Clinical Quick Reference Monthly Newsletter
Ed. 1 - April 2022 - Clinical Concept Review/Electrolytes
Clinical Quick Reference Guides - Clinical Concept Review Electrolytes
This review will help clarify the electrolytes and their importance in clinical situations.
What are Electrolytes?
Electrolytes are minerals in the blood and other body fluids that carry an electric charge.
Electrolytes are essential for basic life functioning, e.g. maintaining electrical neutrality in cells, generating and conducting action potentials in the nerves and muscles.
Electrolytes affect how the body functions in many ways, including:
The amount of water in the body
The blood pH
Muscle function
Other important processes
Sodium, potassium, and chloride are often considered the most clinically significant electrolytes— followed by magnesium, calcium, phosphate, and bicarbonate.
Let’s take a closer look at the most common electrolytes.
Sodium
High or low levels of electrolytes disrupt normal bodily functions and can lead to life-threatening complications. Sodium is one of the most important electrolytes in the extracellular fluid.
It is responsible for maintaining the extracellular fluid volume, and also for regulation of the membrane potential of cells. Sodium is exchanged along with potassium across cell membranes as part of active transport. *Among the electrolyte disorders, hyponatremia is the most frequent. This occurs when the serum sodium level is less than 135 mmol/L. Hyponatremia has neurological manifestations (S/Sx: headaches, confusion, nausea, delirium).
Hypernatremia presents when the serum sodium levels are greater than145 mmol/L. Symptoms of hypernatremia include tachypnea, sleeping difficulty, and feeling restless. Rapid sodium corrections can have serious consequences like cerebral edema and osmotic demyelination syndrome.
Potassium
Potassium is mainly an intracellular ion. The sodium-potassium adenosine triphosphatase pump has the primary responsibility for regulating the homeostasis between sodium and potassium. It pumps out sodium in exchange for potassium, which moves into the cells.
Potassium disorders can cause cardiac arrhythmias. Hypokalemia occurs when serum potassium levels under 3.6 mmol/L; S/Sx: weakness, fatigue, and muscle twitching present in hypokalemia.
Hyperkalemia occurs when the serum potassium levels are above 5.5 mmol/L, which can result in arrhythmias. Muscle cramps, muscle weakness, rhabdomyolysis, myoglobinuria are presenting signs and symptoms in hyperkalemia.
Calcium
Calcium has a significant physiological role in the body, as it is:
*involved in skeletal mineralization,
*contraction of muscles,
*the transmission of nerve impulses,
*blood clotting,
and secretion of hormones.
It is mostly present in the extracellular fluid. Absorption of calcium in the intestine is primarily under the control of the hormonally active form of vitamin D.
Hypocalcemia is low calcium levels in the blood serum. The normal range is 2.1–2.6 mmol/L with levels less than 2.1 mmol/l defined as hypocalcemia. Mildly low levels that develop slowly often have no symptoms. Symptoms may include numbness, muscle spasms, seizures, confusion, or cardiac arrest.
Magnesium
Magnesium is mainly involved in ATP metabolism, contraction and relaxation of muscles, proper neurological functioning, and neurotransmitter release. As muscle contracts, calcium re-uptake by the calcium-activated ATPase of the sarcoplasmic reticulum is brought about by magnesium. Hypomagnesemia occurs when the serum magnesium levels are less under 1.46 mg/dl. It can present with alcohol use disorder and gastrointestinal and renal losses— ventricular arrhythmias, which include torsades de pointes seen in hypomagnesemia
Bicarbonate
The acid-base status of the blood drives bicarbonate levels with the kidneys predominantly regulating bicarbonate concentration (and are responsible for maintaining the acid-base balance). Diarrhea (prolonged episodes) can result in loss of bicarbonate, which could precipitate an imbalance in acid-base regulation.
Chloride
Chloride is an anion found predominantly in the extracellular fluid. Hyperchloremia can occur due to gastrointestinal bicarbonate loss. Hypochloremia presents in gastrointestinal losses like vomiting or excess water gain like congestive heart failure.
Phosphorus
Phosphorus is an extracellular fluid cation. Approximately eighty-five percent of the total body phosphorus is in the bones and teeth in the form of hydroxyapatite; the soft tissues contain the remaining 15%. Phosphate plays a crucial role in metabolic pathways.
Phosphorus imbalance may result due to three processes: dietary intake, gastrointestinal disorders, and excretion by the kidneys.
Medical Terminology
Getting to know these terms will help reinforce the above material.
Ion - atom or group of atoms that has an electric charge. Ions with a positive charge are called cations. Ions with a negative charge are called anions.
Anion - Ions with a negative charge.
Cation - Ions with a positive charge.
Physiology
Becoming familiar with these body systems will help increase understanding of body processes.
sodium-potassium adenosine triphosphatase pump
sodium and potassium move against the concentration gradients
the Na+ K+-ATPase pump maintains the gradient of a higher concentration of sodium extracellularly and a higher level of potassium intracellularly
this concentration gradient is crucial for physiological processes in many cells/organs + plays an ongoing role in stabilizing resting membrane potential of cells
Disclaimer: The above study guide represents study materials, always seek and follow the advice of your medical provider for any acute or chronic medical issues or questions.