A 17-year-old Caucasian boy is brought to the emergency department due to 3 days of worsening cough productive of green sputum. He has also had fever, fatigue, and chest pain with deep inspiration. For the past several years, the patient has had a cough on most days, but his current symptoms are worse than usual. He has had multiple hospitalizations for pneumonia, most recently 18 months ago. He also had a partial small bowel obstruction as a newborn. The patient takes several inhaled and oral medications daily. His sister has similar medical problems. Temperature is 102.3 F (39.1 C) and respirations are 22/min; oxygen saturation is 87% on room air. Examination shows a thin patient in moderate respiratory distress. Cardiac examination is normal. Auscultation of the lungs reveals crackles and scattered wheezes throughout, most prominent at the left base. Chest x-ray reveals hyperinflation, enlarged perihilar lymph nodes, and prominent bronchovascular markings. In addition to vancomycin, the most appropriate initial antimicrobial therapy for this patient should include which of the following?

Question

A 17-year-old Caucasian boy is brought to the emergency department due to 3 days of worsening cough productive of green sputum.  He has also had fever, fatigue, and chest pain with deep inspiration.  For the past several years, the patient has had a cough on most days, but his current symptoms are worse than usual.  He has had multiple hospitalizations for pneumonia, most recently 18 months ago.  He also had a partial small bowel obstruction as a newborn.  The patient takes several inhaled and oral medications daily.  His sister has similar medical problems.  Temperature is 102.3 F (39.1 C) and respirations are 22/min; oxygen saturation is 87% on room air.  Examination shows a thin patient in moderate respiratory distress.  Cardiac examination is normal.  Auscultation of the lungs reveals crackles and scattered wheezes throughout, most prominent at the left base.  Chest x-ray reveals hyperinflation, enlarged perihilar lymph nodes, and prominent bronchovascular markings.  In addition to vancomycin, the most appropriate initial antimicrobial therapy for this patient should include which of the following?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bf96_95dd_8f63_e91458987f07_MD0005_00 Cystic fibrosis (CF) is an autosomal recessive disorder found most commonly in the Caucasian population. CF affects multiple organs (eg, pancreas, gastrointestinal tract), but pulmonary disease is the major cause of morbidity and mortality. CF lung disease is characterized by chronic bacterial colonization with periodic acute exacerbations. Staphylococcus aureus and Pseudomonas aeruginosa are the 2 principle pathogens. This patient's chronic cough, recurrent pneumonias, intestinal obstruction as a newborn, and pertinent family history are concerning for CF. He now has fever, green sputum, and hypoxia, which are suggestive of an acute pulmonary exacerbation. Hyperinflation on chest radiograph is a sign of chronic obstruction from thickened secretions, and prominent bronchovascular markings indicate concurrent inflammation and infection. Empiric treatment of an acute exacerbation typically includes vancomycin for methicillin-resistant S aureus coverage and 2-drug coverage for P aeruginosa. Cefepime and ceftazidime are antipseudomonal cephalosporins; amikacin and tobramycin are aminoglycosides that are also effective against P aeruginosa. Other effective agents include carbapenems, certain fluoroquinolones, aztreonam, and colistin. (Choice A) Ampicillin-sulbactam is a combination third-generation penicillin and beta-lactamase inhibitor commonly used to treat intraabdominal infections. This medication is not effective against P aeruginosa. Extended-spectrum penicillins with activity against P aeruginosa include piperacillin-tazobactam and ticarcillin-clavulanic acid. (Choice C) Ceftriaxone and azithromycin are the recommended antibiotics for community-acquired pneumonia requiring hospitalization. They will cover common causes of pneumonia (eg, Streptococcus pneumoniae, Mycoplasma pneumoniae) but are not active against P aeruginosa. (Choice D) Moxifloxacin, a fluoroquinolone used as monotherapy for community-acquired pneumonia, has limited antipseudomonal activity. Metronidazole is an antibiotic that treats anaerobic and parasitic infections but is also not effective against Pseudomonas. (Choice E) Trimethoprim-sulfamethoxazole is a combination antibiotic used to treat Pneumocystis jirovecii pneumonia, not Pseudomonas. P jirovecii pneumonia is an opportunistic infection found in immunocompromised patients (eg, HIV) but would not be expected in a patient with CF. Educational objective: In patients with cystic fibrosis, pulmonary exacerbations are typically due to Pseudomonas aeruginosa or Staphylococcus aureus. Empiric therapy should include methicillin-resistant S aureus coverage (eg, vancomycin) and 2 drugs active against P aeruginosa (eg, cefepime, amikacin). References: The approach to pseudomonas aeruginosa in cystic fibrosis. (http://www.ncbi.nlm.nih.gov/pubmed/26857769) Managing pseudomonas aeruginosa respiratory infections in cystic fibrosis. (http://www.ncbi.nlm.nih.gov/pubmed/26524327)

A 17-Year-Old Caucasian Boy Is Brought to the Emergency Department