USMLE Step 3 Questions And Answers Latest Solution

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USMLE Step 3 Questions And Answers Latest Solution Pseudogout associations Correct Answer: hemochromatosis, hyperparathyroidism, acromegaly, hypothyroidism Gout crystals Correct Answer: negati... vely 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 Typical bugs in cat bite Correct Answer: Pastuerella multocida, anaerobes Typical bugs in reptile bite Correct Answer: Salmonella, Pseudomonas (snakes) Treatment for animal bite Correct 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 Correct Answer: Eikenella corrodens, streptococci, staphylococci, Haemophilus species, and a multitude of anaerobes Treatment for human bite Correct Answer: Same as animal bite but be careful tendons or bones not involved if clenched fist Common bugs in diabetic foot ulcer Correct Answer: staphylococci, streptococci, enteric gram-negative rods, P. aeruginosa, and anaerobes Treatment of diabetic foot ulcer Correct Answer: Broad until cx results known (if severe infection): must cover GPC, GNR, and anaerobes, eg vanc + mero If mild, cover for staph and strep Aeromonas hydrophila Correct Answer: This gram-negative bacterium is found in freshwater environments, although it may also be pres [Show More]

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