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Difficulty: EasyCardiovascular System

A physician evaluates a 71-year-old retired mechanic who reports worsening shortness of breath over the past week. He states that he frequently wakes up in the middle of the night feeling as though he is suffocating and has resorted to sleeping in a reclining chair. His medical history includes hypertension, hyperlipidemia, and a 40-pack-year smoking history. Current medications include lisinopril and atorvastatin. His blood pressure is 158/92 mmHg, pulse is 98/min, and respiratory rate is 22/min. Physical examination demonstrates distended neck veins when positioned at 45 degrees. Lung auscultation reveals bilateral crackles at the bases and scattered expiratory wheezes. Cardiac auscultation reveals a regular rhythm with a low-frequency diastolic sound heard just after S2 at the apex. Bilateral 2+ pitting edema is present in the lower extremities. Which of the following is the most likely primary pathophysiologic mechanism responsible for this patient's current symptoms?

  1. Increased left ventricular filling pressureAnswer
  2. B
    Chronic airway inflammation and bronchoconstriction
  3. C
    Right ventricular dilation from hypoxic pulmonary vasoconstriction
  4. D
    Sudden obstruction of a main pulmonary artery branch
  5. E
    Alveolar spaces filled with a purulent inflammatory exudate

Answer

The patient's presentation is primarily caused by increased left ventricular filling pressure, which is indicative of acute decompensated heart failure.
The patient presents with classic features of acute decompensated heart failure (ADHF). Key findings include paroxysmal nocturnal dyspnea, orthopnea, elevated jugular venous pressure (JVD), bibasilar crackles, a third heart sound (S3 gallop), and peripheral edema. The underlying pathophysiology involves left ventricular systolic or diastolic dysfunction, leading to increased left ventricular end-diastolic pressure (filling pressure). This pressure is transmitted retrogradely to the left atrium and pulmonary veins, causing pulmonary venous congestion, alveolar edema (crackles), and sometimes peribronchial edema that results in wheezing, commonly referred to as 'cardiac asthma.'

Step-by-Step Solution

1
Identify the key clinical signs from the physical examination.
The patient has elevated jugular venous pressure, an S3 gallop, bilateral basilar crackles, and lower extremity edema.
Recognizing this combination of findings is essential to diagnose acute fluid overload and ventricular dysfunction.
2
Evaluate the patient's respiratory symptoms in the context of the cardiac findings.
The patient has orthopnea, paroxysmal nocturnal dyspnea (PND), and wheezing. The wheezing ('cardiac asthma') is secondary to peribronchial edema from the failing heart, rather than primary lung disease.
To accurately differentiate a primary cardiac etiology (heart failure) from a primary pulmonary etiology (COPD exacerbation), which is a common diagnostic challenge.

Key Concept

Acute decompensated heart failure presents with signs of left-sided (orthopnea, crackles, S3) and right-sided (JVD, peripheral edema) fluid overload due to elevated ventricular filling pressures.
Estimated Time:1m 0s
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Topics

Cardiovascular System

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