Test your basic knowledge |

USMLE Step3 Infectious Disease

Subjects : health-sciences, usmle-step-3

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. when not to give INH therapy if ppd positive and patient asyptomatic
HBIG hep B immunoglobulin
Pt who have been treated before for latent TB
Others lesions are ring enhancing and have mass effect while PML don't
Most common; fibromuscular dysplasia - Rt renal artery more common - angiography string of beads

2. Do we need to give vaccine or immunoglobulin for rabies exposure in previously vaccinated person?
Only vaccine. immunoglobuin not required. previously unvaccinated person will receive both.
Similar pathophysiology as ITP - tx zidovudine
Type 1: patient with dm and pvd; caused by staph/GAS/ e coli/bacteroids; type2 - no associated medical illness - caused by laceration - trauma - surgery - IV drug abuse - caused mainly by GAS
Most common; fibromuscular dysplasia - Rt renal artery more common - angiography string of beads

3. how CMV presents in immunocompromised patients
Bronchoalveolar washing and transbronchial biopsy
Bed rest - NSAID - avoid contact sports; if patient develop SOB due to pharyngeal edema - give corticosteroid
Fever of unknown orign - esophagiti - retinitis - diarrhoea - encephalits
6-12 weeks

4. can HIV transmitted through human bite?
4 months; characterized by knee joint effusion-large amount - joint stiffness - pain
HBIG hep B immunoglobulin
HIV present in very minimal quantities in human saliva. exposure/contact of saliva will never trasmit HIV
If a sample is ELISA positive - it is tested fro western blot for confirmation

5. What are the behavioral interventions decrease the risk of UTI
Postcoital voiding - increased intake of cranberry juice
Td every 10 years - tdap once before 65 and after 65
No skin changes but pain out of proportion; infection spreads along fascial plane rapidly with blister - erythema - and bullae formation; marked tenderness on palpation - and CREPITUS
Vitamin B6 antagonist - can cause peripheral neuropathy if not give with b6

6. HIV patient having fat deposition on back of neck and abdomen - like cushing
HIV lipodystrophy; no correlation with viral load; p/w insulin resistance and dyslipidemia (inc cholesterol - dec HDL)
Due to decrease elasticity of arterial wall; only systolic - diastolic normal - wide pulse pressure
Every 3-4 hours to determine appropritate time to start HAART
CTP subjective; MELD objective; meld uses serum billirubin - inr and serum creatinin. meld used to determine 90 day mortality of liver diease

7. wisconsin - missisipi - ohio
Every 3-4 hours to determine appropritate time to start HAART
Blastomycosis
AMS - focal neurological signs - seizures - multiorgan dysfunction - death; tx; doxycycline; for pregnant give chloramphenicle
At first 4 weeks - then 8-12weks; remeasusing every 2m until viral load is undetectatable. then every 3 months

8. How to give postexposure prophylaxis to patient who received vaccine but titer inadequate
Chlamydia pcr - 88% sensitivity and 99% specificity; if negative think about MUT organims; mycoplasma - ureaplasma and trichomonas; tx MUT with metronidazole
Most common; fibromuscular dysplasia - Rt renal artery more common - angiography string of beads
HBIG hep B immunoglobulin
HIV RNA PCR assay; there may be small amount of virus that are not detectable in ELISA.

9. hypertension in children
Give nystatin suspension or clotrimazol with an oral antifungal eg. fluconazol
Viral load and CD4 count
Most common; fibromuscular dysplasia - Rt renal artery more common - angiography string of beads
Do EBV antibody test

10. when HIV patient develop pcp?
ELISA; initial visit - 6 - 12 and 24 weeks;
Cd4 count
Fever of unknown orign - esophagiti - retinitis - diarrhoea - encephalits
When cd4 count falls below 200. 2p in pcp =200

11. How to tx pseudomonas?
Antipseudomonal penicillin (pipercillin) or cephalosporin (ceftazdidime/cefepime) and aminoglycoside (tobramycin/amikacin)
More than two UTI in six months or more than 3 uti in a year; cipro/bactrim/nitrofurantoin; abx may be given continuous or postcoital
Vaccine titer >10mU/ml
Give nystatin suspension or clotrimazol with an oral antifungal eg. fluconazol

12. What is used for prophylaxis against meningo..meningitis?
Rifampin600mg q12. or cipro
Only vaccine. immunoglobuin not required. previously unvaccinated person will receive both.
CD4 less than 350 and RPR >1:32; HIV infected patient with syphilis >1 yr should have CSF exam before tx. if csf normal tx with benzathine penicillin weekly for 3 weeks.
AMS - focal neurological signs - seizures - multiorgan dysfunction - death; tx; doxycycline; for pregnant give chloramphenicle

