USMLE Forum Archives - USMLE Step 2 CK - IM Questions
IM Questions
TheOne - 09-17-06 11:02
75-year-old female patient of yours with no risk factors for tuberculosis is being admitted into a nursing home. She is in good health though she does have Alzheimer’s disease. She is on no medication and has no chronic medical problems. The patient has lived with her husband up to this point. Her status on past PPDs is unknown. Her physical exam is normal for her age except for her mental status.
1.Which of the following is true regarding evaluation of previous or current tuberculosis infection or disease?
A. 12-mm PPD would be considered positive in this patient.
B. There is no need for a PPD in this patient.
C. If the PPD is negative, no further workup is needed.
D. This patient is considered at moderate risk for having TB infection.
E. Even if the PPD is positive, this patient should not be started on INH immediately.
F. If the PPD is negative, the patient should be rechecked in 10-12 weeks to allow for seroconversion.
The above patient was admitted to the nursing home and one year later her roommate came down with a cough. Her roommate was diagnosed by her physician with probable tuberculosis disease. This roommate has a right apical infiltrate and sputum which is positive for acid fast bacilli. The sputum cultures are pending. Your patient is immediately isolated from her sick roommate.
2. If the previous PPDs (at admission and 3 weeks later) on your patient were negative and the new one is positive, what is the treatment for your patient?
A. Four-drug therapy should be given to this patient until culture results are back.
B. INH should be given to this patient until culture results are back.
C. Further TB workup is done before any treatment. given to th
D. Three-drug therapy should be is patient until culture results are back.
3. Which of the following statements is most correct regarding how the roommate (with probable TB disease) should be treated while her sputum culture results are pending?
A. INH should be given.
B. No treatment until sputum culture results are back.
C. TM-I. hfampin, and pvrazinamide (PZA) should be given.
D. Four drug therapy such as INH. rifampin. PZA. and ethambutol must be given.
TheOne - 09-17-06 11:02
75-year-old female patient of yours with no risk factors for tuberculosis is being admitted into a nursing home. She is in good health though she does have Alzheimer’s disease. She is on no medication and has no chronic medical problems. The patient has lived with her husband up to this point. Her status on past PPDs is unknown. Her physical exam is normal for her age except for her mental status.
1.Which of the following is true regarding evaluation of previous or current tuberculosis infection or disease?
A. 12-mm PPD would be considered positive in this patient.
B. There is no need for a PPD in this patient.
C. If the PPD is negative, no further workup is needed.
D. This patient is considered at moderate risk for having TB infection.
E. Even if the PPD is positive, this patient should not be started on INH immediately.
F. If the PPD is negative, the patient should be rechecked in 10-12 weeks to allow for seroconversion.
The above patient was admitted to the nursing home and one year later her roommate came down with a cough. Her roommate was diagnosed by her physician with probable tuberculosis disease. This roommate has a right apical infiltrate and sputum which is positive for acid fast bacilli. The sputum cultures are pending. Your patient is immediately isolated from her sick roommate.
2. If the previous PPDs (at admission and 3 weeks later) on your patient were negative and the new one is positive, what is the treatment for your patient?
A. Four-drug therapy should be given to this patient until culture results are back.
B. INH should be given to this patient until culture results are back.
C. Further TB workup is done before any treatment. given to th
D. Three-drug therapy should be is patient until culture results are back.
3. Which of the following statements is most correct regarding how the roommate (with probable TB disease) should be treated while her sputum culture results are pending?
A. INH should be given.
B. No treatment until sputum culture results are back.
C. TM-I. hfampin, and pvrazinamide (PZA) should be given.
D. Four drug therapy such as INH. rifampin. PZA. and ethambutol must be given.
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Re: IM Questions
TheOne - 09-18-06 17:05 Answer 1(E), Answer 2(B), Answer 3(C)
Typically all patients <35 years old with a newly positive PPD are started on INH prophylaxis. This patient is older and therefore more susceptible to INH-induced hepatitis. If her PPD is positive (15 mm) she should be worked up for TB disease with a medical history, physical exam, a chest X-ray, and sputum smear and culture x 3. She would probably be watched for the development of TB disease. (Note: this is the correct answer according to the current standard of care but it appears that this may be changed soon as the risk of INH-induced hepatitis is lower than previously thought.)
On admission, this patient had no history of exposure and was at low risk and therefore requires a 15 mm wheal to be considered positive. If this patient’s PPD is negative, she should be retested in 1-3 weeks. This is because of the “booster” phenomenon. If the second test is positive 1-3 weeks after an initial negative test. the patient is assumed to have been infected with tuberculosis in the distant past and is worked up for TB disease.
Once this patient is put in the nursing home, she is at moderate risk for tuberculosis and a 10 mm PPD would be considered positive.
Note that patients who have had recent exposure to tuberculosis and who initially have a negative PPD are rechecked in 10-12 weeks to check for seroconversion.
Unless there is a contraindication, all close contacts with a newly positive PPD should be treated with INH. This patients age is one contraindication but because she was the TB patient’s roommate, lives in a nursing home, and has a newly positive PPD most physicians would start her on INH and monitor her closely for hepatic dysfunction.
Whether to initially treat a patient with TB disease with 3 or 4 drug therapy is a clinical judgement. Usually 4 drug therapy is recommended until the results of drug susceptibility tests are available. 3 drug therapy may be used if there is little possibility of drug resistance. i.e., when all the following criteria are filled:
1) <4% primary resistance to INH in the community,
2) No previous treatment with TB drugs,
3) No known exposure to a patient with drug-resistant disease,
4) Not from a country with a high prevalence of drug resistance.
The typical 3-drug regimen is is Isoniazid (INH), Rifampin. and Pyrazinamide (PZA). The typical 4-drug initial regimen consists of INH, rifampin, PZA. and either ethambutol or streptomycin. Remember that vitamin B6 should also be given with these regimens to prevent INH-induced peripheral neuropathv.
If this patient has previously been treated for tuberculosis, she should be retreated with four-drug regimen— with at least two of the drugs being used are not used in the previous treatment.
For the latest information on the current standards of care for TB. I highly recommend that you read the Center for Disease Control “Core Curriculum on Tuberculosis”. This can be downloaded from their website.
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