USMLE Step 3 2023 TESTS QUESTIONS AND ANSWER WITH COMPLETE SOLUTIONS
Pseudogout associations - answer hemochromatosis, hyperparathyroidism,
acromegaly, hypothyroidism
Gout crystals - answer negatively birefringent needles
Pseudogout crystals - answer positively birefringent needles
Vasculitis associated with chronic Hep B - answer polyarteritis nodosa
Vasculitis associated with chronic Hep C - answer cryoglobulinemia
Best blood test for polyarteritis nodosa - answer There is none. Get abdominal
angiography first, then biopsy of muscle, skin, or sural nerve.
Churg-Strauss - answer vasculitis + eosinophilia + asthma
Takayasu's arteritis - answer young asian female with diminished pulses (usually
preceeded by fatigue, weight loss, arthralgia, anemia, elevated ESR)
Best test for Takayasu's - answer aortic angiography or MRA
Bite cells on blood smear - answer G6PD
Burr/Spur cells on blood smear - answer liver disease
Acanthocytes on blood smear (looks like spur cell but with more rounded spurs) -
answer liver disease, hypothyroidism, alcoholism
Basophilic stippling on blood smear - answer lead poisoning
Schistocytes on blood smear - answer TTP-HUS, DIC, prosthetic heart valve, malignant
htn, sepsis
Target cells on blood smear - answer thalassemia, other hemoglobinopathies, liver
disease
5 causes of microcytic anemia - answer iron deficiency, lead poisoning, anemia of
chronic disease (but usually normocytic), thalassemia, sideroblastic anemia (can also
have high MCV)
Antibody test for celiac disease - answer anti-endomysial, tissue transglutaminase
(small bowel bx is best though)
,Antibiotics for MRSA - answer IV: vanc, linezolid, daptomycin, tigecycline;
if minor infection, can use oral: TMP/SMX, doxy, minocycline, or maybe clindamycin
(there is inducible resistance to clinda though)
Antibiotics for MSSA - answer Oxacillin/nafcillin, dicloxacillin (IV and oral), cefazolin (IV),
cephalexin (oral)
Can you use cephalosporins in pt allergic to PCN? - answer yes, if the rxn is rash only;
no if pt has true anaphylaxis
Antibiotics to use for Staph with PCN allergy - answer cephalosporins if rash only;
macrolides, clindamycin, vancomycin, linezolid, daptomycin, TMP/SMX
Antibiotics for strep - answer PCN, ampicillin, amoxicillin
Antibiotics for GNRs - answer Cephalosporins: cefepime, ceftazidime
PCNs: piperacillin, ticaricillin
Monobactam: Aztreonam
Quinolones: cipro, levo, gati, moxi
Aminoglycs: gentamicin, tobramycin, amikacin
Carbapenems: imipenem, mero, erta
Limitation of ertapenem - answer does NOT cover pseudomonas
Piperacillin and ticarcillin - answer GNRs
strep
anaerobes
Carbapenems - answer good anaerobic coverage
strep
MSSA
Tigecycline - answer MRSA
good GNR coverage
Anaerobes - answer -metronidazole is BEST for abdominal anaerobes (carbapenems,
piperacillin, and ticarcillin have equal efficacy)
-cefoxitin and cefotetan are the ONLY cephalosporins
-respiratory anaerobes: clindamycin
Abx with NO anaerobic coverage - answer aminoglycs, aztreonam, fluoroquinolones,
oxacillin/nafcillin, all cephalosporins EXCEPT cefoxitin and cefotetan
Red man syndrome - answer red, flushed skin from histamine release, associated with
rapid infusion of vancomycin (so slow down the infusion rate)
, Osteomyelitis - answer -most common is staph: oxacillin or nafcillin IV for 4-6 wks for
MSSA; vanc, linezolid or dapto for MRSA
-GNRs: salmonella or pseudomonas, can use orals, but must cx org. first and make
sure it is sensitive (BONE bx and cx)
Cellulitis tx - answer -minor infection: oral dicloxacillin or cephalexin
-severe: IV oxacillin, nafcillin or cefazolin
-PCN allergy: if rash, then cephalosporin; if anaphylaxis, then vanc, linezolid, dapto
(macrolides or clinda for minor infection)
Sequelae of strep infection - answer -throat: rheumatic fever AND glomerulonephritis
-skin: ONLY glomerulonephritis
Gonorrhea tx - answer -ceftriaxone IM
-cefixime oral
-cefpodoxime oral
-ciprofloxacin oral (2d line)
-if pregnant, then ceftriaxone IM
-ALSO treat for chlamydia
Chlamydia tx - answer -azithromycin (single dose)
-doxycycline (for 1 wk)
-if pregnant, then azithro
-ALSO treat for gonorrhea
Recurrent gonorrhea associated with... - answer terminal complement deficiency
(predisposes to any Neisseria infection)
PID tx - answer -outpatient: ceftriaxone (IM) and oral doxy
-inpatient: cefoxitin or cefotetan IV + doxy + (maybe) metronidazole
Abx safe in pregnancy - answer -PCNs
-cephalosporins
-aztreonam
-erythromycin
-azithromycin
Epidydimo-orchitis tx - answer -if <35 yo, then ceftriaxone + doxy
-if >35 yo, then fluoroquinolone
Chancroid - answer -PAINFUL ulcer caused by Hemophilus ducreyi
-swab for gram stain and culture (on Nairobi medium or Mueller-Hinton agar)
-treat with ceftriaxone IM or single dose azithromycin
What treats MRSA and VRE? - answer daptomycin
Pseudogout associations - answer hemochromatosis, hyperparathyroidism,
acromegaly, hypothyroidism
Gout crystals - answer negatively birefringent needles
Pseudogout crystals - answer positively birefringent needles
Vasculitis associated with chronic Hep B - answer polyarteritis nodosa
Vasculitis associated with chronic Hep C - answer cryoglobulinemia
Best blood test for polyarteritis nodosa - answer There is none. Get abdominal
angiography first, then biopsy of muscle, skin, or sural nerve.
