Electroyltes
Terms
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Na, most abundant ECF cation.
Maintains osmotic pressure, acid-base balance, transmits nerve inpulses. -
Sodium
Normal 136 to 145 mEq/L - Changes in sodium most often reflect changes in what?
- water balance
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If no large Na load:
Hypernatremia suggests need for_________, and hyponatremia suggests over ______. -
water
over hydration - Hyponatremia causes 1.
- 1. In Isovolema: Inappropriate ADH release, diuretics, Ace
- Hyponatremia cause 2.
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2. In Hypovolemia:
Water loss through skin, GI, 3rd space, peritonitis. - Hyponatremia cause 3.
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3. In Hypervolemia:
The fluid that remains dilutes the Na, CHF, Cirrhosis, Nephrotic Syndrome - Hypernatremia causes:
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Dehydration
low H20 intake
Cushing's
Diabetes insipidus
Primary aldosteronism
steriods
some narcotics, HCTZ - K, major ICF cation. GI tract is rich in K, insulin promotes cellular uptake of K, aldosterone affects it's tissue distribution and regulates it's renal excretion. Maintains rate and force of heart conduction, nerve conduction ,muscle function ,acid base
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Potasium
Normal 3.5 to 5.0 mEq/L - K ardiac & K ick
- K affects cardiac and skeletal muscle
- Hypokalemia causes:
- low K intake, increased renal excretion, GI and biliary loss.
- Drugs that cause hypokalemia:
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Lasix, thiazides- DIURETICS
steroids, RENAL EXC.
bicarb, ALKALOSIS
glucose, insulin, K SHIFT into CELLS. - Hyperkalemia causes:
- K shift out of cells, ACIDOSIS, crush injuries, decreased renal excretion, hemolysis, phlebotomy(?)
- Drugs that cause hyperkalemia:
- Spironolactone, triamterene, EFFECT on RENAL TUBULES, Tetracycline, TOXICITY, Antineoplastice, RAPID CELL LYSIS, Pen-G, HIGH K in drug content, Heparin- ESP in RENAL INSUF.
- EKG changes in Hyperkalemia:
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Prolonged P-R interval-
Wide QRS-
Elevated T Waves- - EKG changes in Hypokelemia:
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ST segment depression-
Flattened T wave-
also: hypokalemia potentiates Digoxin. - C02, measures kidney function, are lungs compensating for metabolic problem.
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Co2
Normal 22-30 mEq/L
Panic below 15 and greater than 50.
If this is abnormal- look at other eylectolytes - CO2 is bound by proteins as bicarbonate, carbonate an dcarbonic acid and a general guide to the body's buffering capacity.
- Total CO2 content is a bicarbonate and base solution that is regulated by the kidneys. Since over 80% of CO2 is present in the form of bicarbonate this test is a good reflection of bicarb level.
- Low C02 Causes:
- metabolic acidosis--acute renal failure--drugs--bicarb--aldosterone--hydorcortisone--thiazides--metolazone(diuretic effect)
- High CO2 Causes:
- metabolic alkalosis--chronic resp. distress--drugs--methicillin--nitrofurantoin--tetracycline--triamterene--phenformin
- Ca, 99% in teeth and bones, regulated by parathyroid hormone, calcitonin, vit D, androgens, need for bone and teeth formation, clotting, muscle contraction and nerve imipulse conduction
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Calcium
Normal 8.6 - 10.0 mg/dL
Panic below 7 and greater than 12. Always check albumin when calcium is low. - Total calcium is 55% bound mostly to albumin and 45% ionized or free which is considered to be________ _______ calcium.
- physiologically active
- Hypercalcemia three causes representing 90% of all causes:
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Hyperparathyroidism--
neoplasms--
granulomatous disease-- - Other causes of Hypercalcemia:
- Paget's--Prolonged immobilization--hypophosphatemia--vit. D intox--diuretics--ENDOCRINE, thyroid--cushings--adrenal insufficiency
- Hyponatremia will do what to total calcium?
- Increase total calcium.
- Hypernatremia will do what to total calcium?
- Decrease total calcium.
- Magnesium, Ma, hangs out in cartliage and bone, regulates muscle contraction and neuromuscular control, regulates blood clotting.
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Magnesium
Normal 1.3 to 2.5 mEq/L --
or-- 1.8 to 3.0 mg/dL - Signs of elevated Magnesium:
- neuromuscular depression--hypotension--difficulty in urination--CNS depression--Coma--
- Cause of high magnesium:
- Usually iatrogenic (from treatment by MD)--antacids, enemas, TPN, lithium, magnesium ro preterm labor or eclampsia.
- Decreased Magnesium is usuallyu due to________.
- GI or renal disturbance--malabsorption--GI fluid loss--renal disease--nurtritional--endocrine--metabolic.
- Phosphorus, involved in metabolism of carbohydrates and fats, acid base balance, nerve and muscle activity and urinary buffer.
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Phosphorus
Normal 2.7 to 4.5mg/dL - Elevated Phosphorus is most commonly due to__________.
- Renal Failure, acute or chronic, increased tubular reabsorption.
- Endogenous reasons for elevated phosphorus include:
- Reasons for high tissue turn over as in neoplasms, tissue breakdown, bone disease, childhood.
- Exogenous reasons for elevated phosphorus include:
- Increased phosphate load with enemas, laxatives, infusions.
- Low phosphorus causes:
- Renal or intestional loss-- diuretics--acute gout--dialysis--Decreased intestional absorption from malnutrition or malabsorption--Intracellular shift of phosphat in ETOH--DM--Salicylate poisening
- Low phosphorus and low magenesium are often associated with an elevation of ______________.
- Calcium
- BUN, Blood urea nitrogen. Dietary protein is digested and broken down into ammonia where the liver then converts that to urea and the kidneys excrete the urea.
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BUN
Normal 5 to 20 mg/dL
Panic level greater than 100 - Elevated BUN is accumulation of nitrogen known as_________.
- Azotemia.
- Pre-Renal azotemia:
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CHF--
Salt and water depletion--
Shock-- - Post-Renal azotemia:
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Obstruction of UT--
Acute MI--
Stress--
GI bleed--
Increased protein catabolism-
High Protein diet-- - Decreased BUN causes:
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Liver damage--
Increased utilization of protein--
Diet--
Nephrotic syndrome--
SIADH-- - Creatinine, byproduct of muscle creatine phosphate used for energy. The amount made daily is proportional to muscle mass, more specific indicator of renal disease than BUN.
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Creatinine
Normal 0.8 to 1.5 mg/dL - Is a decreased Cr a problem?
- No, this can be normal with decreased muscle mass.
- Elevated Cr causes:
- Diet--Muscle disease--GU obstruction--prerenal azotemia, postrenal aztomia--impaired kidney function
- How much loss of renal function is neede to increase the creatinine from 1.0 to 2.0?
- 50% loss of renal function