Most people do not experience any symptoms until their potassium level reaches 7.0 mEq/L or more. At lower levels, unless the rise in potassium level has been very rapid, symptoms of hyperkalemia are usually absent. If they do present, those symptoms are often mild and nonspecific, like fatigue and generalized weakness.

And luckily, most cases are mild and are without any clinical signs though some patients may complain of muscle weakness.

Symptoms become apparent when the potassium levels rise very high (typically 7.0 mEq/l or higher).


Potassium is an essential electrolyte and maintains essential life functions. It regulates water balance in the body, keeps your heart pumping, contracts and relaxes your muscles, helps the stomach to digest food, and keeps your nerves functioning.

Therefore, when potassium levels rise significantly due to certain reasons, the symptoms that arise will relate to the nervous system, musculoskeletal system, digestive system, and cardiovascular system.

Hyperkalemia produces symptoms, which are often nonspecific. The complaints of the patient usually include:

  • tiredness or weakness
  • numbness or tingling
  • nausea or vomiting
  • breathing trouble (dyspnea)
  • chest pain
  • palpitations and/or irregular heartbeats (arrhythmias)
  • Early signs of muscle twitches/cramps; later muscle weakness
  • Paralysis

Signs can include muscle tenderness accompanying muscle weakness. This is suggestive of rhabdomyolysis (destruction of striated muscle cells).

Severe hyperkalemia symptoms

Severe hyperkalemia symptoms can include chest pain, vomiting, weakness, breathing issues, cardiac arrest, paralysis, and palpitations. If you experience any of the above symptoms, you must immediately visit your healthcare provider

Serious symptoms and complications

Too much potassium in your blood can also cause some serious symptoms. These dangerous and possibly deadly signs include a slow heartbeat (bradycardia) and a weak pulse indicating an adverse effect on the electrical activity of the heart.

These signify a life-threatening situation. Immediate monitoring and corrective measures are urgently warranted.

Periodic paralysis, which is a rare inherited disorder, can cause a sudden onset of hyperkalemia accompanied by muscle paralysis.

Potassium levels in blood higher than 7 mEq/L can lead to significant hemodynamic and neurologic consequences, which include:

  • Bradycardia due to heart block and/or tachypnea (rapid breathing) due to the weakness of the respiratory muscle
  • Muscle weakness and flaccid paralysis
  • Absent deep tendon reflexes.

Levels exceeding 8.5 mEq/L can cause respiratory paralysis or cardiac arrest and can cause sudden death.

Signs on examination

  • Vital signs such as blood pressure, pulse, respiration rate, and temperature are usually normal, except occasional bradycardia may be present due to heart block.
  • Rapid breathing due to respiratory muscle weakness
  • Decreased muscle power due to muscle weakness
  • Flaccid paralysis (reduced muscle tone)
  • Absent deep tendon reflexes

ECG changes

ECG changes in hyperkalemia are typical. They show rhythm changes: Tall peaked T waves, flat p waves, Widened QRS, and prolonged PR interval. They are correlated with high blood levels seen in the diagnostic lab tests to rule out pseudohyperkalemia