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82 Cards in this Set

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how do diuretics increase urine flow?
inhibiting the reabsorption of Na+ at different sites along the nephron
Reabsorption:
ion transport from urine to blood
secretion:
ion transport from blood to urine
What would result if you enhance the delivery of Na+K+H+ exchange site?
augment K+ and H+ secretion

leading to hypokalemia and metabolic alkalosis
Why does inhibiting Na+ reabsorption at the proximal sites(where the majority of reabsorption occurs) not result in great efficacy?
The more distal sites will work harder to compensate for the lack of Na+ reabsorption
What happens if a diuretic acts on the Na/K/H exchange site in the collecting tubule?
it will increase the amount of Na delivered to that site
What is the site of action of osmotic diuretics?
proximal tubule
What is the MoA of osmotic diuretics?
inhibition of H20 reabsorption by osmotic aciton
Where is the site of action of carbonic anhydrase inhibitors?
proximal tubule
What is the MoA of carbonic anahydrase inhibitors?
inhibition of NaHCO3 reabsorption (which enchances Na excretion)
What is the MoA of Loop Diuretics?
inhibition of active salt transport
Where is the site of action of Loop Diuretics?
thick ascending limb of the loop of Henle
Where is the site of action of Thiazides?
Early distal tubule
What is the MoA of Thiazides?
inhibition of NaCl reabsorption
What is the MoA of Potassium-sparing diuretics?
inhibition of Na reabsorption and K secretion by competitive antagonism of aldosterone (spironolactone)

Or by direct action(triamterene or amiloride)
Where is the site of action of potassium sparing diuretics?
late distal tubule and cortical collecting duct
Which group of diuretics are used the least?
osmotic diuretic
Are osmotic diuretics useful in treating Na retention conditions?
No.

They only increase the water excretion
When are osmotic diuretics used?
cerebral edema
acute renal failure due to shock
glaucoma (pulls H20 from tissues to blood)
What do you need to be careful of with osmotic diuretics?
severe dehydration if not taken with adequate water replacement
Name some osmotic diuretics
mannitol
urea
glycerol
isosorbide
Name some anhydrase inhibitors
Acetazolamide
Dorzolamide
What does carbonic anhydrase do?
catalyzes the conversion of H2Co3 to Co2 and H20
What can result if Na/HCO3 are increased in the collecting tubule?
K+ wasting
Why is it useful to have Na/HCO3 retained in the lumen?
increases urinary pH, which will result in renal excretion of weak acids (aspirin)
Acetazolamide can be used to treat what?
high altitude sickness
Why can acetzolamide be used to treat high altitude sickness?
it decreases CSF formation which is a life-threatening complication of high altitude sickness
Dorzolamide is used to treat what?
glaucoma
Name some Loop Diuretics
Furosemide
Ethacrynic Acid
Bumetanide
Loop diuretics promote the excretion of what?
Ca and Mg
Loop diuretics can be used to treat what?
hypercalcemia
Loop diuretics usually treat what type of pt?
pt with impaired renal function who have pulmonary edema, CHF or hypertension
With loop diuretics there is a risk of what?
potent loss of
Na
Cl
K
Mg
Ca
HCO3
H20
What are other adverse effects, besides loss of electrolytes, of loop diuretics?
ototoxicity (with reversible hearing loss)
Furosemdide and ethacrynic acid are what type of diuretic and the pt is at what risk with their use?
they are loop diuretic and can exacerbate gouty attacks
What are the most widely used diuretic agent?
thiazides
Name some thiazides
hydrocholorthiazide
chlorthalidone
indapamide
Thiazide treat what symptoms/diseases?
CHF
hypercalciuria
diabetes insipidus (polyuria)
How do thiazides increase NaCl excretion?
inhibit reabsorption in the early distal tubule by inhibition of the Na/Cl co-transporter on the luminal membrane
Thiazides can promote loss of what electrolyte?
What can you do to decrease this effect?
K+

dietary supplementation
What are some risks of thiazides?
pt with diabetes can become hyperglycemic
maybe because of an impaired pancreatic release of insulin
deplete extracellular fluid volume
unfavorable lipid profile
Do Thiazide promote Ca retention or excretion?
retention!
Thiazide retention of Ca can help with what diseaes?
nephrolithiasis caused by idiopathic hypercalciuria
What organic compounds can block thiazides?
Probenecid, penicillin and salicylates
Name some Potassium-sparing diuretics
spironolactone
amiloride
triamterene
Do you use Potassium sparing diuretics alone or with other drugs?
use as adjuncts to loop or thiazide diuretics to prevent K depletion
Spironolactone competes with what hormone?
aldosterone
What role does aldosterone play in urine formation?
increases Na and K channels
increases activity of Na/K ATPase
promotes salt and water retention
decreases the amount of urine

