An attack often begins with muscle pain, cramping, and stiffness. This is followed by weakness or paralysis that tends to develop rapidly, usually in late evening or the early hours of the morning. The weakness is usually symmetrical; the limb muscles closer to the trunk (proximal) are predominantly affected, and weakness tends to start in the legs and spread to the arms. Muscles of the mouth and throat, eyes, and breathing are usually not affected, but occasionally weakness of the respiratory muscles can cause life-threatening respiratory failure. Attacks typically resolve within several hours to several days, even in the absence of treatment. On neurological examination during an attack, flaccid weakness of the limbs is noted; reflexes are usually diminished, but the sensory system is unaffected. Mental status is not affected. Attacks may be brought on by physical exertion, drinking alcohol, or eating food high in carbohydrates or salt. This may explain why attacks are more common in summer when more people drink sugary drinks and engage in exercise. Exercise-related attacks tend to occur during a period of rest immediately after exercise; exercise may, therefore, be recommended to abort an attack. There may be symptoms of thyroid overactivity, such as weight loss, a fast heart rate, tremor, and perspiration; but such symptoms occur in only half of all cases. The most common type of hyperthyroidism, Graves' disease, may additionally cause eye problems (Graves' ophthalmopathy) and skin changes of the legs (pretibial myxedema). Thyroid disease may also cause muscle weakness in the form of<unk>  myopathy, but this is constant rather than episodic.
Thyrotoxic periodic paralysis
Hypokalemic periodic paralysis
Hyperkalemic periodic paralysis
Zaki syndrome
Thyrotoxic myopathy
Ketosis-prone diabetes
Aicardi–Goutières syndrome
Bartter syndrome