Electrolyte Imbalance + Normal Ranges and Disturbances for Common Electrolytes
Published: 14 May 2018
Published: 14 May 2018
Look at a few of the most common examples:
Patients suffering from congestive heart failure often end up as rebound hospitalisations due to abnormal sodium and potassium levels.
A grandmother with diabetes or hypertension may eventually find herself on the business end of a calcium or magnesium imbalance.
The toddler with explosive diarrhoea and the elite Australian athlete, otherwise wildly unalike, both routinely find themselves on the business end of electrolyte imbalances.
A proper understanding of these imbalances is essential for current management and future prevention.
Electrolyte imbalances occur across many different diagnostic categories.
In Australia, harsh summer environmental exposure, with resulting dehydration, is just one example of a potential root cause1; sadly, more Australians are killed from the ill-effects of heatwaves than all other natural hazards, combined.2
This is just potential cause, however. There are hundreds of other root causes for fluid and electrolyte imbalances, including:
Put simply, electrolytes are naturally occurring minerals with an electric charge.
They exist in the human body and they are also present in food and fluids we ingest every day.
Potassium, magnesium, and sodium are several commonly known electrolytes, but they are not alone; calcium and phosphate also play critical roles. These electrolytes serve crucial functions in the body such as keeping water in balance, regulating the body’s base pH levels, and moving nutrients and waste to and from cells.7
Electrolyte imbalance can be a marker of many common diseases and illnesses.
Assessing a patient for electrolyte imbalance can give practitioners an insight into the homeostasis of the body and can serve as a marker or proxy for the presence of other illnesses.
Practitioners can use physical examination, ECGs, serum electrolyte levels and pathologic signs as methods to assess for electrolyte imbalance.
Certain symptoms can even point to a specific electrolyte that is out of balance in a patient. For example, confusion is a common symptom of hypocalcaemia.8
By using the aforementioned examination techniques, practitioners can pinpoint which electrolytes are out of balance and thus craft a more effective treatment plan for the patient.
There are many different symptoms of electrolyte imbalance that can present themselves in a patient.
Dehydration does not occur at some standardised setpoint; it is caused by consuming too little fluid for the present needs of the body.
This can happen by either decreased consumption or outside factors that cause the body to require more water than normal.
When the body becomes dehydrated, certain symptoms can arise such as dry mouth or increased thirst. However, these are not universal indicators of dehydration. In fact, they may not be clinically useful for diagnosing dehydration.9
Whenever the body is overhydrated or underhydrated – or when the body’s filtration systems do not operate normally – electrolytes no longer function as they should.
Abnormal electrolyte levels can occur anytime the body’s fluid levels fluctuate outside of norms such as after serious burns, vomiting, diarrhoea, and excessive sweating.
Infrequently, overhydration can also result in serious repercussions. Certain medicines and dysfunctions of the liver and kidneys can also throw the body’s electrolytes out of normal range.
While absolutely anyone can develop an electrolyte disorder, the older population are at an increased risk.
Some factors that can increase the risk of an electrolyte imbalance in older populations include:10
Within these risk factors there is increased risk to those who use certain combinations of diuretics and to those with diabetes. Patients who use both thiazides and benzodiazepines are associated with higher rates of hyponatremia, which in turn, is associated with a higher mortality risk.10
The use of angiotensin-converting enzyme inhibitors (ACE inhibitors), potassium and calcium supplements and certain hormones, which are classified as ‘potassium-sparing’, can also lead to imbalances.
Other conditions that can increase the risk of an electrolyte disorder include:
There are several types of tests that can be used to diagnose electrolyte imbalance.
Each type of test has its own pros and cons for detecting various types of imbalances. Here are just a few of the ways practitioners test for electrolyte dysfunction:7
Individuals who experience serious symptoms, tachycardia, mental confusion, sunken eyes, reduced elasticity of the skin and/or a loss of consciousness need immediate medical attention.
Individuals who dehydrate through exercise or activity can typically look to the electrolyte restoration possibilities of sports drinks. An excellent guide to the use of such sports drinks was put out by Australia’s AIS Sports Supplement Framework, an initiative of AIS Sports Nutrition.6
Between these two extremes is a vast middle ground with some patients requiring rapid – though not emergency – medical assistance, and some patients self-correcting without ever knowing anything more than that they ‘felt a bit off’.
Although there are many trace elements that keep the body healthy, several important electrolytes can severely affect patients when they are either too high (hyper…) or too low (hypo…).
Understanding what each electrolyte does, what happens when there isn’t enough of one or too much of another, is essential knowledge for nurses and can help guide electrolyte therapy.
Sodium, or Na, is one of the most important electrolytes in the body and is responsible for a number of important functions, mostly related to fluid and water regulation. The normal accepted range for sodium is 134 to 145 mEq/L.
