NBME questions with correct answers

25 yo F at 27 weeks w/ severe contractions x6 hours, vaginal spotting, contractions every 2-3 mins w/ FHR 130 and no decels, cervic 1-2 cm and 70% effaced, GBS is positive. next step? - answer IM beclamethasone THEN later can give penicillin man w/ 15 yr hx of difficult relaxing hands after tightly gripping objects or shaking hands, difficulty releasing after gripping w/ hands. dx? - answer myotonic muscular dystrophy pt unable to see out of R eye since awakening 2 hrs ago. visual acuity 20/200 in R eye and 20/20 in L. R pupil poorly reactive to light. where is site of lesion? - answer R optic nerve 6 mo old w/ poor feeding, labored breathing, to and fro murmur in 2nd L itnercostal space, loud S2, bounding peripheral pulses, widened pulse pressure. dx? - answer patent ductus arteriosus recurrent lymph node infxns w/ staph a in a kid. what is dx and mechanism? - answer chronic granulomatous dz --> impaired phagocytic oxidative metabolism pt hyperkalemic bc missed 2 dialysis appointments. EKG w/ peaked t waves. next step? - answer IV calcium gluconate --> THEN can give insulin but this works within minutes hyaline casts vs WBC casts? - answer -WBC casts: interstitial nephritis and pyelonephritis -hyaline casts: AKI 4 yo M in MVC, RR 32 w/ grunting and restractions, hypoxic on ABG, CXR 4 hrs later shows diffuse infiltrates on R side. dx? - answer pulmonary contusion asymptomatic 57 yo M smoker, bruit in RUQ, no masses, BUN 23, Cr 1.4. what is cause of bruit? - answer accumulation of lipids in arterial wall --> renal artery stenosis