uWorld 19 Flashcards
what is train-of-four (TOF) stimulation
used during anesthesia to assess the degree of paralysis induced by NMJ-blocking agents
a peripheral nerve is stimulated 4 times in quick succession and the muscular response is recorded
the height of each bar represents the strength of each twitch; higher bars indicate the activation of increasing numbers of individual muscle fibers (myocytes)
what is seen on TOF stimulation when a NON depolarizing NMJ blocker (vercuronium) is administered
competitive inhibition of postsynaptic acetylcholine receptors at the motor endplate prevents some of these fibers from activating, decreasing the strength of the twitch
PROGRESSIVE REDUCTION in each of the 4 responses (FADING PATTERN) as a result of less acetylcholine being released with each subsequent impulse (due to additional effect of presynaptic acetylcholine receptor blockade)
what is seen on TOF stimulation when a depolarizing NMJ blocker (vercuronium) is administered
initially function by preventing depolarization of the motor endplate and show EQUAL REDUCTION of all 4 twitches during TOF stimulation (PHASE I BLOCKADE)
the responses remain equal b/c presynaptic acetylcholine receptor stimulation helps to mobilize presynaptic acetylcholine vesicles for release
persistent exposure to succinylcholine results in eventual transition to PHASE II BLOCKADE as the acetylcholine receptors become desensitized and inactivated (functionally similar to nondeplolarizing blockade)
succinyl choline is commonly administered for what
RAPID-SEQUENCE INTUBATION due to its rapid onset (less than 1 minute)
twisting injury or blow t the lateral knee while the foot is planted (VALGUS STRESS INJURY) to the knee results in what
MEDIAL COLLATERAL LIGAMENT (MCL) injury
what is the valgus stress test
performed when the knee is extended by placing one hand along the lateral thigh and pressing inward while the other hand is placed not eh medial aspect of the ankle and pushed outward
laxity of the knee and/or medial joint line widening indicate MCL injury
how is meniscal injury diagnosed
joint line tenderness while the knee is flexed
medial meniscal injury can occur with twisting moment of the knee and often accompanies MCL injury
what does the act do and what tests are there for its injury
resits anterior movement and the medial rotation of the tibia
injury indicated by increased anterior movement of the tibia in relation to the femur
anterior draw test
Lachman test
excessive backward movement of the tibia in relation to the femur indicates what
posterior draw test
PCL injury
what is ATTRITION BIAS
the loss of subjects differ in their rest of developing the outcome compared to the raining subjects
is a form of SELECTION BIAS
what is misclassification bias
occurs when exposure or the outcome is not identified correctly
random (or nondiffernetial) misclassification affects all the groups the same
Ex: pediatric cuff used on adults in a study but the control and the treatment used the same cuff = random missclassificaiton
NADH methemoglobin reductase does what and a deficiency results in what
reduces ferric (fe3+) iron to ferrous (Fe2+) iron, regenerating hemoglobin from methemoglobin deficiency results in methemoglobinemia
goblin chain denaturation occurs in what disorder
G6PD deficiency
what cytokine causes cachexia
TUMOR NECROSIS FACTOR-ALPHA (aka cachectin) by suppressing appetite and increases basal metabolic rate
along with IL-1beta and IL-6 are main mediators of paraneopalsic cachexia
TNF-alpha is produced by what and mediates what
macrophages fever (along with IL-1), mediates many of symptoms of septic shock, causes hepatic release of ACUTE PHASE REACTANTS (c-reactive protein, fibrinogen, hepcidin)
what does IL-3 do
produced by activated CD4+ Th cells
stimulates growth and fifernetiaiton of myeloid cells
what is the main function of TGF-beta
inhibition of inflammatory response
decreases T-cell proliferation and cytokine prodcution
what is seen histologically in the kidneys from the damage that calcineurin inhibitors (cyclosporine, tacrolimus) do
