Tuesday, December 14, 2010

Alcoholic With Lobar Consolidation

A 57-year-old alcoholic is hospitalized in the intensive care unit after a multivehicle accident. Twenty hours after the accident, the patient develops a fever and a cough productive of purulent sputum. If a chest radiograph shows lobar consolidation and the sputum reveals the presence of gram-negative encapsulated rods, the most appropriate initial therapy would be 

           A. cefotaxime IV 
           B. erythromycin IV 
           C. gentamicin IV + vancomycin IV 
           D. ticarcillin-clavulanic acid IV + vancomycin IV 
           E. trimethoprim-sulfamethoxazole PO 


     The correct answer is A. The patient is presenting with signs and symptoms of pneumonia. Since the 
patients signs and symptoms are appearing 20 hours after admission, his pneumonia is most likely a "community-acquired" pneumonia; one of the criteria for diagnosing a nosocomial infection is that the 
infection must not occur before 48 hours after admission. The appearance of plump gram-negative encapsulated rods in an alcoholic is highly suggestive of Klebsiella pneumonia. The most appropriate treatment of  Klebsiella pneumonia in this patient is the administration of a third-generation cephalosporin, such as cefotaxime, ceftriaxone, or ceftazidime. 

     Erythromycin (choice B) is a macrolide antibiotic used in the treatment of a variety of gram-negative 
and gram-positive infections. Although it is not the treatment of choice in this patient, it is the treatment of 
choice of  Legionella pneumonia. 

     Gentamicin (choice C) is an aminoglycoside antibiotic that is generally added to improve the efficacy 
of broad spectrum antibiotics, such as penicillin and cephalosporins, in the treatment of Pseudomonas and 
Enterococcus infections. 

     Vancomycin (choices C and D) is an antibiotic used in the treatment of life-threatening infections 
caused by gram-positive infections; the use of this agent in a gram-negative infection is inappropriate.