NBME Practice Tests

NBME Practice Tests What antiretroviral prevents entry into a CD4+ t-cell - Enfuvirtide Severe pain after meals (better when she doesn't eat), unintentional weight loss, hx of atherosclerosis + abdominal bruit and absent pedal pulses. What artery could be atherosclerotic? - Superior Mesenteric What is the inheritance pattern of Fragile X? How does transmission change if the mother has fragile X vs. the father? - It is X linked dominant (like hypophosphatemic rickets and Alports) Mothers w/ disease: give it to 50% of daughters and sons Fathers w/ disease: give it to all daughters and no sons What medication could be used for watery nasal decongestion during an allergy attack? - Alpha-adrenergic agonist (phenylephrine alpha 1 alpha 2) in Sudafed and most OTC decongestants Newborn baby with hypothyroidism (no thyroid) has no symptoms. What can the mom transfer to the baby allowing for normal development? - Thyroxine (T4) is transferred in late gestation through the placenta preventing the initial symptoms of congenital hypothyroidism How does enterococcus faecalis develop resistance from vancomycin? - Substitution of d-lactate for d-alanine in peptidoglycan wall 2 days following an acute MI, a pt becomes short of breath and diaphoretic, high HR and pressure. What murmur would be heard? - 4/6 holosystolic murmur heard best over the lower left sternal border and the cardiac apex - from posteromedial papillary muscle rupture (has single blood supply from posterior descending artery) - severe mitral regurgitation occurs 2-7 days after an MI 18 month old who has not eaten in 24 hrs has high pulse, increase respirations, hepatomegaly. His glucose, ketones, and carnitine are decreased in serum, and urine ketones are decreased, and dicarboxylic acids are present. He is given medium chain triglycerides for 6 months which helps. What is deficient? - Very long-chain acyl-Coa dehydrogenase deficiency - hypoketonic hypoglycemia - fat deposits in liver = hepatomegaly - cardiorespiratory distress 3 yo with constant fractures of bones, and blue sclera and normal teeth. What biochemical process is altered? - Procollagen synthesis - Osteogenesis imperfecta - AD - glycosylation of residues and then forms disulfide/hydrogen bonds - triple helix (will not occur in this disease) - no normal type ONE collagen (bone) -treat with bisphosphanates to prevents fractures Cross sections area of an aneurysm is 2cm^2, and the velocity of blood flow is 20cm/sec. What is the flow rate (L/min) through the aneurysm? - Flow rate (Q) = Flow velocity X cross sectional area - 2X20 = 40cm^3/sec - 40X60s = 24000 mm/sec (1cm^3 = 1 mm) - 2.4L/min severe bleed from gunshot wound to abdomen - 3L blood in peritoneum. Cells in liver/kidney = centrilobular pallor and swelling. Why is this occurring? - decreased function of Na+/K+ ATPase - reversible injury from blood loss What does fish oil do? - fish oil/omega 3 fatty acids antagonize VLDL-cholesterol secretion - increase LDL/HDL slightly - decrease FFA delivery to liver 60 yo man with no hx of bleeding problems has elevated PTT what molecule in the kinin cascade can be deficient? - Kallikrein - leads to a build up of high molecular weight kininogen that activates the intrinsic pathway - elevated PTT 23 yo with sjogren and burning pain in feet is relieved with capsaicin. what neurotransmitter is causing pain? - Substance P 18 yo w/ ALL on chemo and low neutrophil count has lung infiltrate with PAS stain of budding fungus. How do you treat him? - amphotericin B - most likely cryptoccocus neoformans 12 yo with 6 months of difficulty walking and leg pain. Atrophy of LE and hammer toes with a high stepping gait. What will a bc show? - Abnormal Myelin sheath - AD - pes cavus, hammer toe - CMT1A/PMP22 mass in ovaries (CA 125 positive cancer) needs to be removed. What structure passing inferior to ovary is at risk of injury? - ureter - passes behind ovary, round ligament, and ovarian vein and artery 52 yo male w/ no past hx come in w/ progressive issues swallowing, double vision, slurred speech, ptosis, and waddling gait. He has fatigable weakness. What is the mechanism of disease? - binding of autoantibodies to the acetylcholine receptor