4/17/19 Flashcards
Given a positive test result, what is the probability that a patient has the disease?
Calculate PPV = a / (a + b)
number of people with disease who test positive among all those who test positive
PPV varies with disease
prevalence
if disease prevalence increases, PPV increases
Hereditary angioedema is a rare AD disorder associated with
painless episodes of swelling involving face, lips, larynx, extremities
Hereditary angioedema is caused by
AD
C1 inhibitor deficiency
Sickle cell disease causes what kinds of hemolysis
intra and extravascular hemolysis
Sickle cell disease causes increase in
indirect bilirubin
lactate dehydrogenase
decreased haptoglobin
What is haptoglobin
Acute phase reactant
- decreased in sickle cell disease
- binds circulating hemoglobin
- reduces renal excretion of free Hgb preventing tubular injury
African american with swelling hands and feet
sickle cell disease
dactylitis (hand-foot syndrome) - vasoocclusive symptoms
Transplant patients (esp. lung) at risk for what virus
CMV
enveloped dsDNA
Herpesviridae family
Patients at risk for CMV infection
transplant
HIV
fetuses (congenital infection)
In HIV, CMV usually causes
esophagitis
colitis
retinitis
CMV histology
- enlarged cells with intranuclear and intracytoplasmic inclusions (viral particles)
- often surrounding halo (owl’s eye)
Ppx for CMV in transplant patients
valganciclovir
Influenza virus is an
enveloped
ssRNA
P450 inducers
phenytoin barbituates rifampin carbamazepine griseofulvin chronic alcohol consumption
P450 inhibitors
isoniazid cimetidine macrocodes azole antifungals grapefruit juice
Tight tie causing lightheadedness
carotid sinus hypersensitivity (baroreceptors)
dilation of internal carotid artery
severe bradycardia, hypotension, syncope
baroreceptors are found in the
carotid sinus
baroreceptors work by
arterial wall stretch as an indication of systemic BP
How does the carotid sinus work
afferent limb: baroreceptors in carotid sinus –> medullary center via Hering nerve (glossopharyngeal nerve CN IX)
efferent limb: from medulla carries PNS impulses via vagus nerve
Carotid massage or pressure can cause
- stimulation of baroreceptors
- increase in PNS output/withdrawal of SNS output to heart and peripheral vasculature
- decreased BP (peripheral vasodilation)
- decreased CO (decreased contractility/SV/HR)
The vagus nerve controls BP by
afferent limb: for nerve fibers of aortic arch baroreceptors
efferent limb: for carotid sinus reflex
What is a low osmolarity in the tubular system
100-300
Where is the lowest osmolarity in the tubule system
distal convoluted tubule
100 mOsm/L