USMLE STEP 3 FINAL REVIEW
PAPER COMPLETE SOLUTIONS
GRADED A PLUS
⫸ 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
PAPER COMPLETE SOLUTIONS
GRADED A PLUS
⫸ 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