Churg-Strauss - answer vasculitis + eosinophilia + asthma
Takayasu's arteritis - answer young asian female with diminished pulses (usually
preceeded by fatigue, weight loss, arthralgia, anemia, elevated ESR)
Best test for Takayasu's - answer aortic angiography or MRA
Bite cells on blood smear - answer G6PD
Burr/Spur cells on blood smear - answer liver disease
Acanthocytes on blood smear (looks like spur cell but with more rounded spurs) -
answer liver disease, hypothyroidism, alcoholism
Basophilic stippling on blood smear - answer lead poisoning
Schistocytes on blood smear - answer TTP-HUS, DIC, prosthetic heart valve, malignant
htn, sepsis
Target cells on blood smear - answer thalassemia, other hemoglobinopathies, liver
disease
5 causes of microcytic anemia - answer iron deficiency, lead poisoning, anemia of
chronic disease (but usually normocytic), thalassemia, sideroblastic anemia (can also
have high MCV)
Antibody test for celiac disease - answer anti-endomysial, tissue transglutaminase
(small bowel bx is best though)
,Antibiotics for MRSA - answer IV: vanc, linezolid, daptomycin, tigecycline;
if minor infection, can use oral: TMP/SMX, doxy, minocycline, or maybe clindamycin
(there is inducible resistance to clinda though)
Antibiotics for MSSA - answer Oxacillin/nafcillin, dicloxacillin (IV and oral), cefazolin (IV),
cephalexin (oral)
Can you use cephalosporins in pt allergic to PCN? - answer yes, if the rxn is rash only;
no if pt has true anaphylaxis
Antibiotics to use for Staph with PCN allergy - answer cephalosporins if rash only;
macrolides, clindamycin, vancomycin, linezolid, daptomycin, TMP/SMX
Antibiotics for strep - answer PCN, ampicillin, amoxicillin
Antibiotics for GNRs - answer Cephalosporins: cefepime, ceftazidime
PCNs: piperacillin, ticaricillin
Monobactam: Aztreonam
Quinolones: cipro, levo, gati, moxi
Aminoglycs: gentamicin, tobramycin, amikacin
Carbapenems: imipenem, mero, erta
Limitation of ertapenem - answer does NOT cover pseudomonas
Piperacillin and ticarcillin - answer GNRs
strep
anaerobes
Carbapenems - answer good anaerobic coverage
strep
MSSA
Tigecycline - answer MRSA
good GNR coverage
Anaerobes - answer -metronidazole is BEST for abdominal anaerobes (carbapenems,
piperacillin, and ticarcillin have equal efficacy)
-cefoxitin and cefotetan are the ONLY cephalosporins
-respiratory anaerobes: clindamycin
Abx with NO anaerobic coverage - answer aminoglycs, aztreonam, fluoroquinolones,
oxacillin/nafcillin, all cephalosporins EXCEPT cefoxitin and cefotetan
Red man syndrome - answer red, flushed skin from histamine release, associated with
rapid infusion of vancomycin (so slow down the infusion rate)
, Osteomyelitis - answer -most common is staph: oxacillin or nafcillin IV for 4-6 wks for
MSSA; vanc, linezolid or dapto for MRSA
-GNRs: salmonella or pseudomonas, can use orals, but must cx org. first and make
sure it is sensitive (BONE bx and cx)
Cellulitis tx - answer -minor infection: oral dicloxacillin or cephalexin
-severe: IV oxacillin, nafcillin or cefazolin
-PCN allergy: if rash, then cephalosporin; if anaphylaxis, then vanc, linezolid, dapto
(macrolides or clinda for minor infection)
Sequelae of strep infection - answer -throat: rheumatic fever AND glomerulonephritis
-skin: ONLY glomerulonephritis
Gonorrhea tx - answer -ceftriaxone IM
-cefixime oral
-cefpodoxime oral
-ciprofloxacin oral (2d line)
-if pregnant, then ceftriaxone IM
-ALSO treat for chlamydia
Chlamydia tx - answer -azithromycin (single dose)
-doxycycline (for 1 wk)
-if pregnant, then azithro
-ALSO treat for gonorrhea
Recurrent gonorrhea associated with... - answer terminal complement deficiency
(predisposes to any Neisseria infection)
PID tx - answer -outpatient: ceftriaxone (IM) and oral doxy
-inpatient: cefoxitin or cefotetan IV + doxy + (maybe) metronidazole
Abx safe in pregnancy - answer -PCNs
-cephalosporins
-aztreonam
-erythromycin
-azithromycin
Epidydimo-orchitis tx - answer -if <35 yo, then ceftriaxone + doxy
-if >35 yo, then fluoroquinolone
Chancroid - answer -PAINFUL ulcer caused by Hemophilus ducreyi
-swab for gram stain and culture (on Nairobi medium or Mueller-Hinton agar)
-treat with ceftriaxone IM or single dose azithromycin
What treats MRSA and VRE? - answer daptomycin
