USMLE Step 3 Questions And Answers Latest Solution
Pseudogout associations Correct Answer: hemochromatosis, hyperparathyroidism, acromegaly,
hypothyroidism
Gout crystals Correct Answer: negatively birefringent needles
Pseudogout crystals Correct Answer: positively birefringent needles
Vasculitis associated with chronic Hep B Correct Answer: polyarteritis nodosa
Vasculitis associated with chronic Hep C Correct Answer: cryoglobulinemia
Best blood test for polyarteritis nodosa Correct Answer: There is none. Get abdominal angiography first,
then biopsy of muscle, skin, or sural nerve.
Churg-Strauss Correct Answer: vasculitis + eosinophilia + asthma
Takayasu's arteritis Correct Answer: young asian female with diminished pulses (usually preceeded by
fatigue, weight loss, arthralgia, anemia, elevated ESR)
Best test for Takayasu's Correct Answer: aortic angiography or MRA
Bite cells on blood smear Correct Answer: G6PD
Burr/Spur cells on blood smear Correct Answer: liver disease
Acanthocytes on blood smear (looks like spur cell but with more rounded spurs) Correct Answer: liver
disease, hypothyroidism, alcoholism
Basophilic stippling on blood smear Correct Answer: lead poisoning
Schistocytes on blood smear Correct Answer: TTP-HUS, DIC, prosthetic heart valve, malignant htn,
sepsis
Target cells on blood smear Correct Answer: thalassemia, other hemoglobinopathies, liver disease
5 causes of microcytic anemia Correct 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 Correct Answer: anti-endomysial, tissue transglutaminase (small bowel
bx is best though)
Antibiotics for MRSA Correct 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 Correct Answer: Oxacillin/nafcillin, dicloxacillin (IV and oral), cefazolin (IV),
cephalexin (oral)
Can you use cephalosporins in pt allergic to PCN? Correct Answer: yes, if the rxn is rash only; no if pt has
true anaphylaxis
Antibiotics to use for Staph with PCN allergy Correct Answer: cephalosporins if rash only; macrolides,
clindamycin, vancomycin, linezolid, daptomycin, TMP/SMX
Antibiotics for strep Correct Answer: PCN, ampicillin, amoxicillin
Antibiotics for GNRs Correct 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 Correct Answer: does NOT cover pseudomonas
Piperacillin and ticarcillin Correct Answer: GNRs
strep
anaerobes
Carbapenems Correct Answer: good anaerobic coverage
strep
MSSA
Tigecycline Correct Answer: MRSA
good GNR coverage
Anaerobes Correct 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 Correct Answer: aminoglycs, aztreonam, fluoroquinolones,
oxacillin/nafcillin, all cephalosporins EXCEPT cefoxitin and cefotetan
Red man syndrome Correct Answer: red, flushed skin from histamine release, associated with rapid
infusion of vancomycin (so slow down the infusion rate)
Osteomyelitis Correct 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 Correct 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 Correct Answer: -throat: rheumatic fever AND glomerulonephritis
-skin: ONLY glomerulonephritis
Gonorrhea tx Correct Answer: -ceftriaxone IM
-cefixime oral
-cefpodoxime oral
-ciprofloxacin oral (2d line)
-if pregnant, then ceftriaxone IM
-ALSO treat for chlamydia
Chlamydia tx Correct Answer: -azithromycin (single dose)
-doxycycline (for 1 wk)
-if pregnant, then azithro
-ALSO treat for gonorrhea
Recurrent gonorrhea associated with... Correct Answer: terminal complement deficiency (predisposes
to any Neisseria infection)
PID tx Correct Answer: -outpatient: ceftriaxone (IM) and oral doxy
-inpatient: cefoxitin or cefotetan IV + doxy + (maybe) metronidazole
Abx safe in pregnancy Correct Answer: -PCNs
-cephalosporins
-aztreonam
-erythromycin
-azithromycin
Epidydimo-orchitis tx Correct Answer: -if <35 yo, then ceftriaxone + doxy
-if >35 yo, then fluoroquinolone
Chancroid Correct 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? Correct Answer: daptomycin
What binds toxin in gas gangrene? Correct Answer: clindamycin
Common bugs in dog bite Correct Answer: Capnocytophaga canimorsus (GNR) most common,
Pasteurella multocida may be present in 25%, anaerobes
Bug that causes overwhelming sepsis in asplenics with dog bite Correct Answer: Capnocytophaga
canimorsus
Pseudogout associations Correct Answer: hemochromatosis, hyperparathyroidism, acromegaly,
hypothyroidism
Gout crystals Correct Answer: negatively birefringent needles
Pseudogout crystals Correct Answer: positively birefringent needles
Vasculitis associated with chronic Hep B Correct Answer: polyarteritis nodosa
Vasculitis associated with chronic Hep C Correct Answer: cryoglobulinemia
Best blood test for polyarteritis nodosa Correct Answer: There is none. Get abdominal angiography first,
then biopsy of muscle, skin, or sural nerve.
