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37 Cards in this Set
- Front
- Back
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Potassium:
-Major ... cation -total body K+ is ...-... meq/kg -75% of total K+ is in ... tissues |
intracellular
33-55 muscle |
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Potassium Level:
Serum level measures ... concentration of potassium Dependent on: -... K+ present in body *Amount ingested vs. excreted -How K+ is ... between ECF and ICF *Multiple factors to control this |
extracellular
Total distributed |
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Hyper/hypokalemia and Total Body K +:
Shifts in serum K+ may occur with or without change in Total body K+ K+ shifting into cells will cause ... state -May require K+ supplementation K+ shifting out of cells will cause ... -Usually transient and readily cleared by kidneys -May lead to ... total body K+! |
hypokalemic
hyperkalemia decreased |
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Potassium Balance by Kidneys:
More than half of filtered K + is ... resorbed by end of proximal convoluted tubule Active K + resorption occurs in the ... loop of Henle Only 10-15% of filtered K + remains at end of ... During total K + depletion, ... is enhanced |
passively
ascending distal convoluted tubule reabsorption |
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gradient between intra/extracellular K+ will have major effect on ... potentials
propagation of ... impulses will be altered w/ hyper/hypokalemia |
membrane
electrical |
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Potassium gradient established by ...
Membrane polarization is ... with increased K+ gradient across membrane |
Na+ - K+ Pump
increased |
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Potassium Shifts:
K+ is shifted from inside cell to outside by: -Severe ... (surgery, trauma, burns) *Cells break down and release K+ -... state *Break down of proteins releases K+ from cells -... deficiency *Diabetes -... administration *Depolarizing NM blockade |
injury
Catabolic Insulin Succinylcholine |
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Potassium Shifts:
K+ is shifted from inside cell to outside by -... *K+ gets transported out in exchange for H+ which is abundant in ECF *Metabolic acid-base disturbance exhibit greater FX on K+ distribution than respiratory disorders |
Acidemia
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Potassium Distribution:
K+ is shifted from inside cell to outside by: -... extracellular osmolality (hyperglycemia) *Water leaves cells; cells become dehydrated; K + shifts out of cell as intracellular concentration of K + increases -... deficiency *... helps tuck K+ into cells *Lack of insulin in diabetes leads to ... |
Increased
Insulin Insulin hyperkalemia |
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K+ is shifted from outside cell to inside by:
Insulin Catecholamines ...emia ...thermia Proliferating tumor cells Transfusion of frozen washed RBC -Cells are potassium poor and take up serum K + |
Alkal
Hypo |
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Insulin and catecholamines
-(Help tuck K + into cells) -Stimulate Na+ - K+ ATPase in skeletal m. -... effect *Enhances transport of K into cells *Decreases [K +] in extracellular space -Extreme stress (increased catecholamines) or beta2 agonism (ex. albuterol) may cause transient ... Beta blockade or lack of insulin (diabetes) will cause ... -Body cannot appropriately keep K + inside cells |
Hypokalemic
hypokalemia hyperkalemia |
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Potassium Distribution in Hyperkalemia:
With normal renal function, kidneys will excrete excess extracellular K + -Transient hyperkalemia may be well tolerated unless renal failure present -With functioning kidneys, excess serum K + is excreted Can lead to ... Total body K + Once gradient is reestablished, ... occurs |
decreased
hypokalemia |
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Important when treating DKA:
-Hyperglycemia, acidosis, low insulin -... leads to excess excretion from kidneys -After correction of acidosis and rehydration, can develop severe ... -Must ... during treatment |
Hyperkalemia
hypokalemia replete K + |
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Increased cell K+ ... – insulin, endogenous catecholamines, beta-2-adrenergic agonists, hypokalemic periodic paralysis, Alkalosis (metabolic > respiratory), hypothermia, barium poisoning, cell growth
increasee cell K+ ... – insulin deficiency, beta-2-adrenergic blockers, hypertonicity, hyperkalemic periodic paralysis, metabolic acidosis (mineral, not organic) and respiratory acidosis, vigorous exercise, digitalis intoxication, succinylcholine, arginine hydrochloride, cell lysis or catabolism |
uptake
efflux |
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With hyperkalemia:
-... [K+] increases minimally (already high) -... [K+] increases more significantly This leads to ... gradient across cell membrane ... polarization of cell with hyperkalemia Membrane is ... and less able to propagate action potential |
Intracellular
Extracellular DECREASED Decreased depolarized |
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With hypokalemia:
-Intracellular [K+] is affected less than extracellular [K+] -This leads to ... gradient across cell membrane -... cell with hypokalemia |
INCREASED
Hyperpolarizes |
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Clinical Hypokalemia:
