Electrolyte disturbances Flashcards
What is present more in intracellular fluid
Potassium (K+)- important for nerve signalling; heart, GI and kidney function
Magnesium (Mg+) - Required for normal nerve and muscle function; bone structure
Phosphate (HPO42-) - Required for ATP(energy) and DNA production; helps control Ca+ levels in body; also found in bones and teeth
What is more in extracellular fluids
Sodium (Na+)- major electrolyte for maintaining osmolarity; affects amount of water in the body; nerve signalling
Calcium (Ca+)- muscle contraction, nerve activation; cell signalling
Chloride(Cl-)- works with Na+ to maintain osmotic balance
Bicarbonate (HCO3)- maintains acid-base balance
Bicarbonate does what
Electrolytes are gained by the diet and lost in a variety of ways; sweat, urine, feces, epithelial sloughing, vomit, diarrhea, abnormalities in endocrine function.
Electrolyte levels in the ECF can be measured by serum chemistry and/or blood gas analysis
Changes in electrolyte levels will affect cell function and viability; especially important and relative concentration of intra-versus extracellular concentrations of sodium, potassium and calcium
Hypokalemia is, causes, and treatment
Low K+ levels
Normally higher level inside cells. In hypokalemia levels drop so the gradient is decreased
Affects ability of muscle cells to depolarize
Symptoms (only occur if there is a significant loss): fatigue, muscle weakness, muscle damage
Causes
Anorexia
GI disease (loss in vomit and diarrhea if very severe)
Loss in urine
Iatrogenic due to chronic use of furosemide
Treatment
Oral supplement
Supplement via IV fluids
Hyperkalemia is, causes, and treatment
Absolute high K+ levels; or increased in the ratio of K+ to Na+
In a normal situation, potassium ions flow out of the cell to reset the muscle
Excess potassium ions in the extracellular compartment results in loss of the ion gradient
Heart muscle is most affected; causes decreased RATE of heart muscle contraction
Causes
Renal disease (impaired excretion of K+)
Urethral obstruction
Addison’s disease- adrenal glands to not produce enough mineralocorticoid (hormone maintains Na+ and K+ levels)
Equine hyperkalemic periodic paralysis disease in Quarter Horses
Iatrogenic- due to inappropriate addition of potassium chloride to fluid therapy
Erroneous calculation- adding too much
Inappropriate mixing of KCl into fluid bags- ALWAYS disconnect bag and mix the KCl well before attaching to IV line
Symptoms
Decreased or irregular heart rate; may lead to decreased blood pressure
Muscle weakness
Tiredness, lethargy
Treatment is fluid therapy to support blood pressure and restore electrolyte balance. Emergency drugs to increase K+ uptake into the cell
Hyponatremia is and causes
Low Na+ levels
In a normal environment, Na+ levels are higher in the extracellular space. Na+ concentration is the main factor maintaining osmolarity of the extracellular fluid. Loss of Na+ causes a decrease in osmolarity and water will shift into cells. This causes cells to swell
Causes
Acute GI disease
Renal disease
Uroperitoneum
Overhydrated with water
Low Na+ levels will also result in a relative increase in K+ levels and patients may also demonstrate muscle weakness
Hypophosphatemia is
Low phosphate levels
Phosphate is required for production of ATP. when phosphate levels are low, there is lack of ATP production and result in weakness
Most commonly seen in the condition Refeeding Injury
In the event of starvation, followed by too rapid reintroduction of food
Also seen during calcium dysregulation
Treatment is by increased dietary intake
hypernatremia is and physiology stages
High Na+ levels
Most common cause is SALT TOXICOSIS
Most common in pigs
Due to ingestion of excess amounts of salt; or normal salt diet in the absence of water
Pathophysiology
Stage 1
Normal to high salt diet
lack/decrease of water
Na+ distributes throughout ECF
Na+ shifts into intracellular space due to equilibrium forces
Stage 2
Ingestion of water/intake fluid
Water goes from extracellular space into intracellular space due to high concentration of Na+ inside cells
Swelling of cells
Stage 3
Cerebral edema and compression occur as a result of restricted cranium space
Clinical signs are neurological: central blindness, lack of proper responses, lethargy → circling → twitching → seizures
Treatment is by very slow re-introduction of water
Prevention: appropriate mixing of diets for livestock; use of species-specific salt blocks; ensure access to water; avoid sudden water intake after period of dehydration
Hypocalcemia is, causes, and treatment
Low Ca+ levels
Half of the Ca+ in blood is bound to albumin; the other half is “free Ca+”; hypocalcemia is decreased in free Ca+ levels
Intracellular Ca+ ions are released during muscle contraction- important for the STRENGTH of muscle contraction
Ca+ entering neurons is responsible for resting
Lack of Ca+ results in decreased muscle contraction
Many causes of hypocalcemia
Parathyroid disease- decreased parathyroid hormone
Lack of dietary intake
Vitamin D deficiency
Vitamin D is required to absorb calcium via the intensitnes
Lack of sunlight
Required to activate vitamin D
Increased demand for Ca+
Late gestation pregnancy
Heavy lactation
Chronic hypocalcemia
Slow, gradual deficiency
Nutritional deficiency; vit D deficiency; hormonal imbalance
Body has time to adjust. Restless parathyroid hormone which causes release of calcium from bone
Will lead to OSTEOPOROSIS= loss of bone density due to decreased calcification; bones become soft and brittle; may bend; increased risk of fracture
Seldom life threatening
Acute hypocalcemia is and clinical signs
Body cannot adjust fast enough
Low Ca+ in ECF causes neurons and muscle cells to depolarize faster
Heart muscles cannot contract efficiently
Heart muscles cannot contract efficiently
Clinical signs
Convulsions
Arrhythmias
Muscle tetany
Can be rapidly fatal from cardiac failure
Treat as an emergency
Can cause
Milk fever
Fresh cows (<72h after parturition)
Can not meet Ca2+ demands of milk production
Eclampsia
Hypercalcemia is
High extracellular free Ca+
Pathophysiology
Acute hypercalcemia causes sudden increase in muscle contraction
Prolongs rest period in neurons→ neurons cannot be reactivated
Results in sudden spurt of muscle contraction (muscle tetany; tachycardia; cardiac arrhythmia); followed by sudden weakness/collapse
If slow increase in calcium, will see calcification of kidneys and other tissues
Most common in dogs, cats
There are MANY causes of hypercalcemia.
Causes of hypercalcemia
Idiopathic Hypercalcemia
Hyperparathyroidism–Increased parathyroid hormone production.Parathyroid hormone increased calcium absorption from diet and releases calcium stores from bone
Hypercalcemia of Malignancy–Certain cancers, will cause the body to produce excessive parathyroid hormone.
Vitamin D Toxicity- Vitamin D increases absorption and activation of bone stores. Occurs with over - supplementation; improper food formulation; accidental ingestion
Also chronic kidney disease
Hyperadrenocorticism (aka Cushing’s Disease)
Iatrogenic hypercalcemia
Iatrogenic hypercalcemia
Occurs with inappropriate administration
of calcium-gluconate by intravenous injection
TECH NOTE on administering calcium by injection
Applies to SQ and IV administration
Intravenous is always be given SLOWLY
Continuously monitoring heart rate and rhythm during administration and for short period after; continuous auscultation and/or ECG
Listen for tachycardia and arrhythmia→means slow down administration rate
Giving too fast will cause sudden cardiac failure and instant death
