A 52-year-old man comes to the emergency department with shortness of breath and dry cough. The patient has been feeling weak over the last several days with some dyspnea on exertion, which he attributes to work-related stress and fatigue. Earlier this morning, he woke up with persistent breathing difficulty that prompted him to come to the emergency department. The patient has a history of mild intermittent asthma for which he occasionally uses an albuterol inhaler. His family history is insignificant. The patient's temperature is 37.1 C (98.8 F), blood pressure is 117/72 mm Hg, pulse is 89/min, and respirations are 18/min. Laboratory analysis reveals a markedly elevated serum brain natriuretic peptide level. Which of the following clinical signs would best correlate with this finding in this patient?

Question

A 52-year-old man comes to the emergency department with shortness of breath and dry cough.  The patient has been feeling weak over the last several days with some dyspnea on exertion, which he attributes to work-related stress and fatigue.  Earlier this morning, he woke up with persistent breathing difficulty that prompted him to come to the emergency department.  The patient has a history of mild intermittent asthma for which he occasionally uses an albuterol inhaler.  His family history is insignificant.  The patient's temperature is 37.1 C (98.8 F), blood pressure is 117/72 mm Hg, pulse is 89/min, and respirations are 18/min.  Laboratory analysis reveals a markedly elevated serum brain natriuretic peptide level.  Which of the following clinical signs would best correlate with this finding in this patient?

Quizplus · Accepted Answer

This clinical presentation - progressive dyspnea, fatigue, and elevated brain natriuretic peptide (BNP) levels - is consistent with congestive heart failure (CHF). BNP is a natriuretic hormone released from ventricular myocytes in response to high ventricular filling pressures and wall stress in patients with CHF. It is derived from the cleavage of the prohormone proBNP, which produces a biologically active BNP and an inert N-terminal proBNP (NT-proBNP). Elevated levels of circulating BNP or NT-proBNP correlate with the severity of left ventricular systolic dysfunction. Conversely, normal values have a very high negative predictive value for CHF as a cause of dyspnea and should prompt a search for noncardiac causes of dyspnea. The third heart sound (S3) is a low-frequency diastolic sound produced by the passive ventricular filling during early diastole; it is best heard over the cardiac apex in the left lateral decubitus position. An abnormal S3 (louder and higher pitch, S3 gallop) is commonly heard in patients with CHF due to left ventricular systolic dysfunction (up to 99% specificity), and it correlates with elevated left atrial and/or ventricular filling pressures and serum BNP levels. (Choice A) Cyanosis can occur in patients with intrinsic lung disease or congenital heart defects with right to left shunting (Eisenmenger syndrome), but it would be rare in CHF unless there is marked hypoperfusion (eg, hypotension, cold and clammy extremities). Cyanosis would not correlate with BNP levels. (Choice B) Peripheral edema is one of the signs of CHF with volume overload; however, compared to S3, it is less specific to the diagnosis of CHF and correlates less closely with BNP levels. Peripheral edema can be seen with several noncardiac conditions, including inferior vena cava obstruction, cirrhosis, and lower extremity venous insufficiency. (Choice C) Neck bruits can be present in patients with carotid artery stenosis. (Choice D) An abdominal or periumbilical bruit that lateralizes to one side can be heard in patients with renal artery stenosis. (Choice F) Although wheezing can sometimes be heard in patients with a CHF exacerbation due to bronchial wall edema, in general it is a sign of bronchial constriction and is present in patients with asthma or chronic obstructive pulmonary disease exacerbation. BNP levels are typically not elevated in patients with dyspnea due to pulmonary or noncardiac causes. Educational objective: Elevated brain natriuretic peptide levels and an audible third heart sound are signs of increased cardiac filling pressures and are noted in patients with congestive heart failure due to left ventricular systolic dysfunction. References: Natriuretic peptides (BNP and NT-proBNP): measurement and relevance in heart failure. (http://www.ncbi.nlm.nih.gov/pubmed/20539843) Usefulness of the third heart sound in predicting an elevated level of B-type natriuretic peptide. (http://www.ncbi.nlm.nih.gov/pubmed/15135714)

A 52-Year-Old Man Comes to the Emergency Department with Shortness