A 33-year-old, previously healthy woman is brought to the emergency department in severe respiratory distress. The patient's shortness of breath began abruptly 2 days ago and has progressively worsened. Over the past 6 months she has had loss of appetite, loose stools, and lightheadedness. Temperature is 38.6 C (101.5 F), blood pressure is 178/102 mm Hg, pulse is 120/min, and respirations are 38/min. Pulse oximetry is 86% on nonrebreather mask. Examination shows marked respiratory distress with intercostal and supraclavicular retractions. The skin is diaphoretic and warm. Cardiopulmonary examination reveals diffuse rales, an S3, and a 2/6 systolic ejection murmur over the left sternal border. The extremities have 1+ pitting edema bilaterally. The patient is placed on positive airway pressure ventilation with improvement in oxygen saturation to 94%. ECG shows sinus tachycardia. Chest x-ray reveals a mildly enlarged cardiac silhouette with pulmonary vascular congestion. Echocardiography shows pulmonary hypertension, left atrial enlargement, and a left ventricular ejection fraction of 75%; there are no wall motion abnormalities. Troponin I is 0.06 ng/mL (normal:

Question

A 33-year-old, previously healthy woman is brought to the emergency department in severe respiratory distress.  The patient's shortness of breath began abruptly 2 days ago and has progressively worsened.  Over the past 6 months she has had loss of appetite, loose stools, and lightheadedness.  Temperature is 38.6 C (101.5 F), blood pressure is 178/102 mm Hg, pulse is 120/min, and respirations are 38/min.  Pulse oximetry is 86% on nonrebreather mask.  Examination shows marked respiratory distress with intercostal and supraclavicular retractions.  The skin is diaphoretic and warm.  Cardiopulmonary examination reveals diffuse rales, an S3, and a 2/6 systolic ejection murmur over the left sternal border.  The extremities have 1+ pitting edema bilaterally.  The patient is placed on positive airway pressure ventilation with improvement in oxygen saturation to 94%.  ECG shows sinus tachycardia.  Chest x-ray reveals a mildly enlarged cardiac silhouette with pulmonary vascular congestion.  Echocardiography shows pulmonary hypertension, left atrial enlargement, and a left ventricular ejection fraction of 75%; there are no wall motion abnormalities.  Troponin I is 0.06 ng/mL (normal: <0.04 ng/mL).  Which of the following is the most appropriate diagnostic step in management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec2b69_be01_01bf_8f63_a5aa2fa5bf98_MD0005_00 This patient's severe respiratory distress and hypoxemia are likely due to pulmonary edema from decompensated heart failure; peripheral edema and an S3 also support the diagnosis. Her warm skin, elevated pulse pressure, and hyperdynamic left ventricular ejection fraction (LVEF) are consistent with high-output heart failure. Thyroid storm, a severe manifestation of hyperthyroidism and a potential cause of high-output heart failure, is suggested by this patient's fever and recent history of anorexia and loose stools. Therefore, diagnostic confirmation with serum TSH is most appropriate. High-output heart failure typically results from a disturbance that causes decreased systemic vascular resistance (SVR). In hyperthyroidism, reduced SVR results from widespread vasodilation caused by increased metabolic demand in the tissues and direct vasodilatory effects of thyroid hormone. There is reflexively increased cardiac output to help maintain blood pressure (direct myocardial effects of thyroid hormone on the myocardium increase contractility and heart rate to further increase cardiac output). High-output heart failure disturbance The high-stroke volume, hyperdynamic state is characterized by elevated pulse pressure and warm extremities, and a pulmonic flow murmur is often present. Due to low SVR, blood returns to the heart quickly and easily, resulting in markedly increased venous return. Despite a sustained increase in cardiac output, the left ventricle is unable to keep up with venous return and decompensated heart failure develops. (Choice A) Antinuclear antibodies are nonspecific and present in many types of autoimmune disease. They are highly sensitive for and useful in ruling out systemic lupus erythematosus but have little use for investigating suspected hyperthyroidism. (Choice B) Coronary angiography is useful in evaluating suspected ischemic heart failure, which usually presents with reduced ejection fraction (ie, low-output heart failure) and often segmental wall motion abnormalities. A slight troponin elevation (due to increased myocardial oxygen demand) is common with decompensated heart failure of any cause and is not an indication for coronary angiography. (Choice C) CT pulmonary angiography is used to diagnose pulmonary embolism. Acute pulmonary embolism typically presents with respiratory distress, hypoxemia, tachycardia, and elevated pulmonary arterial pressure, but pulmonary edema and left atrial dilation are not expected. (Choice E) Certain viruses (eg, coxsackie) can cause dilated cardiomyopathy that may be accompanied or preceded by a viral prodrome (eg, fever, diarrhea). However, reduced LVEF is expected with dilated cardiomyopathy. Educational objective: High-output heart failure results from decreased systemic vascular resistance that leads to increased cardiac output and increased venous return. Hyperthyroidism is a common cause.

A 33-Year-Old, Previously Healthy Woman Is Brought to the Emergency