diuretics and electrolytes Flashcards by Sarah Horvath

what part of the nephron do carbonic anhydrase inhibitors work on?

proximal tubule

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what part of the nephron do loop diuretics work on?

loop of henle

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there is a huge reabsorption of sodium and chloride back into the body at the ____ _____

proximal tubule

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what is the main concentrating segment of the nephron?

loop of henle

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what part of the nephron do thiazide diuretics work on?

distal tubule

they compete for the Na-Cl cotransporter in the DT to inhibit reabsorption.
inhibit only urinary diluting capacity

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where is the final concentration determined?

collecting duct

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where does vasopressin work?

collecting duct

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the definition of chronic kidney disease is: kidney damage for _____ defined by structural or functional abnormalities with or without decreased GFR

> 3 months

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the definition of chronic kidney disease in terms of GFR =?

<60ml/min for >30 months with or without kidney damage

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stage 1 CKD =

damage with normal or increased GFR > 90ml/min

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stage 2 CKD =

damage with mild dec GFR: 60-89

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stage 3 CKD =

moderate dec GFR: 30-59

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normal GFR is above ___

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stage 4 CKD =

severe dec GFRP 15-29

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kidney failure = GFR < ___

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stage 6 CKD =

dialysis

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how does the RIFLE criteria categorize acute kidney disease

it looks at increased CrCl from baseline or reduction in GFR from baseline

urine output criteria is based on oliguria for 6 (risk) , 12(injury), 24h (failure)

review slide 8 for Rifle criteria

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if someone has taken something that has damaged the nephron such as NSAIDS, aminoglycosides, pcn, they have ____ renal failure

intrinsic

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pre-renal failure usually is caused by

dehydration

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post renal failure is usually due to

obstruction - like a stone

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what are carbonic anhydrase inhibitors actually used or these days?

people with increased IOP and long standing COPD and their CO2 is building up. trying to correct acid base abnormalities

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acetazolamide (diamox)
methazolamide (neptazene)
dichlorophenamine (daranide)

are all examples of

carbonic anhydrase inhibitors

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whats the MOA of a carbonic anhydrase inhibitor?

inhibit CA which inhibits H+ secretion in the proximal tubule. bicarb and sodium are blocked from reabsorption. the effect is short lived d/t compensation at the loop of henle

explanation: we are blocking Na and Bicarb from reabsorbing, therefore Na is staying IN the urine (not being reabsorbed back into the body.), water is going to follow and we have a diuresis. it blocks enzyme carbonic anhydrase which normally breaks down hydrogen from bit from our water and our CO2 from our bicarbs. when we block that our bicarb and sodium bind up and go out together and we have water excretion. its a very round about way of getting rid of water. tolerance will develop bc when youre working just in this front part of the nephron there’s a lot of ways that the body is going to compensate later on…lose your effect of diuresis

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which diuretic is associated with tolerance after 2-3 days

carbonic anhydrase inhibitors

acetazolamide (diamox)
methazolamide (neptazene)
dichlorophenamine (daranide)

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which diuretic is associated with hypokalemic metabolic acidosis

carbonic anhydrase inhibitors acetazolamide (diamox) methazolamide (neptazene) dichlorophenamine (daranide)

blurred vision and changes in taste are side effects of

acetazolamide (diamox) methazolamide (neptazene) dichlorophenamine (daranide)

what are 2 examples of osmotic diuretics

mannitol and urea

how do osmotic diuretics work

big bulky molecule, thru osmosis it pulls water into the urine. Non-reabsorbable solute filtered freely at the glomerulous. Uncouples sodium and water reabsorption by increasing the osmotic gradient in the proximal tubule. Sodium reabsorption initially, but water is not, leading to decreased sodium reabsorption distally

mannitol causes ___ of water, ____ intracellular volume, and ____ risk

loss of water, reduced intracellular volume, and hypernatremia risk

T/F Urinary ph is not altered by mannitol induced osmotic diuresis

TRUE

which two drugs can work together to pull fluid out of spaces such as increased ICP and ascites

mannitol and loop diuretics

IV mannitol increases or decreases plasma osmolarity?

INCREASES mannitol draws fluid from intracellular to extracellular spaces. this acutely expands the intravascular fluid volume

what might be a detrimental effect of mannitol?

