Electrolyte Imbalances- Exam 1 Flashcards
Normal calcium range
8.8 - 10.4 mg/dL
Normal chloride range
96 - 106 mEq/L
Normal magnesium range
1.8 - 2.6 mg/dL
Normal phosphorus range
2.7 - 4.5 mg/dL
Normal potassium range
3.5 - 5 mEq/L
Normal sodium range
135 - 145 mEq/L
Substances whose molecules dissociate into ions when placed in water
electrolytes
electrolyte concentrations differ depending on?
fluid compartments
An abnormality in the concentration of electrolytes in the body
electrolyte imbalance
Electrolytes help to regulate what?
cardiac and neuro function
fluid balance
O2 delivery
acid-base balance
3 most essential electrolytes involved in neuro/cardio-function
K+, Na+, Ca++
Type of electrolyte movement of mainly molecules across a permeable membrane from high concentration to low concentration
Diffusion
Is simple diffusion active or passive?
Passive
Type of electrolyte movement that uses carriers to move molecules
facilitated diffusion
Glucose cannot enter most cell membranes without assistance from?
Insulin
Type of electrolyte movement in which molecules move against the concentration gradient
active transport
External energy is required for what type of electrolyte movement?
Active transport
Give an example of active transport
the sodium-potassium pump
Active transport uses what to move sodium into the cell and potassium out of the cell?
ATP
Sodium plays a major role in what 4 things in the body?
- ECF volume and concentration (osmolality)
- Generation and transmission of nerve impulses
- Muscle contractility
- Acid-base balance
Osmolality AKA
concentration
Excreting more sodium = _____ osmolality
decreased
Excreting less sodium = _____ osmolality
increased
Serum sodium levels >145 mEq/L is known as
hypernatremia
Hypernatremia causes hyperosmolality leading to?
cellular dehydration
What is the body’s primary protection from developing hypernatremia?
Thirst
What part of the brain triggers thirst?
Hypothalamus
Hypernatremia is not really a sodium disorder but a ? disorder
Water
Causes of hypernatremia
Excess Na+ intake
Hypertonic IVF
Fluid deprivation
Heat stroke
Diabetes Insipidus
Serum sodium levels <135 mEq/L is what disorder?
Hyponatremia
Causes of hyponatremia
Disease process
Fluid overload in surgical/sepsis pts
Exercise associated: extreme temps, excess water intake, prolonged exercise
Medications: anticonvulsants, SSRIs
What processes in the body is potassium necessary for?
-Transmission and conduction of nerve and smooth muscle impulses
-Cellular growth
-Maintenance of cardiac rhythms
-Acid-base balance
Causes of hyperkalemia
-Excessive intake
-Internal shift (K+ shifting out of cells)
-Retention
-Crush injury
-Severe burns
Clinical manifestations of hyperkalemia
-Increased cell excitability (wide, flat P wave; prolonged PR interval; widened QRS; tall, peak T waves, depressed ST)
-Muscle weakness
-Abdominal/leg cramps
-Diarrhea
Causes of hypokalemia
-Kidney loss of K+
-GI tract losses
-Increased shift of K+ from ECF to ICF
-Magnesium deficiency
-Metabolic alkalosis
-Dietary deficiencies
Clinical manifestations of hypokalemia
-Hyperpolarization of cells impairing muscle contraction
-Cardiac (slightly peaked P wave, ST depression, U wave, heart blocks, ventricular dysrhythmias)
-Skeletal muscle weakness/leg cramps
-Weakness of resp muscles
-Decreased GI motility
-Impaired regulation of arteriolar blood flow
-Hyperglycemia
How does the P wave present on an EKG if a patient is hypokalemic?
Slightly peaked P wave
How does the PR interval present on an EKG if the patient is hypokalemia?
slightly prolonged PR interval
When is a U wave seen on EKG?
If the patient is hypokalemic
How does the P wave present on an EKG if a patient is hyerkalemic?
Wide and flat P wave
True or False
Potassium is a major ICF cation
True
If your patient is hypo/hyperkalemic, what will the nurse monitor for?
ECG changes
UOP before and after administering K+
How should K+ NEVER be given?
IV push or as a bolus
K+ administration should not exceed ? mEq/hr
10 mEq/hr
Why should K+ never be administered faster than 10 mEq/hr?
To prevent hyperkalemia and cardiac arrest
Functions of calcium in the body
-Formation of teeth and bone
-Blood clotting
-Transmission of nerve impulses
-Myocardial contractions
-Muscle contractions
What is needed in order for someone to absorb calcium?
