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. How to dx IM?
Classic triad: fever - pharyngitis - postauricular lymaphdenopahty - caused by EBV
<5000 copies/ml
Cd4 count
Trimethoprime-sulphamethoxazole if intolerant give pentamidine (cause pancreatitis p for p)

2. What is the classic signs of nec fasc?
Vitamin B6 antagonist - can cause peripheral neuropathy if not give with b6
HIV lipodystrophy; no correlation with viral load; p/w insulin resistance and dyslipidemia (inc cholesterol - dec HDL)
Petechial rash developed 3-5th days of illness begins ankle or wrist and spread to palm/soles
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

3. INH
Pt who have been treated before for latent TB
Monospot test which screen heteropile ab that agglutinate horse rbc
Vitamin B6 antagonist - can cause peripheral neuropathy if not give with b6
6-12 weeks

4. How to dx adequate response to HBV vaccine
Jarish-Herxheimer reaction; immunologica reaction due to rupture of sprochetes
Vaccine titer >10mU/ml
N meningitidis colonize in nasopharynx; cause mucosal invasion - systemic bacterimia and seeding in the meninges
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

5. gas gangrene
Clostridium perfringens after penetrative injuries/wounds
Hepatotoxitcity incidence 2.6% - commonly seen in alcoholic - liver disease - >50
Quinoloes (cipro/levo) cure rate 70% - TMP-SMZ
Immune mediated; circulating IgG and IgM to penicillin derivatives

6. Do we need to give vaccine or immunoglobulin for rabies exposure in previously vaccinated person?
Others lesions are ring enhancing and have mass effect while PML don't
Only vaccine. immunoglobuin not required. previously unvaccinated person will receive both.
Mainly clinical - epidemiological and seasonal setting
Every 3-4 hours to determine appropritate time to start HAART

7. clinical manifestation of mucomycosis
Fever - facial swelling - nasal discha - maxilary pain and tenderness - headache - present in DKA - caused by zygomycetes tx surgical debridement and intranasal amphotericin
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
Jarish-Herxheimer reaction; immunologica reaction due to rupture of sprochetes
HIV syndrome or anti-retroviral syndrome; 2-3w after virus exposure. similar to IM.

8. How long abx is given in pseudomonas infection?
Pregnacy - urologic procedure - hip arthoplastu
HIV viral load
2 weeks in neutropenic patients and 7-10 days after catheter removed/patient improved
Blastomycosis

9. What are the behavioral interventions decrease the risk of UTI
2 weeks in neutropenic patients and 7-10 days after catheter removed/patient improved
Gemfibrozil and other fibrate drugs; statin and niacin also work not as good as fibrate drugs like gemfibrozil
Postcoital voiding - increased intake of cranberry juice
Either TB or aspergillosis

10. dame that has already occurred
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
Within 72hrs of unprotected sex with HIV pos person - give two nucleosidase inhibitors (eg. zidovudin - lamivudein - tenofovir -) X4w
Cd4 count

11. What is the Tx of cryptococcal meninngitis
AMS - focal neurological signs - seizures - multiorgan dysfunction - death; tx; doxycycline; for pregnant give chloramphenicle
2 weeks in neutropenic patients and 7-10 days after catheter removed/patient improved
Start with amphotericin B and flucytosin for 2 weeks - if there is clinical improvement discontinue them and start with fluconazol
Others lesions are ring enhancing and have mass effect while PML don't

12. How to tx pseudomonas?
Pegylated interferon and lamivudine
Viral load and CD4 count
Massive (even 20L/day) fluid resuscitaiton which may clear toxin
Antipseudomonal penicillin (pipercillin) or cephalosporin (ceftazdidime/cefepime) and aminoglycoside (tobramycin/amikacin)

13. hypertriglyceridemia in HIV
Exacerbate by HAART; give statin - if triglyceride >500 - give a fibrate
Due to decrease elasticity of arterial wall; only systolic - diastolic normal - wide pulse pressure
Blastomycosis
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

