uWorld 34 Flashcards
what is the course of fetal blood flow from highest O2 concentration to lowest
umbilical vein → liver → IVC → heart → pulmonary circulation or through foramen ovale
pulmonary circulation → ductus arteriosus and pass directly into the descending aorta
what drug that treats UTIs can precipitate THEOPHYLLINE toxicity
CIPROFLOXACIN b/c it is a CYP inhibitor and theophylline is a CYP substrate
how does theophylline work
adenosine receptor blocker
PDE inhibits
used of asthma and COPD b/c it causes bronchodilation by increasing cellular cAMP and it has mild-antiinflammtory effects
what is seen in theophylline toxicity
CNS stimulation (tremor, insomnia, SEIZURES) GI disturbances cardiovascular abnormalities (hypotension, tachycardia, CARDIAC ARRHYTHMIAS)
in southwestern blotting FNA_binding proteins are recognized how
ability to bind SPECIFIC OLIGONUCLEOTIDE PROBES
the concentrations of what substances increase as fluid moves along the proximal tubule
PAH
creatinine
inulin
urea
the concentrations of what substances decrease as fluid moves along the proximal tubule
bicarbonate
glucose
amino acids
what is the rate limiting step of urea synthesis
barcarb, ammonia, and ATP are combined by CARBAMOYL PHOSPHATE SYNTHETASE to yield carbamoyl phosphate
happens in mitochondria
what serves as a regulator of the urea cycle through activation of carbamoyl phosphate synthetase I
N-ACETYLGLUTAMATE
what is the most common urea cycle disorder
ORNITHINE TRANSCARBAMYLASE (OTC) DEFICIENCY
results in excess carbamoyl phosphate, which stimulates pyrimidine synthesis- OROTIC ACID then accumulates and results in increased URINARY OROTIC ACID
HYPERAMMONEMIA (vomiting, confusion/coma) due to impaired ammonia excretion- a METABOLIC EMERGENCY
TACHYPNEA due to cerebral edema from ammonia buildup, resulting in central hyperventilation and respiratory alkalosis
triggered by illness, fasting or increased protein intake
what is seen in uridine monophosphate synthetase (UMPS) deficiency
part of pyrimidine synthesis pathway
deficiency leads to buildup of OROTIC ACID
MEGALOBLASTIC anemia
GROWTH DELAY
NO HYPERAMMONEMIA (differentiates this from OTC deficiency)
what causes tabes doralis
syphilis DIRECTLY damages the DORSAL SENSORY ROOTS
secondary degeneration of DORSAL COLUMNS
what are the clinical findings of tabes doraslis
sensory ataxia
lancinating pains
neurogenic urinary incontinence
associated with Argyll Roberson pupils
what two pathways does insulin binding to the insulin receptor activate
RAS/MAP kinase pathway: CELL GROWTH, DNA SYNTHESIS
PI3K pathway: lipid, protein, and GLYCOGEN (via PROTEIN PHOSPHATASE which activates GLYCOGEN SYNTHASE by dephosphorylation) synthesis
what is the optimal site for a femoral nerve (L2-L4) block
INGUINAL CREASE at the lateral border of the femoral artery
anesthetizes the skin and muscles of the anterior thigh, femur, and knee
also blocks the saphenous nerve (terminal extension of the femoral nerve) to decrease sensation to the media leg below the knee
what is the adductor hiatus
opening i nth e aponeurosis of the adductor magnus at the distal one-third of the femur that allows passage of the femoral vessels into the popliteal fossa
saphenous nerve passes near the hiatus
what is the femoral ring
upper opening of the femoral canal (which contains lymphatic vessels and a lymph node)
glucose is the most inprotant stimulator of glucose relate, how does this work
glucose enters via GLUT-2 and generates ATP via citric acid cycle
ATP binds ATP-sensitive K+ channel that then CLOSES causing MEMBRANE DEPOLARIZATION
this opens voltage-gates calcium channels that RELASE INSULIN
if patient has varices visible only in the gastric fundus (not esophagus or rest of stomach) what is the cause
SPLENIC VEIN THROMBOSIS due to chronic pancreatitis, pancreatic cancer, and abdominal tumors
GASTRIC VARICES only in the fundus form because the SHROT GASTRIC VEINS drain the fundus of the stomach into the splenic vein
blockage of the SMV could lead to varcieal formation where in the stomach
lower stomach (gastroepiploic vein)
also drains pancreas and duodenum via pancreaticoduodenal vein
ow does a cell move from G1 to S
cyclin D-CDK4 hyperphosphorylates Rb (rendering it INACTIVE) causing it to RELASE EF2
how does p27 work
cell cycle INHIBITOR that inhibits cyclin dependent kinases during G1
during a cricothyrotomy is done how
placement of tube between CRICOID and THYROID cartilages and you must go through:
- skin
- SUPERFICIAL CERVIAL FASCIA (including subcutaneous fat and platysma muscle)
- investing laters of pretracheal laters of the deep cervical fascia
- CRICOTHYROID MEMBRANE
meningococci are commonly isolated from where in asymptomatic carriers
oropharynx and nasopharynx
antibodies that successfully impart the pili of meningococcus (important for bacterial attachment to epithelial surfaces) would inhibit pilus-meidated attachment of meningococcus to what
the mucosal epithelium of the NASOPHARYNX, preventing colonization and subsequent invasion
abrupt-onset GROSS HEMATURIA of an otherwise healthy patient with a family history of SICKLE CELL disease suggests what
RENAL PAPILLARY NECROSIS (RPN)
what conditions are associated with renal papillary necrosis (RPN)
SICKLE CELL disease or trait (sickled cells cause obstruction of small kidney vessels, predisposing to ischemia)
ANALGESIC nephropathy: NSAIDs inhibit renal blood flow by decreasing PG synthesis and vasoconstriction the affect arterioles