early arteriolar hyalinization and TUBULAR VACUOLIZATION
what is seen in wischott aldrich
WATER
thrombocytopenia (petechia, purpura, hematemesis and epistaxis)
eczema
recurrent infections (combined B and T-lyphocyte disorder)
increased risk of PYOGENIC INFECTIONS b/c they can’t mount immune response to things with polysaccharide capsule (N. meningitis, H flu, step pneumo)
t-cell defect they get fucked by PCP and HSV
becomes apparent at 6 months
treated with HLA-matched bone marrow
what are the important clinical findings of Chediak higashi
ocular albinism
peripheral neuropathy
immunodeficiency related to dysfunction of phagolysosome formation
what is seen in Krebbe disease
galactocerebroside accumulation
progressive neurodegeneration, peripheral neuropathy, optic atrophy
what is seen in Fabry disease
globotriaosylceramide accumulation
causes angiokeratomas, peripheral neuropathy, and glomerulopathy that typically present in adulthood
what is seen in von Gierke disease
glucose-6-phosphatase deficiency hepatomegaly hypoglycemia seizures lactic acidosis
what is seen in pompe
lysosomal alpha-1,4-glucosidase deficiency
cardiomegaly
severe hypotonia
blood supply to the femoral head derives mainly from where
ascending cervical and retinaclular branches of the MEDIAL CIRCUMFLEX ARTERY (branch off deep femoral)
what arteries form the trochanteric anastomosis
branches of the lateral circumflex and superior and inferior gluteal arteries join with the medial circumflex artery
what vessel is important in children because it supplies the region of the femoral head proximal to the epiphyseal growth plate
artery of ligamentum heres (form the obturator artery)
minimal clinical significance in adults
abdominal and flank bruits are specific for what
renal artery stenosis
but found in minority of patients
what is a root cause analysis
quality improvement measure that aims to identify what, how and why an undesirable outcome occurred
first step is collecting data to obtain complete information about the event or events
RB tumor suppressor gene (anti-oncogene) is located where
Ch 13
a blood flow curve showing cyclical variation in flow during the cardiac cycle, with MAXIMUM FLOW occurring during DIASTOLE and minimal flow occurring during ventricular systole is unique for what tissue
LEFT VENTRICULAR MYOCARDIUM
majority of blood flows through the vascular beds when the myocardium is relaxed and not comprising the vessels
systolic reduction in flow is greatest in subendocardial myocardium (where wall pressure is the highest)- region is prone to ischemia and MI
the right ventricle blood flow appears how throughout the cardiac cycle
relatively constant
pressures in right ventricle are much lower than the left, and as a result the increase in systemic blood pressure during diastole is able to compensate for the rise in right ventricular wall pressure
what are markers of osteoclast activity and what is the most reliable of the three
tartrate-resistant acid phosphatase urinary hydroxyproline (also found in meat products) urinary DEOXYPYRIDINOLINE (most reliable)
what is a reflects osteoblastic activity
bone-specific alkaline phosphatase
what does pyridinoline do
covalently cross-links collagen fibers
these cross-links are the most commonly used method in assessing osteoclastic activity
whats the difference between urticaria and angioedema
urticaria is due to increased permeability of the micro vasculature leading to edema of the SUPERFICIAL DEMRIS
angioedema is involvement of the deep semis and subcutaneous tissue
what is dyskeratosis
abnormal, premature keratinization of individual keratinocytes
strongly eosinophilic and may have small, basophilic nuclear remnant
found in squamous cell carcinoma
what is acantholyisis
loss of cohesion b/w keratinocytes in the epidermis
seen in pemphigus family of disorders
what is acanthosis
diffuse increase in thickness of the status sinus (prickle cell layer) b/w the granular cell layer and the basal layer of the epidermis
psoriasis, seborrheic dermatitis, acanthosis nigricans
what is spongiosis
