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Question 9#

An 84-year-old woman presents to the ED with shortness of breath. She has been coughing for the past 2 to 3 days. The patient has a history of mild dementia, but has been able to maintain independent living at home with the assistance of her daughters and a home health agency. Her daughter denies any fever at home. Vital signs include a heart rate of 102/minute, respiratory rate of 24/minute, blood pressure 142/58 mmHg, and temperature of 37.8°C with a weight of 52 kg. Oxygen saturation is 93% on room air. Upon examination, she appears to be in mild respiratory distress. She is pleasant but oriented only to self. Chest auscultation reveals few crackles in the left upper lung field. WBC count is 12,500, BUN is 30 mg/dL, and creatinine is 1.3 mg/dL. A chest radiograph shows an infiltrate in the left upper lung lobe. What is the best initial course of therapy for this patient?

A) Begin a third-generation cephalosporin and admit her to the hospital
B) Begin a renal-dosed third-generation cephalosporin and a macrolide, and admit her to the hospital
C) Begin a respiratory fluoroquinolone and discharge her home for follow-up
D) Begin a loop diuretic and monitor her oxygen saturation
E) Begin bronchodilator therapy with an inhaled beta-agonist

Correct Answer is B

Comment:

Empiric therapy for community-acquired pneumonia (CAP) includes either a respiratory fluoroquinolone or a third-generation cephalosporin plus a macrolide, the latter to cover for “atypical” pathogens. This would limit the correct answer options to a, b, or c. CAP can be caused by viruses, bacteria, fungi, or protozoa. The common bacterial causes of CAP include Streptococcus pneumoniae, Mycoplasma pneumoniae, Hemophilus influenzae, Chlamydia pneumoniae, and Staphylococcus aureus. Answer a is incorrect as our patient has an estimated creatinine clearance of 26 mL/minute and an adjustment of the antibiotics based on renal function may be indicated depending on the specific drug that is selected. Furthermore, a cephalosporin would not cover Mycoplasma or Chlamydia. The patient in question has several risk factors for poor outcome (age, change in mental status, depressed glomerular filtration rate), so immediate discharge to home would be inappropriate (answer c). There is also a theoretical risk of worsening delirium from fluoroquinolones crossing the blood-brain barrier in patients at risk of delirium. The examination and chest xray do not suggest congestive heart failure, so treatment with a loop diuretic would not be efficacious. Inhaled bronchodilators do not improve outcomes in pneumonia and are used if the patient develops wheezing or other evidence of bronchospasm.