A 12-year-old girl with a history of cystic fibrosis presents to the emergency department … — USMLE Step 2 CK

A $12$ -year-old girl with a history of cystic fibrosis presents to the emergency department with a $1$ -week history of increased cough, purulent sputum production, fatigue, and a $2\text{-kg}$ ( $4.4\text{-lb}$ ) weight loss. She reports a decreased appetite but no fever. Her baseline $\text{FEV}_1$ is $75\%$ of predicted, but today it is $55\%$ . Vital signs are temperature $37.4^\circ\text{C}$ ( $99.3^\circ\text{F}$ ), heart rate $110/\text{min}$ , respiratory rate $24/\text{min}$ , and blood pressure $110/70\text{ mm Hg}$ . Oxygen saturation is $93\%$ on room air. Physical examination reveals coarse crackles scattered throughout both lung fields. Sputum cultures from a routine clinic visit $1$ month ago grew *Pseudomonas aeruginosa* and *Staphylococcus aureus*. Which of the following are the most appropriate initial steps in the management of this patient's acute pulmonary exacerbation? (Select all that apply)

Initiate intravenous therapy with two distinct antipseudomonal antibioticsAnswer
Increase the frequency of mechanical airway clearance therapiesAnswer
C
Initiate intravenous ceftriaxone and azithromycin
D
Administer intravenous furosemide to reduce pulmonary congestion
E
Administer continuous nebulized albuterol as the sole primary intervention

Answer

The correct interventions are to initiate intravenous therapy with two distinct antipseudomonal antibiotics and to increase the frequency of mechanical airway clearance therapies.

An acute pulmonary exacerbation in a cystic fibrosis patient presents with worsened cough, increased sputum production, decline in lung function (FEV1), and constitutional symptoms like weight loss. The cornerstone of management is a multi-modal approach: intensifying mechanical airway clearance to address severe mucous plugging and initiating aggressive empiric antibiotic therapy based on previous sputum cultures. Because this patient is colonized with Pseudomonas aeruginosa, standard-of-care dictates the use of two intravenous antipseudomonal antibiotics (e.g., tobramycin and piperacillin-tazobactam) to achieve synergy, enhance bacterial killing, and prevent the emergence of highly resistant strains during the exacerbation.

Step-by-Step Solution

Identify the primary clinical problem

The patient is experiencing an acute pulmonary exacerbation of cystic fibrosis, evidenced by increased cough, purulent sputum, weight loss, and a significant drop in FEV1.

Recognizing an acute exacerbation is necessary to initiate a comprehensive management bundle.

Review prior microbiologic data to guide empiric therapy

Sputum cultures from 1 month ago show Pseudomonas aeruginosa and Staphylococcus aureus.

Empiric antibiotic therapy in cystic fibrosis must be tailored to the patient's specific historical airway colonizers.

Determine the appropriate antibiotic regimen and pulmonary interventions

Select two synergistic IV antipseudomonal agents (e.g., an aminoglycoside and an antipseudomonal beta-lactam) and intensify airway clearance therapies.

Pseudomonas infections in cystic fibrosis carry a high risk of multidrug resistance. Dual therapy is standard for acute exacerbations requiring hospitalization. Intensified airway clearance is essential to remove the obstructive infected mucus.

Key Concept

Management of acute pulmonary exacerbations in cystic fibrosis requires intensification of airway clearance therapies and targeted broad-spectrum antibiotics (often two antipseudomonal agents if Pseudomonas is known to colonize the patient's airways).

Estimated Time:2m 0s

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