intercellular epidermal edema that histologically appears as an increase in the width of places b/w cells
often associated with spongiotic dermatitis, which encompasses a number of conditions (eczematous dermatitis)
URTICARIA a common transient HYPERSENSITIVITY disorder is characterized by intensely pruritic, raised, erythematous plaques (WHEALS) that arise suddenly and resolve over several hours, what causes this
IgE-meidated degranulation of mast cells
can also be due to non-IgE-mediated degranulation (opiates, radiocontrast agents, physical urticaria) or mast cell independent mechanisms (aspirin, hereditary andgioeurotic edema)
what does somatostatin do
secreted from “delta” cells in the pancreatic islet
decreases secretion of secretin, cholecystokinin, glucagon, insulin, and gastrin
inhibits production of growth hormone from anterior pituitary
what is a somatostatinoma
rare pancreatic islet cell tumor arising from delta cells
present with:
hyperglycemia
steatorrhea (dec secretin and GI motility)
galbladder stones (dec CCK)
hypochlorhydria (dec gastrin)
what is a derivative of the 1st aortic arch
maxillary artery
what is a derivative of the 2nd aortic arch
stapedial artery (typically regresses in humans)
what is a derivative of the 4th aortic arch
part of true aortic arch and the subclavian arteries
what is a derivative of the 6th aortic arch
pulmonary arteries and ductus arteriosus
serum IgG4 antibodies to the M-type phospholipase A2 receptor (PLA2R), a transmembrane protein abundant on podocytes is indicative of what
idiopathic membranous nephropathy
minimal change disease is possibly due to what
abnormal T cell production of glomerular permeability factor that affects the glomerular capillary wall, leading to fusion of the foot processes and marked proteinuria
mixed cryoglobulinemia is seen in patients with what
hepatitis C
renal disease likely due to IgM deposition in the glomerulus that leads to basement membrane thickening and cellular proliferation
what is the MOA of buspirone
partial agonist fo the 5HT1a receptor
no muscle relaxant or anticonvulsant properties
no risk of dependence
slow onset of action
what is seen on water deprivation test in patients with partial nephrogenic diabetes insipidus
slow but steady rise in urine osmolality with increasing serum osmolality after water deprivation
no further increase in urine osmolality with DDAVP, and the urine osmolality remains low
what is seen in patients with primary polydipsia
increase in serum and urine osmolality on water deprivation that is similar to partial nephrogenic DI, however the correction in primary polydipsia is more rapid, and the urine osmolality returns t a level closer to normal (but still sub maximal due to washout of the medullar osmotic gradient)
history of psychiatric disorders or medication-induces xerostomia is usually present
when and why does one see EUVOLEMIC HYPONATREMIA
SIADH
mild increase in extracellular fluid volume surpasses the renin-aldosterone axis and stimulates the production of the natriuretic peptides, leading to excretion of sodium in the urine (natriuresis)- normal body fluid volume and low plasma osmolality
anti-A IgG and anti-B IgG is seen with what blood group(s)
O blood group (OO)
no antigen on RBC
anti-A IgM is seen with what blood group(s)
anti-B IgM is seen with what blood group(s)
anti-A IgM: blood group B (B antigen on RBC)
anti-B IgM: blood group A (A antigen on RBC)
what blood group has no antibodies in the serum
AB
but has A and B antigen on red blood cells
what blood type mother can cause ABO hemolysis in a fetus
O because they have IgG anti-A and anti-B antibodies in serum which can cross the placenta causing hemolysis in the fetus
can occur in first pregnancy unlike Rh disease which requires a previous pregnancy
what is Eptifibatide
inhibits platelet aggregation and thrombosis by blocking the glycoprotein IIb/IIIa receptor (binding site for fibrinogen)
typically used in acute coronary syndrome and in patients undergoing percutaneous coronary intervention
what is ticagrelor
