misty
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A 37-year-old woman with a history of intravenous drug use, hepatitis B, asthma, and acquired immunodeficiency syndrome (AIDS) is admitted to the hospital because of fever, night sweats, and malaise. Her last CD4 count was 1 month ago and measured 180/mm3. Vital signs are: temperature 38.5 C (101.3 F), blood pressure 145/76 mm Hg, and pulse 90/min. Physical examination is significant for a soft diastolic murmur heard best at the lower left sternal border. Auscultation of the lungs reveals diffuse rhonchi. The abdominal and neurologic exams are unremarkable. The next step in managing this patient is
A. analysis and culture of spinal fluid
B. a blood culture
C. a CT of the head
D. a urinalysis
E. an x-ray of the chest
F. an x-ray of the abdomen
I think its blood culture FIRST, but it says chest Xray!!! can anybody explain why diagnose suspected PCP before suspected endocarditis?
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| the_holy_man
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I agree with you. Answer should be blood culture.
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| misty
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thx holy man...
any more opinions, anyone?
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| GLO MD
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chest ray... deffinitely. In fact in real life you ask for both blood culture and at the same time for the chest xray but since the xray is the fastest and cheapest the answer is xray FIRST, is the BEST, FIRST STEP... it doesn't mean that you will not ask for blood cultures but remember the patient needs help now and the fastest thing to do before having the blood cultures and push the antibiotics is to do an xray, plus blood cultures take DAYS and they will not be the best first step.
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| GLO MD
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It's not an issue of diagnosis...it's an issue of the best FIRST step...go from easiest, cheapest and fastest as your first step and then go up...most of the time if not always blood cultures will NOT be the first step...
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| robin082006
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easiest, cheapest and fastest as your first step when you suspect a disease-->chest X ray
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| the_holy_man
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The reason I thought It would be blood culure is that patient need urgent antibiotics, preferably vancomycin due to high suspicion of endocarditis. Antibiotics can be begun immediately after taking sample for blood culture and it only takes 5 minutes(fastest).So if the answer choice is drawing blood for culture, it should be the first step along with calling the radiology department. Cheapest is not a concern here as patient's condition is life threatning and complete workup including blood culture will be done neverhteless. Chest X-ray, sputum for AFB & silver stain, other blood tests and Echo will be an essential part of the workup but will not affect the immediate management. Also the results for blood culture can be expected as early as within 18 hours and will guide further management.
Any more thoughts on this?
Edited by the_holy_man on 07/18/07 - 04:32 AM
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| carvedilol80
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i think xray...think of lung abcess and reactivation of TB or new TB infection or lymphoma as other possible causes...therez a broad differentail and perhaps these can be ruled out fast
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| misty
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its not abt waiting for the blood cultures.... ofcoz noone will wait for culture results...but the first step ... shldnt u rather take bld cultures, push an antibiotic and then send for xray?
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| GLO MD
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I understand your point but before pinching and getting blood out because as you know it takes time to get the various blood samples for blood cultures you MUST order a chest xray in this case...FASTEST, CHEAPEST and DEFFINITELY NEEDED!!!, just because she has a murmur it doesn't mean she has endocarditis...you don't even know if it's a new murmur or not...It can be a possibility but as I told you before this is not the issue...the issue in the USMLE's is about knowing the first, second third steps in case scenarios and this case has to start with a chest xray. Blood cultures will never be the first step as I recall. Getting the patient to an xray is even most urgent then pushing antibiotics.... and the patient can surely wait 10 or 15 mins for an xray.
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| the_holy_man
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Lets take this discussion further. Ofcourse in real life situation(or in CCS) both chest X-ray and blood culture will be ordered at same time. Now if chest X-ray shows bilateral interstitial infilterates or lung abcess or pneumonia or nothing, would you start the treatment for that condition before drawing blood cultures in this case? However since we would suspect endocardiits in this case, we can start treatment(vancomycin) for the same after drawing blood for culture and do X-rays later. X-ray would not affect the immediate management in this case.
Now the question of suspecting endocarditis, its not just the murmer but the overall history. He is an IV drug abuser with AIDS and presenting with fever over 101, night sweats and malaise and no obvious respiratory, urinary or GI symptoms, the suspicion of endocarditis is very high and treatment should be started ASAP before confirming the diagnosis microbiologically or by echo.
