Spasticity

Spasticity happens when certain muscles stay tight or stiff, making movement harder and less controlled. Damage to the brain or spinal cord disrupts normal signals between the nervous system and the muscles, which often causes spasticity. This muscle tightness can range from mild stiffness to severe, painful spasms that interfere with daily activities.

Conditions like stroke, multiple sclerosis, cerebral palsy, or spinal cord injury often trigger spasticity. Brain injuries, infections affecting the nervous system, or other disorders that impact nerve pathways controlling muscle movement can also lead to spasticity.

Definition of Symptom

Spasticity is a neurological symptom where certain muscles stay contracted for long periods, making them harder to move and reducing flexibility. It often involves increased muscle tone, where the muscles feel tighter than normal. This tightness can vary from mild stiffness to severe restriction in movement.

Sometimes, spasticity includes clonus, which is a series of rapid, involuntary muscle contractions that can happen when the muscle is stretched or triggered by certain movements. Common features of spasticity symptoms include:

• Muscle stiffness that limits range of motion.
• Muscle tightness that does not relax easily.
• Jerking or twitching movements.
• Clonus episodes after stretching or sudden movement.

Symptom	Description
Muscle stiffness	Muscles feel rigid and resist movement.
Increased tone	Continuous tension in muscles.
Clonus	Repeated, rhythmic muscle contractions.
Muscle tightness	Persistent feeling of muscle being pulled or shortened.

Spasticity can affect different muscle groups, but it often appears in the legs, arms, and sometimes the face. The severity of the symptom can change depending on activity level, temperature, or underlying conditions.

Spasticity is not a disease itself but a sign of nerve pathway disruption between the brain, spinal cord, and muscles. This disruption interferes with normal muscle control and reflexes.

Possible Causes/Diseases Condition

Spasticity occurs when damage to the brain or spinal cord affects how nerves control muscle movement. This damage disrupts normal signals between the nervous system and muscles, leading to stiffness, tightness, or spasms. Common neurological conditions linked to spasticity include:

• Cerebral palsy (CP), including spastic cerebral palsy
• Multiple sclerosis (MS)
• Amyotrophic lateral sclerosis (ALS)
• Stroke
• Traumatic brain injury (TBI)
• Spinal cord injury (SCI)

In cerebral palsy, brain injury before or shortly after birth can lead to spasticity. In MS, immune system damage to nerve fibers can cause muscle stiffness. ALS affects nerve cells that control voluntary muscles, sometimes leading to spasticity. Stroke can damage areas of the brain that manage movement, resulting in increased muscle tone.

TBI may cause similar effects if motor control regions are injured. SCI interrupts nerve pathways in the spinal cord, which can trigger involuntary muscle contractions. Below is a simplified table showing some causes and the part of the nervous system affected:

Cause	Primary Area Affected	Common Onset Pattern
Cerebral palsy (CP)	Brain motor control centers	Birth/early life
Multiple sclerosis (MS)	Central nervous system (CNS)	Gradual, episodic
ALS	Motor neurons in CNS	Progressive
Stroke	Brain tissue	Sudden
TBI	Brain motor regions	Sudden
SCI	Spinal cord	Sudden

Other Non-Disease Causes

Spasticity can also result from factors not linked to a disease. These causes often involve physical injury, environmental conditions, or certain medical procedures. Common non-disease causes include:

• Traumatic brain injury from accidents or falls.
• Spinal cord injury without underlying illness.
• Lack of oxygen to the brain during near-drowning or choking events.
• Post-surgical complications affecting the nervous system.

Injuries to the brain or spinal cord can disrupt normal nerve signals, causing muscles to tighten or spasm even without an ongoing disease process. Prolonged immobility, such as being in a cast or wheelchair for extended periods, can also contribute. Limited movement may lead to muscle shortening and increased tone.

How It Causes the Symptom

Spasticity develops when the central nervous system cannot properly control muscle activity. Damage to the brain or spinal cord disrupts the normal flow of nerve signals. In healthy movement, the brain sends signals through the spinal cord, telling muscles when to contract and relax.

When these pathways are damaged, the signals become unbalanced or overactive. This disruption leads to increased muscle tone. The muscles may stay partially contracted even when not in use, or they may contract suddenly without control. Key effects of the signal problem include:

• Excessive muscle contraction
• Prolonged stiffness in affected muscles
• Overactive reflexes that trigger stronger-than-normal responses

The imbalance between signals that tighten muscles and those that relax them causes the symptom. The severity of spasticity depends on how much nerve communication is disrupted and which muscles are involved. It can range from mild tightness to strong, involuntary spasms.

Possible Complications

Spasticity can cause pain that ranges from mild discomfort to more constant aching. This pain may come from muscle overuse, joint strain, or muscle spasms. It can affect sleep and daily activities. Reduced range of motion is common when muscles remain tight for long periods. Limited flexibility can make walking, dressing, and other movements more difficult. Over time, joints may become stiff and harder to move.

Coordination problems can occur when muscle stiffness interferes with smooth, controlled movements. This can make tasks that require precision, such as writing or buttoning clothes, more challenging. Muscles affected by spasticity may lose strength if they are not used regularly. Weakness can develop alongside stiffness, making it harder to maintain balance or perform physical activities.

One long-term risk is the development of contractures. Muscles and tendons can shorten permanently, locking joints in one position. Contractures can be painful and may require surgery to correct. Other possible issues include:

Complication	Possible Impact
Skin breakdown	Higher risk of pressure sores
Joint problems	Dislocation or subluxation
Hygiene challenges	Difficulty cleaning affected areas
Mobility loss	Increased dependence on assistance

If not managed, these complications can limit independence and reduce quality of life.

When to Seek Medical Attention

Spasticity can sometimes be managed with regular care, but certain changes require prompt medical review. Seek medical attention if muscle stiffness or spasms appear suddenly without a known cause. This is especially important if symptoms affect movement, speech, or vision. Get urgent care if spasticity happens along with:

• Weakness, numbness, or paralysis
• Trouble breathing or swallowing
• Severe headache or stiff neck
• Loss of balance or coordination
• Confusion, dizziness, or seizures

If spasticity gets worse over time, happens more often, or starts to limit self-care and movement, a healthcare provider should check your treatment. Painful stiffness that disrupts sleep, daily activities, or mood should also be discussed with a clinician.

Sometimes, spasticity may be linked to other health issues such as a urinary tract infection. Infections can make muscle tightness worse in people with neurological conditions, so new or increased symptoms may mean you need testing. A medical evaluation may include:

Assessment	Purpose
Physical exam	Check muscle tone and range of motion.
Neurological exam	Look for nerve or brain involvement.
Medical history	Find possible triggers or related conditions.