binds DP P2Y12 receptor on platelets, which prevent platelet aggregation by blocking ADP-mediated activation of GP IIb/IIIa receptor complex
what are echinocandin antifungals
caspofungin- block gluten synthesis
how does flu cytosine work
inhibits the synthesis of DNA (replication) and RNA (protein synthesis) in fungal cells
how does griseofulvin work
enters fungal cells and binds microtubules, inhibiting mitosis
CPY450 inducer
how does gabapentin work
blocking voltage-gated (presynaptic) calcium channels, thereby attenuating excitatory neurotransmitter release
basement membrane splitting is seen on light microscopy using silver or PAS stains in what kidney problem
membrnaoproliferative glomerulonephritis (MPGN)
glomeruli have lobular appearance with proliferate mesangial cells and increased mesangial matrix
GRANULAR DEPOSITS seen on immunoflourescnece
uniform, diffuse capillary wall thickening on LM is a sign of what kidney problem
membranous glomerulopathy
granular deposits of IgG and C3 on immunofluorescence
typical nephrotic syndrome presentation
what is seen on immunofluorescence of focal segmental glomerulosclerosis (FSGN)
IgM and C3 deposits may be seen in the sclerotic areas due to nonspecific trapping of these components
what are the deposits made of in good pastures
IgG and C3 linear deposits from anti-GBM antibodies targeting type IV collagen glomerular crescents (RPGN) on LM (proliferating parietal cells with an infiltration of monocytes and macrophages are seen on LM
viral RNase H does what
removes the RNA primary, allowing for completion of newly synthesized DNA
important pharmaceutical targets for the treatment of retroviruses such as HIV
what is seen on the CSF of herpes simplex encephalitis
HEMORRHAGIC LYMPHOCYTIC PLEOCYTOSIS with INCREASED protein and normal glucose
also abnormal MRI signal in the bilateral TEMPORAL LOBES
TX: IV acyclovir
what kind of receptor is Human epidermal growth factor receptor 2 (HER2)
TYROSINE KINASE
blockade of HER2 w/ trastuzumab downregulates CELLULAR PROLIFERATION and PROMOTES APOPTOSIS
what is bevacizumab
monoclonal antibody to vascular endothelial growth factor (VEGF) which binds a TYROSINE KINASE
treats METASTATIC cancers (colon, lung)
what is denosumab
human monoclonal antibody against RANKL
used to reduce skeletal-related events if bets to bone occurs
when are aromatase inhibitors (anastrozole, letrozole) used for
adjunct therapy for postmenopausal patients who have breast cancer with ER and/or PR tumor expression
changes in the concentration and ratios of components such as ______ can shift the balance of urine to cause salt precipitation and stone formation
calcium phosphate oxalate uric acid citrate
increased concentrations of all (BUT CITRATE) promote formation of stones
high urine concentrations of what has stone-preventing effect by binding free (ionized) calcium, preventing its precipitation and facilitating its excretion
CITRATE
potassium citrate is often prescribed to prevent recurrent calcium stones in adults when dietary modifications are unsuccessful
what is required for the formation of uric acid and cysteine stones, and also promotes calcium oxalate crystal formation
acidic pH
hyperuricosuria is associated with what conditions
gout
myeloproliferative disorders
situations of high purine and alcohol intake
can be idiopathic
what is a pancreatic pseudocyst
common compilation of pancreatitis
collection of fluid rich in enzymes and inflammatory debris
inflammatory reaction in the walls of the surrounding organs
what makes up a pancreatic pseudocyst
walls consist of granulation tissue and NO epithelial lining
fibrosis, thickening and organization of the walls occur with tie
formation of firm fibrotic pseudocyst walls (“maturation” of pseudocyst) takes about 4 to 6 weeks following the episode of acute pancreatitis
what is the most common location for a pseudocyst
the lesser peritoneal sac, bordered by the stomach, duodenum and transverse colon
walls are closely adherent to the surrounding hollow organs
when are glycogen-rich cuboidal epithelium seen in the pancreas
serous pancreatic neoplasms
when is columnar mucinous epithelium found in the pancrease
