NBME 4- Q45...Answer A or E? - usmlekey

[ArchivalUser]

45. A 32-year-old man with AIDS comes to the emergency department because of a 1-week history of temperatures to 40°C (104°F) and cough productive of small amounts of clear sputum. Current medications include trimethoprim-sulfamethoxazole and three antiretroviral agents. His temperature is 39.7°C (103.5°F), pulse is 100/min, respirations are 20/min, and blood pressure is 126/60 mm Hg. There is no lymphadenopathy or edema. Moist crackles are heard over the right lung base. Cardiac examination shows no abnormalities. An x-ray of the chest shows an infiltrate in the right lower lobe. Which of the following is the most likely causal organism?

A)Aspergillus fumigatus

B)Candida albicans

C)Pneumocystis jiroveci (formerly P. carinii)

D)Rhodococcus equi

E)Streptococcus pneumoniae

Can anyone plz shed light on what the answer wud be between A and E and Why?? Thanks!

[ArchivalUser]

E)Streptococcus pneumoniae

it is lobar pneumonia.

aspergillus occurs only in a pre-existing cavitary lesion ... which would be in the apices.


also another confuser is PCP... but it doesnt cause lobar pneumonia.

[ArchivalUser]

Thanks nats_k

[ArchivalUser]

he is already on Tmx sulfa for prophylaxis of PCP

[ArchivalUser]

i recently took nbme 4. had marked A)aspergillus and got it wrong

My argument would be tmp-smx covers Streptococcus pneumoniae

http://en.wikipedia.org/wiki/Trimethopri...ethoxazole

so since pt is on TMP/SMX options C and E are automatically eliminated

[ArchivalUser]

Nope its E i took the exam and got it right.. I think a question along similar lines is there in UW. You can eliminate E since its the only option with infiltrative pneumonia

[ArchivalUser]

hy its E
nat is right