The reason I was tempted to log on to prep4usmle and answer this qs in the first place is because I had an exactly similar case(like copy and paste) in my real exam as CCS. I did all investigations and started vancomycin after drawing blood. CBC showed lymphocytosis(normal neutrophils), X-ray showed bilateral interstitial infiltrates, UA normal and I was tempted to start TMP-Sulfa. Later sputum gram stain and silver stain results came in- all negative. 12 hours later blood culture results showed MRSA sensitive only to vanco. Then I did the echo and it confirmed the diagnosis and case ended.The issue is not just the fastest and cheapest but which approach will best serve the patient.
Edited by the_holy_man on 07/19/07 - 06:32 AM
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| GLO MD
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This is not an issue of the real world but an issue of a TEST QUESTION and what will get you the right answer in this case is a chest Xray...sorry I have to disagree, there is no other way around.... this question has to be answered like that. Try to think of it in terms of an exam and what they want you to answer...sometimes the answer for this questions is not what you or another experienced physician would do for the patient...well this is just an exam and we have to get the best score possible. GL and take care... sorry again that I had to disagree!!! 
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| GLO MD
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I mean it my friend 95% of the time (if not more) if you answer blood cultures as your first step in ANY case you will surely get it wrong. Blood cultures will almost never (I would say never but I think it is a very harsh word), be the answer to the first step in a case.
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| misty
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I still dont get it.....i think only holyman seems to agree here!! the issues is not relying on the results of bl culture...but so that we can START antibiotics right? okay let me present my point again....as far as i can think on this case...i am more tilted to the diagnosis of endocarditis than PCP...so what wld u want to dofirst in suspected endocarditis?? ofcoz TREAT....so before i start the first dose of antibiotics....i take bl cultures
now considering that we start treating this patient thinking its actually endocarditis:
1) take bl cultures, start antibiotics
2) send for xray ( just 15 mins as someone said)- shows fluffy infiltrates= PCP we stop antibiotics and start treatmet for PCP. so all that time for xray...if dat much time u keep on treating for endocarditis, it wld only help but not harm the patient right?
Now if start managing as if he has PCP,so what we do is
1) send fr xray
2) after 15 minutes or whatever= clear CXR
3) damn its endocarditis
4) TAKE BLOOD CULTURES
5( start antibiotics
ISSUE IS:- in a patient who is not coming with minor complaints or diagnoses....we wld want to start treatment whenever we can isnt it? treating for endocarditis is not delaying teh diagnossi or managemnet of any other things...for for pcp maybe it is.
seriously how much time does it take to draw blood???
& the reason why I am suspecting endocarditis first is the fact that even though this pateint has rhonchi...she has NO RESPIRATORY symptoms whatsoever!! her history is most suggestive of endocarditis than PCP....and the only reasonw hy u guys are suspecting PCP is low CD4.....now it makes me think that is a trap!!!
to all those who are saying fastest cheapest investigation.....wld u do CXR if patient presents with s/s more suggestive of endocarditis just becoz cxr is fastest and cheapest???? CD4< 200 doesnt automatically make her PCP +ve!!!! she is prone...doesnt necessarily have it!!!!
maybe the low CD4 count is to fool u....
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| GLO MD
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Blood cultures will never be the answer for the first test to do in ANY case. That's it bottom line...it doesn't matter what the possible diagnosis is. I think you are drowning yourself with this case and I understand your every point but I'm telling you..this is a game of WORDS if they ask you for the FIRST step of management blood cultures will NEVER be the right answer....the only time when blood cultures could be the right answer is when they ask you for the more sensible test for something for example..... I don't know if I'm not explaining myself. This is not a matter of diagnosis...forget blood cx's they will NEVER be the right answer as the best first step IN ANY case. Sorry for not agreeing with you.  You can still choose to don't believe me and hang on to the cx's and I can assure you that you will get it wrong in the exam.
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| misty
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hmmmm....guess we have to think not only what we wld do, but allso what the examiners wld want..heheheh! I hope this q doesnt appear on the exam!!!!Not as an mcq atleast!
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| misty
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Thx GLOMD and holyman...dat was a nice discussion
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