Churg-Strauss Correct Answer: vasculitis + eosinophilia + asthma
Takayasu's arteritis Correct Answer: young asian female with diminished pulses (usually preceeded by
fatigue, weight loss, arthralgia, anemia, elevated ESR)
Best test for Takayasu's Correct Answer: aortic angiography or MRA
Bite cells on blood smear Correct Answer: G6PD
Burr/Spur cells on blood smear Correct Answer: liver disease
Acanthocytes on blood smear (looks like spur cell but with more rounded spurs) Correct Answer: liver
disease, hypothyroidism, alcoholism
Basophilic stippling on blood smear Correct Answer: lead poisoning
Schistocytes on blood smear Correct Answer: TTP-HUS, DIC, prosthetic heart valve, malignant htn,
sepsis
Target cells on blood smear Correct Answer: thalassemia, other hemoglobinopathies, liver disease
5 causes of microcytic anemia Correct 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 Correct Answer: anti-endomysial, tissue transglutaminase (small bowel
bx is best though)
Antibiotics for MRSA Correct 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 Correct Answer: Oxacillin/nafcillin, dicloxacillin (IV and oral), cefazolin (IV),
cephalexin (oral)
Can you use cephalosporins in pt allergic to PCN? Correct Answer: yes, if the rxn is rash only; no if pt has
true anaphylaxis
Antibiotics to use for Staph with PCN allergy Correct Answer: cephalosporins if rash only; macrolides,
clindamycin, vancomycin, linezolid, daptomycin, TMP/SMX
Antibiotics for strep Correct Answer: PCN, ampicillin, amoxicillin
Antibiotics for GNRs Correct 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 Correct Answer: does NOT cover pseudomonas
Piperacillin and ticarcillin Correct Answer: GNRs
strep
anaerobes
Carbapenems Correct Answer: good anaerobic coverage
strep
MSSA
Tigecycline Correct Answer: MRSA
good GNR coverage
Anaerobes Correct 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 Correct Answer: aminoglycs, aztreonam, fluoroquinolones,
oxacillin/nafcillin, all cephalosporins EXCEPT cefoxitin and cefotetan
Red man syndrome Correct Answer: red, flushed skin from histamine release, associated with rapid
infusion of vancomycin (so slow down the infusion rate)
Osteomyelitis Correct 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 Correct 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 Correct Answer: -throat: rheumatic fever AND glomerulonephritis
-skin: ONLY glomerulonephritis
Gonorrhea tx Correct Answer: -ceftriaxone IM
-cefixime oral
-cefpodoxime oral
-ciprofloxacin oral (2d line)
-if pregnant, then ceftriaxone IM
-ALSO treat for chlamydia
Chlamydia tx Correct Answer: -azithromycin (single dose)
-doxycycline (for 1 wk)
-if pregnant, then azithro
-ALSO treat for gonorrhea
Recurrent gonorrhea associated with... Correct Answer: terminal complement deficiency (predisposes
to any Neisseria infection)
PID tx Correct Answer: -outpatient: ceftriaxone (IM) and oral doxy
-inpatient: cefoxitin or cefotetan IV + doxy + (maybe) metronidazole
Abx safe in pregnancy Correct Answer: -PCNs
-cephalosporins
-aztreonam
-erythromycin
-azithromycin
Epidydimo-orchitis tx Correct Answer: -if <35 yo, then ceftriaxone + doxy
-if >35 yo, then fluoroquinolone
Chancroid Correct 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? Correct Answer: daptomycin
What binds toxin in gas gangrene? Correct Answer: clindamycin
Common bugs in dog bite Correct Answer: Capnocytophaga canimorsus (GNR) most common,
Pasteurella multocida may be present in 25%, anaerobes
Bug that causes overwhelming sepsis in asplenics with dog bite Correct Answer: Capnocytophaga
canimorsus
