It is a condition in which there is too much muscle, so the arms or legs, for example, are stiff and difficult to move.
Muscle strength is regulated by signals from the brain to the nerves and tells the muscle to contract.
Hypertonia occurs when the brain or spinal cord regions that control these signals are damaged.
This can occur for many reasons, such as a blow to the head, strokes, brain tumors, toxins that affect the brain, neurodegenerative processes such as multiple sclerosis or Parkinson’s disease, or neurodevelopmental abnormalities such as cerebral palsy.
Hypertonia often limits the ease with which joints can move.
Walking can become stiff, and people can fall because it is difficult for the body to react quickly enough to regain balance if it affects the legs.
If the hypertonia is severe, it can cause a joint to “freeze,” which doctors call a joint contracture.
Spasticity is a term that is often used interchangeably with hypertonia.
Spasticity, however, is a particular type of hypertonia in which muscle spasms are increased by movement. In this type, patients usually have exaggerated reflex responses.
Stiffness is another type of hypertonia in which muscles have the same amount of stiffness regardless of the degree of movement.
Stiffness usually occurs in Parkinson’s disease, which involves the basal ganglia (a deep region of the brain).
To distinguish these types of hypertonia, the doctor, as a patient, will relax and then move the arm or leg at different speeds and in different directions.
The prognosis depends on the severity and its cause. In some cases, such as cerebral palsy, hypertonia may not change throughout life.
In other cases, it can get worse along with the underlying disease. If hypertonia is mild, it has little or no effect on a person’s health.
If there is moderate hypertonia, falls or joint contractures can impact the health and safety of a person.
If it is so severe that it causes immobility, the possible consequences include increased fragility and fracture of the bones, infection, bedsores, and pneumonia.
Muscle relaxant medications such as baclofen, diazepam, and dantrolene can be prescribed to reduce spasticity.
These medications can be taken orally, but you can inject baclofen directly into the cerebrospinal fluid through an implanted pump.
Botulinum toxin is often used to relieve hypertonia in a specific body area because its effects are local, not throughout the body.
People with hypertonia should try to preserve as many movements as possible by exercising within their limits and using physiotherapy.
- The resistance to externally imposed articulation movement is present at very low movement speeds, does not depend on the set speed, and does not present a rate or angle threshold.
- The simultaneous co-contraction of agonists and antagonists can occur, which is reflected in an immediate resistance to an inversion of the direction of movement around a joint.
- The limb does not tend to turn towards a particular fixed posture or an extreme joint angle.
- Voluntary activity in distant muscle groups does not cause involuntary movements in stiff joints, although rigidity may worsen.
Infant hypertonia is a relatively common disability found by the pediatric neurosurgeon.
In recent decades, several treatment options have been available for administration. However, the key to the successful use of these treatments is understanding the various forms of childhood hypertonia and the characteristics that distinguish them.
There are three main types of childhood hypertonia: spasticity, dystonia, and stiffness.
It is an increase dependent on the speed of resistance to movement of a muscle when it is passively stretched. It results from an interruption of the descending motor pathways that typically release GABA within the spinal cord.
Common causes of spasticity include cerebral palsy and traumatic brain injury. Other causes include stroke, meningitis, and anoxic encephalopathy.
It refers to the involuntary stereotypic patterns of extremity movement with associated hypertonia that end in a fixed posture with sustained muscular contractions of a rigid nature (resistance to movement of the lead tube).
When the limb moves passively, the tone tends to decrease.
In children, it has been defined as “resistance to joint movement imposed externally,” which is present even at very low movement speeds and does not depend on rate.
The simultaneous co-contraction may be present, and the resistance to alteration in the direction of movement.
No involuntary movement patterns are observed in association with voluntary distal movement in an extremity, and the limb does not tend to return to a fixed posture or extreme angle.