Uworld test 1 block 3 Flashcards
Whipple disease vs. ischemic colitis
ischemic colitis is a cause of lower GI hemorrhage in elderly. pts have CRAMPY ABD. PAIN, tenderness to palpation, and BLOODY STOOL. mechanisms: hypoperfusion secondary to diminished cardiac output and occlusion of the bowel vascular supply. weak lower extremity pulses indicate extensive atherosclerosis. histo findings: mucosal hemorrhage, ecchymosis, patchy necrosis. the, thickened, edematous bowel wall with blood in the lumen. if transmural infarction occurs, perforation may result.
Whipple disease: NON BLOODY, malabsorptive diarrhea. cardiac manifestations, arthralgias, neuropathy
Leiomyoma presentation
often asymptomatic, but may be associated with pelvic pressure and pain, menorrhagia, or reproductive difficulties. leiomyomas are the most common in women in their thirties and forties.
brief overview of beta oxidation
sequential removal of 2 carbon units from fatty acids. 4 step process. step 1 catalyzed by acyl CoA dehydrogenase, which may be short, medium, or long. if deficient, ketones will be low even during a fast.
metformin vs. rosiglitazone
rosiglitazone is a PPAR agonist that incr. transcription of insulin responsive genes like GLUT4. therefore, it increases insulin sensitivity.
metformin can be an oral hypoglycemic even without beta cell function by decr. gluconeogenesis and incr. glycolysis (FA says incr. glucose uptake but this is probably secondary).
main locations of celiac, tropical sprue, and crohn disease
celiac: duodenum
tropical sprue: jejunum and ileum
crohn: may be anywhere but ILEUM most common
esophageal achalasia: causes, manifestations
aka esophageal aperistalsis. caused by damaged ganglion cells in the myenteric plexus (btw the inner circular and outer longitudinal layers of the muscularis propria). important for regulating bowel motility and relaxing the LES. damage to gangion cells may be idiopathic or due to a known insult like Chagas’ disease.
causes solid and liquid dysphagia, putrid breath, high LES pressure on esophageal manometry, bird-beak on barium swallow, and incr. risk for squamous cell carcinoma.
Causes of G6PD vs. autoimmune hemolysis
G6PD: precipitated by oxidative stresses of sulfa drugs, antimalarials, infections, and fava beans
autoimmune hemolytic anemias are most commonly asymptomatic but can be precipitated by other factors:
1. warm agglutinin (IgG): SLE, CLL, alpha-methyldopa, peincillin, cephalosporins
2. cold agglutinin (IgM): CLL, mycoplasma pneumonia, infectious mononucleosis.
broca aphasia, frontal eye fields, and wernicke aphasia: where in the brain is the lesion?
broca: inferior frontal gyrus
frontal eye field is higher than Broca’s area
Wernicke: sensory temporal gyrus.
prostatitis presentation
fever, pelvic pain, urinary frequency, and dysuria. tenderness on DRE.
may be acute or chronic. acute usually bacterial (C. trachomatis and N. gonorrhoeae in young adults; E. coli and pseudomonas in older adults). prostatic secretions show WBCs.
chronic prostatitis: dysuria with pelvic or low back pain. WBCs but no organisms on culture.
renal plasma flow
RPF = MAP/TVR.
TVR in the nephron = resistance in the afferent + resistance in the efferent. if RPF decreases and MAP was constant, than resistance in the afferent or efferent went up.
What are the sensory corpuscles?
Pacini corpuscles: rapidly adapting mechanoreceptors found in the subcutaneous skin and the mesentery, peritoneum, and joint capsules. vibration and pressure
meissner corpuscles: large myelinated fibers in hairless skin. position sense and fine touch.
merkel discs: large myelinated fibers that adapt SLOWLY (unlike previous 2). found in basal epidermal hair and hair follicles. senses deep touch, pressure, position.
free nerve endings: pain and temp.
C are slow and unmyelinated; Adelta are fast and myelinated
What are the important unmyelinated fibers?
postganglionic autonomic nervous system axons, slow pain. first order bipolar sensory neurons of olfaction.
What happens during MHC class II processing?
class II is made of an alpha and a beta chain. during antigen processing, the invariant chain brings the alpha and beta chains together to form a stable complex in the RER. then, the MHC invariant complex leaves the RER, goes through the golgi, and enters an endocytic compartment in which the invariant chain is proteolytically degraded and an external protein is inserted between the alpha and beta chains.
viral proteins are degraded into peptides, which are removed from the cytosol by transporters associated with antigen processing, which stud the ER. once inside, the peptides assemble into what I believe is an MHC I molecule.
genetic heterogeneity vs. allelic heterogeneity vs. phenotypic heterogeneity vs. polyploidy
genetic heterogeneity: mutations of different genes cause similar phenotypes (ex. Marfan and homocysteinuria and MEN2B)
allelic heterogeneity: different mutations n the same gene cause similar phenotypes
phenotypic heterogeneity: mutations of the same gene cause different phenotypes.
lichen sclerosis vs. lichen simplex chronicus vs. leukoplakia
lichen sclerosis: thinning of the epidermis and fibrosis of the dermis that presents as a white patch with parchment-like vulvar skin. often in postmenopausal women. probably autoimmune. benign but incr. risk for squamous cell carcinoma. manifestation: vaginal pain and pruritis with dyspareunia, dysuria, and possibly pain with defecation.
Leukoplakia: mucosal surfaces like mouth and genitals. labia majora are NOT mucosal. most classic cause is EBV in immunosuppressed.
lichen simplex chronicus: hyperplasia of the vulvar squamous epithelium. leukoplakia with thick, leathery vulvar skin. associated with chronic irritation and scratchy. no incr. risk of squamous cell cancer.
