Electrolytes Flashcards
(46 cards)
1
Q
The role of electrolytes in the body
A
- Maintain osmotic pressure
- Water distribution
- Maintain blood pH
- Enzyme cofactors
- Participate in redox reactions
- Involved with the heart and other muscles
2
Q
Major cation of the extracellular fluid
A
Sodium
3
Q
Function of sodium
A
- Maintain normal distribution of water and osmotic pressure in extracellular fluid
- Contributes to the osmolality of blood
- Included in the anion gap calculation
4
Q
Organ that regulates sodium
A
Kidneys
5
Q
How much sodium is reabsorbed in the kidneys?
A
60-70%, along with HCO-3 and water
6
Q
Adult sodium reference ranges (General)
A
- Serum or plasma: 136 – 145 mEq/L ( 136 – 145 mmol/L)
- Abnormal high >145: Frequently in the 150s rarely in the 160s
- Abnormal low 160
7
Q
Causes of Hypernatremia
A
- Profuse sweating
- High salt intake
- Decrease ADH
8
Q
Causes of Hyponatremia
A
- Depletional due to vomiting, diarrhea, polyuria
2. Dilutional due to retention of water (edema, cardiac failure)
9
Q
What is the major intracellular cation?
A
Potassium
10
Q
Clinical signs of low extracellular potassium
A
- Muscle weakness
- tachycardia
- Irritability
- Paralysis
11
Q
Clinical signs of high extracellular potassium
A
- Mental Confusion
- Bradycardia
- Weakness
- Numbness
- Tingling
12
Q
How does potassium move through the kidneys?
A
Almost completely reabsorbed in the proximal tubules, then secreted in the distal tubules
13
Q
Adult potassium reference ranges
A
- Serum: 3.5 – 5.1 mEq/L ( 3.5 – 5.1 mmol/L)
- Plasma: 3.5 – 4.5 mEq/L (3.5 – 4.5 mmol/L)
- Panic Value (critical)
< 3.1 or >5.9
14
Q
Causes of Hyperkalemia
A
- IV infusion of K+ solutions
- Renal failure
- DKA
15
Q
Causes of Hypokalemia
A
- Starvation
- Alkalosis
- Vomiting, diarrhea,
- Slight hypokalemia intestinal fistulas
16
Q
What is the major extracellular anion?
A
Chloride
17
Q
Function of Chloride
A
Water distribution, osmotic pressure
18
Q
Movement of Chloride in the kidneys
A
- Passively reabsorbed with sodium in the proximal tubules
2. Actively reabsorbed in the ascending limb of Henle by the chloride pump
19
Q
Adult Chloride Reference ranges (general)
A
- Serum or plasma: 96 - 108 mEq/L ( 96 - 108 mmol/L)
- Abnormal high >108
> 110 often seen in premies - Abnormal low <96
20
Q
Causes of Hyperchloremia
A
- Dehydration
- Kidney disease
- Salicylate intoxication (>30 ug/dL)
21
Q
Causes of Hypochloremia
A
- Vomiting
- Salt-losing nephritis
- Metabolic acidosis
22
Q
TCO2 (total CO2 and Bicarbonate) Constituents
A
- Physiologically dissolved CO2
- CO2 bound to amine group in proteins
- HCO3 or CO3
- Carbonic acid
- Bicarbonate ions make up about 98% of TCO2 in plasma
23
Q
Adult CO2 Refernce ranges (General)
A
- Serum or plasma: 22 - 29 mEq/L ( 22 - 29 mmol/L)
- Abnormal high >29
Frequently in the 30 - 40s - Panic Value (critical)
< 10 or > 40
24
Q
Causes of Hypercapnia
A
- Metabolic alkalosis due to vomiting
2. Hypokalemia states
25
Causes of hypocapnia
1. Renal diseases, diarrhea
| 2. Respiratory alkalosis
26
Physiochemical state of calcium in normal plasma
1. 50% free
2. 40% protein bound
3. 10% complex
27
Physiochemical state of Phosphate in normal plasma
1. 55% free
2. 10% protein bound
3. 35% complex
28