14. How to differentiate gonococcal and nongonoccal urethritis?
Tampoon in nostril/vagina. think t for t - staph release exotoxin --activation of t cells directly--release of massive cytokines.
HIV syndrome or anti-retroviral syndrome; 2-3w after virus exposure. similar to IM.
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
Tx with amoxicillin or ceftriaxone. 90% are disease free after one year after tx

15. when not to give INH therapy if ppd positive and patient asyptomatic
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
Pt who have been treated before for latent TB
Markedly elevated csf pressure >200 - inc protein - low glucose ; tx amphotericin and flucytosine
Mainly clinical - epidemiological and seasonal setting

16. When to give abx to prevent recurrent uti
Start with amphotericin B and flucytosin for 2 weeks - if there is clinical improvement discontinue them and start with fluconazol
Oropharyngeal secretions; hence named as kissing disease
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
Pregnacy - urologic procedure - hip arthoplastu

17. When to tx asymptomatic bacteriurea >100 -000?
Pregnacy - urologic procedure - hip arthoplastu
Tampoon in nostril/vagina. think t for t - staph release exotoxin --activation of t cells directly--release of massive cytokines.
Vaccine titer >10mU/ml
When cd4 count falls below 200. 2p in pcp =200

18. What is characteristic for dx of rocky mountain spotted fever?
<500 copies/ml
Petechial rash developed 3-5th days of illness begins ankle or wrist and spread to palm/soles
Markedly elevated csf pressure >200 - inc protein - low glucose ; tx amphotericin and flucytosine
Clostridium perfringens after penetrative injuries/wounds

19. 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
Leukocytosis >100 cells - dec glucose - inc protien - inc opening pressure; in viral there will be lymphocytosis - normal glucose (virus doesn't eat) -
Upper lobes; any fibrosis in this area suggestive of latent TB
Bronchoalveolar washing and transbronchial biopsy

20. patient with diagnosed case of cryptococcal meningitis p/w severe headache and vomiting
Immune mediated; circulating IgG and IgM to penicillin derivatives
Jarish-Herxheimer reaction; immunologica reaction due to rupture of sprochetes
Need lumbar puncture to relieve pressure; they have high opening pressure >350
6-12 weeks

21. How often HIV postiive patients CD4 count needs to be evaluated?
250 neutrophil/mm3 in peritoneal fluid - tx empiric abx; if tremor or other neuro sign give lactulose
Every 3-4 hours to determine appropritate time to start HAART
Quinoloes (cipro/levo) cure rate 70% - TMP-SMZ
HIV present in very minimal quantities in human saliva. exposure/contact of saliva will never trasmit HIV

22. pneumococcal vaccine indication?
Doesn't exceed more than 15 mm and size significantly decreases after 15 years
High risk 19-64; 1-2 dose - above 65; one dose
Blastomycosis
Within 6 months viral load will be <50

23. damae that is about to occur?
<5000 copies/ml
Immunocompromised patient ? dec vision - weakness/tingling of extremities or other neurological symptoms - MRI nonenhancing lesion in parietooccipital region
HIV viral load
Harrt ---rapid improvement of immune function---increased inflammatory reaction--worsening of clinical symptoms; self limiting....needs no tx

24. which heart valve is closer to ventricular conduction system/
If a sample is ELISA positive - it is tested fro western blot for confirmation
Oropharyngeal secretions; hence named as kissing disease
Aortic valve; endocardiits of AR p/w AV block and LBBB
Antipseudomonal penicillin (pipercillin) or cephalosporin (ceftazdidime/cefepime) and aminoglycoside (tobramycin/amikacin)

25. where TB normally affects
Postcoital voiding - increased intake of cranberry juice
Upper lobes; any fibrosis in this area suggestive of latent TB
Voriconazol. mycetoma-surgical removal
HIV present in very minimal quantities in human saliva. exposure/contact of saliva will never trasmit HIV

