ConditionWhole body & general
Electrolyte Disorders (Electrolyte Imbalance)
Electrolyte disorders are abnormal blood levels of the minerals that carry an electric charge, mainly sodium, potassium, calcium, magnesium, chloride, phosphate and bicarbonate. These minerals control fluid balance, nerve signals, muscle contraction and heart rhythm. Imbalances are common with vomiting, diarrhea, kidney disease, heart failure, and medicines such as diuretics. Mild ones often cause no symptoms. Severe ones can cause confusion, muscle weakness, seizures and dangerous heart rhythms, and need urgent treatment.
Also called: Electrolyte imbalance, electrolyte abnormalities, electrolyte disturbance
At a glance
- What it is
- Too high or too low blood levels of key minerals such as sodium, potassium, calcium and magnesium.
- Common causes
- Vomiting, diarrhea, sweating, kidney disease, heart or liver failure, diuretics and other medicines, hormone problems.
- Symptoms
- Fatigue, weakness, cramps, nausea, confusion, palpitations; seizures or cardiac arrest when severe.
- Diagnosis
- Basic or comprehensive metabolic panel (blood test), ECG.
- Treatment
- Correct the level by mouth or IV, at a safe speed, and treat the cause.
When to get help
Call 911 or go to the ER
- Confusion, seizures, extreme drowsiness or collapse
- Palpitations, a very slow or irregular heartbeat, chest pain or fainting
- Severe muscle weakness or paralysis, or difficulty breathing
- Muscle spasms of the hands, face or throat with tingling around the mouth
See a doctor within a day or two
- Prolonged vomiting or diarrhea with dizziness, very little urine or weakness
- A blood test result showing a markedly abnormal sodium, potassium or calcium
- New muscle cramps, weakness or nausea after starting a diuretic or blood pressure medicine
Book a routine appointment
- Mild abnormal results on a routine blood test
- Ongoing monitoring in kidney disease, heart failure or with diuretics
Usually safe to manage at home
- Mild cramps or tiredness after heavy sweating, relieved by oral rehydration solution
Why electrolytes matter
Electrolytes dissolve in body fluids and carry charges. The body tightly controls their levels through the kidneys, hormones (such as aldosterone, ADH and parathyroid hormone) and the gut. Even small changes can affect the brain, muscles and heart.
Main electrolyte disorders
| Disorder | Typical normal range | Common causes | Key symptoms |
|---|---|---|---|
| Hyponatremia (low sodium) | 135 to 145 mmol/L | Diuretics, SIADH, heart or liver failure, excess water, vomiting | Nausea, headache, confusion, falls, seizures |
| Hypernatremia (high sodium) | Dehydration, not drinking (older adults), diabetes insipidus | Thirst, confusion, weakness | |
| Hypokalemia (low potassium) | 3.5 to 5.0 mmol/L | Vomiting, diarrhea, diuretics, laxatives | Weakness, cramps, constipation, palpitations |
| Hyperkalemia (high potassium) | Kidney disease, ACE inhibitors, ARBs, spironolactone, supplements | Often none; weakness, dangerous heart rhythms | |
| Hypocalcemia (low calcium) | About 8.5 to 10.5 mg/dL | Low vitamin D, after thyroid surgery, kidney disease, low magnesium | Tingling, cramps, spasms, seizures |
| Hypercalcemia (high calcium) | Overactive parathyroid, cancer, excess vitamin D | Thirst, constipation, kidney stones, confusion | |
| Hypomagnesemia (low magnesium) | About 1.7 to 2.2 mg/dL | Alcohol, diarrhea, diuretics, long-term PPIs | Tremor, cramps, arrhythmias; causes low potassium and calcium |
| Phosphate imbalance | Kidney disease (high), malnutrition and refeeding (low) | Weakness, bone and heart problems |
Ranges vary slightly between labs.
Common causes
- Fluid losses: vomiting, diarrhea, heavy sweating, burns
- Not drinking enough, especially in older adults or during illness
- Drinking too much water, for example during endurance events
- Kidney disease: the kidneys cannot regulate electrolytes (chronic kidney disease)
- Heart failure and liver cirrhosis: fluid retention dilutes sodium
- Medicines: diuretics, ACE inhibitors and ARBs, laxatives, some antidepressants, chemotherapy, lithium
- Hormone disorders: adrenal insufficiency, SIADH, parathyroid disease, diabetes and ketoacidosis
- Eating disorders and refeeding after starvation
- Alcohol use disorder
Symptoms
Symptoms depend on which electrolyte is affected, how far it is out of range, and how quickly it changed. Rapid changes cause more symptoms than slow ones. General signs include:
- fatigue and lethargy
- muscle weakness, cramps, twitching or spasms
- nausea, vomiting, constipation or diarrhea
- headache, confusion, irritability
- numbness or tingling
- irregular or fast heartbeat
- seizures in severe cases
Diagnosis
- Basic metabolic panel: sodium, potassium, chloride, bicarbonate, glucose, urea and creatinine.
- Calcium, magnesium and phosphate levels.
- Urine tests: urine sodium, potassium and osmolality help find the cause.
- ECG: potassium and calcium problems can cause characteristic changes and dangerous rhythms.
- Hormone tests: cortisol, thyroid, parathyroid hormone, as needed.
Treatment
Treatment corrects the level and addresses the cause:
- Oral replacement: potassium, magnesium or calcium tablets, or oral rehydration solution for mild losses.
- IV fluids and electrolytes in hospital for severe cases.
- Careful correction of sodium: chronic low sodium must be raised slowly, because overly rapid correction can cause serious brain damage (osmotic demyelination).
- High potassium: emergency treatment with IV calcium to protect the heart, insulin and glucose to shift potassium into cells, and medicines or dialysis to remove it.
- Medicine changes: stopping or adjusting diuretics or other causes.
- Treating the underlying disease: kidney, heart, hormone or liver problems.
Prevention
- Drink fluids when vomiting or having diarrhea; oral rehydration solutions contain the right balance of salts and sugar.
- During long exercise in heat, drink to thirst and use electrolyte drinks rather than large amounts of plain water.
- Have regular blood tests if you take diuretics, ACE inhibitors, ARBs or lithium, or have kidney or heart disease.
- Do not take potassium supplements or salt substitutes (which contain potassium) without medical advice if you have kidney disease or take medicines that raise potassium.
Frequently asked questions
What are the symptoms of an electrolyte imbalance?
Common symptoms include fatigue, muscle weakness, cramps, nausea, headache, confusion, numbness or tingling, and irregular heartbeat. Severe imbalances can cause seizures and life-threatening heart rhythm problems.
What causes electrolyte imbalance?
Common causes are vomiting, diarrhea, heavy sweating, not drinking enough or drinking too much water, kidney disease, heart or liver failure, hormone disorders, and medicines such as diuretics and blood pressure tablets.
How do you fix an electrolyte imbalance?
Mild imbalances can be corrected with oral rehydration solutions, diet changes or supplements. Severe ones need hospital treatment with IV fluids or medicines, corrected at a safe speed. Treating the underlying cause prevents recurrence.
Are sports drinks good for electrolytes?
Sports drinks can help replace sodium and fluid during long or intense exercise in heat. For illness with vomiting or diarrhea, oral rehydration solutions are better because they have more sodium and less sugar.
Sources
This guide was written from current patient and clinical guidance, including:
- MedlinePlus: Fluid and electrolyte balance; Electrolyte panel
- National Kidney Foundation: Hyperkalemia
- Merck Manual Consumer Version: Overview of electrolytes
- American Academy of Family Physicians: Hyponatremia: evaluation and management
- NHS: Dehydration