Renal Flashcards
Isosmotic principle
extracellular osmolality = intracellular osmolality
mammalian cell membranes cannot sustain an osmotic gradient
60-40-20 rule
total body weight = 60% water
ICF = 40% body mass
ECF = 20% body mass
starling forces determine
intravascular vs extravascular volume distribution
Osmotic pressure gradients determine
intracellular vs extracellular fluid distribution
Diuretic Sites of action:
Osmotic Diuretics
Carbonic anhydrase inhibitors
Loop diuretics
Thiazides
K+ sparing diuretics
Aquaretics
Osmotic Diuretics - Proximal Tubule
Carbonic anhydrase inhibitors - Proximal tubule
Loop diuretics - Thick ascending loop of henle
Thiazides - Distal tubule
K+ sparing diuretics - late distal tubule/ collecting duct
Aquaretics - collecting duct
Osmotic Diuretics include
mannitol
urea
Osmotic diuretics MOA
inhibit nephron H2O and solute reabsorption via generation of a luminally directed osmotic pressure gradient
Osmotic Diuretics use
intracranial pressure reduction (mannitol), intraocular pressure reduction (mannitol), hyponatremia (urea)
Carbonic Anhydrase Inhibitors include
acetazolamide
Carbonic Anhydrase inhibitors MOA
inhibit carbonic anhydrase activity
allowing H+ reabsorption and excretion of Na+
fewer H+ ions to be excreted
Carbonic Anhydrase Inhibitors use
Glaucoma
Acute mountain sickness
metabolic alkalosis
urine alkalinization
Loop diuretics MOA
inhibit Na+ - K+ - 2Cl- cotransporter in TALH
prevent Na+ from being absorbed
more potent - 20-25% sodium secretion
Loop Diuretics include
furosemide
bumetanide
torsemide
Loop diuretic use
edematous states
hypercalcemia
hyponatremia
Thiazide/ Thiazide-like diuretics include
HCTZ, CTZ, metolazone, chlorthalidone
Thiazide/ Thiazide-like diuretics use
HTN, Ca urolithiasis, NDI
Thiazide/ Thiazide-like diuretics MOA
inhibits Na+ - Cl- cotransporter in early DT (cortical diluting segment)
affects diluting capacity but not concentrating ability
there are mechanisms that allow for the body to reabsorb elsewhere - not as potent as loops
K+ sparing diuretic (mineralocorticoid receptor antagonists) MOA
Mineralocorticoid receptor antagonists - antagonize aldosterone action in principle cells - inhibit Na+ reabsorption and K+ excretion
K+ sparing diuretic use
hyperaldosteronism
hypokalemia
HFrEF
resistant HTN
Lithium tox - amiloride
K+ sparing diuretic (mineralocorticoid receptor antagonists) includes
spironolactone
eplerenone
Amiloride is used for
lithium toxicity
K+ sparing Diuretics (ENaC inhibitors) MOA
epithelial sodium channel (ENaC) inhibitors - direct inhibition of apical Na+ uptake via ENaC in principal cells
reverse hypokalemia when using a loop diuretic
K+ sparing Diuretics (ENaC inhibitors) includes
amiloride
triamterene (trimethoprim)
Aquaretics (vaptans) include
Tolvaptan
Lixivaptan
Aquaretics (vaptans) use
Hyponatremia
Aquaretics (vaptans) MOA
block AVP action in late DT and CD
inhibit urine concentration by preventing AVP - stimulated AQP2 insertion into luminal membrane of principal cells
Aquaretics (vaptans) includes
talvaptan
Cardiorenal Axis
Bidirectional functional interaction
heart –> kidneys
if something happens to the heart, something will happen to the kidneys
Reno-cardiac
kidneys insulted first –> leads to cardiac dysfunction
Cardio-renal
heart insulted first –> leads to kidney dysfunction
Type 5 cardiorenal syndrome is when
systemic conditions lead to simultaneous injury and/or dysfunction of heart and kidney
Diuretic use in management of ___________ syndromes
cardiorenal
all Loop Diuretics are pharmacodynamically equivalent - they differ in
potency not efficacy
