Hyperkalemia, a high serum potassium level, is not common in the general population, but it is a worrisome risk for those hospitalized and those with certain medical conditions. In the general population, hyperkalemia rates are reported to be less than 5%, while up to 10% of hospitalized patients may be affected.1 It’s also more common in men, possibly because of increased muscle mass, and higher rates of rhabdomyolysis and neuromuscular disease.1
Diagnosed at serum potassium >5.0 mEq/L to 5.5 mEq/L, hyperkalemia is often asymptomatic at mild or lower levels. However higher potassium levels can be life-threatening.1 As potassium is critical to nerve and muscle cell functioning, it impacts the heart muscle and can cause cardiac arrhythmias, muscle weakness and paralysis if not treated appropriately and in a timely manner.
A number of conditions can cause hyperkalemia and are correlated to higher incidences of it than occur in the general population. That includes patients with reduced kidney function, who may be diagnosed with chronic kidney disease (CKD). The kidneys filter and regulate the amount of potassium retained or excreted in urine, and worsening kidney function can cause increasing amounts of potassium retention. Uncontrolled diabetes can affect kidney function, leading to hyperkalemia.2,3
Also at risk are those taking medications affecting the renin-angiotensin-aldosterone system (RAAS), the signaling pathway regulating blood pressure. The drugs may prevent the kidneys from excreting the proper amounts of potassium. Therefore, patients taking these medications for chronic heart failure are at increased risk.2,3
Less often, hyperkalemia can be caused by Addison’s disease (which causes adrenal insufficiency), a diet high in potassium, dehydration, and severe injuries including burns, which cause the body to release excess potassium into the blood.
With mild or moderate hyperkalemia, most patients are asymptomatic. Patients may have nonspecific complaints of fatigue, weakness, syncope or palpitations.1 Other mild or nonspecific symptoms can include nausea, numbness or tingling, possibly developing slowly over weeks or months. Those with sudden or severe hyperkalemia may experience shortness of breath, palpitations, chest pain, vomiting or nausea.4
Patients usually become symptomatic at serum potassium levels of 6.5 mEq/L to 7 mEq/L, however those with a more acute shift in levels maybe more symptomatic than someone with steady higher numbers.1
The condition is often discovered based on screening lab tests for complaints with nonspecific etiology or ordered due to potential electrolyte abnormalities. A clinician may suspect hyperkalemia if the medical history is positive for the conditions or medication use previously mentioned, as well as recently receiving total parenteral nutrition, succinylcholine, non-steroidal anti-inflammatory drugs or potassium penicillin.1
For someone with hyperkalemia, a physical exam can reveal edema, hypoperfusion symptoms, hypertension, muscle tenderness from rhabdomyolysis, muscle weakness, depressed deep tendon reflexes, or flaccid paralysis. Recommended lab testing includes urinalysis and serum blood urea nitrogen and creatinine to evaluate renal function and disease, and urine potassium, sodium and osmolality to help determine cause. A number of other blood tests are recommended as well. An EKG is recommended as hyperkalemia can cause potentially fatal cardiac arrhythmias. Those without typical EKG changes who are asymptomatic, should have hyperkalemia confirmed before beginning aggressive therapy, as pseudohyperkalemia is common.1
Incidence and Disease Burden
Documented rates of hyperkalemia vary. A 2017 study done using Medicare and commercial data from Medicare and Truven Health Analytics MarketScan Commercial Claims data showed hyperkalemia prevalence rates of 2.3% and 0.09% respectively. Of those with hyperkalemia, 64.8% of those in the Medicare population also had CKD, as did 31.8% of the commercially insured group. Researchers adjusted for CKD severity, and found an annual mortality rate of 24.9% in the Medicare CKD/hyperkalemia group, compared to 10.4% for those with CKD but no hyperkalemia.2
The presence of hyperkalemia is a big risk factor for all-cause mortality, not just for those with pre-existing or advanced CKD, but even those without CKD. A retrospective analysis of 15,803 patients with CKD and cardiovascular disease (CVD) receiving antihypertensive medications, showed that those with hyperkalemia had higher hospital admission and mortality rates than those without hyperkalemia.3 A Veterans Administration study of 240,000 U.S. patients with at least one serum potassium measurement and one hospitalization in one year, showed increased odds of dying within a day of a hyperkalemic event, regardless of kidney function status. Those with CKD were more likely to experience a hyperkalemic event than the non-CKD group, and the risk of death was correlated incrementally with hyperkalemia severity. They defined moderate hyperkalemia as a serum potassium level ≥5.5 mg/dL.3
In addition to an increased mortality risk, hyperkalemia is associated with increased emergency department (ED) visits and hospitalizations. That not only affects health status but also has economic consequences. One study found that costs were more than two times higher for patients with hyperkalemia and CKD than for those with CKD without hyperkalemia, in both Medicare and private payer groups. The study found that inpatient care costs comprised more than 50% of health care costs for patients with CKD and hyperkalemia.2
