Hypo and Hyper Na+/K+ Flashcards
(122 cards)
1
Q
What is the most common form of RTA?
A
RTA Type 4
lack of aldosterone or failure to respond to it
2
Q
What is the role of the NK2Cl transporter in the TAL?
A
helps give rise to dilute tubular fluid and hypertonic renal medullary interstitium in combo w/ water impermeability and direction of flow outside TAL
3
Q
What transporter is target of loop diuretics?
A
NK2CL transporter in TAL
4
Q
What is the role of insulin?
A
hormone primarily responsible for cell uptake of K+
can cause HYPOk w/ normal acid-base balance
5
Q
What occurs in SIADH?
A
causes euvolemic hyponatremia
6
Q
What is the role of the V2 receptor in the collecting duct?
A
mediates response to ADH
leads to insertion of AQ2 water channels in luminal membrane for water reabsorption
7
Q
What electrolyte disturbance can be caused by vomiting episodes?
A
hypoNa, hypoK, hypovolemia
metabolic alkalosis w/ renal retention of K & Na
8
Q
What is sensed by special sensors in brain?
A
body osmolality
9
Q
What is DDVAP (desmopressin)?
A
V2 agonist used to tx central DI
10
Q
What is tolvaptan?
A
V2 receptor antagonist that can be used orally to pts w/ persistent hyponatremia despite use of initial therapies
11
Q
What is ADH?
A
hormone released by PP whose receptor-mediated water-retaining effects are blocked by vaptans
12
Q
What is the effect of alcohol?
A
consumption decreases ADH secretion
13
Q
What is given to pt w/ hypokalemia and acidosis?
A
potassium salt (formed w/ acetate)
14
Q
What is an invasive method to tx life-threatening hyperkalemia?
A
dialysis
15
Q
When would you consider RTA in a pt?
A
acidemia w/ normal AG and serum CR level and NO diarrhea
16
Q
What can cause pseudohyponatremia?
A
large volume of LIPID in plasma
17
Q
What occurs if give pt digoxin with a loop diuretic?
A
toxicity of digoxin is increased by K+ loss induced by loop diuretic
18
Q
What is a toxicity of loop diuretic?
A
ototoxicity
19
Q
What is mannitol?
A
osmotic diuretic used to eliminate excess intracellular volume
20
Q
What type of solution is used to tx acute severe hyponatremia?
A
hypertonic solution (3% NaCl, causes cells to shrink)
21
Q
What can cause pseudohyperkalemia?
A
cell lysis in a collected blood sample
22
Q
What is the fxn of osmotic diuretics?
A
cause polyuria (excrete excess glucose in urine)
23
Q
What acts @ proximal tubule?
A
osmotic diuretics and carbonic anhydrase inhibitors
24
Q
What is affected @ prox tubule?
A
where can increase or decrease fraction of filtered load that is reabsorbed
determines Na+ excretion
25
What is route for Mg2+ and Ca2+ reabsorption?
both paracellular @ TAL; Ca2+ paracellular @ prox tubules
26
What is a potential AE of spironolactone used by males?
gynecomastia
27
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
28
What is caused by both loop and thiazide diuretics?
hyperuricemia
can increase risk of gout
29
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
30
What is CI for loop diuretics and not good time for thiazides?
pregnancy
31
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
32
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
33
What are PE findings of hypovolemia?
thirst, tenting of skin, sunken eyes and oliguria
stronger stimulus for ADH release
34
What can cause hyperkalemia?
tissue necrosis
35
What is a common cause of hypervolemic hyponatremia?
heart failure
36
What portion of nephron increase K+ reabsorption when plasma levels are low?
distal nephron (esp collecting duct)
37
What are sxs of hyper aldsteronism?
hypervolemic hypernatremia
hypokalemia w/ metabolic alkalosis
urinary Cl- loss even w/ low plasma levels and HTN
38
What is an AE assoc w/ admin of tolvaptan for >30 days?
hepatotoxicity
39
What class of diuretics act in collecting duct?