26. What are the subjective /objective measure of encephalopathy?
CTP subjective; MELD objective; meld uses serum billirubin - inr and serum creatinin. meld used to determine 90 day mortality of liver diease
Monospot test which screen heteropile ab that agglutinate horse rbc
Rifampin600mg q12. or cipro
Leukocytosis >100 cells - dec glucose - inc protien - inc opening pressure; in viral there will be lymphocytosis - normal glucose (virus doesn't eat) -

27. 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
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
Aspergillosis. common in bone marrow transplants. typically involves lungs and sinuses
S. pneumonie. differentitate this from atypical pneumonia and pcp which are gradual onset - non productive cough -

28. rifampin
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
Most common; fibromuscular dysplasia - Rt renal artery more common - angiography string of beads
Reddish orange discoloration of urine - feces - sweat - tears - sputum
Vaccine titer >10mU/ml

29. oligodendrocyte with intranuclear inclusion and demyelination in HIV patient
PML; focal neurological deficit like MM; no specific tx; regress with HAART
Pegylated interferon and lamivudine
AA gradient >35 or Po2 <70
Tx with amoxicillin or ceftriaxone. 90% are disease free after one year after tx

30. What is the pathophysiology of Meningococcal meningitis?
At first 4 weeks - then 8-12weks; remeasusing every 2m until viral load is undetectatable. then every 3 months
Non pregnant premanopausal - elderly - dm - sci - chronic foley
N meningitidis colonize in nasopharynx; cause mucosal invasion - systemic bacterimia and seeding in the meninges
4 months; characterized by knee joint effusion-large amount - joint stiffness - pain

31. 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

32. when western blot is done for HIV testing
If a sample is ELISA positive - it is tested fro western blot for confirmation
Fever of unknown orign - esophagiti - retinitis - diarrhoea - encephalits
Due to decrease elasticity of arterial wall; only systolic - diastolic normal - wide pulse pressure
250 neutrophil/mm3 in peritoneal fluid - tx empiric abx; if tremor or other neuro sign give lactulose

33. INH
250 neutrophil/mm3 in peritoneal fluid - tx empiric abx; if tremor or other neuro sign give lactulose
Hepatotoxitcity incidence 2.6% - commonly seen in alcoholic - liver disease - >50
Aspergillosis. common in bone marrow transplants. typically involves lungs and sinuses
Non pregnant premanopausal - elderly - dm - sci - chronic foley

34. How to confirm dx if pcp?
Bronchoalveolar washing and transbronchial biopsy
Others lesions are ring enhancing and have mass effect while PML don't
Massive (even 20L/day) fluid resuscitaiton which may clear toxin
Hepatotoxitcity incidence 2.6% - commonly seen in alcoholic - liver disease - >50

35. How to dx progressive multifocal leukoencephalopathy
HIV lipodystrophy; no correlation with viral load; p/w insulin resistance and dyslipidemia (inc cholesterol - dec HDL)
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
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
Immunocompromised patient ? dec vision - weakness/tingling of extremities or other neurological symptoms - MRI nonenhancing lesion in parietooccipital region

36. How to differentiate different types of necrotizing fascitis?
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
Oropharyngeal secretions; hence named as kissing disease
Bed rest - NSAID - avoid contact sports; if patient develop SOB due to pharyngeal edema - give corticosteroid
Fever of unknown orign - esophagiti - retinitis - diarrhoea - encephalits

37. what if monospot test is neg in IM?
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
2 weeks in neutropenic patients and 7-10 days after catheter removed/patient improved
Do EBV antibody test
Jarish-Herxheimer reaction; immunologica reaction due to rupture of sprochetes

38. How to tx chronic hep B
Pegylated interferon and lamivudine
Most common; fibromuscular dysplasia - Rt renal artery more common - angiography string of beads
Do EBV antibody test
Either TB or aspergillosis

