Hyperkalemic periodic paralysis

Alternative names:

adynamia episodica hereditaria; periodic paralysis - hyperkalemic

Symptoms:

• weakness/paralysis
  • most commonly located in the shoulders and hips
  • arms and legs may also be involved
  • occurs intermittently
  • may occur on awakening
  • may be triggered by rest after exercise
  • may be triggered by fasting
  • usually lasts for less than 2 hours

• spontaneous recovery of normal strength between attacks
• normal alertness during attacks

Signs and tests:

The health care provider may suspect hyperkalemic periodic paralysis based on a family history of the disorder, the episodic nature of symptoms, demonstration of normal or high results of a potassium test, and elimination of other disorders as the cause of intermittent weakness.

Between attacks, examination is normal. During an attack, reflexes may be decreased or absent. Weakness is flaccid rather than spastic, and is greater in proximal muscle groups (near the body, such as shoulders and hips) than in distal groups (away from the body, such as arms and legs). Attempt to trigger an attack by reducing potassium levels (by administering insulin and glucose) is unsuccessful, but attacks may be triggered by administration of potassium.

Serum potassium is normal or high during attacks and may be normal or high between attacks.