A 68-year-old woman comes to the emergency department due to a month-long history of increasing palpitations. She has had no associated chest pain or shortness of breath but has experienced unusual fatigability. The patient has also noted a 4-kg (8.8-lb) weight loss on her home scale and has been waking with increasing frequency at night to urinate. She was diagnosed with osteopenia on bone densitometry at age 65; she increased her intake of "milk, yogurt, cheese, and other foods with lots of calcium" and started a vitamin D supplement, but repeat DXA 2 months ago revealed a significant interval decline in bone density. The patient's medical history is otherwise unremarkable, and she does not use tobacco, alcohol, or illicit drugs. Her mother died of breast cancer at age 62 and her father died in a motor vehicle collision at age 40. Temperature is 36.7 C (98 F), blood pressure is 151/68 mm Hg, pulse is 122/min, and respirations are 16/min. The thyroid gland is diffusely enlarged and nontender. Lid lag is noted on eye examination. The lungs are clear to auscultation. The heart has an irregularly irregular tachycardia with a variable intensity of S1. Laboratory results are as follows: Which of the following should be addressed next in treatment of this patient's condition?

Question

A 68-year-old woman comes to the emergency department due to a month-long history of increasing palpitations.  She has had no associated chest pain or shortness of breath but has experienced unusual fatigability.  The patient has also noted a 4-kg (8.8-lb) weight loss on her home scale and has been waking with increasing frequency at night to urinate.  She was diagnosed with osteopenia on bone densitometry at age 65; she increased her intake of "milk, yogurt, cheese, and other foods with lots of calcium" and started a vitamin D supplement, but repeat DXA 2 months ago revealed a significant interval decline in bone density.  The patient's medical history is otherwise unremarkable, and she does not use tobacco, alcohol, or illicit drugs.  Her mother died of breast cancer at age 62 and her father died in a motor vehicle collision at age 40.  Temperature is 36.7 C (98 F), blood pressure is 151/68 mm Hg, pulse is 122/min, and respirations are 16/min.  The thyroid gland is diffusely enlarged and nontender.  Lid lag is noted on eye examination.  The lungs are clear to auscultation.  The heart has an irregularly irregular tachycardia with a variable intensity of S1.  Laboratory results are as follows:  Which of the following should be addressed next in treatment of this patient's condition?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bec4_c6c5_8f63_7743567b6d72_MD0005_00 This patient has symptomatic hyperthyroidism, likely due to Graves disease (diffuse goiter, elevated free T4, suppressed TSH). She also has hyperthyroid complications including rapid atrial fibrillation (irregularly irregular tachycardia with variable S1 intensity) and progressive bone loss with mild hypercalcemia. Cardiovascular manifestations are common and can include other supraventricular arrhythmias (eg, atrial flutter, paroxysmal atrial tachycardia), hypertension, coronary vasospasm, myocardial ischemia, and congestive heart failure. Thyroid hormones cause an increase in sympathetic activity due to increased responsiveness to catecholamines, which is responsible for many of the symptoms of hyperthyroidism (eg, palpitations, tachycardia, anxiety, tremors). Atrial fibrillation occurs in 10%-20% of patients with hyperthyroidism. Beta blockers (eg, propranolol, atenolol) are recommended to ameliorate hyperadrenergic symptoms and control heart rate and should be initiated as soon as hyperthyroidism is noted. The patient can then be considered for specific treatment including antithyroid medications (eg, methimazole), radioiodine ablation, or thyroidectomy. However, these interventions can take several weeks, and so patients should be treated initially with beta blockers to manage symptoms caused by excessive sympathetic activity (Choice C). (Choice B) Hyperglycemia is common in thyrotoxicosis due to insulin resistance. However, this patient has only mild hyperglycemia, which is likely to improve with treatment of the underlying condition. Increased urination is common in hyperthyroidism due to increased thirst and hypercalcemia and does not indicate more severe hyperglycemia. (Choice D) Electrical cardioversion can restore sinus rhythm in atrial fibrillation, but patients with hyperthyroidism and an uncorrected hyperadrenergic state will likely fail to convert or maintain sinus rhythm. Patients should be treated first with beta blockers, followed by antithyroid therapy to achieve euthyroidism prior to cardioversion. Cardioversion also increases the risk for thromboembolism in patients without adequate anticoagulation. (Choice E) Systemic glucocorticoids inhibit conversion of T4 to T3 and are occasionally used for life-threatening hyperthyroidism/thyroid storm, which is characterized by pronounced tachycardia (eg, >140/min), hyperpyrexia, and altered mental status. They are also used in some patients with subacute (de Quervain) thyroiditis (which would cause neck pain) who do not respond to nonsteroidal anti-inflammatory drugs and for certain patients with amiodarone-induced thyrotoxicosis. Educational objective: Cardiovascular manifestations (eg, supraventricular arrhythmias) are common in hyperthyroidism due to excessive sympathetic activity. Patients with symptomatic tachycardia or those in atrial fibrillation must be treated initially with beta blockers to control symptoms and heart rate. References: Hyperthyroidism and cardiovascular complications: a narrative review on the basis of pathophysiology. (http://www.ncbi.nlm.nih.gov/pubmed/24273583) Short-term effects of ß-adrenergic antagonists and methimazole in new-onset thyrotoxicosis caused by Graves' disease. (http://www.ncbi.nlm.nih.gov/pubmed/22975536)

A 68-Year-Old Woman Comes to the Emergency Department Due to a Month-Long