USMLE-Rx: Week of 08/29/16 Flashcards
Describe the pathophysiology of hemochromatosis.
Iron overload (through genetic, physiologic, or environmental causes) leads to deposition of iron in the liver, pancreas, and heart. As such, patients often present with cardiomyopathy, diabetes (“bronze diabetes”), and liver failure. Treated with phlebotomy or deferoxamine.
In terms of labs, how can you differentiate anemia of chronic disease from iron-deficiency anemia?
Primarily the ferritin: in ACD, ferritin will be high; in IDA, ferritin will be low. The MCV will also be normal in ACD.
What channels are blocked by the drug that treats malignant hyperthermia?
Dantrolene blocks the ryanodine receptors
What cancer drug is also an abortifacient?
Methotrexate
To which lymph nodes do the testes drain?
To the para-aortic: the scrotum is an outpouching of the abdomen, so they drain to the para-aortic lymph nodes –just like the other abdominal organs.
Dislodged pieces of cartilage and subchondral bone are seen in the joints of those with what disease?
Osteoarthritis
One unfortunate side effect of levodopa is ___________.
autoimmune hemolysis
Disproportionately large arm span, ectopic lens displacement, and aortic regurgitation result from a defect in which chromosome?
15 –Marfan syndrome (AD)
Describe the genetics of neurofibromatosis (both types).
Type 1: chromosome 17, Lisch nodules
Type 2: chromosome 22, bilateral Schwannomas, cloudy vision due to cataracts
______-ductal coarctation of the aorta is found in Turner syndrome.
Pre (with one arm smaller than the other – the left, due to insufficient blood flow –patients with only one X chromosome TURN around)
What drug category are the -triptylines?
TRIcyclic antidepressants
The tricyclic antidepressants have the same side effects of what other class of drugs?
The anticholinergics (such as atropine)
A defect in the degradation of which amino acid can lead to dark, bloodless urine and black cartilage?
Tyrosine (cartilage as black as a TYRE)
In a hypercapneic event, what molecules buffer the excess protons?
Intracellular proteins! Importantly, there is not enough bicarb around to buffer protons, so increased protons lead to increased CO2 (Le Chatlier’s principle).
Chloramphenicol targets the same bacterial mechanism as what other antibiotics?
Clindamycin and macrolides – the 50S subunit
