uWorld 28 Flashcards
what happens if you administer naloxone to a patine already in withdrawal
more severe withdrawal symptoms and potentially cause SEIZURES
neural tube defects occur due to FAILED FUSION of the neural tube during the 4th week of fetal development; what can be seen in the AMNIONIC FLUID due to leakage of fetal CSF
ALPHA-FETOPROTEIN (AFP)- crosses the placenta so can be measured in mothers serum
ACETYLCHOLINESTERASE
duodenal atresia is an example of failure of what
apoptosis
Hirschsprung’s disease is an example of failure of what
failure of migration
what cofactor is required for ALA synthase and thus a deficiency can cause microcytic hypochromic anemia
PYRIDOXINE (B6)
what are the side effects of using dihydropyridine calcium channel blockers (amlodipine, nifedipine) as antihypertensive mediations
PERIPHERAL EDEMA- related to preferential dilation of pre capillary vessels (arteriolar dilation), which leads to increased capillary hydrostatic pressure
-ACEI can normalize the increased hydrostatic pressure via post capillary venodilation
dizziness or lightheadedness
flushing
what prevents the SUPERFICIAL and what prevents the HEMATOGENOUS spread of CANDIDA
superficial: T LYMPHOCYTES
hematogenous: NEUTROPHILS
disseminated candidiasis (candidaemia, endocarditis) is more likely in what patients
those with NEUTROPENIA (since neutrophils protect against hematogenous spread of Candidia)
otherwise immunocompromised (cancer with chemotherapy)
those with inherited IMPAIRMENTS of pHAGOCYTOSIS
a T cell deficiency like AIDS predisposes one to what kind of Candida infection
SUPERFICIAL (oral/esophageal candidiasis, cutaneous candidiasis, Candida vulvovaginitis)
what is EFFECT MODIFICATION
when the effect of an exposure on an outcome is modified by another variable (not a bias)
EX: smoking status modified the effect of the new estrogen receptor agonist (exposure) on DVT incidence (outcome).
Smokers had a higher risk (RR over 1 and p value less than 0.05) while nonsmokers did not (p-value greater than 0.05)
a natural phenomenon that should be DESCRIBED NOT CORRECTED
what does a RR greater than one and a P less than 0.05 mean
increased risk (RR over 1) statistical significance (p less than 0.05)
effect modification is easily confused with what
how are they separated
easily confused with CONFOUNDING
STRATIFIED ANALYSIS (analyzing the cohort as different subgroups) can help distinguish b/w the two
with effect modification, the different strata will have different measures of association (one p-value less than 0.05 and one above 0.05)
with confounding, stratification usually reveals no significant difference between the strata (both when separated will have p-values less than 0.05)
what is a confounder
something that is associated with both exposure and outcome and affects the measure of association b/w the exposure and outcome, such that there initially appears to be a statistically significant association b/w the 2 on crude analysis, but once STRATIFIED by the confounding variable, the association disappears
what are the most common pathogens causing nosocomial bloodstream infections
coagulase-negative staph
staph aureus
enterococci
candida species
indwelling central catheters predispose patients to what
bacteremia
sepsis
should be monitored regularly for signs and symptoms of infection
what are the 3 most predisposing factors for hypoglycemia in a patient with type 1 diabetes
excessive insulin dose
inadequate food intake
physical activity/exercise
why does exercise cause hypoglycemia in T1DM
if pt is on EXOGENOUS INSULIN the insulin will continue to be released form the injection site during exercise despite falling glucose levels
normally as glucose goes down in exercise, this stops the release of insulin and counter-regulatory hormones (glucagon) will increase endogenous glucose production via gluconeogenesis and glyogenolysis
what up regulates GLUT-4 in skeletal muscle
INSULINE MUSCLE CONTRACTION (NO, AMP-activated kinase, Ca-calmodulin-activated protein kinase)
what does “degenerate” mean when referring to genetic code
more than 1 codon can code for a particular amino acid
what is the wobble hypothesis s
certain tRNA can recognize MULTIPLE DIFFERENT CODONS coding for the SAME ANIMO ACID
first 2 nucleotides require traditional watson crick base pairing, the third “wobble” spot may undergo less stringent (nontraditional) base pairing
what is the adherence site for DEXTRAN from strep viridans
