Hypotonia is a medical term which means loss of muscle tone or poor muscle tone. The condition is mainly observed in infants. A healthy muscle even while at rest has some amount of stiffness and tension; this can be expressed as tone of the muscle. In hypotonia the tone is lacking, as a result the limbs become rubbery and infant is not able to keep his knees and elbows bent.
This applies in all muscles and hence such infants find difficult to suck while feeding and their developmental motor skills are retarded.Such infants and children have problems from maintaining good posture and mobility. There are several diseases that can cause hypotonia. It can be since birth or may be acquired due to some medical condition or injury.
Hypotonia in infants is easily detected because of loss of muscle tone, but diagnosis of underlying cause is challenging task even for the pediatrician. Treatment is involved in managing the cause. Many children grow out of the condition with physical therapy, speech therapy and occupational therapy. Some children may require wheelchair or other assistance if hypotonia is severe.
What Are The Causes Of Hypotonia In Infants?
Hypotonia is a symptom and it can manifest due to several underlying causes. Hypotonia can be present since birth or may develop later during infancy. At birth it is regarded as congenital hypotonia where as if it is later on it is called acquired hypotonia.
It can result from neurological diseases or muscular problems. Inheritance, injury and illnesses can cause damage to the brain, spinal cord, muscle junction etc. Here are some of the underlying causes for hyportonia in infants:
Causes of hypotonia at birth:
- Premature baby has increased risk of developing hypotonia. However, most babies grow out of it after few years.
- Hypothyrodism since birth: Lack of thyroid hormone in infants can cause loss of muscle tone. In severe cases there may be associated mental retardation.
- Severe infection leading to serious condition called sepsis.
Genetic causes: Hypotonia is common feature in certain genetic condition such as:
- Down syndrome
- Tay-sachs disease
- Trisomy 13
- Prader willi syndrome
- Marfan’s syndrome
Brain and spinal cord problems:
- Injury to brain or spinal cord during childbirth.
- Infection affecting brain such as meningitis and encephalitis.
- Kernicterus: It is a condition that can damage brain of the infant. It is caused by high level of bilirubin and jaundice in new born.
- Cerebral palsy
- Myesthenia gravis
- Muscular dystrophy
Other causes may include hypoglycemia, congestive cardiac failure, inherited metabolic diseases.
Signs And Symptoms Of Hypotonia In Infants
Hypotonia can develop at any age but most often it is seen in infants. The signs and symptoms of hypotonia in children are as follows:
- Weakness of muscles that is noticeable as the infant grows.
- Initially after birth the child is not able to suck properly.
- No control of neck muscles leading to bending of head on one side.
- Flexible joints and is not able to stand or place weight on legs.
- Frequently falls due to weak muscles of joints.
- Delayed milestones, especially motor skills.
- Weak cry
- Poor reflexes
- Weak posture
- Clumsy behavior
- Protrusion of abdomen as the abdominal muscle is weak. They are not able to hold the abdominal organs.
- Difficulty in lifting or reaching any object.
Alternative Therapies For Hypotonia In Infants
Hypotonia is a symptom of an underlying medical condition. It is not a disease in itself. Treatment thus involves managing hypotonia as well as the underlying cause. Management of hypotonia needs a multidisciplinary approach. Depending on the cause, the child may need to be consulted to a pediatrician, neurologist, orthopedic surgeon, a physiotherapist, occupational therapist, speech therapist and so on.
During the first year of infancy physiotherapist and pediatrician role is much more crucial. As the child grows up, physiotherapist teaches the parents how to assist the child while sitting and walking. As the child grows, occupational therapist makes the child learn activities of daily life. He needs to know fine finger skills that will help him during feeding, dressing on his own.
Some children may need speech and language therapy which will help to speak and swallow, because of weakness of deglutination muscles. Children having severe hypotonia may not be able to walk or stand. They may need wheelchair. Older children may need to wear braces and cast to protect against injury because of loose joints. Hypotonia in infants is a chronic condition and may need a prolonged period of treatment.