K+ sparing diuretics
block Na+/K+ exchange to counterbalance AE of loop and thiazide diuretics
40
What is spironolactone?
aldosterone antagonist
effects in principal cells of collecting duct to act as K+ sparing diuretic
41
What is MOA of triamterene?
blocks ENaC channels in principal cells of collecting tubule and duct
42
What is role of aldosterone?
hormone whose levels decrease in response to dietary Na+ load to help facilitate its renal elimination
43
What are some causes of hyperkalemia?
anything that interferes w/ normal renin secretion or angiotensin II generation or the actions of angio II/aldosterone
44
What type of solution is used to tx hypernatremia?
hypotonic (0.45% NaCl causes cells to swell)
45
What dz causes hyperkalemia despite nl GFR?
Addison dz
46
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
47
How do loop and thiazide diuretics cause hyponatremia?
excess loss of Na+ and H2O
48
What is a potential AE of spironolactone in females?
hirsutism
49
How is free water clearance related to urine osm?
free H2O clear is zero when urine is isotonic
+ when urine is dilute
- when urinary solute returned to body
50
What is Fanconi syndrome?
cause of type 2 RTA due to impaired ability to reabsorb filtered HCO3 in prox tubule
51
What is a consequence of tx hyponatremia too rapidly?
osmotic demyelination
52
What ion exchanges w/ cellular K+ during acid base maintenance?
HYDROGEN
reason acidosis can cause hyperkalemia
53
What is administered to raise threshold potential when people present w/ hyperkalemia?
calcium
54
What is significant about intercalated cells?
change phenotype and assoc w/ maintenance of acid-base balance
55
What cells do thiazide diuretics target?
intercalated cells in distal nephron
56
What is equivalent to infusing volume of distilled water?
administer 5% solution of dextrose
57
Why is tolvaptan still used?
slow progression of APKD
58
What is the aldosterone antagonist w/ greater selectivity?
eplerenone
59
Describe GFR requirements for diuretics
thiazide do NOT work if GFR<30 ml/min
loop diuretics work if GFR<30 ml/min
can be cause of hyperkalemia if GFR<5
60
What remains unchanged when excreting max dilute or max conc urine?
elimination of solute
61
What is the most common electrolyte abnormality seen in clinical practice?
HYPOnatremia
Na+ conc <135
62
What is the effect of licorice?
dose dependently potentiates aldosterone effects and increases systolic blood pressure
63
What changes occurs with step change in daily sodium intake?
increase in body weight
64
What cells are primary target of K+ sparing diuretics?
principal cells in collecting duct
65
What receptors sense body Na+ content via measure effective blood volume?
stretch receptors
66
What is the role of TRPV5 receptor?
Ca2+ reabsorption in DCT
major site of regulation w/ calcitriol (to increase synthesis) and PTH (regulate conductance)
67
What increases K+ excretion from distal nephron?
increased tubular fluid flow rate
68
What are K+ losing diuretics?
thiazides, loops, carbonic anhydrase inhibitors, osmotic diuretics
69
What occurs with abuse of laxatives?
extra renal K+ losses leading to hypokalemia that can occur +/- concurrent metabolic acidosis
70
What occurs in severe hypokalemia, DI and vaptan use?
polyuria
71
What is glomerulotubular balance?
forces acting across proximal tubular epithelium that result in proportional amounts of isotonic fluid reabsorption from prox tubule
72
What loop diuretic can be used in pts w/ sulfa allergy?
ethacrynic acid
73
What defines hypokalemia and outcome?
plasma K+ <3.5
hyperpolarizes most cell membranes
can be caused by K+ losing diuretics
74
Hypovolume v hypervolume
too little or too much sodium in body
75
What is a cause of hyperosmolar hyponatremia?
hyperglycemia
76
What prevents plasma potassium toxicity from dietary intake?
rapid redistribution of K+ into cells
77
What is role of TPRV6 channel?
Mg2+ reabsorption in DCT which somewhat blocked in TAL by loop diuretics
will downregulate in presence of thiazides leading to more profound Mg2+ loss in urine
78
What is an important indication for loop diuretics?
ASCITES that occurs in liver dz due to impaired synthesis of plasma proteins and increased portal venous pressure
79
What is indication for salt tablets?
tx for hypovolemic hyponatremia
80
What volume is expanded by infusion of 0.9% NaCl solution?
extracellular volume
81
What drives water movement across cell membranes?
osmotic pressure
82
What promotes excretion of urine and can cause hypovolemic hyponatremia?
diuretic
83
What sx is among neuromuscular manifestations of hypokalemia?
constipation
84
What type of paralysis is seen in worsening hyperkalemia?
