Individuals who experience repeated episodes of sudden leg weakness should seek prompt medical attention, states Healthgrades. There are many causes of leg weakness, from general fatigue to life-threatening conditions such as stroke.
Leg weakness may occur as part of general fatigue over the whole body, or it may occur in one or both legs, Healthgrades explains. Many people perceive muscle weakness when they are tired or ill, but true weakness is characterized as a loss of muscle strength and function.
True weakness in the legs can be caused by sciatica, a spinal problem leading to the pinching or compressing of nerves as they leave the spinal cord through the vertebrae. Neuromuscular diseases such as multiple sclerosis can also cause muscle weakness in the legs, as reported by Healthgrades.
Sudden-onset leg weakness may be a sign of stroke, which can be a life-threatening condition, requiring immediate medical attention, warns Healthgrades. This is especially true if the weakness is felt on only one side or accompanied by serious symptoms such as blurred vision, numbness, severe headache, high fever, fainting or change in consciousness. Because there are so many causes of persistent sudden leg weakness, individuals should consult a health care professional as soon as possible for evaluation if experiencing this condition.