An ambulance transports a 65-year-old male to the acute care bay following two days of pro… — USMLE Step 2 CK

An ambulance transports a $65$ -year-old male to the acute care bay following two days of progressively worsening shortness of breath. The patient reports producing increased amounts of thick, yellowish sputum and feeling unusually fatigued. His past medical history is significant for ischemic cardiomyopathy with a left ventricular ejection fraction of $35\%$ , as well as severe chronic obstructive pulmonary disease.

Upon arrival, his temperature is $37.7^\circ\text{C}$ ( $99.9^\circ\text{F}$ ), blood pressure is $138/86\text{ mmHg}$ , heart rate is $108/\text{min}$ , and respiratory rate is $26/\text{min}$ . Pulse oximetry reveals an oxygen saturation of $87\%$ on room air.

Physical examination shows an alert patient in mild respiratory distress, utilizing accessory muscles of respiration. The jugular venous pressure is estimated at $6\text{ cm H}_2\text{O}$ (normal: $5-8\text{ cm H}_2\text{O}$ ). Cardiac auscultation reveals a regular rate and rhythm with normal heart sounds; no third heart sound ( $S_3$ ) or murmurs are appreciated. Pulmonary auscultation reveals a prolonged expiratory phase with diffuse bilateral wheezing, but no dependent crackles. There is chronic trace bilateral pedal edema.

Initial laboratory studies are as follows:
Serum B-type natriuretic peptide (BNP): $180\text{ pg/mL}$ (Baseline: $220\text{ pg/mL}$ )
Leukocyte count: $9,500/\mu\text{L}$
Thyroid-stimulating hormone (TSH): $1.2\text{ }\mu\text{U/mL}$ (Reference: $0.5-5.0\text{ }\mu\text{U/mL}$ )
Free T4: $0.6\text{ ng/dL}$ (Reference: $0.9-1.7\text{ ng/dL}$ )

Arterial blood gas (room air):
pH: $7.28$
pCO $_2$ : $64\text{ mmHg}$
pO $_2$ : $55\text{ mmHg}$
HCO $_3^-$ : $29\text{ mEq/L}$

A sputum Gram stain reveals numerous neutrophils and moderate gram-negative diplococci.

Which of the following is the most appropriate pharmacological step in the management of this patient?

A
Administer intravenous furosemide and sublingual nitroglycerin
B
Calculate expected respiratory compensation using Winter's formula
Administer systemic glucocorticoids, nebulized bronchodilators, and an oral macrolideCevap
D
Administer intravenous piperacillin-tazobactam and vancomycin
E
Initiate oral levothyroxine for primary hypothyroidism

Cevap

The most appropriate pharmacological step is to administer systemic glucocorticoids, nebulized bronchodilators, and an oral macrolide.

This patient is experiencing a severe acute exacerbation of chronic obstructive pulmonary disease (COPD), characterized by the cardinal symptoms of increased dyspnea, increased sputum volume, and increased sputum purulence. The physical examination supports this diagnosis (diffuse wheezing, use of accessory muscles) while actively ruling out acute decompensated heart failure (normal JVP, no S3, clear lung bases, BNP below baseline). In patients with COPD exacerbations presenting with all three cardinal symptoms (or two if one is increased purulence), antibiotics are indicated. The Gram stain showing gram-negative diplococci strongly suggests Moraxella catarrhalis, making an oral macrolide (e.g., azithromycin) an excellent targeted choice. Alongside antibiotics, standard pharmacological management includes systemic glucocorticoids and nebulized short-acting bronchodilators to reduce airway inflammation and relieve bronchospasm. (Note: Noninvasive positive pressure ventilation is also indicated for his acute-on-chronic respiratory acidosis with pH < 7.30, but the question specifically asks for the pharmacological step).

Adım Adım Çözüm

Differentiate between an acute COPD exacerbation and an acute decompensated heart failure (ADHF) exacerbation based on physical exam and laboratory findings.

The normal jugular venous pressure, lack of dependent crackles, absent S3 gallop, and a BNP level below the patient's baseline effectively rule out ADHF, pointing toward a COPD exacerbation.

Patients with a dual history of COPD and heart failure require careful clinical differentiation, as the pharmacological therapies for one condition can sometimes worsen the other.

Analyze the sputum Gram stain to determine the most appropriate antimicrobial strategy.

The presence of gram-negative diplococci highly suggests Moraxella catarrhalis. Narrow-spectrum targeted therapy with a macrolide (like azithromycin) or a respiratory fluoroquinolone is indicated rather than broad-spectrum agents.

Antibiotic stewardship requires tailoring therapy to the likely pathogen based on rapid diagnostics and avoiding unnecessarily broad coverage (like vancomycin and piperacillin-tazobactam) in uncomplicated cases.

Select the comprehensive pharmacological bundle for a severe COPD exacerbation.

The standard of care includes systemic glucocorticoids (to reduce airway inflammation), short-acting bronchodilators (albuterol/ipratropium to relieve bronchospasm), and targeted antibiotics.

These interventions reduce symptom severity, shorten recovery time, and prevent treatment failure in COPD exacerbations.

Anahtar Kavram

Management of Acute COPD Exacerbations vs. Heart Failure Exacerbations

Tahmini Süre:1m 30s

Soru

Cevap

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