A 30-year-old woman complains of palpitations, fatigue, heat intolerance, and insomnia. She is otherwise healthy. She and her husband desire children and are not interested in contraception. On physical examination, her extremities are warm and she is tachycardic. There is diffuse thyroid enlargement and proptosis, as well as thickening of the skin in the pretibial area. Laboratory testing reveals a free T4 value of 3.2 ng/dL (normal 0.9-2.4) with an undetectably low TSH level. Radioiodine uptake at 24 hours is 42% (normal 10%-30%). What is the best treatment plan for this patient?
Antithyroid drugs are the treatment of choice in a patient with Graves disease who may become pregnant. Iodine 131 has been used successfully in Graves disease and is a reasonable option if the patient is willing to practice secure contraception for at least 6 months. However, it often causes permanent hypothyroidism and may worsen ophthalmopathy in some patients. The treatment of choice is the oral agent propylthiouracil. Propylthiouracil is chosen in cases such as this owing to low transplacental transfer. Methimazole is preferred in men and non–childbearing women because it can be given once daily. Propranolol relieves the adrenergic symptoms resulting from Graves disease but will not treat the underlying disease. Subtotal thyroidectomy is reserved for thyrotoxic pregnant women who have had severe side effects to medication. Surgical complications include hypoparathyroidism and recurrent laryngeal nerve injury. Corticosteroids are used in thyroid storm but not in the stable patient with Graves disease.
A 50-year-old woman is evaluated for hypertension. Her blood pressure is 130/98. She complains of polyuria and mild muscle weakness. She is on no blood pressure medication. On physical examination, the PMI is displaced to the sixth intercostal space. There is no sign of congestive heart failure and no edema.
Laboratory values are as follows:
The patient denies the use of diuretics or over-the-counter agents to decrease fluid retention or promote weight loss. She does not eat licorice.
Which of the following is the most useful initial diagnostic test?
The patient has diastolic hypertension with unprovoked hypokalemia. She is not taking diuretics. There is no edema on physical examination. Inappropriate aldosterone overproduction is a prime consideration in hypertension with hypokalemia. Hypersecretion of aldosterone increases distal tubular exchange of sodium for potassium with progressive depletion of body potassium. The hypertension is caused by increased sodium absorption. Interestingly, peripheral edema does not occur despite the sodium retention. Elevated aldosterone level and low plasma renin activity suggest the diagnosis of primary hyperaldosteronism. The plasma aldosterone to renin ratio is a useful screening test. A high ratio of greater than 30 strongly suggests aldosterone oversecretion. Lack of suppression of aldosterone (ie, autonomous overproduction), however, is necessary to definitively diagnose primary hyperaldosteronism. High aldosterone levels that are not suppressed by a 2-L saline load prove the diagnosis. CT scan of the adrenal glands is then ordered to distinguish an aldosterone-producing tumor from bilateral adrenal hyperplasia. Renin levels alone lack specificity. Suppressed renin activity occurs in about 25% of hypertensive patients with essential hypertension. Twenty-four-hour urine for free cortisol would be used in the workup of a patient with Cushing syndrome. Urinary metanephrine is a screening test for pheochromocytoma. Renal angiography is a test for renal artery stenosis. None of these diagnoses are as likely as hyperaldosteronism, given this clinical presentation.
A 36-year-old woman presents with delirium and congestive heart failure. Her husband indicates that she has been losing weight and becoming more anxious and irritable over the past 3 months. Over the past several weeks she has developed dyspnea and peripheral edema. She has previously been healthy and takes no medications. Her husband says that she drinks alcohol moderately and has never used illicit drugs. On physical examination, she is awake, anxious, and confused. Her temperature is 38°C and her heart rate is 142 and regular. She has jugular venous distension to 16 cm above the sternal angle as well as bibasilar rales. In addition, she has a diffuse goiter with a soft bruit over each lobe, as well as a stare expression and exophthalmos. CXR shows pulmonary edema and cardiomegaly. Her EKG reveals sinus tachycardia but is otherwise unremarkable. What is the best approach to management of this patient?