Spironolactone blocks this action
Name some reasons for increased production of bile.
fetal-maternal blood group incompatibility
extravascular blood
polycythemia
hemoglobinopathies
induction of labor
Does breast feeding cause an increase or decrease in bile excretion
decrease in excretion
Why would an neonate have an increase in enterohepatic circulation of bile?
Bile is released into the small intestines, but keeps getting reabsorped
Hormones and drugs cause an increase or decrease in bile excretion?
decrease
What causes a decrease in bile excretion?
inborn errors of metabolism
prematurity
hepatic hypoperfusion
cholestatic syndrome
obstruction
hormones and drugs
breast feeding
increased enterohepatic circulation
When dealing with neonatal jaundice, which type of bilirubin can be treated with phototherapy?
unconjugated
What type of bilirubin elevation is Crigler-Najar I/II?
unconjugated
Which is less severe Crigler-Najar I or II?
Crigler-Najar II is less severe
Does Crigler-Najar I response to Phenobarbital?
no
What does phenobarbital do?
helps enzymes conjugate bilirubin
What are the levels of unconjugated bilirubin in a person with Crigler-Najar I?
15-45mg/dL
When would symptoms of Gilbert's be noticible?
during stress
What is the pathological problem in Gilbert's
a mutation in the gene that codes for Bilirubin UDP glucuronyltransferase.
What does bilirubin UDP glucuronyltransferase do?
it binds unconjugated Bilirubin with glucuronic Acid to make it water soluble and be excreted as bile
What is the first question you should ask?
Is the bilirubin unconjugated or conjugated.
What could cause an increase in unconjugated bilirubin?
hemolysis or extravascular blood
What is the second question that you would ask when dealing with a jaundice neonate?
Is it intrahepatic or extrahepatic?
Why is it important to know if it is intra or extrahepatic?
It helps with prognosis and determining the need for surgery
Why can't you eat up to 4 hours before getting imaging on the gallbladder?
it contracts after eating.
How can you evaluate the biliary tree?
use Ultrasound
What does a HIDA scan (radionucleotide scan) show?
It shows uptake of the liver and the excretions into the small bowel
When taking a biopsy, what are you looking at?
The way cells are arranged
portal triad
bile ducts
fibrosis
What is the idiopathy of intrahepatic jaundice?
neonatal hepatitis
or
prematurity (may not ever know)
What are some anatomical reasons for intrahepatic jaundice?
Congential fibrosis
Caroli's
What is Caroli's disease/syndrome?
It is a congenital condition where there is multifocal, segmental dilatation of large intrahepatic bile ducts
What are some metabolic causes of intrahepatic jaundice?
AA
lipid
CHO (galactosemia)
a-1-antitrypsin
CF
Hypopit
HypoT4
hemochromatosis
TPN/NPO
Tyrosinemia
bile acid
What are characteristics of Tyrosinemia?
progressive liver failure
renal tubular dysfunction
hypophosphatemic rickets
Biliary atresia is intra or extrahepatic?
extrahepatic
Pt is discovered to have choledochal cyst. How should you treat that?
surgery (surgical emergency)
Name the different causes of extrahepatic(ductular) jaundice.
biliary atresia
choledochal cyst
spontaneous perforation
mass
bile duct stricture
PFIC
BRIC
Alagille's syndrome
Nonsyndromic paucity
In a typical workup sequence, what is the first thing you would o?
Fractionate the bilirubin (direct vs indirect) and get a full hepatic panel
You order a full hepatic panel--What results will you get?
AST, ALT, GGT, albumin, TP (total protein)
Alkaline phosphatase
If GGT is elevated--what does that indicate?
bile duct problems
Are pediatric's Alkaline phosphatase usually depressed or elevated compared to adults?
elevated