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USMLE Step 3 Questions and Answers
Pseudogout associations Ans: hemochromatosis,
hyperparathyroidism, acromegaly, hypothyroidism
Gout crystals Ans: negatively birefringent needles
Pseudogout crystals Ans: positively birefringent needles
Vasculitis associated with chronic Hep B Ans: polyarteritis nodosa
Vasculitis associated with chronic Hep C Ans: cryoglobulinemia
Best blood test for polyarteritis nodosa Ans: There is none. Get
abdominal angiography first, then biopsy of muscle, skin, or sural
nerve.
Churg-Strauss Ans: vasculitis + eosinophilia + asthma
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Takayasu's arteritis Ans: young asian female with diminished
pulses (usually preceeded by fatigue, weight loss, arthralgia,
anemia, elevated ESR)
Best test for Takayasu's Ans: aortic angiography or MRA
Bite cells on blood smear Ans: G6PD
Burr/Spur cells on blood smear Ans: liver disease
Acanthocytes on blood smear (looks like spur cell but with more
rounded spurs) Ans: liver disease, hypothyroidism, alcoholism
Basophilic stippling on blood smear Ans: lead poisoning
Schistocytes on blood smear Ans: TTP-HUS, DIC, prosthetic heart
valve, malignant htn, sepsis
Target cells on blood smear Ans: thalassemia, other
hemoglobinopathies, liver disease
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5 causes of microcytic anemia Ans: iron deficiency, lead poisoning,
anemia of chronic disease (but usually normocytic), thalassemia,
sideroblastic anemia (can also have high MCV)
Antibody test for celiac disease Ans: anti-endomysial, tissue
transglutaminase (small bowel bx is best though)
Antibiotics for MRSA Ans: 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 Ans: Oxacillin/nafcillin, dicloxacillin (IV and
oral), cefazolin (IV), cephalexin (oral)
Can you use cephalosporins in pt allergic to PCN? Ans: yes, if the
rxn is rash only; no if pt has true anaphylaxis
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Antibiotics to use for Staph with PCN allergy Ans: cephalosporins
if rash only; macrolides, clindamycin, vancomycin, linezolid,
daptomycin, TMP/SMX
Antibiotics for strep Ans: PCN, ampicillin, amoxicillin
Antibiotics for GNRs Ans: Cephalosporins: cefepime, ceftazidime
PCNs: piperacillin, ticaricillin
Monobactam: Aztreonam
Quinolones: cipro, levo, gati, moxi
Aminoglycs: gentamicin, tobramycin, amikacin
Carbapenems: imipenem, mero, erta
Limitation of ertapenem Ans: does NOT cover pseudomonas
Piperacillin and ticarcillin Ans: GNRs
© 2025 All rights reserved
USMLE Step 3 Questions and Answers
Pseudogout associations Ans: hemochromatosis,
hyperparathyroidism, acromegaly, hypothyroidism
Gout crystals Ans: negatively birefringent needles
Pseudogout crystals Ans: positively birefringent needles
Vasculitis associated with chronic Hep B Ans: polyarteritis nodosa
Vasculitis associated with chronic Hep C Ans: cryoglobulinemia
Best blood test for polyarteritis nodosa Ans: There is none. Get
abdominal angiography first, then biopsy of muscle, skin, or sural
nerve.
Churg-Strauss Ans: vasculitis + eosinophilia + asthma
© 2025 All rights reserved
, 2 | Page
Takayasu's arteritis Ans: young asian female with diminished
pulses (usually preceeded by fatigue, weight loss, arthralgia,
anemia, elevated ESR)
Best test for Takayasu's Ans: aortic angiography or MRA
Bite cells on blood smear Ans: G6PD
Burr/Spur cells on blood smear Ans: liver disease
Acanthocytes on blood smear (looks like spur cell but with more
rounded spurs) Ans: liver disease, hypothyroidism, alcoholism
Basophilic stippling on blood smear Ans: lead poisoning
Schistocytes on blood smear Ans: TTP-HUS, DIC, prosthetic heart
valve, malignant htn, sepsis
Target cells on blood smear Ans: thalassemia, other
hemoglobinopathies, liver disease
© 2025 All rights reserved
, 3 | Page
5 causes of microcytic anemia Ans: iron deficiency, lead poisoning,
anemia of chronic disease (but usually normocytic), thalassemia,
sideroblastic anemia (can also have high MCV)
Antibody test for celiac disease Ans: anti-endomysial, tissue
transglutaminase (small bowel bx is best though)
Antibiotics for MRSA Ans: 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 Ans: Oxacillin/nafcillin, dicloxacillin (IV and
oral), cefazolin (IV), cephalexin (oral)
Can you use cephalosporins in pt allergic to PCN? Ans: yes, if the
rxn is rash only; no if pt has true anaphylaxis
© 2025 All rights reserved
, 4 | Page
Antibiotics to use for Staph with PCN allergy Ans: cephalosporins
if rash only; macrolides, clindamycin, vancomycin, linezolid,
daptomycin, TMP/SMX
Antibiotics for strep Ans: PCN, ampicillin, amoxicillin
Antibiotics for GNRs Ans: Cephalosporins: cefepime, ceftazidime
PCNs: piperacillin, ticaricillin
Monobactam: Aztreonam
Quinolones: cipro, levo, gati, moxi
Aminoglycs: gentamicin, tobramycin, amikacin
Carbapenems: imipenem, mero, erta
Limitation of ertapenem Ans: does NOT cover pseudomonas
Piperacillin and ticarcillin Ans: GNRs
© 2025 All rights reserved
