NBME

Question 1

Buildup of urine uroporphyrin with blistering lesions on sun-exposed areas?

Answer 1

porphyria cutanea tarda

defect in uroporphyrinogen decarboxylase –> buildup of uroporphyrin in urine (tea-colored urine) + blistering photosensitivity

most common porphyria (impaired heme synth)

pathway starts with glycine + succinyl-CoA; RLS affected in sideroblastic anemia (B6 deficiency or genetic enzyme defect)

Question 2

shunt vs. physio dead space

Answer 2

shunt = low ventilation, normal perfusion (V/Q–>0) - wasted blood

physio dead space = ventilation without perfusion (wasted air)

Question 3

Cold agglutinin vs warm agglutinin - Ig types and disease associations

Answer 3

cold = IgM, CLL, mycoplasma pneumo and mono

warm = IgG, SLE, CLL, and with some drugs

Question 4

Sites of gluconeogenesis

Answer 4

LIVER

also kidney and intestinal epithelium

NOT muscle (no G6Pase)

Question 5

First vs second gen antihistamines (h1)

Answer 5

first: brompheniramine, dephenhydramine, hydroxyzine, chlorpheniramine, meclizine
second: loratadine, ceftirazine, fexofenadine

Question 6

epimere vs hypomere

Answer 6

epimere - cells of myotomes that give rise to skel mm of the back

hypomere = cells of myotomes that differentiate into skel mm of the lateral and anterior regions of thorax and abdomen

Question 7

Inferior alveolar nerve, aka

Answer 7

mandibular branch of V3 (goes through mandibular and mental foramina onto chin)

Question 8

Cause of hemochromatosis

Answer 8

Hepcidin mutation –> decreased hepcidin –> increased release of Fe from intestinal enterocytes and macrophage stores (no Fe regulation) –> slow accumulation of iron in tissues