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Difficulty: HardCardiovascular System

A 71-year-old man is brought to the emergency department by his wife due to progressively worsening shortness of breath and a persistent, dry cough over the past 48 hours. He states that the breathlessness is most severe when he lies down, forcing him to sleep in a recliner chair. His medical history includes hypertension, osteoarthritis, and severe chronic obstructive pulmonary disease (COPD) for which he uses a daily tiotropium inhaler. Two weeks ago, he was prescribed daily high-dose naproxen for severe bilateral knee pain. His temperature is 37.1°C (98.8°F), blood pressure is 172/96 mmHg, pulse is 112/min, and respirations are 26/min. Pulse oximetry shows 88% on room air. Physical examination reveals a patient in moderate respiratory distress using accessory muscles of respiration. Lung auscultation demonstrates diffuse, high-pitched expiratory wheezes and a prolonged expiratory phase. Cardiac auscultation reveals a regular tachycardia without murmurs; no extra heart sounds are audible. Jugular venous pressure is estimated at 12 cm H2O. Chest radiography reveals baseline hyperinflation with new, bilateral, hazy interstitial opacities and thickening of the interlobular septa. Arterial blood gas on room air shows a pH of 7.47, PaCO2 of 32 mmHg, and PaO2 of 56 mmHg. Which of the following is the most appropriate next step in the pharmacologic management of this patient?

  1. Intravenous furosemideAnswer
  2. B
    Intravenous methylprednisolone and nebulized albuterol
  3. C
    Intravenous piperacillin-tazobactam
  4. D
    Intravenous 0.9% sodium chloride
  5. E
    Inhaled fluticasone and salmeterol

Answer

Intravenous furosemide
This patient is presenting with acute decompensated heart failure (ADHF) masquerading as a COPD exacerbation (so-called 'cardiac asthma'). The recent initiation of high-dose NSAIDs (naproxen) promoted sodium and water retention, precipitating volume overload in a patient with underlying hypertensive heart disease. While the diffuse wheezing and history of COPD strongly tempt a diagnosis of a COPD exacerbation, several critical findings point to ADHF: elevated jugular venous pressure (12 cm H2O), orthopnea, and a chest radiograph showing interstitial opacities and thickened interlobular septa (Kerley B lines). Furthermore, the arterial blood gas shows a primary respiratory alkalosis driven by hypoxemia-induced hyperventilation, which is typical of early pulmonary edema. In contrast, an acute COPD exacerbation severe enough to cause this level of respiratory distress typically presents with CO2 retention and respiratory acidosis. The most appropriate initial pharmacologic therapy is an intravenous loop diuretic (e.g., furosemide) to reduce volume overload and alleviate pulmonary congestion.

Step-by-Step Solution

1
Analyze the patient's presentation and medical history.
The patient has acute respiratory distress, wheezing, orthopnea, and a history of both COPD and hypertension. He recently started naproxen, a medication known to cause sodium and water retention.
Identifying the trigger (NSAIDs) helps narrow the differential diagnosis toward volume overload and acute decompensated heart failure (ADHF).
2
Evaluate the physical examination and radiographic findings to differentiate between ADHF and a COPD exacerbation.
Despite the wheezing (cardiac asthma), the elevated jugular venous pressure (12 cm H2O) and chest radiograph showing interstitial opacities with thickened interlobular septa (Kerley B lines) point directly to cardiogenic pulmonary edema.
Wheezing is non-specific and can occur in ADHF due to peribronchial edema compressing the airways.
3
Interpret the arterial blood gas (ABG) findings.
The ABG shows a primary respiratory alkalosis (pH 7.47, PaCO2 32 mmHg).
Early pulmonary edema causes hypoxemia-driven hyperventilation and respiratory alkalosis. In contrast, a COPD exacerbation severe enough to cause this level of distress typically results in CO2 retention and respiratory acidosis.
4
Determine the most appropriate initial management based on the established diagnosis of ADHF.
The correct intervention is to administer an intravenous loop diuretic, such as furosemide.
Loop diuretics provide rapid diuresis and mild venodilation, directly addressing the underlying volume overload precipitating the pulmonary edema.

Key Concept

Differentiation and management of 'cardiac asthma' (Acute Decompensated Heart Failure presenting with wheezing) versus a primary COPD exacerbation.
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Topics

Cardiovascular System

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