Vit D
Serum ____ affects total calcium levels
albumin
Calcium balance is controlled by
parathyroid hormone
What is released when calcium levels are low?
Parathyroid hormone
What is released when calcium levels are too high?
calcitonin
What stimulates parathyroid hormone release?
low calcium levels
What stimulates release of calcitonin?
high calcium levels
Calcitonin is produced by?
The thyroid gland
Ca++ : 7.6 mg/dL
What does this result tell us?
Hypocalcemia
Causes of hypocalcemia
-Less Ca++ entering the blood: inadequate Vit D, malnutrition, decreased production of PTH, chronic renal failure
-Excess excretion: renal insufficiency, burns, rhabdo, pancreatitis, cirrhosis, diarrhea, laxative abuse
-Multiple blood transfusions
Clinical manifestations of hypocalcemia
-Tetany
-Laryngeal stridor
-Dysphagia
-Perioral tingling
-Cardiac dysrhythmias
A patient’s serum calcium level shows a result of 11.6, what is this patient’s diagnosis?
Hypercalcemia
Causes of hypercalcemia
-Hyperparathyroidism
-Malignancy
-Excessive intake
-Prolonged immobilization
-Excessive Vit D intake
Clinical manifestations of hypercalcemia
-Neuro: fatigue, lethargy, weakness, stupor, coma, depressed reflexes, confusion, personality changes, psychosis
-ECG changes
-Anorexia, N/V
-Bone pain
-Flank pain from kidney stones
-Polyuria, dehydration
True or False
Phosphate is a primary cation in ICF
False
it is a primary ANION in ICF
where is the majority of phosphorus located?
bones and teeth
Phosphorus is essential to what body functions?
Functions of muscle, red blood cells, and nervous system
(also involved in acid-base buffering, ATP production, cellular uptake of glucose, metabolism of carbs, proteins, and fats)
Phosphate levels are controlled by what?
The parathyroid hormone
Phosphate has a reciprocal relationship with?
Calcium
Maintenance of phosphate levels in the body requires what?
adequate renal function
Causes of hyperphosphatemia
-AKI or CKD
-Chemotherapy
-Hypoparathyroidism
-Tumor lysis
-Rhabdo
-Excessive intake of phosphate or Vit D
Clinical manifestations of hyperphosphatemia
-Often asymptomatic
-Neuromuscular irritability and tetany
-Calcified deposit in soft tissues like joints, arteries, skin, kidneys, corneas
Clinical manifestations of hypophosphatemia
-Often asymptomatic
-CNS depression, confusion
-Muscle weakness, pain
-Cardiomyopathy
-Respiratory failure
Your patient’s phosphorus levels are 1.5, what is their diagnosis?
hypophosphatemia
Your patient’s phosphorus levels are 8.7, what is their diagnosis?
Hyperphosphatemia
Causes of hypophosphatemia
-Malnourishment/malabsorption
-Diarrhea
-ETOH abuse
-Use of phosphate-binding antacids
-During parenteral nutrition with inadequate replacement
Drugs that block vasopressin (ADH)
Convaptan
Tolvaptan
Tol
Normal serum magnesium level
1.8 mg/dL - 2.6 mg/dL
Functions that require magnesium
DNA & protein synthesis
Na+/K+ pump
Normal cardiac function
Where is magnesium absorbed?
GI tract
Where is magnesium excreted?
Kidneys and stool
Where is 50-60% of magnesium contained in the body?
Bone
What causes high serum magnesium levels?
-Increased intake with renal insufficiency
-Txment of migraines or menstrual cramps
-Excess IV magnesium admin
-Decreased output
Clinical manifestations of hypermagesium
ECG changes
Hypotension
Lethargy/Somnolence
N/V
Impaired reflexes
Respiratory or cardiac arrest
Magnesium acts as what at high doses?
A sedative
Magnesium serum levels <1.8 mg/dL is what?
Hypomagnesemia
Low serum magnesium is caused by
Prolonged fasting/starvation
Chronic alcoholism
Fluid loss from GI tract
Prolonged parenteral nutrition w/o supplementation
Diuretics
Large blood transfusion
Clinical manifestations of hypomagnesemia
Hyperactive deep tendon reflexes
Muscle cramps
Tremors
Seizures
Cardiac dysrhythmias
Corresponding hypocalcemia and hypokalemia