This patient has thyroid storm, a medical emergency. The presence of fever, severe tachycardia, congestive heart failure, and CNS changes (delirium, psychosis, seizure, or coma) help separate thyroid storm from uncomplicated hyperthyroidism. Other factors that point toward storm or impending storm include atrial fibrillation, abdominal symptoms, jaundice, and the absence of a precipitating event. Even with treatment, the mortality of thyroid storm can be 10% to 20%, so admission to an intensive care unit for close monitoring is mandatory. Propranolol, generally contraindicated in decompensated congestive heart failure, improves the high-output CHF and, in high doses, helps block conversion of T4 to the active hormone T3 . Propylthiouracil blocks the uptake and organification of iodide by the thyroid gland, and oral iodides prevent the release of preformed T4 and T3 from the thyroid gland. Relative adrenal insufficiency is often present, so corticosteroids are administered routinely in thyroid storm. Patients with mild to moderate hyperthyroidism are usually evaluated and treated as an outpatient. Impending or threatened thyroid storm can be managed on the general medicine ward or in the ICU as clinically indicated, but overt thyroid storm (as in this patient) requires ICU care. If an outpatient has a diffuse goiter and if the cause of hyperthyroidism is unclear, radioiodine uptake can be measured to distinguish Graves disease (normal or increased RAI uptake) from painless thyroiditis (low RAI uptake). In thyroid storm, however, immediate treatment takes precedence over measuring the 24-hour radioiodide uptake. Furthermore, thyroiditis rarely, if ever, causes thyroid storm. Thyroid-stimulating immunoglobulin assays are rarely needed to diagnose Graves disease. Methimazole is often used in mild to moderate hyperthyroidism because of ease of dosing, but propylthiouracil blocks T4 to T3 conversion and should be used in thyroid storm. Although the febrile, tachycardic patient with hyperthyroidism can appear septic, other features of this case strongly suggest that thyroid storm, not infection, is the cause of her illness. Antibiotics without proper management of her hyperthyroidism would probably prove fatal.
A 58-year-old man is referred to your office after evaluation in the emergency room for abdominal pain. The patient was diagnosed with gastritis, but a CT scan with contrast performed during the workup of his pain revealed a 2-cm adrenal mass. The patient has no history of malignancy and denies erectile dysfunction. Physical examination reveals a BP of 122/78 with no gynecomastia or evidence of Cushing syndrome. His serum potassium is normal. What is the next step in determining whether this patient’s adrenal mass should be resected?
This patient has what is commonly referred to as an adrenal incidentaloma. If the mass is greater than 1 cm, the first step is to determine whether it is a functioning or nonfunctioning tumor via measurement of serum metanephrines (pheochromocytoma) and dexamethasone suppressed cortisol (Cushing syndrome) levels. As the patient has no history of malignancy, a CT-guided fine-needle aspiration is not required. The patient has normal BP and potassium; therefore, plasma aldosterone/plasma renin ratio to evaluate primary hyperaldosteronism is not required. There are no signs of feminization or erectile dysfunction, so sexsteroid measurement is not indicated. Unenhanced CT would be required after appropriate serum workup to determine true size and characteristics (Hounsfield units [HU]). Malignant indicators include large-size (> 4-6 cm), irregular margins, soft tissue calcifications, tumor inhomogeneity, or high unenhanced CT attenuation values greater than 10 HU. CT scans should be performed in 6 months and again in 1 year to ensure stability of the adrenal mass, but only after a functioning tumor has been excluded.
On routine physical examination, a 28-year-old woman is found to have a thyroid nodule. She denies pain, hoarseness, hemoptysis, or local symptoms. Serum TSH is normal. Which of the following is the best next step in evaluation?
Palpable thyroid nodules are common, occurring in about 5% of all adults. Thyroid fine-needle biopsy now plays a central role in the differential diagnosis of thyroid nodules. If the TSH is normal, as it is in this patient, then fine-needle aspirate biopsy is indicated and will distinguish cysts from benign lesions or neoplasms. In about 14% of such cases, biopsy will be suspicious or diagnostic for malignancy and surgery will be necessary. Thyroid scan can show a “hot” nodule, which is almost always benign, but the TSH is suppressed in most autonomously overactive nodules. Thyroid sonography by itself cannot rule out malignancy in palpable nodules. Thyroid cancer can present even in a young, asymptomatic patient like this, so option e would not be appropriate.
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