13. What is the Tx of STD uretheritis?
Fever of unknown orign - esophagiti - retinitis - diarrhoea - encephalits
Tx emptirically both gonococcus and chlamydia; 30% gono have coexsiting chlamydial infection; single dose ceftriaxone for gono and Azithromycin for chlamydia. if no improvement give metronidazol for trichomonas infection
At first 4 weeks - then 8-12weks; remeasusing every 2m until viral load is undetectatable. then every 3 months
Every 3-4 hours to determine appropritate time to start HAART

14. How to tx chronic hep B
Others lesions are ring enhancing and have mass effect while PML don't
No skin changes but pain out of proportion; infection spreads along fascial plane rapidly with blister - erythema - and bullae formation; marked tenderness on palpation - and CREPITUS
Pegylated interferon and lamivudine
Bronchoalveolar washing and transbronchial biopsy

15. How often viral load is monitored after HAART?
Staph - GBS - proteus - pseudomona - e coli - candida - bacteroids; organisms isolated only from deep curettage of ulcer
HBIG hep B immunoglobulin
At first 4 weeks - then 8-12weks; remeasusing every 2m until viral load is undetectatable. then every 3 months
Only vaccine. immunoglobuin not required. previously unvaccinated person will receive both.

16. How to differentiat PML from toxoxplasmosis - cns lymphoma adn brain abscess

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

17. How to give postexposure prophylaxis for HIV
Within 72hrs of unprotected sex with HIV pos person - give two nucleosidase inhibitors (eg. zidovudin - lamivudein - tenofovir -) X4w
HIV RNA PCR assay; there may be small amount of virus that are not detectable in ELISA.
Vaccine titer >10mU/ml
HIV lipodystrophy; no correlation with viral load; p/w insulin resistance and dyslipidemia (inc cholesterol - dec HDL)

18. How long we tx chronic prostatis?
Rifampin600mg q12. or cipro
6-12 weeks
If a sample is ELISA positive - it is tested fro western blot for confirmation
Immune mediated; circulating IgG and IgM to penicillin derivatives

19. What is tx for herpes zoster
Similar pathophysiology as ITP - tx zidovudine
Acyclovir
6-12 weeks
Bronchoalveolar washing and transbronchial biopsy

20. How to dx bacterial meningitis from CSF study?

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

21. drugs work well on hypertriglyceridia?
Chlamydia pcr - 88% sensitivity and 99% specificity; if negative think about MUT organims; mycoplasma - ureaplasma and trichomonas; tx MUT with metronidazole
Gonococcal with purulent discharges and presence of multiple diplococi and neurotrophils in urethral swab; non gonoccal (chlamydia) are watery disch - swab abacterial - sometimes have intracellular organism
Gemfibrozil and other fibrate drugs; statin and niacin also work not as good as fibrate drugs like gemfibrozil
Hepatotoxitcity incidence 2.6% - commonly seen in alcoholic - liver disease - >50

22. How to dx adequate response to HBV vaccine
Ampicillin-sublactam; most bites contain eikenella
Vaccine titer >10mU/ml
Pegylated interferon and lamivudine
Viral load and CD4 count

23. foot infections in DM
Staph - GBS - proteus - pseudomona - e coli - candida - bacteroids; organisms isolated only from deep curettage of ulcer
Pregnacy - urologic procedure - hip arthoplastu
Aspergillosis. common in bone marrow transplants. typically involves lungs and sinuses
Tampoon in nostril/vagina. think t for t - staph release exotoxin --activation of t cells directly--release of massive cytokines.

24. What is fatal consequence of RMSF?
Harrt ---rapid improvement of immune function---increased inflammatory reaction--worsening of clinical symptoms; self limiting....needs no tx
Leukocytosis >100 cells - dec glucose - inc protien - inc opening pressure; in viral there will be lymphocytosis - normal glucose (virus doesn't eat) -
Doesn't exceed more than 15 mm and size significantly decreases after 15 years
AMS - focal neurological signs - seizures - multiorgan dysfunction - death; tx; doxycycline; for pregnant give chloramphenicle

25. infiltrate in upper lobe of lung?
ELISA; initial visit - 6 - 12 and 24 weeks;
ELISA and western blot of synovial fluid.
Either TB or aspergillosis
Only vaccine. immunoglobuin not required. previously unvaccinated person will receive both.

