An electrolyte is a substance that produces an electrically conducting solution when dissolved in water. Electrolytes carry a charge and are essential for life. All higher forms of life need electrolytes to survive.
Contents of this article:
Here are some key points about electrolytes. More detail and supporting information is in the main article.
- Electrolytes are vital for the normal functioning of the human body
- Fruit and vegetables are good sources of electrolytes
- Electrolytes include sodium, potassium, calcium and bicarbonate
- The symptoms of electrolyte imbalance can include twitching, weakness and, if unchecked, seizures
- Elderly people are particularly susceptible to electrolyte imbalance
- Hypercalcemia - too much calcium - is common in cancer patients
- Kidney disease and severe dehydration can cause electrolyte imbalance
- Patients with diabetes or heart failure have an increased risk of low sodium levels.
What are electrolytes?Electrolytes regulate our nerve and muscle function, our body's hydration, blood pH, blood pressure, and the rebuilding of damaged tissue. Various mechanisms exist in our body that keep the concentrations of electrolytes under strict control.
Fresh fruits and vegetables are rich in electrolytes.
Our muscles and neurons are sometimes referred to as the "electric tissues" of the body. They are reliant on electrolyte movement between extracellular, interstitial and intracellular fluid (fluid inside, outside or between cells).
A muscle contraction needs calcium (Ca2+), sodium (Na+) and potassium (K+) to be present. Wrong electrolyte levels can lead to either weak muscles, or muscles that contract too severely.
Our heart, muscle and nerve cells use electrolytes to maintain voltages across their cell membranes and to carry electrical impulses to other cells.
The level of an electrolyte in the blood can become too high or too low. Body electrolyte levels tend to alter when water levels in the body change - when our level of hydration goes up or down.
Electrolyte levels are kept constant by our kidneys and several hormones. When we exercise we sweat and lose electrolytes, mainly sodium and potassium.
To maintain constant electrolyte concentrations in our body fluids, these electrolytes must be replaced. Fresh fruits and vegetables are good sources of sodium and potassium and replace lost electrolytes. Excess electrolyte levels in our blood are filtered out by our kidneys.
If we do not consume the necessary levels of electrolytes there can be health consequences. The most common imbalances are hypernatremia and hyponatremia (too much or too little sodium), and hyperkalemia and hypokalemia, (excessive and insufficient levels of potassium).
Doctors refer to a low electrolyte level with the prefix hypo- and to a high level with the prefix hyper-.
Elderly people and electrolyte levels
As older people are more susceptible to dehydration and over-hydration, they are also more prone to abnormal electrolyte levels. This is because our kidneys do not work as efficiently when we become elderly.
Some seniors who have mobility problems, and do not have daily access to help, may experience fluctuating levels of food and fluid intake - these two factors can have an impact on their levels of electrolytes.
Symptoms of electrolyte imbalance
Electrolyte imbalance can cause bone disorders.
An electrolyte imbalance can be manifested in several ways. The symptoms will depend on which electrolyte is out of balance, and whether that level is too high or too low.
An altered level of magnesium, sodium, potassium,or calcium may produce one or more of the following symptoms:
- Irregular heartbeat
- Bone disorders
- Blood pressure changes
- Nervous system disorders
- Fatigue, lethargy
- Muscle spasm.
Signs and symptoms may include: frequent urination, irregular heart beat, lethargy, fatigue, moodiness and irritability, nausea, stomach pain, vomiting, extreme muscle weakness, being very thirsty, dry mouth or throat, total loss of appetite, coma, confusion and constipation.
As these symptoms may also be the result of the cancer itself or cancer treatment, it is sometimes difficult for hypercalcemia to be identified straight away.
Causes of electrolyte imbalance
- Kidney disease
- Vomiting for prolonged periods
- Severe dehydration
- Heatwaves - A report found that the number of cases of electrolyte imbalances increases significantly during heatwaves1
- Acid/base (pH) imbalance (acid and alkaline balance in the body is disproportionate)
- Congestive heart failure
- Cancer treatment
- Some drugs, such as diuretics or ACE inhibitors. A study revealed that 20% of patients taking diuretics commonly prescribed for high blood pressure or heart conditions end up with reduced sodium and potassium levels2
- Severe and persistent vomiting and nausea during pregnancy.3
Calcium, potassium and sodium levels
Low sodium levels (hyponatremia)
Hyponatremia may result from not eating enough foods containing sodium, too much sweating and urinating, or being over-hydrated.
When large amounts of fluids which do not contain sodium are given intravenously, the patient may develop hyponatremia. Diuretics cause the kidneys to expel excess sodium and water quicker - sometimes the excretion of sodium can be faster than the excretion of water.
When sodium levels are low, our bodies can produce too much of an antidiuretic hormone which tells our kidneys to retain water - this commonly happens in patients who have pneumonia, stroke and those taking certain medications, such as anticonvulsants and some SSRI (selective serotonin reuptake inhibitor) antidepressants.
Patients with diabetes, heart failure, liver failure and kidney disorders have a higher risk of experiencing low sodium levels.
Symptoms of hyponatremia - people suffering from hyponatremia may experience, confusion, headache, irritability, loss of appetite, muscle weakness, nausea, vomiting, fatigue, decreased consciousness, hallucinations, and even coma.
