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Zorluk: KolayCardiovascular System

A 68-year-old man comes to the emergency department with worsening shortness of breath over the past 48 hours. He has a 45-pack-year smoking history, type 2 diabetes mellitus, and long-standing hypertension. The patient reports waking up multiple times during the night feeling like he cannot catch his breath. His temperature is 37.0 C (98.6 F), blood pressure is 168/94 mmHg, pulse is 102/min, and respirations are 24/min. Oxygen saturation is 90% on room air. Examination shows distended neck veins while sitting upright. Chest auscultation reveals diffuse wheezing. Cardiac examination demonstrates a rapid rate, regular rhythm, and an extra low-frequency diastolic sound. There is 2+ pitting edema in both lower extremities. Which of the following laboratory tests is most useful to confirm the primary cause of this patient's symptoms?

  1. Serum B-type natriuretic peptideCevap
  2. B
    Arterial blood gas on room air
  3. C
    Sputum culture and Gram stain
  4. D
    Outpatient spirometry with bronchodilator
  5. E
    Serum alpha-1 antitrypsin level

Cevap

Serum B-type natriuretic peptide
The correct option identifies a highly sensitive and specific laboratory test for heart failure. The patient's presentation of orthopnea, paroxysmal nocturnal dyspnea, jugular venous distention, an S3 gallop, and pedal edema is classic for acute decompensated heart failure. The diffuse wheezing is secondary to peribronchial edema, known as cardiac asthma. B-type natriuretic peptide is secreted by the ventricular myocardium in response to stretch from volume overload, making it the most useful laboratory test to differentiate heart failure from a primary pulmonary etiology like a COPD exacerbation.

Adım Adım Çözüm

1
Identify key clinical findings in the physical examination.
The patient has jugular venous distention, an S3 gallop (extra low-frequency diastolic sound), paroxysmal nocturnal dyspnea, and bilateral lower extremity pitting edema.
Recognizing these classic signs points toward a diagnosis of acute decompensated heart failure.
2
Evaluate confounding symptoms.
The patient has a heavy smoking history and wheezing on exam, which might initially suggest a COPD exacerbation.
Wheezing can occur in heart failure due to peribronchial edema, a condition often referred to as 'cardiac asthma'.
3
Select the most specific laboratory test to differentiate the etiologies.
Serum B-type natriuretic peptide (BNP) is ordered.
BNP is released by the ventricles in response to stretch and volume overload, making it highly specific for confirming heart failure rather than a primary pulmonary cause.

Anahtar Kavram

Differentiating acute decompensated heart failure from COPD exacerbation using clinical signs (S3 gallop, JVD) and B-type natriuretic peptide testing.
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Konular

Cardiovascular System

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