FLACCID paralysis
twitching/weakness and numbness/prickling sensation
85
What occurs when K+ (and Cl-) are lost in urine due to diuretics?
metabolic alkalosis due to cells donating K+ while taking up H+ to maintain plasma K+ levels near normal
86
Where do loop diuretics act?
high ceiling effects exerted in TAL
87
What becomes prominent in severe hypokalemia?
U waves
88
What acids have less effect on plasma K+?
organic acids
89
Hyponatremia v hypernatremia
too much or too little WATER diluting body Na+ content
90
What can be hidden source of excessive K+ intake?
antibiotics
91
What is a healthy way to transiently raise extracell K+ levels?
exercise
92
What is most common cause of nephrogenic DI?
lithium to tx bipolar disorder
93
How to tx nephrogenic DI due to lithium toxicity?
amiloride
94
What is MOA of thiazide and indication?
medium Na+ losing ability b/c block of transporter in DCT
tx nephrogenic DI
95
What is furosemide?
LOOP diuretic
96
What is caused by lack of ADH secretion or failure of kidneys to respond to ADH?
diabetes insipidus
can lead to euvolemic hypernatremia
97
What change in HR is consequence of hyperkalemia?
BRADYCARDIA
b/c hyperkalemia increases K+ conductance in SA node tissue to cause membrane hyperpolarization
higher risk of arrhythmia
98
What is impaired in Bartter syndrome, use of loop diuretics, and hypokalemia?
concentrating ability of kidneys
results in polyuria, nocturia
99
What type of metabolic alkalosis is seen w/ thiazide and loop diuretics?
HYPOchloremic secondary to K+ loss
100
What is problematic with diuretics?
nonadherence due to urgent need to urinate
101
What interval is widened by hyperkalemia?
QRS interval
102
What is administered as the coma cocktail?
GLUCOSE in pts presenting w/ hyperkalemia
103
How does urinary output of Na+ change as BP increases?
increased sodium urinary output
104
What is nephrogenic diabetes insipidus?
form of DI when kidney fails to respond to ADH
105
What is osm of urine when use max dose of furosemide?
ISOTONIC urine (irrespective of plasma ADH levels)
106
What is autoregulation?
myogenic mechanism and tubuloglomerular feedback that maintains RBF and GFR at range of MAP
107
What is hypomagnesemia?
plasma level <1.7
often seen w/ hypoK and Ca2+
clinical sxs of muscle weakness, tremors, tetany, seizures, paresthesias, torsades de pointes
108
What is role of magnesium?
crucial cofactor in many biological processes
normal level regulation via reabsorb through TRPM6 channels in DCT
109
What extrinsic factors modify intrinsic renal relationship btwn arterial pressure and sodium excretion?
Ang II
ANP
SNS activity
110
What is a sign of neglect in nursing homes?
hypovolemic hypernatremia
111
What is MOA of amiloride?
diuretic that blocks epithelial Na channels in principal cells of collecting ducts
rapid onset of action
112
When is not a good time to take loop or thiazide diuretic?
bedtime
113
What characterizes fluid removal response to diuretics?
rapid and massive
114
What signifies that too much sodium is in 1 compartment?
EDEMA
indication for loop diuretic
115
What promotes free water clearance?
aquaretic
116
What is RTA type 1?
RTA w/ hypokalemia due autoimmunity (causes fibrosis w/ impaired fxn in cortical collecting duct)
117
What channels are blocked by amiloride and triamterene in collecting duct cells?
ENaC
118
What is determined by extracellular K+ levels?
resting membrane potential
119
What defines tx of chronic hyponatremia or hypernatremia?
SLOW rate of correction
120
What drugs interfere w/ renin secretion and ability of diuretics to cause diuresis?
NSAIDs
121
What co-transporter in DCT further dilutes tubular fluid?
NaCl
target of thiazide diuretics
122
What is typical route for KCl administration for pt w/ hypokalemia?
ORAL
