test #45 5.4 Flashcards
when to involve ethics committee or risk management?
basically never on USMLE. handle it on your own.
sudden onset headache and nuchal rigidity
subarachnoid hemorrhage
meningeal irritation from blood
can also see papilledema and pupillary dilation, but no other focal neurological signs
xanthochromia
blood in CSF
diff between intracerebral hemorrhage & subarachnoid hemorrhage
intracerebral: focal neurological impairment
subarachnoid: no focal issues
carrier frequency for mom 1/30
carrier frequency for dad: 1/100
chance child will have disease?
(1/30 x 1/2) x (1/100 x 1/2)
what % of observations fall in 1 standard deviation of mean
68%
what % of observations fall in 2 standard deviations of mean
95%
what % of observations fall in 3% of standard deviation of mean
99.7%
normal pulmonary arterial pressure
< 20mmHg
definition of pulmonary artery hypertension
> 25mmHg
major causes of pulmonary artery HTN
- hereditary (AD: BMPR2 mutation)
- left heart failure
- chronic hypoxia: obstructive sleep apnea, COPD
- chronic thromboembolism
- HIV infxn
idiopathic pulmonary artery HTN inheritence
autosomal dominant w/ variable penetrance
2 hit:
- mutation in BMPR2. normally suppresses smooth muscle proliferation
- activates disease process (i.e. infxn, drug)
cardiac sounds that can arise w/ pulmonary HTN (2)
- accentuated S2
2. holosystoic tricuspid regurg (diastolic) due to increased ‘afterload’
etiology of pulmonary HTN in COPD, obstructive sleep apnea, interstitial lung disease
hypoxic vasoconstriction
compensation for chronic respiratory acidosis
3-5 days
(at least 24hr)
kidney excrete acid & retain HCO3-
> 30
Kussmal breathing
shallow breathing seen in diabetic ketoacidosis, attempt to blow off CO2 to compensate for metabolic acidosis (low bicarb, low CO2, low pH)
adverse effects of succinylcholine (3)
- malignant hyperthermia in genetically susceptible people
- hyperkalemia in pts w/ burns, myopathy, crush injury, denervation -> quadriplegia, guillan-barre
(due to upregulation of muscle nAChR & rhabdomyolysis –> increase K+ efflux)
- bradycardia, from parasympathetic stimulation or tachycardia, from sympathetic ganglion effects
side effects of atracurium
- release histamine ->
bp drop, flushing, bronchoconstriction - spontaneous degradation to laudanosine –> seziure
but, good for renal/hepatic insufficiency
baclofen mechanism
GABAb at level of spinal cord
CNS
phase I of succinylcholine
strong agonist of nAChR
binds & depolarizies
insensitive to AChE, so prolonged depolarization –> twitching
potentiate: AchE inhibitors, bc Ach will help further depolarize & inactivate muscle.
eventually degraded by plasma cholinesterases
phase II of succinylcholine
w/ continuous infusion or SLOW metabolizers
eventually nAChR insensitive to succinylcholine, which can bind & block site, but can no longer depolarize
–> becomes nondepolarizing blocker
antidote: AChE inhibitors (increase Ach concentration)
infective dose of shigella, salmonella, and vibrio cholera, ETEC
least --> most shigella -- 10 - 10^2 salmonella -- 10^ 7 vibrio cholera: 10^5- 10^7 ETEC: 10^ 8-10^ 10
why is shigella so infective? when does infxn start
- survive stomach acid & bile
- uniquely bind to mucosal M cells in peyer’s patches
24-72 hrs incubation
tenesmus
painful spasm of rectum associated w/ urge to defecate, yet little passage of stool occurs