What Causes Poor Muscle Tone?

Conditions list medically reviewed by George Krucik, MD, MBA

Hypotonia, or poor muscle tone, is usually detected at birth or during infancy. If your infant has hypotonia, they may appear limp at birth and not be able to keep their knees and elbows bent. Your child may continue to struggle with feeding and... Read More

Hypotonia, or poor muscle tone, is usually detected at birth or during infancy. If your infant has hypotonia, they may appear limp at birth and not be able to keep their knees and elbows bent. Your child may continue to struggle with feeding and motor skills as they grow.

Many different diseases and disorders cause the symptoms of hypotonia. It’s easily recognizable because it affects muscle strength, motor nerves, and the brain. However, diagnosing the disease or disorder that is causing the problem can be challenging.

Hypotonia is sometimes called floppy muscle syndrome.

Signs of hypotonia

Depending on the underlying cause, hypotonia can appear at any age. Signs of hypotonia in infants and children include:

  • poor or no head control
  • delay in gross motor skills development, such as crawling
  • delay in fine motor skills development, such as grasping a crayon

Signs of hypotonia at any age include:

  • decrease in muscle tone
  • decrease in strength
  • poor reflexes
  • hyperflexibility
  • speech difficulties
  • decrease in activity endurance
  • weakened posture

Causes of hypotonia

Hypotonia can be triggered by a problem with the nervous system or muscular system. Sometimes it’s the result of an injury, illness, or inherited disorder. Sometimes a cause is never identified.

Some children are born with hypotonia that is not related to a separate condition. This is called benign congenital hypotonia. Physical, occupational, and speech therapy can help your child gain muscle tone and stay on track with development. Some children with benign congenital hypotonia have minor developmental delays or learning disabilities. These disabilities may continue through childhood.

Hypotonia can be caused by conditions that affect the brain, central nervous system, or muscles. These conditions include:

  • cerebral palsy
  • brain damage, which can be caused by lack of oxygen at birth
  • muscular dystrophy

In many cases, these chronic conditions require lifelong care and treatment.

Hypotonia can also be caused by genetic conditions. These conditions include:

  • Down syndrome
  • Prader-Willi syndrome
  • Tay-Sachs disease
  • trisomy 13

Children with Down syndrome and Prader-Willi syndrome often benefit from therapy. Children with Tay-Sachs disease and trisomy 13 typically have shortened lives.

Rarely, hypotonia is caused by botulism infections or contact with poisons or toxins. However, the hypotonia often goes away after you recover.

When to see a doctor

Hypotonia may be diagnosed at birth. In some cases, however, you may not notice your child’s condition until they’re older. An indicator is that your child is not meeting developmental milestones. Schedule regular appointments for your child with a doctor. Be sure to mention any concerns you have about your child’s progress.

Your doctor will assess your child’s development and run tests if they have concerns. Tests may include blood tests and MRI and CT scans.

If you notice sudden signs of the condition in a person of any age, seek emergency medical care.

Treating hypotonia

Treatment varies depending on how your child is affected. Your child’s general health and ability to participate in therapies will shape a treatment plan. Some children work frequently with physical therapists. Depending upon your child’s abilities, they may work toward specific goals such as sitting upright, walking, or taking part in sports. In some cases, your child may need help with their coordination and other fine motor skills.

Children with severe conditions may need wheelchairs for mobility. Because this condition makes joints very loose, it’s common to have joint dislocations. Braces and casts can help prevent and correct these injuries.

What is the long-term outlook for people with hypotonia?

The long-term outlook depends on the following:

  • underlying cause
  • age
  • severity
  • muscles affected

Having hypotonia can be challenging. It’s often a lifelong condition, and your child will need to learn coping mechanisms. They may also need therapy. However, it’s not life-threatening, except in the cases of motor neuron or cerebellar dysfunction. 

Medically reviewed by University of Illinois-Chicago, College of Medicine on April 11, 2016Written by Julie Roddick and Marissa Selner


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This feature is for informational purposes only and should not be used to diagnose. Please consult a healthcare professional if you have health concerns.

Conditions list medically reviewed by George Krucik, MD, MBA