USMLE Forum Archives - USMLE Step 2 CK - IM 5
IM 5
TheOne - 10-29-06 16:03
A 74-year-old woman, who has been followed for the past 25 years for chronic obstructive
pulmonary disease (COPD) comes to the emergency department complaining of 48 hours of
temperatures to 38.6 C (101.4 F) and worsening shortness of breath. She has a chronic
productive cough, which has become more copious. On physical examination, she has rhonchi
and increased fremitus in the posterior mid-lung field. A Gram's stain reveals many epithelial
cells and multiple gram-positive and gram-negative organisms; no neutrophils are seen. Which
of the following is the most likely organism causing the symptoms?
A. Escherichia coli
B. Haemophilus influenzae
C. Klebsiella pneumoniae
D. Mycobacterium tuberculosis
E. Mycoplasma pneumoniae
TheOne - 10-29-06 16:03
A 74-year-old woman, who has been followed for the past 25 years for chronic obstructive
pulmonary disease (COPD) comes to the emergency department complaining of 48 hours of
temperatures to 38.6 C (101.4 F) and worsening shortness of breath. She has a chronic
productive cough, which has become more copious. On physical examination, she has rhonchi
and increased fremitus in the posterior mid-lung field. A Gram's stain reveals many epithelial
cells and multiple gram-positive and gram-negative organisms; no neutrophils are seen. Which
of the following is the most likely organism causing the symptoms?
A. Escherichia coli
B. Haemophilus influenzae
C. Klebsiella pneumoniae
D. Mycobacterium tuberculosis
E. Mycoplasma pneumoniae
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#2
Re: IM 5 kingkong - 10-29-06 19:03 I WILL ALSO GO WITH KLEBSIELLA.KINDLY EXPLAIN WHY MYCOBACTERIUM CAN'T BE.
#3
Always think "Common"
TheOne - 10-30-06 18:22 The correct answer is B. This patient, with a long history of chronic obstructive
pulmonary disease (COPD), has evidence of a community-acquired pneumonia. The
common organisms causing pneumonias in patients with COPD are Streptococcus
pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.
This patient has no other history suggestive of Escherichia coli (choice A) infection
elsewhere (such as in the urinary tract), and primary E. coli pneumonia is rare.
Klebsiella pneumoniae (choice C) is typically found in alcoholic patients and it may
cavitate.
There is no evidence of tuberculosis (choice D) by history. Tuberculosis usually
presents with a more chronic presentation. Furthermore, it would generally be found as
an upper lobe infiltrate, consistent with reactivation tuberculosis. Much less commonly,
tuberculosis may present as a primary infection, but this is generally seen in patients
with an underlying immunocompromised state. In the setting of primary tuberculosis, a
lower lung field pneumonia is in fact possible.
Mycoplasma pneumoniae (choice E) does not present with a lobar consolidation and is
generally a disease of younger people who present with fever, malaise of at least several
days duration, and a nonproductive cough. The chest x-ray film in a patient with
Mycoplasma pneumonia would classically reveal faint bilateral interstitial infiltrates.
#5
Re: IM 5 bingousmle - 07-20-10 01:48 A Gram's stain reveals many epithelial cells and multiple gram-positive and gram-negative organisms and a history of COPD suggests infection with H Influenzae
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