USMLE Step 3 Exam Prep Questions And Answers (202472025)
Pseudogout associations - ✔✔hemochromatosis, hyperparathyroidism, acromegaly,
hypothyroidism
Gout crystals - ✔✔negatively birefringent needles
Pseudogout crystals - ✔✔positively birefringent needles
Vasculitis associated with chronic Hep B - ✔✔polyarteritis nodosa
Vasculitis associated with chronic Hep C - ✔✔cryoglobulinemia
Best blood test for polyarteritis nodosa - ✔✔There is none. Get abdominal
angiography first, then biopsy of muscle, skin, or sural nerve.
Churg-Strauss - ✔✔vasculitis + eosinophilia + asthma
Takayasu's arteritis - ✔✔young asian female with diminished pulses (usually
preceeded by fatigue, weight loss, arthralgia, anemia, elevated ESR)
Best test for Takayasu's - ✔✔aortic angiography or MRA
Bite cells on blood smear - ✔✔G6PD
Burr/Spur cells on blood smear - ✔✔liver disease
,Acanthocytes on blood smear (looks like spur cell but with more rounded spurs) -
✔✔liver disease, hypothyroidism, alcoholism
Basophilic stippling on blood smear - ✔✔lead poisoning
Schistocytes on blood smear - ✔✔TTP-HUS, DIC, prosthetic heart valve, malignant
htn, sepsis
Target cells on blood smear - ✔✔thalassemia, other hemoglobinopathies, liver
disease
5 causes of microcytic anemia - ✔✔iron deficiency, lead poisoning, anemia of
chronic disease (but usually normocytic), thalassemia, sideroblastic anemia (can also
have high MCV)
Antibody test for celiac disease - ✔✔anti-endomysial, tissue transglutaminase (small
bowel bx is best though)
Antibiotics for MRSA - ✔✔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 - ✔✔Oxacillin/nafcillin, dicloxacillin (IV and oral), cefazolin
(IV), cephalexin (oral)
Can you use cephalosporins in pt allergic to PCN? - ✔✔yes, if the rxn is rash only;
no if pt has true anaphylaxis
,Antibiotics to use for Staph with PCN allergy - ✔✔cephalosporins if rash only;
macrolides, clindamycin, vancomycin, linezolid, daptomycin, TMP/SMX
Antibiotics for strep - ✔✔PCN, ampicillin, amoxicillin
Antibiotics for GNRs - ✔✔Cephalosporins: cefepime, ceftazidime
PCNs: piperacillin, ticaricillin
Monobactam: Aztreonam
Quinolones: cipro, levo, gati, moxi
Aminoglycs: gentamicin, tobramycin, amikacin
Carbapenems: imipenem, mero, erta
Limitation of ertapenem - ✔✔does NOT cover pseudomonas
Piperacillin and ticarcillin - ✔✔GNRs
strep
anaerobes
Carbapenems - ✔✔good anaerobic coverage
strep
MSSA
Tigecycline - ✔✔MRSA
good GNR coverage
Anaerobes - ✔✔-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 - ✔✔aminoglycs, aztreonam, fluoroquinolones,
oxacillin/nafcillin, all cephalosporins EXCEPT cefoxitin and cefotetan
Red man syndrome - ✔✔red, flushed skin from histamine release, associated with
rapid infusion of vancomycin (so slow down the infusion rate)
Osteomyelitis - ✔✔-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 - ✔✔-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 - ✔✔-throat: rheumatic fever AND glomerulonephritis
-skin: ONLY glomerulonephritis
Gonorrhea tx - ✔✔-ceftriaxone IM
-cefixime oral
-cefpodoxime oral
-ciprofloxacin oral (2d line)
-if pregnant, then ceftriaxone IM
-ALSO treat for chlamydia