39. if a patient received BCG vaccine - how big is his PPD induration

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

40. can HIV transmitted through human bite?
Leukocytosis >100 cells - dec glucose - inc protien - inc opening pressure; in viral there will be lymphocytosis - normal glucose (virus doesn't eat) -
HIV present in very minimal quantities in human saliva. exposure/contact of saliva will never trasmit HIV
Do EBV antibody test
Immunocompromised patient ? dec vision - weakness/tingling of extremities or other neurological symptoms - MRI nonenhancing lesion in parietooccipital region

41. What is the mch of ampicillin induced rash in IM
Start with amphotericin B and flucytosin for 2 weeks - if there is clinical improvement discontinue them and start with fluconazol
Viral load and CD4 count
Staph - GBS - proteus - pseudomona - e coli - candida - bacteroids; organisms isolated only from deep curettage of ulcer
Immune mediated; circulating IgG and IgM to penicillin derivatives

42. chshould we tx IM with abx (ampicilin) if throat cx is positive?
Rifampin600mg q12. or cipro
ELISA and western blot of synovial fluid.
Throat cx of positive of GAS means bacteria are colonized bur not infected in IM. tx with ampi can trigger maculopaular rash
Quinoloes (cipro/levo) cure rate 70% - TMP-SMZ

43. foot infections in DM
4 months; characterized by knee joint effusion-large amount - joint stiffness - pain
Trimethoprime-sulphamethoxazole if intolerant give pentamidine (cause pancreatitis p for p)
Staph - GBS - proteus - pseudomona - e coli - candida - bacteroids; organisms isolated only from deep curettage of ulcer
Quinoloes (cipro/levo) cure rate 70% - TMP-SMZ

44. What is fatal consequence of RMSF?
Vitamin B6 antagonist - can cause peripheral neuropathy if not give with b6
HBIG hep B immunoglobulin
AMS - focal neurological signs - seizures - multiorgan dysfunction - death; tx; doxycycline; for pregnant give chloramphenicle
Mainly clinical - epidemiological and seasonal setting

45. causative organisms of uti
Only vaccine. immunoglobuin not required. previously unvaccinated person will receive both.
Within 6 months viral load will be <50
Most common E coli; less common; klebsiella - enterobacter - proteus - staph - groupd d strep
HIV present in very minimal quantities in human saliva. exposure/contact of saliva will never trasmit HIV

46. what parameters increases risk of neurosyphilis in HIV patient
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.
If a sample is ELISA positive - it is tested fro western blot for confirmation
Quinoloes (cipro/levo) cure rate 70% - TMP-SMZ
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

47. how CMV presents in immunocompromised patients
Fever of unknown orign - esophagiti - retinitis - diarrhoea - encephalits
ELISA and western blot of synovial fluid.
S. pneumonie. differentitate this from atypical pneumonia and pcp which are gradual onset - non productive cough -
Mainly clinical - epidemiological and seasonal setting

48. acute onset +rusty sputum
S. pneumonie. differentitate this from atypical pneumonia and pcp which are gradual onset - non productive cough -
Vaccine titer >10mU/ml
Jarish-Herxheimer reaction; immunologica reaction due to rupture of sprochetes
Pregnacy - urologic procedure - hip arthoplastu

49. hypertension in children
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
N meningitidis colonize in nasopharynx; cause mucosal invasion - systemic bacterimia and seeding in the meninges
AMS - focal neurological signs - seizures - multiorgan dysfunction - death; tx; doxycycline; for pregnant give chloramphenicle

50. How often viral load is monitored after HAART?
At first 4 weeks - then 8-12weks; remeasusing every 2m until viral load is undetectatable. then every 3 months
Vitamin B6 antagonist - can cause peripheral neuropathy if not give with b6
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
Exacerbate by HAART; give statin - if triglyceride >500 - give a fibrate