<unk>  causes episodes of extreme muscle weakness, with attacks often beginning in childhood. Depending on the type and severity of the<unk> P, it can increase or stabilize until the fourth or fifth decade where attacks may cease, decline, or, depending on the type, continue on into old age. Factors that can trigger attacks include rest after exercise, potassium-rich foods, stress, fatigue, weather changes, certain pollutants (e.g., cigarette smoke) and fasting. Muscle strength often improves between attacks, although many affected people may have increasing bouts of muscle weakness as the disorder progresses (abortive attacks). Sometimes with<unk> P those affected may experience degrees of muscle stiffness and spasms (myotonia) in the affected muscles. This can be caused by the same things that trigger the paralysis, dependent on the type of myotonia. Some people with<unk>  have increased levels of potassium in their blood <unk>  during attacks. In other cases, attacks are associated with normal blood potassium levels (normokalemia). Ingesting potassium can trigger attacks in affected individuals, even if blood potassium levels do not rise in response. In contrast to<unk> P, hypokalemic periodic paralysis (noted in humans) refers to loss-of-function mutations in channels that prevent muscle depolarisation and therefore are aggravated by low potassium ion concentrations.
Hyperkalemic periodic paralysis
Hypokalemic periodic paralysis
Potassium-aggravated myotonia
Thyrotoxic periodic paralysis
Paroxysmal exercise-induced dystonia
Myotonia congenita
Glycine encephalopathy
Thyrotoxic myopathy