Physiochemical state of Magnesium in normal plasma
1. 55% free
2. 30% protein bound
3. 15% complex
29
Calcium Location
1. 99% in bones and teeth as hydroxyapatite
30
Calcium functions
1. Nerve impulse transmission
2. Cofactor in certain enzymes
3. Coagulation of blood
4. Skeletal mineralization
5. Preserve cell membrane integrity and permeability
31
Calcium regulation
1. Small intestine, kidneys, skeleton
| 2. Hormones: parathyroid hormone (PTH), 1,25-dihydroxycholecalciferol: vitamin D, calcitonin
32
Adult Calcium Reference Ranges (general )
1. Serum or plasma: 8.4 – 10.2 mg/dL ( 2.10 – 2.55 mmol/L)
2. Panic Value (critical)
11. 8 mg/dL
33
Ionized (free) Calcium significance
1. Free calcium (Ca2+) is the best indication of calcium status bc it is biologically active and tightly regualted by PTH and vitamin D
2. Measured by ISE in whole blood or serum
3. temperature and pH dependent
34
Causes of Hypercalcemia
1. Hyperparathyroidism
2. Cancer metastatic to the bone, lung and kidney
3. Multiple myeloma: plasma cell dysgrasia
4. Sarcoidosis: benign disease causing increases in plasma proteins and thus calcium
5. Hyperthyroidism
35
Causes of Hypocalcemia
1. Hypoparathyroidism
2. Hypothyroidism
3. Vitamin D deficiency
4. Malabsorption
5. Renal failure
6. Rickets
7. Osteomalacia
36
Phosphorus Location and form
1. 100% phosphate
2. Equally distributed intra and extracellularly
3. Intracellular phosphorus occurs as a component of macromolecules such as phospholipids and phosphoproteins
37
Phosphate Adult Reference Ranges
1. Serum: 2.7 -4.5 mg/dL
38
Causes of Hypophosphatemia
1. Intracellular Shifts
2. Lowered renal PO4 threshold
3. Decreased intestinal PO4 absorption
4. Intracellular PO4 loss
39
Causes of Hyperphosphatemia
1. Decreased renal exretion
2. Increased PO4 intake
3. Increased extracellular PO4 load
40
Magnesium Location and Form
1. 55% is in the skeleton and intracellular
41
Magnesium function
1. Cofactor for more than 300 enzymes
3. Required for E-S formation
3. Activator for many enzyme systems
42
Magnesium Reference ranges for Adults
1. Serum (in three different units)
0.66 – 1.07 mmol/L
1.32 – 2.14 mEq/L
1.60 - 2.60 mg/dL
Frequently see values >5.0 mg/dL in patients treated for pregnancy induced hypertension using magnesium sulfate.
43
Causes of Magnesium deficiency
1. Impairment of neuromuscular function
2. Hyperirritability
3. Tetany
4. Convulsions
5. EKG changes
6. Hypertension
7. MI
8. Cardiac dysrhythmia
9. Coronary vasospasm
10. Premature arteriosclerosis
44
Magnesium deficiency DDX
1. Hypercalcemia and hypocalcemia
| 2. Evaluate parathyroid function in renal failure, and disorders of bone and mineral metabolism
45
Conditions associated with low blood levels of magnesium include:
1. chronic alcoholism
2. childhood malnutrition
3. Diabetic acidosis (during treatment)
4. malabsorption
5. acute pancreatitis
6. hyperthyroidism
7. Chronic glomerulonephritis
8. Aminoglycoside treatment
9. Primary hypoparathyroidism
46
Causes of Hypermagnesemia
1. Excessive intake:
a. antacids
b. rectally
c. Purgation (cleansing)
d. parenterally ( treatment of pregnancy induced hypertension or treatment of magnesium deficiency)
2. End Stage Renal Disease or failure (reduced excretion)
3. Addison disease – aldosterone
4. Hypothyroidism