Hyponatraemia is considered to be a serum sodium below 134 mEq/L. A common cause of hyponatraemia is water retention due to cardiac or renal or hepatic failure.
Other causes of hyponatraemia include some medicines, psychogenic polydipsia (excessive water intake) and syndrome of inappropriate ADH (antidiuretic hormone) secretion, and chronic or severe vomiting and diarrhoea.
Common symptoms of hyponatraemia include confusion, agitation, nausea and vomiting, muscle weakness, spasms or cramps.
Hypernatraemia is defined as a serum sodium greater than 145 mEq/L.
Causes of hypernatraemia can be thought of simply as anything that leads to excessive water loss or salt gain. For example, water depletion or dehydration may be caused by vomiting or diarrhoea.
Excessive ingestion of sodium is rare, but the administration of infusions containing sodium such as sodium chloride or sodium bicarbonate may lead to hypernatraemia.
Clinical features of hypernatraemia may include fever, irritability, drowsiness, irritability, lethargy and confusion.
Potassium, or K, is responsible for the functioning of excitable tissues such as skeletal and cardiac muscle and nerves. The normal range for potassium is 3.5 to 5.0 mmol/L.
Hypokalaemia is defined as a serum potassium less than 3.5 mmol/L. A low serum potassium may be caused by decreased oral intake, increased renal or gastrointestinal loss of potassium, or a shift of potassium within the body’s fluid compartments (from outside the cell where it should be, to inside the cell).
Common clinical features of hypokalaemia range from muscle weakness and ileus (lack of peristalsis), to serious cardiac arrhythmias such as ventricular tachycardias.
Hyperkalaemia, a serum potassium greater than 5.0 mmol/L, may be caused by excessive intake, tissue damage from burns or trauma, medicines such as potassium sparing diuretics, and most commonly, due to renal failure.
Magnesium, or Mg, is another element that has a strong effect on muscle contractions. The normal plasma range for magnesium is 0.70 to 0.95 mmol/L.
Hypomagnesaemia, or a decreased plasma magnesium level, may be caused by decreased intake or increased loss of magnesium. Clinical signs include confusion, irritability, delirium, muscle tremors and tachyarrhythmias.
Hypermagnesaemia is when the level of magnesium in the blood is above the normal range. Fortunately, this is uncommon. Symptoms include poor reflexes, low blood pressure, respiratory depression, and cardiac arrest. This is usually caused by the excessive administration of magnesium and lithium therapy, often in the presence of renal failure.
Calcium, or Ca, is an important element in the body as it helps to control nerve impulses, muscle contractions and has a role in clotting. The serum calcium range should be between 2.20 to 2.55 mmol/L when normal.
Hypocalcaemia, the presence of low serum calcium levels in the blood, is relatively rare because the bones always act as a reservoir for this electrolyte. However, parathyroid disease, vitamin D deficiency, septic shock and acute pancreatitis can cause this problem. Some symptoms include tetany (involuntary muscle contraction), mental changes and decreased cardiac output.
Hypercalcaemia, elevated levels of calcium in the blood, again arises from parathyroid problems and vitamin D issues. Signs of this form of electrolyte imbalance include nausea, vomiting, polyuria, muscular weakness and mental disturbance.
Phosphate, or P, is an electrolyte used in several functions throughout the body. Although a phosphate imbalance isn’t as well known as some of the other imbalances, it can still cause problems with your patient’s condition. The normal range of phosphate in the plasma is generally between 0.8 to 1.3 mmol/L. The signs and symptoms of either abnormal reading are usually subtle.
For hypophosphataemia, when levels of phosphate in the blood are below the normal range, the symptoms generally include muscle weakness, heart failure, seizure, and coma. It may be caused by vitamin D deficiency, hyperparathyroidism, or alcoholism. Hypophosphataemia may also be present, in addition to other electrolyte disturbances, in re-feeding syndrome, which is associated with the commencement of total parental nutrition (TPN).
Hyperphosphataemia, when levels of phosphate in the blood are above the normal range, can be caused by kidney disease, parathyroid issues, and metabolic or respiratory acidosis. Symptoms are usually not present, and they are related to hypocalcaemia. Renal patients can experience hardened calcium deposits when this condition goes untreated.
Improper management of electrolyte imbalances can worsen the baseline condition.
For example, overly aggressive treatment of hypo- and hyperkalemia can cause cardiac arrhythmias.11
Some additional complications that can be caused by electrolyte imbalance include:11
Many electrolyte imbalances self-correct without any ill-effects. A simple drink of water can correct others.
However, electrolyte imbalances can be much more than just a nuisance – they can cause severe complications when left untreated. It is important for practitioners to correctly test for and diagnose electrolyte imbalances in order to treat them in an appropriate and timely fashion.