The Clinical Journal of Sport Medicine says that athletes who drink excessive amounts of fluids during prolonged exercise - particularly novice marathon runners - can develop dangerously low sodium levels.
High sodium levels (hypernatremia)
This is usually caused by water loss (dehydration) or the use of diuretics. Diuretics can cause both hyponatremia and hypernatremia. The first symptom of hypernatremia is thirst. Typically, patients with hypernatremia feel weak and sluggish.
When sodium levels are too high, people can suffer from confusion, paralysis, seizures and eventually coma. The best treatment is to increase water intake - sometimes this has to be done intravenously.
Low potassium levels (hypokalemia)
Some electrolyte imbalances can cause changes in heart rhythm.
Hypokalemia is often caused by using diuretics. Diuretics tend to make the kidneys excrete more potassium and water in urine.
Diarrhea and vomiting can also cause hypokalemia. If potassium levels drop slightly, there will usually be no symptoms. Prolonged slightly low potassium levels may lead to lower insulin production, resulting in an increase in blood sugar levels.
Symptoms of hypokalemia - if potassium levels drop too low the patient will suffer from fatigue, confusion, muscle weakness and cramps. If levels fall even lower, the person can become paralyzed, and have arrhythmias (unusual heart rhythms).
Patients with heart failure who take digoxin and have moderately low potassium levels are likely to develop abnormal heart rhythms. An interesting article published by The Cochrane Library looked at the benefits of diuretics for heart failure patients, while others wonder whether the changes in electrolyte levels might not outweigh the benefits.8
Low potassium is treated with potassium supplements by mouth - this can be either in tablet or liquid forms.
Patients can also raise their potassium levels by changing their diet.
Hypokalemia caused by diuretics can sometimes be resolved by switching to a potassium-sparing diuretic.
High potassium levels (hyperkalemia)
This is much more serious than hypokalemia. Hyperkalemia is usually caused by either kidney failure or medications that lower the amount of potassium excreted by the kidneys, such as the diuretic spironolactone, and angiotensin-converting enzyme (ACE) inhibitors that are used for hypertension (high blood pressure).
Patients taking these medications combined with potassium supplements or food high in potassium tend to have rapidly increasing potassium levels because their kidneys cannot get rid of it fast enough. They should stop taking the potassium supplements and change their diets. In some cases drugs that speed up the excretion of potassium are needed. Individuals with abnormal heart rhythms may be given calcium intravenously.
Researchers at the University of Texas Southwestern Medical Center in Dallas reported that heart drugs can cause a dangerous build up of potassium.
Low calcium levels (hypocalcemia)
Individuals with hypocalcemia might experience numb hands or feet
This can happen as a result of a sudden widespread blood infection, as well as infections in other tissues. If the body produces less parathyroid hormone, calcium levels can also drop - this might occur after the removal of the parathyroid glands during neck surgery.
Other reasons for hypocalcemia include anticonvulsant medications, such as phenytoin and phenobarbital, or an underactive thyroid gland.
Symptoms of hypocalcemia - people with hypocalcemia may experience numbness in the hands and/or feet, confusion, and even seizures. Treatment includes taking oral calcium supplements, and treating the disorder that caused it.
High calcium levels (hypercalcemia)
This can happen if a bone is broken down and calcium is released into the bloodstream. When cancer spreads to the bone there may be calcium release into the bloodstream. In severe cases of Paget's disease hypercalcemia can become very debilitating.
If levels of parathyroid hormone are too high hypercalcemia is much more likely - this is usually the result of a tumor in the parathyroid gland. Some cancers can cause parathyroid hormone levels to rise above normal levels. If thyroid hormone levels are abnormally high, calcium levels can rise excessively.
Symptoms of hypercalcemia - if calcium levels increase slightly most people do not have any symptoms. If levels are higher, the patient will experience dehydration because the kidneys automatically excrete more water. When levels are very high, the patient will experience nausea, loss of appetite, vomiting and confusion. There is also a risk of coma and death.
Very high levels of calcium need to be treated immediately.
What is an electrolyte panel?
The test is used to screen for any electrolyte or acid-base imbalances (the body's balance between acidity and alkalinity) and to check the effect of treatment on a known imbalance that is disrupting the proper bodily function of an organ.
An electrolyte panel is sometimes included as part of a routine physical. It can be done as a standalone test or as part of a basic metabolic panel or comprehensive metabolic panel.
The electrolyte panel is often used with hospitalized patients or those who are brought to the emergency room because acid-base and electrolyte imbalances are frequently part of acute and chronic illnesses.
If a single electrolyte is found to be either too high or too low, the doctor will keep testing for that imbalance until levels are back to normal. If an acid-base imbalance is found, blood gas tests may be done. These measure the pH, oxygen and carbon dioxide levels in an arterial blood sample to determine how severe the imbalance is and see how the patient responds to treatment.
Electrolytes may also be tested if the patient is prescribed certain drugs, especially diuretics or ACE inhibitors.
Video - Electrolytes
The bone density and fracture risk of older individuals do not improve with increased calcium intake. This is the finding of two new studies recently published in The BMJ.
Diabetes patients are at risk for a wide variety of negative health outcomes during the progression of their disease. One such area of concern is kidney function. New research hopes to spark further investigation into ways to tackle these disorders with dietary potassium.