DIABETES mellitus: nonenzymatic glycosylation causes changes in vascular walls, leading to renal vasculopathy and hypo perfusion
PYELONEPHRITIS and urinary tract obstruction: compression of medullary vasculature, leading to ischemia
what is seen in fanconi syndrome
polyuria
acidosis
hypophosphatemia
patients receiving PARENTERAL NUTRITION (through a central venous CATHETER) are at high risk for what kind of infection
CANDIDEMIA (candida in the blood stream)
see BRANCHING PSEUDOHYPHAE with BLASTOCONIDIA
TX: echinocandins (caspofungin and relatives) for all species and C albicans fluconazole pretty much always works
what medications are associated with osteoporotic fracutres
anticonvulsants that induce CYP450 (phenobarbital, phenytoin, carbamazepine)- ↑ Vit D catabolism
aromatase inhibitors: ↓ estrogen
medroxyprogesterone: ↓ estrogen
GnRH agonists: ↓ testosterone and estrogen
PROTON PUMP INHIBITORS: ↓ CALICUM ABSORPTION
Glucocorticoids: ↓ bone formation
Unfractioned Hep: ↓ bone formation
Thiazolidinediones (pioglitazone, rosiglitazone): ↓ bone formation
what is the most common benign tumor of the breast and what characterizes it
FIBROADENOMA
young women 15-35
nodules that are well-demarcated, painless, mobile, and spherical
usually discovered by palpable inspection
often increase in size during pregnancy, lactation, or with estrogen therapy
usually regress after menopause
benign-appearing cellular or MYXOID STROMA that encircles epithelium-lined glandular cystic spaces
well-defined border but may compress and distort the surrounding glandular epithelium
why is seen in mamarry duct ectasia
ductal dilation
inspissated breast secretions
chronic granulomatous inflammation in the preductal and interstitial areas
what characterizes sclerosing adenomas (seen in fibrocystic change)
central acinar proliferation and compression with surrounding fibrotic tissue and peripheral ductal dilation
what are plexiform lesions
interlacing tufts of small vascular channels
seen in pulmonary hypertension due to underlying lung, vascular, or cardiac disease and in idiopathic or familial pulmonary arterial hypertension (PAH)
what is seen in PAH (pulmonary arterial hypertension)
dyspnea and exercise intolerance in women 2-40
usually do to inactivating mutations in pro-apoptotic BMPR2 gene → endothelial and smooth muscle cell proliferation leading to vascular remodeling, elevated pulmonary vascular resistance, and progressive pulmonary hypertension
what is BOSETAN
ENOTHELIN-RECEPTOR ANTAGONIST that blocks the effects of endothelia (a potent vasoconstrictor that also stimulates endothelial proliferation)
decreases pulmonary arterial pressure
lessens progression of vascular and rich ventricular hypertrophy
used to treat IDIOPATHIC PULMONARY ARTERIAL HYPERTENSION (PAH)
what accounts for most deaths in Cystic Fibrosis in the united states
pneumonia
bronchiectasis
cor pulmonale
what is the “squirt sign” and when is it seen
forceful expulsion of stool after rectal examination
seen in Hirschsprung disease (but not in CF and both have meconium so can use this to differentiate)
what is the most common cause of mortality in Hirschsprung
ENTEROCLOLITIS (diarrhea, abdominal pain/distension, and fever
what increases the expression of phenylethanolamine-N-methyltransferase (conversion of norepi to epi)
CORTISOL
what is Werdnig-Hoffman syndrome
anterior horn cell damage
lower motor neuron lesion signs are present: flaccid weakness, areflexia, muscle atrophy, fasciculation (“floppy child” syndrome)
what kind of rash is seen in ROSEOLA INFANTUM
3-5 days of high fever followed by blanching maculopapular rash
starts on the TRUNK and spread to the face and extremities
infection is typically benign and self limited
seen in children less than 2
where are endorphins synthesized and released rom
corticotrophin cells in anterior pituitary
what are the action of TGF-beta
arrest of the cell cycle (tumor suppressing agent)
promotion of angiogenesis (allows tumor mets to survive after resistance to TGF)
stimulation of fibroblasts to lay down extracellular matrix proteins (implication in atherosclerosis and fibrotic diseases)
what causes septic shock
ENDOTOXIN release into the BLOODSTREAM
endotoxins are found on the outer membrane of GRAM-NEGATIVE bacterial, which is composed of LIPOPOLYSACCHARIDE )LPS)
LPS is realized during destruction of bacterial cell wall
long, heat-stable molecular with 3 regions:
O antigen
core polysaccharide
LIPID A- responsible for TOXIC PROPERTIES of LPS that lead to GRAM-NEGATIVE SEPSIS and ENDOTOXIC SEPTIC SHOCK
how does LIPID A of the LPS induce shock
activation of MACROPHAGES and GRANULOCYTES resulting in synthesis of endogenies PYROGENS (like IL-1), prostaglandins, and inflammatory mediators (like TNF-alpha and interferon)
FEVER (IL-1), hypotension, diarrhea, oliguria, vascular compromise, and DIC
what is flagellar (H) antigen seen on E. Coli
heat-labile protein which is one component of the serologic classification of the enterobacteriaceae
what is verapamils action in the pacemaker cells and cardiomyocytes
pacemaker cells: slows the depolarization that occurs in phase 0 (diastolic depolarization)
-decreases SA node drying and slows AV node conduction
cardiac myocytes: decrease the amount of intracellular calcium available for excitation- contraction coupling within cardiomyocytes
-this can reduce contractility (which may be harmful in pts with impaired ventricular function)