CHF in patients with poor myocardial function pulm edema

mannitol used to be used for prophylaxis against ARF and differential diagnosis of acute oliguria buuuuut....

there is no benefit giving mannitol before giving contrast dye and we use labs diagnostiacally.

what are 2 indications for mannitol?

increased ICP and IOP

T/F Evidence exists to show that mannitol is nephroprotective

FALSE. no true evidence exists

T/F Mannitol is no better than plain saline pre-radiocontrast dye

TRUE except in renal transplant surgery- less incidence of ARF

How is mannitol used to diagnose acute oliguria

well first of all emily says is not really used for this anymore bc we have labs.. BUT UO is increased when the cause of acute oliguria is decreased intravascular fluid volume if glomerular or renal tubular function is severely compromised, mannitol will not increase urine output.

T/F mannitol requires an intact BBB because you need the gradient to create an osmotic difference

TRUE

what does mannitol do to CSF volume?

decreases by decreasing the rate of CSF formation

urea has concerning side effects such as

venous thrombosis and tissue necrosis

T/f Increased BUN after admin of urea is a sign of acute renal failure

FALSE

which class is the biggest offender of electrolyte abnormalities

loop diuretics

loop diuretics cause ``` ___natremia _____kalemia ____calcium ____mg metabolic____ ```

``` hypoNA hypoK hypoCa hypoMg metabolic alkalosis (think K is dec) ``` normally Na K Cl are reabsorbed and brought back into the blood and then passively along with these there is movement of ca and mg. when we block this co-transporter("simport") we are keeping sodium in the urine... and thats where we get our diuresis is the water following the sodium... but we are also now losing K Cl, and then secondarily Ca and Mg

T/F with loop diuretics, peripheral vasodilation precedes the onset of diuresis

TRUE. also get renal vasodilation and inc RBF

T/F Lasix does not dec ICP by changing cerebral blood flow or plasma osmolarity.

TRUE. ICP is decreased by systemic diuresis, decreasing CSF production, and improving cellular water transport.

T/F the combination of lasix and mannitol is more effective in decreasing ICP than either drug alone.

TRUE

loop diuretics + amino glycoside or cephalosporin =

nephrotoxicity

T/F Thiazide Diuretics inhibit urinary diluting and concentrating capacity

FALSE. inhibit only urinary diluting capacity, not concentrating capacity.

what acid base abnormality do TZD's cause

hypokalemic metabolic alkalosis

T/F If a patient takes TZD's they may have prolonged weakness

TRUE because they potentiate non-depolarizing nmb.

T/F patient taking TZD's have an increased likelihood of developing dig tox

true - d/t hypoK

T/F TZD's increase the elimination of uric acid

FALSE - decrease so you get hyperuricemia

where do potassium sparing diuretics work

collecting duct

potassium sparing diuretics - amiloride & triamterene- MOA

inhibit Na reabsorption induced by aldosterone inhibit active counter transport of Na and K in the collecting duct

potassium sparing diuretics -spironolactone and eplerenone- MOA

compete for aldosterone receptor sites in the DT to block Na reabsorption and K secretion

which two drugs are used in combination for refractory edematous states such as CHF and cirrhosis of the liver

K sparing (spironolactone) + lasix

what is the principle side effect of K-sparing diuretics

hyperkalemia.

T/F Unlike thiazides, K-sparing diuretics do not produce hyperuricemia or hyperglycemia

TRUE

what should you give for hyperkalemia

IV calcium | gluconate preferred

how does kayexalate work

binds potassium in the colon exchange for sodium

patiromer and sodium zirconium cyclosilicate work how?

oral GI potassium binder to increase fetal excretion

Na replacement: no more than __mEq in the first 24h, no more than ___ in the first 48

12, 18

VAPTANS - vasopression receptors should never be used for

HYPOvolemic HYPOnatremic only for euvolemic and hypervolemic hyponatremia

vaptans - vasopressin receptor blockers should only be used for

euvolemic and hypervolemia hyponatremia

hyperca ----> _____parathyroidism

hyper

hypoca ----> ____parathyroidism

hypo

thiazides effect on ca

hold on

calcium levels are dependent on

albumin

tx of hypercalcemia

fluids, loop diuretics, IV biphosphonates

how do biphosphonates work

inhibit osteoclasts, inhibit bone breakdown. forces the body to take calcium and resubmit it into the bone structure.... but complications include kidneyy damage, hypocalcemia, atypical fx, burn a hole in your esophagus...

when is a study statistically significant

p < 0.05