patient because one/both of these may be the underlying cause (but not a complication or aftermath) of the amenorrhea. Educational objective: Exercise-induced amenorrhea is due to a decrease in the pulsatile secretion of LH, which leads to a decline in estrogen production. It can lead to osteopenia, osteoporosis, breast and vaginal atrophy, mild hypercholesterolemia, and infertility.

Question 16

A 40-year-old woman comes to the clinic after noticing a small swelling in the front of her neck.  She has no pain, dysphagia, hoarseness, or difficulty breathing.  She also has no hyper- or hypothyroid symptoms such as heat or cold intolerance, fatigue, or weight changes.  Physical examination shows a mobile nodule in her left thyroid lobe.  The patient has no history of neck irradiation or family history of thyroid illness.  She currently takes no medications.  The rest of the physical examination is unremarkable. 
Which of the following is the best next step in evaluation of this patient?

Accepted Answer

Explanation: 11ec2b69_bedb_3522_8f63_59eb14141e44_MD0005_00 Patients with thyroid nodules should be evaluated for risk of malignancy (eg, family history, radiation exposure in childhood, cervical lymphadenopathy), compressive symptoms (eg, hoarseness, difficulty swallowing), and functional status (eg, euthyroid, hyperthyroid, hypothyroid). Definitive diagnosis of thyroid cancer can be made with fine-needle aspiration (FNA), but the goal of the clinical assessment is to determine which patients will require this invasive procedure. Initial testing to evaluate a thyroid nodule should include a serum TSH level and thyroid ultrasound. Patients with suspicious ultrasound findings (eg, large size, hypoechoic, microcalcifications, internal vascularity) or cancer risk factors should undergo FNA (Choice B). In addition, patients with normal or elevated TSH have a higher risk of malignancy and should be considered for FNA depending on ultrasound findings. Low TSH levels suggest a hyperfunctioning nodule, which has a lower risk of malignancy and should be evaluated with thyroid scintigraphy (Choice C). A "hot" nodule (increased isotope uptake in the nodule with decreased surrounding uptake) is rarely malignant and may be treated as benign hyperthyroidism. (Choice A) A CT scan of the neck can diagnose retrosternal goiter in patients with compressive symptoms (eg, hoarseness, dysphagia), but it is otherwise less sensitive than thyroid ultrasound for evaluation of nodules. (Choice D) Serum anti-thyroid peroxidase antibody titers are elevated in patients with chronic autoimmune (Hashimoto) thyroiditis, which usually presents with hypothyroidism and a normal-sized or diffusely enlarged thyroid. Educational objective: Thyroid nodules should be evaluated with TSH and thyroid ultrasound. Patients with suspicious findings on ultrasound should undergo fine-needle aspiration with cytology of the nodule. Patients with low TSH should have a radionuclide thyroid scan. References: Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer. (http://www.ncbi.nlm.nih.gov/pubmed/19860577)

Question 17

A 26-year-old woman comes to the office due to fever, sweating, heat intolerance, and shortness of breath.  Her symptoms began a week ago and have become progressively worse.  The patient has also had severe pain in the anterior neck, which radiates to the angle of the jaw and ears and is worse when she turns her head.  She adds that she has "been under a lot of stress lately since I was laid off from my job.  I have been babysitting to make some extra money, but I think one of the kids gave me 'the flu.'  I had a runny nose, cough, and fever a few weeks ago."  Medical history is unremarkable, and the patient takes no medications.  She has smoked a pack of cigarettes a day for the last 7 years, and smoked marijuana for a few months as a teenager.  The patient is not sexually active and has never been pregnant.  Her last menstrual period was 2 weeks ago.  She is adopted, and her family history is unknown.  Temperature is 38.3 C (100.9 F), blood pressure is 156/60 mm Hg, pulse is 110/min, and respirations are 22/min.  The thyroid gland is diffusely enlarged, firm, and very tender.  The extremities are warm and moist.  Eye examination shows lid lag but no proptosis.  The remainder of the examination is unremarkable.  Laboratory results are as follows:
 Which of the following is the best treatment for this patient?

