For the Patient with Hyperkalemia (elevated potassium in blood)
Includes our Hyperkalemia Patient Handout with a Low Potassium Diet
By Kruti Vora and Michael Butman, M.D.
Background
Potassium is amongst the most important electrolytes in the human body. It is primarily located in the intracellular space and plays a vital role in virtually all cellular functions; it is involved in the heartbeat, muscle contraction and nerve conduction. Due to the vital role potassium plays, it is tightly regulated by the kidneys. Potassium levels may be affected by certain medications, gastrointestinal disorders, hormonal disorders, kidney disease and other conditions. When this occurs, it may require patients to modify their dietary intake of potassium to help prevent it from rising to levels that are dangerously high or from dropping to levels that are dangerously low.
How are potassium levels measured?
Potassium levels can be measured through a small sample of venous blood. The concentration of potassium in the serum of the blood is typically 3.7 to 5.2 mEq/L. Potassium levels that are lower than 2.5 mEq/L or greater than 6.0 mEq/L can be dangerous. Potassium can also be measured in blood plasma (the liquid portion of blood left over after blood cells and white cells are removed). It is typically slightly lower than that measured in the serum.
Conditions that can cause low potassium levels (hypokalemia) are typically due to a lack of intake or excessive losses. A lack of intake is typically seen in eating disorders such as anorexia or bulimia. Excessive losses are typically seen in gastrointestinal disorders that are associated with diarrheal illnesses or vomiting. Hereditary disorders affecting the kidneys’ ability to reabsorb potassium may cause excessive losses as well. Hyperaldosteronism, a disorder of the adrenal gland which results in excessive production of the hormone aldosterone will directly affect the kidneys ability to retain potassium and result in low potassium levels in the blood. Many medications such as diuretics, antibiotics, laxatives, and insulin may do the same.
High potassium, known as hyperkalemia, is most often due to the kidneys’ inability to excrete potassium. This can be due to diseases that damage the kidneys directly or indirectly by either compromising the blood flow to the kidneys or preventing the excretion of urine produced by the kidneys. When the kidney function is compromised it is known as acute or chronic kidney disease. Chronic kidney disease is most often caused by diabetes and hypertension, but can be caused by antibiotics, NSAIDs, medications such as ACE- inhibitors or angiotensin II blockers, dehydration, and kidney stones. Thus, any diseases that affect the kidneys’ ability to excrete potassium may, by extension, affect potassium levels in the blood.
Potassium levels can also be falsely elevated (factitious hyperkalemia or pseudohyperkalemia). This can occur when potassium is released by damaged blood cells within a sample of blood, a process known as hemolysis. Since the vast majority of potassium is found in the body is inside of cells, hemolysis can release excess potassium and artifactually elevate the concentration of potassium in a sample. Hemolysis may occur at any point during the collection, transportation, handling, storage, and processing of the blood sample. Certain diseases may also predispose to pseudohyperkalemia. These include high platelet counts (thrombocytosis), cancers of the white blood due to the fragility of the cell membranes, being asplenic (having had your spleen removed), or due to a genetic condition called familial pseudohyperkalemia.
What happens if my potassium is too high or low?
If potassium levels are too high or low, a variety of bodily functions may be dysregulated. The heart may beat in an abnormal rhythm or stop functioning altogether. Patients may also have fatigue, weakness, muscle cramps, and numbness or paralysis.
What is a low potassium diet?
Patients with chronic kidney disease or other renal insufficiency may not be able to excrete excess potassium in the urine. As a result, patients may need to follow a low potassium diet to keep their potassium levels within a safe and normal range.
The typical amount of dietary potassium required for patients with normal renal function and potassium excretion is . . .
Please Click Here to print the full Patient Handout on Hyperkalemia
for those with hyperkalemia from the APP.
References
High potassium (hyperkalemia) When to see a doctor. (2018, January 11). Retrieved from https://www.mayoclinic.org/symptoms/hyperkalemia/basics/when-to-see-doctor/sym-20050776
Low potassium (hypokalemia). (2020, July 11). Retrieved from https://www.mayoclinic.org/symptoms/low-potassium/basics/definition/sym-20050632
Lewis, J. L., By, Lewis, J. L., & Last full review/revision Apr 2020| Content last modified Apr 2020. (n.d.). Overview of Potassium's Role in the Body - Hormonal and Metabolic Disorders. Retrieved from https://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/electrolyte-balance/overview-of-potassium-s-role-in-the-body
Potassium Test. (2020, August 19). Retrieved from https://www.ucsfhealth.org/medical-tests/003484
Office of Dietary Supplements - Potassium. (n.d.). Retrieved from https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/
Guideline: Potassium intake for adults and children. (2012). Retrieved from https://www.who.int/nutrition/publications/guidelines/potassium_intake_printversion.pdf
Appendix 10. Food Sources of Potassium. (n.d.). Retrieved from https://health.gov/our-work/food-nutrition/2015-2020-dietary-guidelines/guidelines/appendix-10/
Lowering your potassium levels. (2017, June). Retrieved from https://renal.org/wp-content/uploads/2017/06/KCUK-Potassium_web.pdf
Patient education: Low-potassium diet (Beyond the Basics). (2019, October 15). Retrieved from https://www.uptodate.com/contents/low-potassium-diet-beyond-the-basics#H5
Asirvatham, J., Bjornson, L., & Moses, V. (2013). Errors in potassium measurement: A laboratory perspective for the clinician. North American Journal of Medical Sciences, 5(4), 255. doi:10.4103/1947-2714.110426
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