26. damae that is about to occur?
6-12 weeks
When cd4 count falls below 200. 2p in pcp =200
HIV viral load
Either TB or aspergillosis

27. low grade fever - maculopapular rash - lymphadenopathy
HIV syndrome or anti-retroviral syndrome; 2-3w after virus exposure. similar to IM.
More than two UTI in six months or more than 3 uti in a year; cipro/bactrim/nitrofurantoin; abx may be given continuous or postcoital
Chlamydia pcr - 88% sensitivity and 99% specificity; if negative think about MUT organims; mycoplasma - ureaplasma and trichomonas; tx MUT with metronidazole
Fever of unknown orign - esophagiti - retinitis - diarrhoea - encephalits

28. rifampin
Rifampin600mg q12. or cipro
Reddish orange discoloration of urine - feces - sweat - tears - sputum
Leukocytosis >100 cells - dec glucose - inc protien - inc opening pressure; in viral there will be lymphocytosis - normal glucose (virus doesn't eat) -
Chlamydia pcr - 88% sensitivity and 99% specificity; if negative think about MUT organims; mycoplasma - ureaplasma and trichomonas; tx MUT with metronidazole

29. causative organisms of uti
Exacerbate by HAART; give statin - if triglyceride >500 - give a fibrate
Upper lobes; any fibrosis in this area suggestive of latent TB
Most common E coli; less common; klebsiella - enterobacter - proteus - staph - groupd d strep
If a sample is ELISA positive - it is tested fro western blot for confirmation

30. acute febrile reaction develops after starting penicilin tx to syphilis patient
AA gradient >35 or Po2 <70
If a sample is ELISA positive - it is tested fro western blot for confirmation
Jarish-Herxheimer reaction; immunologica reaction due to rupture of sprochetes
No skin changes but pain out of proportion; infection spreads along fascial plane rapidly with blister - erythema - and bullae formation; marked tenderness on palpation - and CREPITUS

31. INH
Massive (even 20L/day) fluid resuscitaiton which may clear toxin
250 neutrophil/mm3 in peritoneal fluid - tx empiric abx; if tremor or other neuro sign give lactulose
If a sample is ELISA positive - it is tested fro western blot for confirmation
Hepatotoxitcity incidence 2.6% - commonly seen in alcoholic - liver disease - >50

32. gas gangrene
Within 72hrs of unprotected sex with HIV pos person - give two nucleosidase inhibitors (eg. zidovudin - lamivudein - tenofovir -) X4w
Fever - facial swelling - nasal discha - maxilary pain and tenderness - headache - present in DKA - caused by zygomycetes tx surgical debridement and intranasal amphotericin
<5000 copies/ml
Clostridium perfringens after penetrative injuries/wounds

33. How long abx is given in pseudomonas infection?
Aortic valve; endocardiits of AR p/w AV block and LBBB
High risk 19-64; 1-2 dose - above 65; one dose
2 weeks in neutropenic patients and 7-10 days after catheter removed/patient improved
Others lesions are ring enhancing and have mass effect while PML don't

34. what if monospot test is neg in IM?
Do EBV antibody test
AMS - focal neurological signs - seizures - multiorgan dysfunction - death; tx; doxycycline; for pregnant give chloramphenicle
Mainly clinical - epidemiological and seasonal setting
Similar pathophysiology as ITP - tx zidovudine

35. after exposure of HIV when antibody testing is performed?
If a sample is ELISA positive - it is tested fro western blot for confirmation
ELISA; initial visit - 6 - 12 and 24 weeks;
<500 copies/ml
<5000 copies/ml

36. How to tx IM?
Bed rest - NSAID - avoid contact sports; if patient develop SOB due to pharyngeal edema - give corticosteroid
Due to decrease elasticity of arterial wall; only systolic - diastolic normal - wide pulse pressure
Tx with amoxicillin or ceftriaxone. 90% are disease free after one year after tx
Think about cutaneous cryptococous; lesions looks like molluscus contagiousm. present in face/trunk/anywherer; dx biopsy of lesion which shows granulomatous inflammation with multinucleated giant cell

37. How to dx IM?
Do EBV antibody test
More than two UTI in six months or more than 3 uti in a year; cipro/bactrim/nitrofurantoin; abx may be given continuous or postcoital
Rifampin600mg q12. or cipro
Classic triad: fever - pharyngitis - postauricular lymaphdenopahty - caused by EBV

38. after bone marrow transplant - patient develop headache - fever - cought and chest pain. What is dx?
Fever - facial swelling - nasal discha - maxilary pain and tenderness - headache - present in DKA - caused by zygomycetes tx surgical debridement and intranasal amphotericin
Reddish orange discoloration of urine - feces - sweat - tears - sputum
Aspergillosis. common in bone marrow transplants. typically involves lungs and sinuses
Only vaccine. immunoglobuin not required. previously unvaccinated person will receive both.