FIBRIN/PLATELET aggregates (which are deposited at sites of endothelial damage)
what factors are associated with better TREATMENT ADHERENCE in an adolescent
CLOSE PEERS WITH COMPLEMENTARY BEHAVIORAL PRACTICES
positive family functioning
physician empathy
immediate benefits of treatment
adolescents are also less able to weight the risks and benefits of their decision b/c prefrontal cortex (center of executive function) is not fully formed until 3rd decade of life
what is the difference between TRACTION and PULSION diverticula (a way of classification)
TRACTION: created by inflammation and subsequent scarring of the gut wall, which typically results in pulling and out pouching of ALL gut wall layers (TRUE DIVERTICULA)
PULSION: increased intraluminal pressure created during strained bowel moments (due to chronic constipation or something) causes the MUCOSA and SUBMUCOSA to herniate through areas of focal weakness in the muscularis (FALSE DIVERTICULA)
diverticulosis most commonly affects where
SIGMOID COLON and is usually seen in peeps over 60
most peeps asymptomatic but can present with HEATOCHEZIA due to disruption of the arterioles adjacent to the diverticula
what are the symptoms of diverticulosis
LEFT LOWER quadrant pain
low-grade fever
constipation or diarrhea
due to INFLAMMATION
where and from what would one see a traction diverticula
mid esophagus
mediastinal lyphadenitiis caused by TB or final infection
the graph of serum creatinine and GFR looks like what
not linear (serum creatinine begins to rise sharply at GFR below 60
when GFR is normal, relatively large decreased in GFR result in only small increases in serum creatine
when the GFR is significantly decreased, small decrement in GFR produce relatively large changes in serum creatine
every time GFR halves, serum creatinine doubles
what substances undergo no tubular reabsorption or secretion (filtered amount = excreted amount)
INULIN
mannitol
what substances undergo net tubular reabsorption (excreted amount
glucose
sodium
urea
what substances undergo net tubular secretion (excreted amount»_space; filtered amount)
PAH
creatinine
transduction of mechanical sound waves into nerve impulses occurs where
ORGAN of CORTI
- sound reaches middle ear by vibrating the tympanic membrane
- the vibration is transferred to the oval window by the ossicles
- vibration of the oval window causes vibration of the basilar membrane, which in turn causes bending of the hair cell cilia against the tectorial membrane
- hair bending causes oscillating hyperpolarization and depolarization of the auditory nerve, thereby creating nerve impulses from sound
NOISE INDUCED hearing loss results from what
trauma to the STEREOCILIATED HAIR CELLS of the ORGAN of CORTI
HIGH-FREQUENCY hearing is lost FIRST (regardless of frequency of sound causing it)
bilateral
what is the cochlear cupula
apex of the cochlea and is distant form the oval window
the distal cochlea primly registered LOW-FREQUENCY sound
where do meningiomas tend to arise
DURAL REFLECTIONs (fall cerebra, tentorium cerebelli)
slow-growing (benign) intracranial tumor typically of adult
may present with SEIZURE, headache, or focal neurologic deficits depending on size and location
what is thoracic outlet syndrome (TOS)
COMPRESSION of the LOWER trunk of the BRACHIAL PLEXUS as it passes through the THORACIC OUTLET
presents with:
upper extremity numbness, tingling, and weakness
upper extremity swelling (compression of SUBCLAVIAN VEIN)
exertional arm pain (compression of SUBCLAVIAN ARTERY)
most commonly occurs in SCALENE TRIANGLE
what is the scalene triangle
formed by the anterior and middle scalene muscles and the first rib
the brachial plexus TRUNKS and subclavian ARTERY pass b/w the anterior and middle scenes; the subclavian vein runs anteromedial to the triangle
where do the anterior and middle scalene originate and insert
anterior: C3-C6 transverse processes and attaches to the scalene tubercle of the first rib
posterior: C2-C7 transverse processes and inserts into the posterior of the first rib
what can cause thoracic outlet syndrome (TOS)
anomalous cervical rib (extra one)
scalene muscular anomalies
injury (repetitive overhead arm movements, trauma)
all antidepressants carry a risk of inducing what into susceptible patients
MANIA bipolar I (manic episodes) are at greater risk
what is the most important factor in determining prognosis of bladder cancer
TUMOR STAGE and depends on the DEGREE of INVASION into the bladder wall and adjacent tissues
