Hypo and Hyper Na+/K+ Flashcards
What is the most common form of RTA?
RTA Type 4
lack of aldosterone or failure to respond to it
What is the role of the NK2Cl transporter in the TAL?
helps give rise to dilute tubular fluid and hypertonic renal medullary interstitium in combo w/ water impermeability and direction of flow outside TAL
What transporter is target of loop diuretics?
NK2CL transporter in TAL
What is the role of insulin?
hormone primarily responsible for cell uptake of K+
can cause HYPOk w/ normal acid-base balance
What occurs in SIADH?
causes euvolemic hyponatremia
What is the role of the V2 receptor in the collecting duct?
mediates response to ADH
leads to insertion of AQ2 water channels in luminal membrane for water reabsorption
What electrolyte disturbance can be caused by vomiting episodes?
hypoNa, hypoK, hypovolemia
metabolic alkalosis w/ renal retention of K & Na
What is sensed by special sensors in brain?
body osmolality
What is DDVAP (desmopressin)?
V2 agonist used to tx central DI
What is tolvaptan?
V2 receptor antagonist that can be used orally to pts w/ persistent hyponatremia despite use of initial therapies
What is ADH?
hormone released by PP whose receptor-mediated water-retaining effects are blocked by vaptans
What is the effect of alcohol?
consumption decreases ADH secretion
What is given to pt w/ hypokalemia and acidosis?
potassium salt (formed w/ acetate)
What is an invasive method to tx life-threatening hyperkalemia?
dialysis
When would you consider RTA in a pt?
acidemia w/ normal AG and serum CR level and NO diarrhea
What can cause pseudohyponatremia?
large volume of LIPID in plasma
What occurs if give pt digoxin with a loop diuretic?
toxicity of digoxin is increased by K+ loss induced by loop diuretic
What is a toxicity of loop diuretic?
ototoxicity
What is mannitol?
osmotic diuretic used to eliminate excess intracellular volume
What type of solution is used to tx acute severe hyponatremia?
hypertonic solution (3% NaCl, causes cells to shrink)
What can cause pseudohyperkalemia?
cell lysis in a collected blood sample
What is the fxn of osmotic diuretics?
cause polyuria (excrete excess glucose in urine)
What acts @ proximal tubule?
osmotic diuretics and carbonic anhydrase inhibitors
What is affected @ prox tubule?
where can increase or decrease fraction of filtered load that is reabsorbed
determines Na+ excretion
What is route for Mg2+ and Ca2+ reabsorption?
both paracellular @ TAL; Ca2+ paracellular @ prox tubules
What is a potential AE of spironolactone used by males?
gynecomastia
What can influence stone formation?
increase risk w/ more Ca2+ in urinary pelvis by loop diuretics
decrease risk w/ less Ca2+ in urinary pelvis by thiazide diuretics
What is caused by both loop and thiazide diuretics?
hyperuricemia
can increase risk of gout
What is 1st line tx for symptomatic hospitalized pt w/ hyponatremia?
If fails, what is next used?
fluid restriction
if fails to tx, indication for vaptans
What is CI for loop diuretics and not good time for thiazides?
pregnancy
What is MOA and indication for acetazolamide?
inhibitor of carbonic anhydrase (causes Na+ HCO3 diuresis w/ hyperchloremic acidosis)
used for urinary alkalization to hasten elimination of weak acid toxins, tx of metabolic alkalosis, acute mtn sickness and glaucoma
What is MOA and indication for conivaptan?
V2 receptor antagonist to cause H2O excretion w/o solute excretion
used to tx euvolemic and hypervolemic hyponatremic if unresponsive to other tx
What are PE findings of hypovolemia?
thirst, tenting of skin, sunken eyes and oliguria
stronger stimulus for ADH release
What can cause hyperkalemia?
tissue necrosis
What is a common cause of hypervolemic hyponatremia?
heart failure
What portion of nephron increase K+ reabsorption when plasma levels are low?
distal nephron (esp collecting duct)
What are sxs of hyper aldsteronism?
hypervolemic hypernatremia
hypokalemia w/ metabolic alkalosis
urinary Cl- loss even w/ low plasma levels and HTN
What is an AE assoc w/ admin of tolvaptan for >30 days?
hepatotoxicity
What class of diuretics act in collecting duct?
K+ sparing diuretics
block Na+/K+ exchange to counterbalance AE of loop and thiazide diuretics
What is spironolactone?
aldosterone antagonist
effects in principal cells of collecting duct to act as K+ sparing diuretic
What is MOA of triamterene?
blocks ENaC channels in principal cells of collecting tubule and duct
What is role of aldosterone?
hormone whose levels decrease in response to dietary Na+ load to help facilitate its renal elimination
What are some causes of hyperkalemia?
anything that interferes w/ normal renin secretion or angiotensin II generation or the actions of angio II/aldosterone
What type of solution is used to tx hypernatremia?
hypotonic (0.45% NaCl causes cells to swell)
What dz causes hyperkalemia despite nl GFR?
Addison dz
What organ does not have space for cells to swell?
BRAIN (in setting of hyponatremia)
lack of space leads to sxs of encephalopathy and possible uncal herniation +/-death
How do loop and thiazide diuretics cause hyponatremia?
excess loss of Na+ and H2O
What is a potential AE of spironolactone in females?
hirsutism