During morning rounds, a 68-year-old female is evaluated on her third day of hospitalizati… — USMLE Step 2 CK

During morning rounds, a $68$ -year-old female is evaluated on her third day of hospitalization for community-acquired pneumonia. She initially presented with a fever, productive cough, and worsening shortness of breath. Her medical history includes chronic obstructive pulmonary disease (COPD) and osteoarthritis. On admission, she was started on intravenous levofloxacin and oral prednisone.

Today, she reports feeling much better and is tolerating a regular diet. Her temperature is $37.1^\circ C$ ( $98.8^\circ F$ ), blood pressure is $128/78$ mm Hg, pulse is $82$ /min, and respiratory rate is $16$ /min. Pulse oximetry shows $94\%$ on room air.

Physical examination reveals a normal jugular venous pressure of $6$ cm $H_2O$ . Lung auscultation shows prolonged expiration and scattered end-expiratory wheezes, but the bibasilar crackles heard on admission have resolved. She has trace bilateral pitting edema at the ankles, which is unchanged from her baseline.

Laboratory results from this morning show:
Leukocyte count: $7,500/mm^3$
Thyroid-stimulating hormone (TSH): $0.6$ $\mu U/mL$ (Normal: $0.4-4.0$ $\mu U/mL$ )
Free thyroxine (T4): $0.7$ ng/dL (Normal: $0.9-1.7$ ng/dL)

Arterial blood gas (room air):
$pH$ : $7.38$
$PaCO_2$ : $54$ mm Hg
$PaO_2$ : $72$ mm Hg
$HCO_3^-$ : $31$ mEq/L

Sputum cultures obtained on admission have grown Streptococcus pneumoniae that is susceptible to penicillin, amoxicillin, ceftriaxone, levofloxacin, and vancomycin.

Which of the following is the most appropriate next step in management?

Transition to oral amoxicillinAnswer
B
Continue intravenous levofloxacin
C
Initiate oral levothyroxine
D
Administer intravenous furosemide
E
Initiate noninvasive positive pressure ventilation

Answer

Transition to oral amoxicillin

This patient was admitted for a community-acquired pneumonia (CAP) exacerbation of her COPD and was appropriately started on empiric intravenous levofloxacin. She is now clinically stable, afebrile, and tolerating an oral diet, meeting the criteria for transition to oral antibiotics. Her sputum culture grew Streptococcus pneumoniae that is susceptible to narrow-spectrum agents such as penicillin and amoxicillin. Good antibiotic stewardship dictates stepping down from a broad-spectrum intravenous fluoroquinolone to a targeted, narrow-spectrum oral agent (like amoxicillin) to minimize collateral damage, such as Clostridioides difficile infection, and to prevent the development of antimicrobial resistance.

Step-by-Step Solution

Assess the patient's clinical trajectory and readiness for step-down therapy.

The patient is afebrile, hemodynamically stable, breathing comfortably on room air, and tolerating an oral diet.

These criteria indicate that the patient no longer requires intravenous antibiotics or acute hospital-level interventions.

Review the microbiological data to tailor therapy.

Sputum culture grew Streptococcus pneumoniae that is fully susceptible to multiple agents, including penicillin and amoxicillin.

Empiric broad-spectrum therapy should be narrowed once culture and sensitivity data are available.

Select the most appropriate targeted therapy.

Oral amoxicillin is selected over continuing intravenous levofloxacin.

Amoxicillin is a highly effective, narrow-spectrum oral agent for susceptible S. pneumoniae, aligning with principles of antibiotic stewardship to reduce collateral damage and resistance.

Key Concept

Antibiotic Stewardship and De-escalation

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