Hypertonia: Description, Causes and Risk Factors:
Hypertonia is a condition in which there is too much muscle tone so that arms or legs, for example, are stiff and difficult to move. Muscle tone is regulated by signals that travel from the brain to the nerves and tell the muscle to contract. Hypertonia happens when the regions of the brain or spinal cord that control these signals are damaged. This can occur for many reasons, such as a blow to the head, stroke, brain tumors, toxins that affect the brain, neurodegenerative processes such as in multiple sclerosis or Parkinson's disease, or neurodevelopmental abnormalities such as in cerebral palsy.
Hypertonia may also result from injury, disease, or conditions that involve damage to the central nervous system (CNS). Examples include spasticity, dystonia (prolonged muscle contractions that cause twisting and repetitive movements or abnormal posture) and rigidity.
Hypertonia often limits how easily the joints can move. If it affects the legs, walking can become stiff and people may fall because it is difficult for the body to react quickly enough to regain balance. If hypertonia is severe, it can cause a joint to become "frozen," 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 the muscles' spasms are increased by movement. In this type, patients usually have exaggerated reflex responses.
Rigidity is another type of hypertonia in which the muscles have the same amount of stiffness independent of the degree of movement. Rigidity usually occurs in diseases such as Parkinson's disease, that involve the basal ganglia (a deep region of the brain). To distinguish these types of hypertonia, a doctor will as the patient to relax and then will move the arm or leg at different speeds and in a variety of directions.
The prognosis depends upon the severity of the hypertonia and its cause. In some cases, such as cerebral palsy, the hypertonia may not change over the course of a lifetime. in other cases, the hypertonia may worsen along with the underlying disease. If the hypertonia is mild, it has little or no effect on a person's health. If there is moderate hypertonia, falls or joint contractures may have an impact on a person's health and safety. If the hypertonia is so severe that is caused immobility, potential consequences include increased bone fragility and fracture, infection, bed sores, and pneumonia.
Symptoms include increased muscle tone, rapid muscle contraction
s, muscle spasms
, involuntarycrossing of the legs (scissoring) and fixed joints. Hypertonia can vary from mild muscle stiffness tosevere, painful, and uncontrollable muscle spasms.
The first step in diagnosing hypertonia is obtaining the history of the child, such as details aboutpregnancy, delivery, post-natal complications, nutrition and any infections.A complete physical examination is done, looking for other neurological problems, developmentalmilestones, differences between upper and lower body tone, nutritional status, skin disorders, orsigns of a genetic dysmorphism (a major difference in the shape of the body or organ comparedto the average shape that is caused by a genetic mutation). It is important to determine if thehypertonia worsens or improves over time, or is fixed.
Other diagnostic tools include:
Laboratory tests that can identify certain causes (e.g., infections, genetic)
- Imaging techniques (e.g., CT scan, MRI) to help find any neurological malformation orevidence of traumatic causes.
- Electromyography, a test that evaluates nerve and muscle function.
Muscle relaxing drugs such as baclofen, diazepam, and dantrolene may be prescribed to reduce spasticity. All of these drugs can be taken by mouth, but baclofen may also be injected directly into the cerebrospinal fluid through an implanted pump. Botulinum toxin is often used to relieve hypertonia in a specific area of the body because its effects are local, not body-wide. People with hypertonia should try to preserve as much movement as possibly by exercising within their limits and using physical therapy.
Drugs that affect the dopamine system (dopamine is a chemical in the brain) such as levodopa/carbidopa, or entacapone, are often used to treat the rigidity associated with Parkinson's disease.
Physiotherapy has been shown to be effective in controlling hypertonia with the use of static stretching which reduces motoneuron excitability. Other interventions include icing, inhibitory pressure (applying firm pressure over muscle tendon), promoting body heat retention, and rhythmic rotation (slow repeated rotation of affected body part to stimulate relaxation). A more unconventional method for limiting tone is to deploy quick repeated passive movements to an involved joint in cyclical fashion; this has also been demonstrated to show results on persons without physical disabilities. For a more permanent state of improvement, exercise and patient education is imperative. Isokinetic, aerobic, and strength training exercises should be performed as prescribed by a physiotherapist, and stressful situations that may cause increased tone should be minimized or avoided.
NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.