Sodium and potassium are electrolytes, or minerals with an electric charge. The cells in the body have to keep a balance between the number of electrolytes with a negative charge and the number of electrolytes with a positive charge within the cell. Both sodium and potassium have a positive charge. Electrolytes must also stay within a certain range in the fluids of the body. Keeping them within this range is one of the responsibilities of the kidneys.
Low Sodium Levels
The normal range of sodium in the bloodstream is 135 to 145 mEq/L. If the sodium level drops lower than 135 mEq/L, this is referred to as hyponatremia. This can happen for many reasons, explains Gary Singer, M.D., Assistant Professor of Clinical Medicine at the Washington University School of Medicine, in "Harrison's Principles of Internal Medicine." It can be due to diarrhea, vomiting, burns, excessive sweating, heart failure, high blood glucose levels, diuretics, constantly drinking an excessive amount of water, cirrhosis of the liver or kidney abnormalities.
High Sodium Levels
Dr. Singer writes that if the sodium level in the bloodstream is higher than the normal range, this is called hypernatremia. Thus, hypernatremia describes sodium levels higher than 145 mEq/L. People usually develop higher than normal sodium levels in the bloodstream by losing water. This can happen via heat exposure, exercise, watery diarrhea, kidney abnormalities and the poor control of diabetes mellitus.
Low Potassium Levels
The normal range for potassium in the bloodstream is just 3.5 to 5.0 mEq/L. If the potassium level goes lower than 3.5 mEq/L, this is described as hypokalemia. Most of the potassium in the body is actually inside of the muscle cells, as only two percent is found outside of the cells, according to James Lewis, III, M.D. of Nephrology Associates in "The Merck Manual for Healthcare Professionals." People can develop low potassium levels in the blood by losing potassium due to kidney disorders, vomiting, diarrhea, diuretics or the long-term abuse of laxatives.
High Potassium Levels
Hyperkalemia refers to potassium levels in the bloodstream that are higher than the normal range, or higher than 5.0 mEq/L. This can be the result of kidneys damaged so much by diabetes mellitus, sickle cell disease or lupus that they can no longer excrete potassium, explains Kerry Cho, M.D., Assistant Clinical Professor of Medicine at the University of California, in "Current Medical Diagnosis & Treatment." It may also be due to strenuous exercise, severe infections, internal bleeding and injury to the skeletal muscle, which releases potassium from the muscle cells into the blood.
References
- "Current Medical Diagnosis & Treatment 2011"; Stephen McPhee, M.D. and Maxine Papadakis, M.D.; 2011
- "Harrison's Principles of Internal Medicine"; Anthony Fauci, et al.; 2008
- Merck: Disorders of Potassium Concentration
