Electrolytes are minerals in your blood, including sodium, potassium, calcium, phosphorus, magnesium, and bicarbonate. They help your nerves, muscles, and heart work properly and keep the body’s fluid and acid balance steady. The kidneys are the main organ that keeps these levels in a safe range, so kidney problems and some medicines can throw them off.
Low sodium (hyponatremia)
Low sodium usually means there is too much water in the body compared with sodium. Causes include some water pills (diuretics) and antidepressants, heart, liver, or kidney disease, hormone problems, and drinking large amounts of fluid. Mild cases may cause no symptoms. Lower levels can cause nausea, headache, confusion, unsteadiness, and falls. Severe or sudden low sodium can cause seizures and is a medical emergency. Treatment depends on the cause and must be done carefully, because correcting sodium too quickly can also be harmful.
High potassium (hyperkalemia)
Potassium can build up when the kidneys cannot remove enough of it. Some medicines raise potassium too, including certain blood pressure medicines, potassium-sparing water pills, NSAIDs, potassium supplements, and salt substitutes. High potassium often causes no symptoms, but very high levels can cause muscle weakness and dangerous heart rhythms. Treatment may include reviewing medicines, adjusting your diet, water pills, or medicines that remove potassium through the gut.
Low potassium (hypokalemia)
Low potassium can be caused by vomiting, diarrhea, some water pills, or certain hormone problems. It can cause weakness, cramps, constipation, and abnormal heart rhythms.
Calcium and phosphorus
In later stages of chronic kidney disease, phosphorus can rise and calcium and vitamin D levels can change. Over time this can weaken bones and harm blood vessels. Treatment can include diet changes, phosphate binders taken with meals, and vitamin D or other medicines.
Acid balance (metabolic acidosis)
Healthy kidneys remove acid from the body. In CKD, acid can build up, shown by a low bicarbonate level on blood tests. Over time this can weaken bones and muscles and may speed up kidney disease. It is sometimes treated with bicarbonate tablets or diet changes.
Get emergency care for severe weakness, a racing or irregular heartbeat, confusion, or a seizure.
These can be signs of a dangerous electrolyte problem.Questions to ask at your visit
- Which of my electrolytes are out of range, and why?
- Could any of my medicines or supplements be causing this?
- Do I need to change what I eat or drink?
- How often should my levels be checked?
This guide is general education and is not a substitute for medical advice. Talk with Dr. Salim or your care team about your own situation. Informed by patient materials from the National Kidney Foundation; learn more at kidney.org.