mucinous cystic neoplasms of the pancreas
when are atypical cells forming papillary projections seen in the pancreas
papillary variant of pancreatic adenocarcinoma
the blood supply tot he PROXIMAL URETER comes from where
what about the distal ureter
proximal ureter: the RENAL ARTERY
distal ureter: superior vesical artery
in between: anastomotic and highly variable, with possible afferent branches form the gonadal, common iliac, aorta, and uterine arteries
how is the blood supply established in a kidney transplant
anastomosing the DONOR RENAL ARTERY with the RECIPIENT EXTERNAL ILIAC ARTERY
proximal 1/3 of donor ureter is preserved and used to establish continuity from the collecting system of the kidney to the recipients bladder
distal part is susceptible to ischemia due to lack of anastomotic connections
what is a recognized complication of renal transplant and causes leakage of urine 5-10 days following transplant
distal ureteral ischemia
what is an aspergilloma (mycetoma)
aspergillus COLONIZATION of a PREEXISTING LUNG CAVITY forming a FUNGUS BALL
may be asymptomatic or may cause cough and HEMOPTYSIS
not contagious
when does one see invasive aspergillosis
invasive pulmonary aspergillosis occurs in severely immunosuppressed and neutropenic patients and is characterized by primary lung involvement with cough, hemoptysis, pleuritic chest pain, fever
necrotizing pneumonia and granuloma formation also occur
extra pulmonary involvement is common
what is a EUNUCHOID BODY HABITUS and when is it seen
result of testosterone deficiency
tall stature and gynecomastia
facial and body hair is sparse or absent and muscle mass is decreased
seen in KLINEFELTER
when does one see short stature, hypotonia, intellectual disability and obesity
prader-willi
microdeletion of paternal ch 15p11-13
when does one see macroorchidism, large jaw, and intellectual disability
FRAGILE X SYNDROME
X-linked disorder w/ mutations in FMR1 gene
arachnodactylyl, scoliosis, and aortic rood dilation are signs of what
Marfan
fibrillar defect
when are necrotizing inflammation and pulmonary hemorrhage seen
granulomatosis with polyangitis
presents sub acutely with cough, dyspnea, and hemoptysis and neuritic syndrome
fevers, hemodynamic instability, tachypnea, and evidence of urinary tract infection with urosepsis is likely complicated by what
ACUTE RESPIRATORY DISTRESS SYNDROME (ARDS)
sepsis and pulmonary infections are the two most common risk factors for ARDS
what is AR ORGANIC ACIDEMIA
deficiency of enzyme METHYLMALONYL-CoA MUTASE
result is a build up of methylmalonic acid and propionic acid leading to METABOLIC ACIDOSIS
HYPOGLYCEMIA results from overall increased metabolic rate leading to increased glucose utilization and direct toxic inhibition of gluconeogenesis by the organic acids
KETONES are produced in preens of hypoglycemia
HYPERAMMONEMIA occurs from organic acids directly inhibiting the urea cycle
what are the signs of organic acidemia (methylmalonaly-CoA mutase deficiency)
anion gap metabolic acidosis
hypoglycemia
ketosis
hyperammonemia
evaluated during METHYLMALONIC ACID AND PROPIONIC ACID
wha is propionic acidemia
deficiency in propionyl-CoA carboxylase
hyperammonemia
hypoglycemia
metabolic acidosis
NO elevated METHYMALONIC ACID
production of ketones in the presence of hypoglycemia is the normal response of what
fasting state (as keynotes provide fuel for brain)
fatty acid oxidation disorder, like medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, can present with what
hypoglycemia
hyperammonemia
metabolic acidosis
urea cycle defects typically present with what
hyperammonemia without hypoglycemia or ketosis
nutritional deficiencies can result in what kind of myopathy
dilated
Thiamine (B1) (wet beriberi heart disease) or chronic anemia
what is seen histologically in viral myocarditis
lymphocytic interstitial inflammatory infiltrate, w/ focal across of myocytes adjacent to areas of inflammatory cells
toxic agents like alcohol, cocaine, iron (in hemochromatosis), or doxorubicin may cause what heart problem
dilated cardiomyopathy
