Hyperkalemia Diagnosis with History, Physical Examination and Tests

With hyperkalemia, symptoms may be absent and when present they are not specific. In view of its possible dangerous outcome, early diagnosis becomes important.

A suspicion of hyperkalemia can be obtained from the medical history, symptoms if any and physical examination.

Confirmation can be obtained only from the lab tests and ECG changes.

History

  • Medical history of the patient includes gathering information relevant information about the patient.
  • Regarding his eating habits and exclusive affinity to certain foods that could be high in potassium.
  • Whether he is a heart patient or having hypertension or diabetes and is on heart healthy diet with low sodium and high potassium foods
  • Whether he/she is taking any drugs that could cause this condition.
  • Whether he is on potassium supplements, salt substitutes, and such additives that are high in potassium.
  • Whether he has or had any kidney problem.

Rule out other causes of hyperkalemia as explained.

Physical examination

  • Vital signs are usually normal. These include blood pressure, pulse, respiratory rate and temperature.
  • General finding may show muscle weakness and fatigue.
  • Slow heart rate (bradycardia)
  • Tachypnea (rapid breathing) due to respiratory muscle weakness.
  • Depressed or absent deep tendon reflexes.

Diagnostic tests

  • Serum potassium to determine its level in blood.
  • Kidney function tests to rule out kidney insufficiency.
  • In case of renal failure, serum calcium is checked because hypocalcemia can cause cardiac rhythm changes
  • Complete blood count (CBC) with platelet count
  • A comprehensive metabolic panel is a blood test, which measures your sugar (glucose) level, electrolyte and fluid balance, kidney function, and liver function.
  • Arterial blood gases to rule out acidosis
  • Serum creatinine phosphokinase (CPK) and calcium level measurements to rule out rhabdomyolysis (breakdown of skeletal muscle tissue).
  • Urine studies for potassium, sodium and osmolality

ECG changes in hyperkalemia

Electrocardiogram (ECG) is done to check for changes indicative of hyperkalemia. These include the peaked T-wave, flattened P-wave with prolonged PR interval, or a totally absent P-wave, and wide QRS complex. St depression is another important feature.

These changes are more indicative of potassium levels of 6.5-8.0 mEq/L. These ECG changes reverse with the success of the appropriate treatment.

However, a normal EKG may be seen even with severe hyperkalemia.

 

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