malformed teeth (Hutchinsons incisors and mulberry molars) are typical late manifestations of what congenital bug
SYPHILIS
what is seen histologically in an amnionic fluid embolism (AFE) and what are signs of it
FETAL SQUAMOUS CELLS and MUCIN in the MATERNAL PULMONARY ARTERIES
hypoxia
hypotensive shock
DIC
what drugs would exacerbate myopathy caused by statins (hint: think about metabolism)
statins are metabolized by CYP450 so CYP450 inhibitors would decrease statin metabolism thus increasing the serum concentration and thus increased risk for myopathy
ketoconazole, erythromycin, HIV protease inhibitors, grapefruit juice, cyclosporine, INH
the immune reaction of TB is mediated by what
Th1 cells
caveating granuloma made up of:
T lymphocytes
epithelioid activated macrophages
Longhand giant cells (with horseshoe shaped arrangement of nuclei)
proliferating fibroblasts (synthesize collagen)
in a patient successfully being treated for eczema with corticosteroid cream, what is seen at the site of application of the cream
dermal atrophy/thinning
associated with the loss of dermal collagen, drying, cracking, and/or tightening of the skin, telangiectasis, and ecchymosis
what are the histologic findings of eczema
intraepidermal vesicles
superficial epidermal hyperkeratosis producing scales
epidermal hyperplasia (acanthosis)
chronic inflammatory infiltrate within the dermis
what does entcapone do
stops the peripheral breakdown of levodopa to 3-OMD by blocking COMT- increases levodopa bioavailability to the brian
Tolcapone works both peripherally and centrally
used in Parkinson’s pts who experience end-of-dose “wearing off” periods with levodopa/carbidopa therapy
what parkinson drug likely enhances the endogenous effects of dopamine
AMANTADINE- increases dopamine synthesis/release and inhibiting the reuptake of dopamine
acute joint pain, swelling, and erythema with restricted range of motion is consistent with what
SYNOVITIS
potential causes: septic arthritis (gonococcal, nongonococcal) crystal arthropathy (gout) hemarthrosis rheumatic disease
acute synovitis is best evaluated how
DIAGNOSTIC ARTHROCENTESIS and SYNOVIAL FLUID analysis
fluid should be sent for: crystal analysis, cell count, Gram stain, and culture
what happens to a strawberry-type capillary hemangioma (juvenile hemangioma)
they FIRST GROW then they typically spontaneously REGRESS at or before puberty (usually start to fate between 1-3 years, and regress by 7 in 95% of cases)
lesion consists of unencapsulated aggregates of closely packed, thin-walled capillaries
can occur in liver, spleen, and kidneys
what would a uterine specimen show if a patient has an ectopic pregnancy
DECIDUALIZED ENDOMETRIUM- DIALTED, COILED endometrial glands and VASCUALRIZED EDEMATOUS STROMA
occur int he luteal phase of the menstrual cycle, under the influence of PROGESTERONE, as the endometrium prepares for implantation
embryonic trophoblastic tissue will be absent
tubal ligation (permanent sterilization) is a risk factor for what
ECTOPIC PREGNANCY
methotrexate can cause both lung and liver toxicity, what is recommended for baseline
baseline chest x-ray and liver function tests are recommended
classic galactosemia is caused by what
galactose-1-phosphate metabolism
galactose-1-phosphate uridyl transferase (GALT) is deficiency (no production of UDP-galactose and glucose-1-phosphate)
untreated galactosemia can cause what and why
irreversible eye and liver damage
build up of galacticol in cells
hematogenous osteomyelitis usually affects what part of the bone
METAPHYSIS of long bones (of young boys usually)
what is chronic suppurative osteomyelitis
a condition in which necrotic bone (sequestrum) serves a reseviro for infection and becomes covered by a poorly constructed shell of new bone called an INVOLUCRUM
one or more sinus tracts develop to drain the purulent material into the soft tissue or out to the skin
TX: antibiotics and debridement of necrotic bone
who is melanoma characterized on gross inspection (ABCDE)
Asymmetric shape irregular or jagged Border variability of Color Diameter (greater than 0.5-1cm) Evolution in size and appearance over time
histologically what does melanoma look like
melanoma cells congregate in poorly formed nests and are large with irregular nuclei, clumped chromatin, and prominent nucleoli
what is the most important prognostic factor in malignant melanoma
BRESLOW Depth
multinucleate giant melanocytes are a characteristic finding in what
lentigomeligna melanoma