39. pathophysiology of toxic shock syndrom?
Most common; fibromuscular dysplasia - Rt renal artery more common - angiography string of beads
Tampoon in nostril/vagina. think t for t - staph release exotoxin --activation of t cells directly--release of massive cytokines.
Postcoital voiding - increased intake of cranberry juice
Tx emptirically both gonococcus and chlamydia; 30% gono have coexsiting chlamydial infection; single dose ceftriaxone for gono and Azithromycin for chlamydia. if no improvement give metronidazol for trichomonas infection

40. when we see echym gangrenosum?
Type 1: patient with dm and pvd; caused by staph/GAS/ e coli/bacteroids; type2 - no associated medical illness - caused by laceration - trauma - surgery - IV drug abuse - caused mainly by GAS
Reddish orange discoloration of urine - feces - sweat - tears - sputum
Pts with pseudomonas bacerimia have this. they have perivascular bacterial invasion of the media and adventitia of arteries and veins. then ishcemic necrosis; skin and mucous membrane have nodular patches wtih hemorrhage and ulceration
Upper lobes; any fibrosis in this area suggestive of latent TB

41. acute onset +rusty sputum
When cd4 count falls below 200. 2p in pcp =200
Fever of unknown orign - esophagiti - retinitis - diarrhoea - encephalits
S. pneumonie. differentitate this from atypical pneumonia and pcp which are gradual onset - non productive cough -
Hepatotoxitcity incidence 2.6% - commonly seen in alcoholic - liver disease - >50

42. Tx of choice for human bites
N meningitidis colonize in nasopharynx; cause mucosal invasion - systemic bacterimia and seeding in the meninges
Ampicillin-sublactam; most bites contain eikenella
Aortic valve; endocardiits of AR p/w AV block and LBBB
Monospot test which screen heteropile ab that agglutinate horse rbc

43. systolic HTN in elderly
CTP subjective; MELD objective; meld uses serum billirubin - inr and serum creatinin. meld used to determine 90 day mortality of liver diease
HBIG hep B immunoglobulin
Think about cutaneous cryptococous; lesions looks like molluscus contagiousm. present in face/trunk/anywherer; dx biopsy of lesion which shows granulomatous inflammation with multinucleated giant cell
Due to decrease elasticity of arterial wall; only systolic - diastolic normal - wide pulse pressure

44. What are indicators for progression of HIV
HIV syndrome or anti-retroviral syndrome; 2-3w after virus exposure. similar to IM.
Viral load and CD4 count
Most common; fibromuscular dysplasia - Rt renal artery more common - angiography string of beads
Vaccine titer >10mU/ml

45. what parameters increases risk of neurosyphilis in HIV patient
Type 1: patient with dm and pvd; caused by staph/GAS/ e coli/bacteroids; type2 - no associated medical illness - caused by laceration - trauma - surgery - IV drug abuse - caused mainly by GAS
Most common; fibromuscular dysplasia - Rt renal artery more common - angiography string of beads
Gemfibrozil and other fibrate drugs; statin and niacin also work not as good as fibrate drugs like gemfibrozil
CD4 less than 350 and RPR >1:32; HIV infected patient with syphilis >1 yr should have CSF exam before tx. if csf normal tx with benzathine penicillin weekly for 3 weeks.

46. worsening of TB after starting HAART in HIV
Start with amphotericin B and flucytosin for 2 weeks - if there is clinical improvement discontinue them and start with fluconazol
When cd4 count falls below 200. 2p in pcp =200
Harrt ---rapid improvement of immune function---increased inflammatory reaction--worsening of clinical symptoms; self limiting....needs no tx
Td every 10 years - tdap once before 65 and after 65

47. When to tx influenza with antiviral therapy?
When patient is older >65 - pregnant - cardiac of pulmonary disease; patient without above risks are treated when they come within 48 hours of symptom onset
Only vaccine. immunoglobuin not required. previously unvaccinated person will receive both.
Doesn't exceed more than 15 mm and size significantly decreases after 15 years
HIV viral load

48. patient with diagnosed case of cryptococcal meningitis p/w severe headache and vomiting
Need lumbar puncture to relieve pressure; they have high opening pressure >350
HIV RNA PCR assay; there may be small amount of virus that are not detectable in ELISA.
Every 3-4 hours to determine appropritate time to start HAART
Pts with pseudomonas bacerimia have this. they have perivascular bacterial invasion of the media and adventitia of arteries and veins. then ishcemic necrosis; skin and mucous membrane have nodular patches wtih hemorrhage and ulceration

49. when western blot is done for HIV testing
S. pneumonie. differentitate this from atypical pneumonia and pcp which are gradual onset - non productive cough -
Classic triad: fever - pharyngitis - postauricular lymaphdenopahty - caused by EBV
AMS - focal neurological signs - seizures - multiorgan dysfunction - death; tx; doxycycline; for pregnant give chloramphenicle
If a sample is ELISA positive - it is tested fro western blot for confirmation

50. How to dx lyme arthritis?
250 neutrophil/mm3 in peritoneal fluid - tx empiric abx; if tremor or other neuro sign give lactulose
Blastomycosis
ELISA and western blot of synovial fluid.
HIV syndrome or anti-retroviral syndrome; 2-3w after virus exposure. similar to IM.