Accepted Answer

Explanation: Subacute thyroiditis (ST) is a self-limited condition. The hyperthyroid phase may last a few weeks, followed by a transient hypothyroid phase and eventual return to a euthyroid state. Treatment is primarily supportive, and most cases can be managed with a nonsteroidal anti-inflammatory drug to relieve pain; glucocorticoids can be used in severe or refractory cases. In addition, patients can be given a beta blocker (eg, propranolol, atenolol) to minimize the hyperadrenergic symptoms of thyrotoxicosis (eg, sweating, palpitations). (Choices A and E) Suppurative infection of the thyroid gland (infectious thyroiditis) is a rare condition that causes high-grade fever and pain at the thyroid gland. Patients will often have evidence of a thyroid abscess on examination or ultrasound, but are usually euthyroid as involvement of the thyroid gland is focal. Bacterial thyroid infections are treated with systemic antibiotics, and surgical drainage may be required. (Choice B) Thyrotoxicosis in ST is due to release of preformed thyroid hormone. Antithyroid drugs (eg, methimazole), which work by decreasing the synthesis of thyroid hormones, are ineffective. (Choice D) Radioiodine thyroid ablation is used for definitive treatment of Graves disease and nodular thyroid disease. It is not necessary in ST, which is a self-limited illness, and would not be effective as thyroid uptake of the radioiodine dose is very low. Educational objective: Subacute thyroiditis is a self-limited condition. Treatment consists primarily of nonsteroidal anti-inflammatory drugs for pain relief and beta blockers to minimize thyrotoxic symptoms. Severe or refractory cases may require glucocorticoid therapy.

Question 18

A 30-year-old woman comes to the office due to tingling and numbness in both of her distal lower extremities for the last 3 months. Her symptoms are gradually worsening. She also has had intense fatigue. She has not had any weight change, constipation, skin dryness, headaches, or visual changes. The patient was diagnosed with primary hypothyroidism secondary to Hashimoto thyroiditis when she was 10 years old. She is currently on 100 mcg per day of levothyroxine orally. Her mother also has hypothyroidism. The patient does not use tobacco, alcohol, or recreational drugs. Her menstrual cycles have been irregular for the last 6 months. Her last menstrual period was 2 months ago. She is sexually active with one partner. Blood pressure is 114/78 mm Hg and pulse is 72/min. She weighs 69 kg (152 lbs) and is 163 cm (5'4") tall. Her thyroid is nonpalpable. Her mucous membranes are moist and pale. Her tongue appears to be bald. She does not have any scleral icterus. Vibration and proprioception are decreased in both of her lower extremities distally. Pain and temperature sensations appear normal. Her ankle jerks are absent, but other reflexes are brisk. Babinski is present, and Romberg signs is positive. The rest of the physical examination is unremarkable. Stool obtained from the rectal examination is negative for occult blood. Laboratory results reveal a hemoglobin of 8 g/dL and hematocrit of 24%. Her total leukocyte count is 3,200/mm³. Her platelet count is 300,000/mm³. Basic serum chemistries are within normal limits. Her total T4 level is 8.2 mcg/dL (normal 4-12 mcg/dL) and TSH level is 2.4 micro IU/mL. Which of the following is most crucial to monitor during the first few days of treatment in the above patient?

Accepted Answer

Explanation: Treatment with vitamin B12 in patients with moderate to severe megaloblastic anemia can cause hypokalemia, which can sometimes be very severe and life-threatening. Hypokalemia results following the uptake of potassium by newly forming red blood cells. Serum potassium levels should therefore be monitored during the first 48 hours. Potassium is replaced depending on the measured serum potassium levels. Some physicians transfuse packed red blood cells in patients with severe megaloblastic anemia before vitamin B12 supplementation to prevent hypokalemia. (Choices A, B, D, and E)These parameters are not necessary to monitor during the first few days of B12 therapy. Educational objective: Patients with moderate to severe megaloblastic anemia can have severe hypokalemia during the first 48 hours of treatment with vitamin B12. Close monitoring and supplementation of potassium is required during this period.

Question 19

A 29-year-old man comes to the emergency department complaining of palpitations, sweating, and severe headache.  His symptoms resolve spontaneously by the time he is evaluated.  He has had at least 2 similar episodes during the past 2 months.  The patient's family history is unremarkable.  He does not use tobacco, alcohol, or illicit drugs.  His primary care provider saw him after the first episode and prescribed an anxiolytic medication.  However, the patient felt drowsy at his job and stopped the medication.  Physical examination shows a thin man who appears anxious and diaphoretic.  The thyroid is normal to palpation without any obvious nodules.  His temperature is 36.7 C (98 F), blood pressure is 126/84 mm Hg, pulse is 86/min, and respirations are 16/min.  During his prior emergency department visit for an identical episode, his blood pressure was 150/100 mm Hg and pulse was 120/min.  The laboratory results at that time showed normal thyroid function tests. Endocrine studies yield results highly suspicious of a neuroendocrine tumor.  Which of the following is the best next step in management of this patient?

