There are many diseases that cause muscle spasms. According to the American Academy of Orthopaedic Surgeons, muscle spasms or cramps are an involuntary and forcible contraction of a muscle that does not relax. The AAOS notes that spasms can affect any muscle that's under voluntary control, and that spasms can affect a whole muscle, part of a muscle or several muscle groups. Muscle spasms can be symptomatic of debilitating conditions.
Amyotrophic Lateral Sclerosis
Amyotrophic lateral sclerosis is a disease that can cause muscle spasms. According to the ALS Association, ALS—also known as Lou Gehrig's disease—is "a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord." Upper motor neurons travel from the brain to the spinal cord, and lower motor neurons travel from the spinal cord to muscles throughout the body. ALS, notes ALSA, involves the degeneration of upper motor neurons, and when motor neurons perish, a person's brain loses the ability to manage muscle control and movement. Upper motor neuron damage is characterized by tight, stiff and spastic muscles and exaggerated reflexes. The term lateral in the name amyotrophic lateral sclerosis describes the location in a person's spinal cord where nerve cells are affected. Degeneration of this area leads to scarring or hardening—sclerosis—of the lateral or the far left and right portions of the spinal cord.
Parkinson's Disease
According to the National Institute of Neurological Disorders and Stroke—a division of the National Institutes of Health—Parkinson's disease is a degenerative central nervous system disorder, and it's believed that at least 500,000 Americans currently have Parkinson's disease, although the actual number may be much higher. NINDS states that Parkinson's disease is a movement disorder characterized by four principle symptoms, including tremor or trembling of the hands, arms, legs, jaw or head, muscle rigidity in the limbs and trunk, bradykinesia or slow movements and postural instability. NINDS also notes that the lack of movement associated with Parkinson's disease may cause muscle spasms or cramps, particularly in the legs and toes, and that Parkinson's patients may develop pain secondary to spinal nerve root compression or muscle spasms.
Poliomyelitis
According to the U.S. National Library of Medicine and the National Institutes of Health, poliomyelitis is "a viral disease that can affect a person's nerves and lead to partial or full paralysis." Poliomyelitis, which is caused by an infection of the polio virus, is transferred between people by person-to-person contact, contact with infected mucus from an infected person's nose or mouth or by contact with infected feces. The NIH states that there are three basic patterns of poliomyelitis infection, including subclinical, non-paralytic and paralytic. The subclinical infection is the only one of the three that does not involve some degree of muscle spasm. Non-paralytic poliomyelitis is characterized by back pain, excessive fatigue and muscle spasms in any part of the body, among many other symptoms. Paralytic poliomyelitis is characterized by fever lasting several days, breathing difficulty and muscle spasms in the calf, neck or back, among other symptoms.
