Renal Flashcards
list the functions of the kidney using AWETBED
acid base balance
water balance
electrolytes
toxin removal
blood pressure control
erythropoietin production
vitamin D metabolism
this is a beast of a flaschard. For each of the following locations, list what is moving in/out, and what the resulting osmolarity is:
- proximal convoluted tubule
- the descending limn of the loop of henle
- the ascending limb of the loop of henle
- thick ascneding limb of the loop of henle
- distal convoluted tubule
- collecting duct
proximal convoluted tubule: water and solutes are moving out, meaning the fluid entering into the loop of henle is similar to plasma in terms of osmolarity
descending limb of the loop of henle: water is moving out but NOT NaCl, making the fluid entering the ascending limb of the loop more concentrated
Ascending limb of the loop of henle: NaCl is moving out but NOT water
Thick ascending limb of the lop of henle: NaCl is moving out but water is not, increasing the concentration in the extracellular space and leaving the urinary space hypotonic when it enters into the distal convoluted tubule
Dital convuluted tubule: water moves out which results in the final concentration of the urine fluid moving into the collecting duct
Collecting duct: water moves out
what ultimately allows the concentration of the urine?
the intrmedullary concentration gradient
using the acronym COLTP, what are the different mechanisms of action classes for diruetics and where do they act?
carbonic anhydrase inhibitors: proximal convoluted tubule
osmotic diruetics: descneding limbs of the loop of henle
loop diruetics: thick ascending limb of the loop of henle
thiazide diruetics: distal convuluted tubule
potassium sparing diruetics: collecting duct
birefly explain the MOA of carbonic anhydrase inhibitor drugs
they inhibit the formation of carbonic acid (inhibit bicarbonate and H+ formation), H+ is usually exchanged for sodium as sodium leaves the lumen of the proximal convolute tubule into the tubular epithelial cells, less H+ means sodium stays in the lumen and therefore so does water, blocking to reabsorption of bicarbonate, sodium, and water
what kind of drug is acetazolamide? What is it’s primary use? What are some adverse effects of this drug?
a carbonic anhydrase inhibitor
treatment of ACUTE glaucoma in dogs when topical treatment doesn’t work
this drug is self limiting due to it causing acidosis, causes drowsiness and disorientation, hypersensitivity, hyperkalemia
why don’t we give cats acetazolamide?
they are way more sensitive to adverse effects than dogs. topical ones are better for cats with glacuoma
briefly describe how osmotic diurects work and list the most comonly used one. how is it normally given?
they are solutes essentially that have an increased osmolarity compared to plasma. they pass thru the glomerulus but are not reabsorbed. they are pharmacologically inert but are osmolarily active; they limit tubular reabsorption in the descending portions of the lop of henle (water does not leave because it stays with the high concentration of solutes)
mannitol: given IV
what are 3 effects of mannitol in terms of pharmacodynamics?
increased cardiac output, decrease rigidity of RBC membranes (enhanced blood flow), reduced hematocrit
what is mannitol used for in practice? What are some things to consider when you are using it?
used to treat increased intracranial pressure MUST HAVE INTACT BBB: you want the water to be sucked out of the brain tissue and into the blood vessels
when using it: give IV and use a test dose and watch for a response, and you need in tact tissue barriers otherwise they way worsen the situation
what are some adverse effects of mannitol?
- the patient needs to be well hydrated before it is used because it can dehydrate the patient
- can cause cardiac arrythmias because you are loosing electrolytes in the urine
- acute hyponatremia (sodium is being peed out)
- dont use it in patients that have congestive heart failure or pulmonary edema
- the body will compensate when this drug is being given so dont just stop the drug use, gradually decrease
what is the most commonly used diuretic in vet med? what is it’s MOA category?
furosemide (lasix)
it is a loop diuretic
describe how loop diuretics work
act in the thick ascending limb of the loop of henle, in this region water cannot move in or out, but normally sodium is moved out. this drug blocks the exchanger that moves sodium out (prevents sodium reabsroption). more sodium stays in the tubule=more water stays in the tubule and is excreted out. It also effects the Cl equilibrium which increass renin production, which leads to increased blood pressure and an increase in renal perfusion. Also reduced renal oxygen consumption because normall moving sodium out of the tubule is n active process requiring oxygen
what is a diuretic used in dogs that is thought to have less adverse effects on the RAAS compared t furosemide?
torsemide
list some things furosemide is used for
mobilizing edema/ascites of cardiac, renal, or hepatic origin
for reducing exercise induced pulmonary hemorrhage in horses
for renal failure to try and increase urine production in acute oliguric renal failure, not anuric
can treat hypercalcemia (can pee out excess calcium)
