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Difficulty: HardPulmonary and Critical Care

A 73-year-old woman is brought to the emergency department due to a 4-day history of progressively worsening shortness of breath and an increase in the volume and purulence of her sputum. Her medical history includes severe chronic obstructive pulmonary disease (COPD) and ischemic cardiomyopathy with a left ventricular ejection fraction of 35%.

Vital signs are temperature 38.1°C (100.6°F), blood pressure 146/88 mmHg, pulse 112/min, and respirations 28/min. Pulse oximetry shows 87% on room air.

Physical examination shows a patient in respiratory distress using accessory muscles. Jugular venous pressure is estimated at 7 cm H2O. Chest auscultation reveals a prolonged expiratory phase with diffuse polyphonic wheezing. There is no lower extremity edema.

Laboratory studies show:
Leukocyte count: 14,200/mm³
B-type natriuretic peptide: 85 pg/mL

Arterial blood gas (room air):
pH: 7.26
PaCO2: 68 mmHg
PaO2: 50 mmHg
HCO3-: 30 mEq/L

A sputum Gram stain reveals numerous polymorphonuclear leukocytes and gram-negative coccobacilli. She is promptly started on noninvasive positive-pressure ventilation, nebulized ipratropium-albuterol, and intravenous methylprednisolone.

Which of the following is the most appropriate additional pharmacologic intervention for this patient?

  1. Oral azithromycinAnswer
  2. B
    Intravenous vancomycin and piperacillin-tazobactam
  3. C
    Intravenous furosemide
  4. D
    Intravenous sodium bicarbonate
  5. E
    Intravenous metoprolol

Answer

The most appropriate additional intervention is the administration of oral azithromycin.
The correct intervention is oral azithromycin. This patient is experiencing a severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD), characterized by the three cardinal symptoms: increased dyspnea, increased sputum volume, and increased sputum purulence. In the setting of an AECOPD with increased sputum purulence, or if the patient requires mechanical ventilation (including noninvasive positive-pressure ventilation), antibiotic therapy is strongly indicated. The Gram stain showing gram-negative coccobacilli suggests Haemophilus influenzae or Moraxella catarrhalis. A macrolide like azithromycin (or an advanced generation cephalosporin or amoxicillin-clavulanate) provides excellent coverage for these typical respiratory pathogens and atypical organisms, directly addressing the inciting infection.

Step-by-Step Solution

1
Analyze the patient's clinical presentation.
The patient has the cardinal symptoms of a COPD exacerbation (worsening dyspnea, increased sputum volume, increased sputum purulence) with fever and a normal BNP.
Differentiating between a COPD exacerbation and acute decompensated heart failure is crucial in a patient with a history of both.
2
Interpret the arterial blood gas (ABG) results.
The ABG shows a pH of 7.26, PaCO2 of 68 mmHg, and HCO3- of 30 mEq/L, indicating an acute-on-chronic respiratory acidosis.
To guide ventilatory and medical management, and to rule out concurrent metabolic acidosis.
3
Identify the required interventions based on the diagnosis.
The patient requires NIPPV, systemic corticosteroids, bronchodilators, and antibiotics targeting common respiratory pathogens.
Standard of care for a severe COPD exacerbation with all three cardinal symptoms includes these four modalities.
4
Select the most appropriate antibiotic therapy.
Azithromycin is selected to cover Haemophilus influenzae (suggested by gram-negative coccobacilli on Gram stain), Moraxella catarrhalis, and atypical organisms.
It provides targeted, appropriate coverage without violating antibiotic stewardship by using unnecessarily broad agents.

Key Concept

Patients with acute exacerbations of COPD presenting with increased sputum purulence require targeted antibiotic therapy (e.g., a macrolide, fluoroquinolone, or amoxicillin-clavulanate) in addition to bronchodilators, systemic corticosteroids, and ventilatory support.
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Topics

Pulmonary and Critical Care

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