Serum [K +] < ... meq/L Causes: -K + shifting to ... space -Increased K + loss from GI or kidneys *Diarrhea *Hyperaldosteronism .(Aldosterone keeps ... and dumps ... at renal tubule) |
3.5
intracellular Na+ K+ |
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Hypokalemia:
[K +] < ... meq/L will develop clinical manifestations -Sooner if rapid decline in levels All systems effected, especially cardiovascular |
2.5
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Hypokalemia: neuromuscular
Malaise, Generalized weakness. Fatigue, Hyporeflexia, Cramps, Paresthesias Later – Paralysis, ... (breakdown of cells w/in the body) |
rhabdomyolysis
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Hypokalemia: GI
... – impairing motility of smooth muscle cells. it distends. |
intestinal ileus
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Hypokalemia: Renal
... absorption of ammonia -Contributes to hepatic encephalopathy ... glomerular filtration -increased ... excretion -leads to metabolic ... Urine concentrating defects -Dump more water due to inability to resorb ... Nephrogenic Diabetes Insipidus -Less effective ...: unable to exchange Na (in) for K (out) to keep water |
Increased
Decreased acid alkalemia Na aldosterone |
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hypokalemia: endocrine
-... intolerance |
glucose
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Hypokalemia: Cardiovascular
Exacerbation of ... Orthostatic ... Potentiation of digitalis -(Acts by inhibiting Na/K ATPase) ***Cardiac ...*** EKG: -Dysrhythmia -QT prolongation - ... (triad) |
HTN
hypotension Dysrhythmias ST depression T wave flattening or inversion U waves |
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Hyperkalemia has prominent ... waves
hypokalemia has prominent ... waves |
T
U |
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Hypokalemia tx:
K + repletion -Oral *K+ supplementation (potassium chloride) *Foods rich in potassium *Salt substitute -IV *...; must be diluted before administration <40 mEq/L *May induce local ... and phlebitis if too conc. *10-20meq/L in saline *No more than 40meq in 1hr *20meq IV will increase [K] by 0.25meq/L EKG monitoring |
Slowly
pain |
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Hyperkalemia:
Serum [K +] > ... meq/L Causes: -Oliguric renal failure -Severe hemolysis -Excessive tissue breakdown -“...” –most common *... occurs during blood draw *Cellular breakdown if sample not analyzed within 30min |
5.5
Pseudokyperkalemia Hemolysis |
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Hyperkalemia: Other causes:
... -Reduce aldosterone levels ... -K+ sparing diuretic Other medications -Trimethorprim -Triamterene -Amiloride |
ACE inhibitors
Spironolactone |
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Hyperkalemia:
Derangement of membrane polarization ... rise in K + more well tolerated than ... rise in K + -Can develop cardiac arrest at lower levels if rise is ... ... manifestations most significant |
Slow
rapid rapid Cardiac |
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Hyperkalemia:
GI: ... Neurologic: weakness, paresthesias, arreflexia, ascending paralysis Vascular: ... -Na+ is retained in attempt to rid body of K+ |
n/v/d
HTN |
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Hyperkalemia: cardiac manifestations
look at slide 41 at the same time Early: [K]=6.5-7.5 meq/L -Peaked T waves -Shortened QT interval -Prolonged PR interval Later: [K]= 7.5-8.0 meq/L -QRS widening -Flattened P waves Later: [K]= 10-12 meq/L -QRS degrades into sine wave pattern -Ventricular fibrillation -Complete heart block |
ok
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Hyperkalemia: tx
... “true” hyperkalemia D/C any ... administration Treat hyperkalemia: 1. stabilize cardiac ... (calcium gluconate/calcium chloride IV) 2. shift K+ ... cells (... to ...) (Insulin, Bicarbonate, Beta-agonism [albuterol]) 3. remove K+ from body -urine: diuretics (furosemide) -stool: cation exchange resin (sodium polystyrene) -dialysis: peritoneal or hemodialysis (urgent) |
Confirm
K+ membrane into ECF to ICF |
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look at slides 47-48
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ok
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Lab Studies:
R/o ... -Most common cause hyper-K + Assess renal function -BUN/creat -24-hr urine for creatinine clearance Measure urine K +, Na +, osmolality -Renal excretion is impaired if < ... mEq/L |
pseudohyperkalemia
20 |
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Lab studies:
CBC -Anemia may indicate ... Chemistry -Low bicarbonate will reveal ... -Hyperglycemia suggest ... -Increased CK present with ... |
RBC lysis
metabolic acidosis DM rhabdomyolysis |
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Treatment:
If life-threatening toxicity present, immediately stabilize cardiac membrane -IV ... Identify and remove excess K + intake -d/c oral or parenteral supplementation -Remove K + - containing salt substitutes -Review patient’s diet and change tube feeds or oral intake to low-K + diet |
Calcium
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Treatment:
Enhance K + uptake by cells to shift K + from ECF to ICF -Parenteral ... and ... infusion *20-30min onset *4hr duration -Correct metabolic acidosis with ... -Beta-2 agonist (...) |
glucose and insulin
NaHCO3 albuterol |
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Treatment:
Remove K + from body: -Urine *... *D/C K + -sparing diuretics, ACE-I -Stool *Kayexelate -... if indicated |
Lasix
Dialysis |
