Treatment:

The best treatment is rapid reduction in thyroid hormone levels. Potassium should also be given during the attack. It is preferred that potassium be given by mouth, but if weakness is severe, intravenous potassium may be necessary. (Note: intravenous potassium should be given only if kidney function is adequate and if the person is monitored in the hospital.)

Weakness that involves the muscles used for breathing or swallowing is an emergency and patients must be taken to a hospital. Dangerous heart arrhythmias may also occur during attacks.

A diet that is low in carbohydrates and salt may be recommended to prevent attacks. In addition, medications called beta-blockers may reduce the number and severity of attacks while hyperthyroidism is brought under control.

Acetazolamide, a medication that is effective in preventing attacks in people with familial periodic paralysis, is usually not effective with thyrotoxic periodic paralysis.

Expectations (prognosis):

Chronic attacks will eventually result in progressive muscle weakness that is present even between attacks. Thyrotoxic periodic paralysis responds well to treatment. Treatment of hyperthyroidism will prevent attacks and may even reverse progressive muscle weakness.

Complications:

• heart arrhythmias during attacks
• difficulty breathing, speaking, or swallowing during attacks (rare)
• progressive muscle weakness

Calling your health care provider:

Go to the emergency room or call the local emergency number (such as 911) if intermittent muscle weakness occurs, particularly if there is a family history of periodic paralysis or thyroid disorders.

Fainting and difficulty breathing, speaking, or swallowing are among the emergency symptoms.