Accepted Answer

Explanation: 11ec2b69_bed6_ef5c_8f63_17e5547c412f_MD0005_00 Abdominal imaging is the next step for localizing a pheochromocytoma after biochemical confirmation of the tumor. Both CT and MRI are highly sensitive for localizing pheochromocytomas, which are usually located in the adrenal glands. Clinically active pheochromocytomas are typically >4-4.5 cm in diameter and have a high tissue density on CT scan (generally 40-50 Hounsfield units). Larger tumors are more likely to have central necrosis and calcification. MRI usually shows high intensity on T2-weighted images. Patients with negative abdominal imaging usually require further testing such as the metaiodobenzylguanidine (MIBG) scan, which is a functional scintigraphy with I¹²³ labeled MIBG (Choice C). MIBG resembles norepinephrine, is taken up by adrenergic tissue, and can detect tumors not detected by CT or MRI. In addition, MIBG is also performed in patients with large tumors (>5 cm diameter) as they have a higher risk of malignancy and possible extra-adrenal disease. Younger patients and those with a familial disorder also require MIBG after initial CT or MRI as they have a higher risk of extra-adrenal and multiple tumors. ¹²³ (Choices A and E) Removal of the tumor is performed only after localization, adequate preoperative control of blood pressure for 10-14 days with an alpha blocker, and intravascular fluid volume repletion with liberal fluid and salt. Intraoperative complications are much higher with inadequate preoperative alpha blockade and intravascular fluid deficiency. Beta blockers are given only to patients with adequate and complete alpha blockade. Beta-blocking agents started before alpha blockade can lead to paradoxical increase in blood pressure. (Choice B) Chromogranin A (CGA) is stored and released from dense-core secretory granules of neuroendocrine cells and is elevated in nearly 80% of patients with pheochromocytoma. However, elevated CGA levels are not specific for pheochromocytoma and can be elevated in other neuroendocrine tumors (eg, carcinoid) or in patients with mild renal insufficiency. CGA is sometimes used in addition to measuring catecholamine and metanephrine levels in patients with possible drug interference to biochemical testing. Educational objective: Abdominal imaging (CT or MRI) is the next step for localizing a pheochromocytoma after biochemical confirmation of the tumor. Patients with negative abdominal imaging usually require further testing, such as the metaiodobenzylguanidine scan. Removal of the tumor is performed only after adequate preoperative control of blood pressure for 10-14 days with an alpha blocker, and intravascular fluid volume repletion with liberal fluid and salt. Beta blockers are given only to patients with adequate and complete alpha blockade. References: Phaeochromocytoma. (http://www.ncbi.nlm.nih.gov/pubmed/16112304) The utility of metaiodobenzylguanidine (MIBG) scintigraphy in patients with pheochromocytoma. (http://www.ncbi.nlm.nih.gov/pubmed/18193324)

Question 20

A 40-year-old woman comes to the clinic after noticing a small swelling in the front of her neck.  She has no pain, dysphagia, hoarseness, or difficulty breathing.  She also has no hyper- or hypothyroid symptoms such as heat or cold intolerance, fatigue, or weight changes.  Physical examination shows a mobile nodule in her left thyroid lobe.  The patient has no history of neck irradiation or family history of thyroid illness.  She currently takes no medications.  The rest of the physical examination is unremarkable. After performing the appropriate investigation, a diagnosis of papillary thyroid cancer is made.  Which of the following is the best next step in management of this patient?

Accepted Answer

Explanation: Management of differentiated thyroid cancer (papillary, follicular) depends on the extent of disease, patient age, and comorbid conditions. Surgery is recommended for differentiated thyroid cancer in patients who are good surgical candidates, but the specific surgery and adjuvant therapies depend on the stage at diagnosis. Ultrasound of the neck and cervical lymph nodes is the primary modality for initial staging of thyroid cancer. Total thyroidectomy is recommended for large papillary thyroid cancers, extra-thyroid tumor extension, distant metastases, and in patients with a history of head or neck radiation exposure (Choice C). More extensive neck dissection is indicated for patients with involvement of adjacent neck structures or regional lymph nodes. Papillary cancers <1 cm (microcarcinoma) with no lymph node involvement usually have a favorable prognosis and may be managed with simple thyroid lobectomy (Choice D). (Choice A) TSH is a growth factor for papillary thyroid cancer. High-dose levothyroxine is used following thyroidectomy to replace normal thyroxine production and to suppress TSH stimulation of any potentially residual malignant tissue. (Choice B) Radioactive iodine is used as adjuvant therapy following thyroidectomy for patients at risk for metastatic disease, such as those with very large tumors, invasive tumors, or lymph node involvement. Educational objective: Ultrasound of the neck and cervical lymph nodes is the primary modality for initial staging of thyroid cancer. Patients with a small (<1 cm) papillary thyroid tumor may be treated with thyroid lobectomy. Total thyroidectomy is recommended for tumors >1 cm in diameter, tumor extension outside of the thyroid, distant metastases, and in patients with a history of head or neck radiation exposure. References: Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer. (http://www.ncbi.nlm.nih.gov/pubmed/19860577)

Exam 1: Advanced Clinical Medicine