Nocturnal Leg Cramps: This condition is characterized by sudden, involuntary contractions of the leg muscles, often occurring at night before sleep. It's a common issue that can be related to muscle fatigue, dehydration, or electrolyte imbalances.

Restless Legs Syndrome (RLS): A disorder that causes a strong urge to move one's legs, often accompanied by uncomfortable sensations. While it doesn't always cause spasms, the discomfort can lead to involuntary movements.
Periodic Limb Movement Disorder (PLMD): Involves involuntary movements of the legs or arms during sleep, which can sometimes be perceived as spasms before falling asleep.
Muscle Strain or Overuse: Recent physical activity or overuse of the leg muscles can lead to spasms, especially if the individual is not accustomed to such exertion.

Peripheral Artery Disease (PAD): Although less common, intermittent claudication (pain in the legs when walking) can sometimes be mistaken for nocturnal leg cramps. Missing PAD could lead to severe consequences, including limb loss.
Neurological Disorders (e.g., Multiple Sclerosis, Peripheral Neuropathy): Certain neurological conditions can cause muscle spasms. While these are less likely, they are critical to diagnose due to their significant impact on the patient's quality of life and the potential for serious complications.

Hypocalcemia or Hypomagnesemia: Electrolyte imbalances, particularly low calcium or magnesium levels, can cause muscle cramps and spasms. These conditions are less common but can be serious if not addressed.
Dystonia: A neurological disorder that causes involuntary muscle contractions, leading to repetitive movements or abnormal postures. It's rare for dystonia to present solely as leg spasms before sleep, but it's a possibility in some cases.