When we think about how to keep our bodies healthy, we often think about nutrients in one way: “Do I have enough?” But is there ever a situation when you can have too much of a nutrient? Depending on the state of your health, the answer is yes.
Potassium and Reduced Kidney Function or CKD
For people with reduced kidney function (such as those with chronic kidney disease or CKD), too much potassium can be dangerous, even fatal. Fortunately, many patients know that elevated potassium levels are a threat. In a survey by the National Kidney Foundation, 50 percent of CKD patients said high potassium was a very important health concern. However, CKD patients who were surveyed were not necessarily aware of their potassium levels. In my own practice, many of my patients are not aware of their potassium levels until I point out to them that their levels are abnormal. This disconnect is a real problem and concern without real-world knowledge can lead to dangerous outcomes.
Why Potassium Levels Matter
Potassium is an important electrolyte vital for the normal functioning of the heart. In healthy people, normal blood potassium levels are maintained when potassium intake (via diet) is balanced with the uptake of potassium by the cells and excretion by the kidneys. For most people, normal blood potassium levels are between 3.5 to 5.0 milliequivalents per liter (mEq/L).
When the kidneys are not functioning properly, the body can’t effectively remove potassium from the body, causing blood potassium levels to be out of balance. As a result, these people are at risk of developing hyperkalemia, or high blood potassium levels. CKD patients with blood potassium levels >5.5 mEq/L have a higher risk of dying within 24 hours of the event. 
Even more challenging, some medicines prescribed to patients with CKD or heart failure can actually cause hyperkalemia as a side effect. For these patients, managing their potassium levels becomes even more important, so that they’re able to continue taking these life-saving medicines.
What Are the Symptoms of Hyperkalemia?
In the United States, approximately three million people have hyperkalemia. As the number of people with chronic conditions such as CKD climbs, more people are expected to experience hyperkalemia. It is important to know that for most people, high potassium develops slowly over weeks or months. Patients may not even notice any symptoms of hyperkalemia, but doctors can identify it in laboratory tests. When symptoms do occur, people may experience muscle paralysis, heart palpitations, nausea or vomiting, shortness of breath or chest pain.
Without treatment, people with severe hyperkalemia can be at risk for abnormal heart rhythms and sudden death. If you experience a combination of any of these symptoms, it is important that you go to the emergency room or call 911 immediately.
Can Hyperkalemia Be Managed?
As a nephrologist, I work with my patients regularly to make sure I am frequently checking their potassium levels. However, potassium monitoring is also part of the routine physical many people receive from their primary care provider.
If you have CKD or other chronic conditions such as diabetes or heart disease too much potassium can become a problem, and you should talk to your doctor about managing your potassium levels. A simple checkup can provide you with the information you need to take charge of your health.
Your treatment plan is determined by testing your kidney and heart function and assessing how rapidly the disorder developed and the severity of your illness. Your doctor may recommend water pills or medicines such as potassium binders, which help rid the body of excess potassium.
Dietary Restriction to Reduce Potassium
The most common question my patients ask about managing their potassium levels is related to diet and what they should eat to maintain healthy potassium levels. Dietary restriction of potassium is challenging because many of the guidelines are contrary to guidelines for a heart-healthy diet which is high in potassium.
In fact, potassium is found in many popular and healthy foods, including bananas, oranges, potatoes, milk, artichokes, avocados, cantaloupes, raisins, squashes, tomatoes, steaks and hamburgers. For this reason, your doctor may recommend that you work with a nutritionist or dietitian who can guide you toward foods that will help you stay healthy.
Additional Advice for CKD Patients
Did you ever think a doctor would tell you to watch out for fruits and veggies? Or that too much potassium could be a bad thing for some people? I know this may seem contrary to usual nutritional advice, but that’s why it’s so important to make sure people with CKD, heart failure and other chronic conditions are aware of the risks of too much potassium.
Patient Education and Plan of Treatment
Fortunately, through patient education and the design of a treatment plan that meets their needs, patients can keep their kidneys healthy and thriving. If you have CKD or a chronic condition, talk to your doctor about your risk for hyperkalemia and learn more about the disease here.
- Rastegar A, Soleimani M. Hypokalaemia and hyperkalaemia. Postgrad Med J. 2001;77:759-764.
- National Kidney Foundation. Hyperkalemia: Survey of Awareness and Experience Among Adults with CKD. Accessed November 5, 2018.
- National Kidney Foundation. What is Hyperkalemia? Accessed November 6, 2018.
- Evans KJ, Greenberg A. Hyperkalemia: A review. J Intensive Care Med. 2005;20(5):272-290.
- National Kidney Foundation. Your Kidneys and High Potassium (Hyperkalemia).
- Collins AJ, et al. Association of Serum Potassium with All-Cause Mortality in Patients with and without Heart Failure, Chronic Kidney Disease, and/or Diabetes. Am J Nephrol c. 2017;46(3):213-221.
- Einhorn LM, et al. The frequency of hyperkalemia and its significance in chronic kidney disease. Arch Intern Med. 2009; 169(12)
- Desai A. Hyperkalemia Associated with Inhibitors of the Renin-Angiotensin-Aldosterone System. Circulation. 2008; 118:1609-1611
- Betts KA, et al. The prevalence of hyperkalemia in the United States. Current Medical Research and Opinion. https://doi.org/10.1080/03007995.2018.1433141. Accessed April 26, 2018.
- Hoerger TJ, et al. The Future Burden of CKD in the United States: A Simulation Model for the CDC CKD Initiative. American Journal of Kidney Diseases. 2015; 65(3): 403-411.
- Kraft MD, et al. Treatment of electrolyte disorders in adult patients in the intensive care unit. Am J Health-Syst Pharm. 2005;62:1663-1682.
- Duman, S. Rational approaches to the treatment of hypertension: diet. Kidney Int Suppl (2011). 2013; 3(4): 343-345.
Some of Dr. Weir’s research in hyperkalemia treatment has been supported by Relypsa, Inc. (a Vifor Pharma Group company), and he has served on the Steering Committee and as principal investigator of a clinical trial funded by the company.
Matthew R. Weir, M.D.
Matthew R. Weir, M.D. is attending physician and Director of the Division of Nephrology in the Department of Medicine at the University of Maryland Hospital, Baltimore. He is also Professor of Medicine at the University of Maryland School of Medicine. Dr. Weir has written extensively on nephrology, transplantation, and hypertension and is currently reviewing manuscripts for more than 30 major medical journals and is on the on the editorial board of 18 journals. He has presented at numerous international scientific meetings, hospitals, and medical schools. In addition, he is a member of several associations, including the American Society of Nephrology and the American Heart Association. Dr. Weir received his medical degree from the University of Virginia, Charlottesville. He completed his internship and residency programs in medicine at the Waterbury and Yale-New Haven Hospitals in Connecticut and completed his nephrology training at the Brigham and Women’s Hospital, Harvard Medical School, in Boston, Massachusetts. He then moved to then to the University of Maryland where he has been a full-time faculty member since 1983. In his spare time, Dr. Weir enjoys long distance running, playing golf and traveling.