What are the symptoms of hyperkalemia?

Hyperkalemia is a metabolic disorder caused by elevated blood potassium levels, often associated with impaired renal potassium excretion, medication effects, and high-potassium diets. The primary symptoms involve the heart and neuromuscular system, including cardiac abnormalities, neuromuscular symptoms, gastrointestinal discomfort, urinary system disturbances, and sensory abnormalities. A detailed analysis is as follows:

1. Cardiac abnormalities: This is the most dangerous symptom. Early signs often include palpitations and arrhythmias, manifesting as bradycardia and irregular heart rhythms. Some individuals may experience chest tightness or a sensation of chest pressure. As serum potassium rises, myocardial excitability decreases, potentially leading to ventricular fibrillation or cardiac arrest in severe cases.

2. Neuromuscular symptoms: These typically begin in the lower limbs and gradually spread upward. Initial symptoms include leg weakness and heaviness, with limbs feeling weak during walking. Subsequently, weakness extends to the upper limbs. In severe cases, muscle flaccidity and difficulty moving occur, potentially progressing to quadriplegia.

3. Gastrointestinal discomfort: Elevated potassium affects gastrointestinal smooth muscles, causing spasms that result in nausea and vomiting—often of gastric contents—accompanied by persistent abdominal pain and bloating. Some individuals may develop frequent diarrhea with loose stools. These symptoms are easily confused with gastrointestinal dysfunction and should be differentiated through serum potassium testing.

4. Urinary system abnormalities: Hyperkalemia is often accompanied by kidney dysfunction. As the kidneys' ability to excrete potassium declines, urination is also affected, leading to reduced urine output (less than 400 mL per day). In severe cases, this can progress to anuria, with darkened urine color.

5. Sensory abnormalities: Electrolyte imbalances stimulate nerve endings, causing numbness and tingling in the hands and feet—most notably at the fingertips and toes. Some people report a crawling sensation on the skin, as if insects are moving across it. These symptoms typically resolve gradually once potassium levels decrease.

To prevent hyperkalemia, regular monitoring of blood potassium levels is essential. Patients with kidney disease should strictly limit intake of high-potassium foods such as bananas and spinach. When taking potassium-sparing diuretics, antihypertensive medications, or similar drugs, dosage adjustments should be made under medical supervision; self-medication should be avoided.