Welcome to the Rare Classroom, a new series from Patient Worthy. Rare Classroom is designed for the curious reader who wants to get informed on some of the rarest, most mysterious diseases and conditions. There are thousands of rare diseases out there, but only a very small number of them have viable treatments and regularly make the news. This series is an opportunity to learn the basics about some of the diseases that almost no one hears much about or that we otherwise haven’t been able to report on very often.

Eyes front and ears open. Class is now in session.

The disease that we will be learning about today is:

Hyperkalemia

What is Hyperkalemia?

• Defined as elevated potassium levels in the blood​
• Hyperkalemia occurs when serum potassium levels are > 5.0 milliequivalents per liter (mEq/L)​
• Hyperkalemia is not a disease in and of itself. It occurs as the result of an underlying condition or certain medications​
• Frequently occurs in patients with other serious health concerns​
• Extremely high levels of potassium in the blood can lead to cardiac arrest and death​
  • A retrospective analysis showed up to 19% of those with heart failure have hyperkalemia
• Normal mechanisms maintain potassium level between 3.5 and 5.0 mEq/L​
• Normal mechanisms buffer extracellular potassium against a large intracellular potassium pool providing minute-to-minute control, and urinary excretion of potassium​
• Potassium is obtained through the diet. People typically ingest more potassium than needed.​
• Excess potassium is secreted primarily through urine​
• Normally when potassium intake is high, the kidneys adapt and potassium excretion is increased​

How Do You Get It?

• Hyperkalemia results from:​
  • Excess intake of potassium​
  • Decreased excretion of potassium​
  • A shift of potassium from the intracellular to the extracellular space​
• In most cases, hyperkalemia is triggered by chronic kidney disease
  • A study examining the presence of hyperkalemia in those with chronic kidney disease showed:​
  • More than one-half of the patients had potassium levels above the conventional limit of 5.0 mEq/L​
  • One-quarter of the patients had potassium levels>5.5 mEq/L​
• It can also appear alongside:
  • Heart failure​
  • Diabetes​
  • Sickle cell disease​
  • Lupus​
  • Extensive soft tissue injury​
  • High dietary potassium intake​
  • Reduced aldosterone production​
  • Primary adrenal disease
    • Addison disease​
    • Congenital adrenal hyperplasia​
  • The use of certain medications​
    • Renin-angiotensin-aldosterone system, or RAAS, (ACE) inhibitors​
      • 20% of patients receiving angiotensin­-converting enzyme inhibitors (ACEi) and 31% of patients receiving angiotensin receptor blockers (ARB) had hyperkalemia 
    • Nonsteroidal anti-inflammatory drugs (NSAIDs)​

What Are The Symptoms?

• Can be asymptomatic or only mild symptoms​
• Nausea​
• Fatigue​
• Muscle weakness​
• Tingling sensations​
• Flaccid paralysis (paralysis or weak muscle tone)​
• EKG changes​
• Unless the rise in potassium has been very rapid, symptoms of hyperkalemia are usually not apparent until potassium levels are very high (typically 7.0 mEq/l or higher, which is considered severe hyperkalemia).​

How Is It Treated?

• Treatment approach is based on the underlying cause and the severity of symptoms​
• Treatment approaches include:
  • A diet low in potassium​
  • Discontinuation of medications that increase potassium levels​
  • Sodium polystyrene sulfonate: Removes potassium via the digestive tract​
  • Diuretics: Removes potassium via the urinary tract​
  • IV Insulin and glucose: Quickly moves potassium into cells​
  • IV calcium: Temporarily protects the heart and muscles​
  • Dialysis: Filters potassium from blood. Used primarily if kidney function is seriously impaired.​
• “Even mild hyperkalemia (≥5.0 mEq/L) is associated with an increased risk of adverse renal events and increased mortality in patients with chronic illnesses” – ZS Pharma​
• Is potentially life threatening due to risk of cardiac arrhythmias and cardiac arrest​

Where Can I Learn More???

• Check out our cornerstone on this disease here.