Another study showed that 67,000 ED visits in 2011 were a direct result of elevated potassium levels. Of these, half of patients were admitted to the hospital, staying an average of 3.2 days. Mean hospital charges were $24,178 per stay. Of these patients, 84% were older than 45. Medicare annual hospital costs for hyperkalemia as a primary diagnosis in 2011 were about $697 million.3
Treatment Options for Hyperkalemia
Before treatment occurs, the diagnosis should be confirmed, especially if there’s not a good reason for elevated serum potassium. Pseudohyperkalemia is common and could be due to specimen handling or collection issues. The patient’s symptoms, hyperkalemia levels, rapidity of development, and reasons for the event should help direct treatment.1
Treatment and management of hyperkalemia can be acute or chronic. Patients with severe acute hyperkalemia should be treated quickly, as the mortality rate can exceed 30%.3 For example, a patient with confirmed hyperkalemia of 6.5 mEq/L or elevated potassium levels higher than 5.5 mEq/L in at-risk patients would get aggressive treatment.1
Acute treatment can be separated into emergency/aggressive management, and subacute management. Emergency treatment may include nebulized or inhaled beta-2–receptor agonists such as albuterol or salbutamol. That should start acting within 30 minutes, lasting 2 to 4 hours. Treatment could also include intravenous insulin and glucose to stimulate intracellular potassium uptake, especially for hyperglycemic patients.1 In addition, calcium gluconate salt can be administered for membrane stabilization3 and to stabilize any cardiac response. It should be given early if there’s cardiac toxicity shown via EKG.1 Patients should also discontinue any external potassium intake.
Subacute management would move potassium move it into the intracellular space or out of the body. This returns the cell membrane electrophysiology to normalcy, and helps prevent cardiac arrhythmias. This level of management may also include sodium bicarbonate, loop diuretics, dialysis, and sodium polystyrene sulfonate, a potassium-binding resin.3
Treating and managing severe hyperkalemia should involve a multidisciplinary team, including cardiology, nephrology, pharmacy (to ensure all nephrotoxic products that raise potassium levels are discontinued) and nutrition. After the hyperkalemia incident resolves, patients will need to follow a low potassium diet.1
Chronic Management of Hyperkalemia
Efforts to manage chronic hyperkalemia and those at risk for recurrent hyperkalemia, mainly focus on eliminating potassium sources from the diet, as well as medications that can exacerbate it. A dietician can advise patients on the dietary portion.3 Ingesting food-based potassium is not a common cause of hyperkalemia for those with normal renal function, but can be for those with CKD.1 Foods high in potassium should be limited for patients with CKD.3 Eliminating or decreasing foods high in potassium can go against other medical advice for healthy dietary consumption to reduce kidney disease, hypertension, and other cardiovascular diseases. Food high in potassium include fruits (oranges, raisins/dried fruit, bananas, melons etc),3 seaweed, nuts, lima beans, tomatoes, vegetables (spinach, potatoes, avocados, beets, carrots), and red meats.1
Potassium supplements should likely be eliminated. Clinicians should consider lowering or eliminating dosages of medications like RAAS inhibitors, if they are potentially a cause of the patient’s hyperkalemia. An observational study of 279 patients with CKD showed that when clinicians discontinued RAAS inhibitors, 66.6% did so due to hyperkalemia, and 13.8% did not initiate RAAS inhibitor therapy because of the risk.3 Fluids like total parenteral nutrition, and even massive blood transfusions should be eliminated or at least carefully considered if needed.1 Dialysis and loop diuretics can also be part of chronic management.3 Those with end-stage renal failure and other chronic disorders may need continual monitoring and blood work.1 The National Kidney Foundation also mentions using potassium binders and diuretics to remove excess potassium.4
While hyperkalemia can be an emergent and dangerous situation, most patients have an excellent prognosis. Those with CKD, diabetes, CVD or others at risk should be monitored more closely for nonspecific hyperkalemia symptoms, at hyperkalemia can be present and cause damage at moderate levels. Care should be taken for those with end-stage renal failure and other chronic disorders, with frequent monitoring and blood work.1
1. Simon LV, Hashmi MF; Farrell MW. Hyperkalemia. Treasure Island,FL: StatPearls Publishing; 2019.
2. Fitch K, Woolley JM, Engel T, Blumen H. The clinical and economic burden of hyperkalemia on Medicare and commercial payers. Am Health Drug Benefits. 2017;10(4):202-210.
3. Dunn JD, Benton WW, Orozco-Torrentera E, Adamson RT. The burden of hyperkalemia in patients with cardiovascular and renal disease. Am J Manag Care. 2015;21(15 Suppl):s307-15.
4. National Kidney Foundation. A to Z Health Guide: What is hyperkalemia? kidney.org website. https://www.kidney.org/atoz/content/what-hyperkalemia. Accessed October 25, 2019.