USMLE Step 3 Exam Questions With Correct Answers

©THEBRIGHT EXAM STUDY SOLUTIONS 8/19/2024 2:07 PM




USMLE Step 3 Exam Questions With
Correct Answers


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

,©THEBRIGHT EXAM STUDY SOLUTIONS 8/19/2024 2:07 PM
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

,©THEBRIGHT EXAM STUDY SOLUTIONS 8/19/2024 2:07 PM
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

, ©THEBRIGHT EXAM STUDY SOLUTIONS 8/19/2024 2:07 PM
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

What binds toxin in gas gangrene? - answer✔✔clindamycin

Common bugs in dog bite - answer✔✔Capnocytophaga canimorsus (GNR) most common,
Pasteurella multocida may be present in 25%, anaerobes

Bug that causes overwhelming sepsis in asplenics with dog bite - answer✔✔Capnocytophaga
canimorsus

Typical bugs in cat bite - answer✔✔Pastuerella multocida, anaerobes

Typical bugs in reptile bite - answer✔✔Salmonella, Pseudomonas (snakes)

Treatment for animal bite - answer✔✔Amox/clavulanate
PCN allergy: doxy OR TMP/SMX OR fluoroquinolone PLUS clinda for anaerobes
Severe infxn: use IV (like unasyn)
Duration: 3-5 days for prophy, 7-14 days for infection

Typical bugs in human bites - answer✔✔Eikenella corrodens, streptococci, staphylococci,
Haemophilus species, and a multitude of anaerobes