Stiff Baby Syndrome: What to do with a Hypertonic Baby

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A tense baby will catch your attention in an instant. If they are tense something must be wrong!

But what if they are tense all the time? Surely this isn’t normal.

If your baby constantly looks on edge, has a clenched fist, or a very strong latch, it is possible that they are hypertonic.

This is a scary thought and will be unsettling for parents from the sheer look of discomfort on your baby’s face. Their inability to move freely is something that requires medical intervention to work through.

Hopefully this serves as a good starting point to learn more about hypertonic babies so you can identify the problem early and seek the right assistance.

hypertonic baby symptoms

What Is Hypertonia?

Hypertonicity is a condition where the muscles of your baby are very tight. You cannot easily bend the legs and arms of your baby and they will have difficulty relaxing.

While hypertonia affects the muscles, this is actually a neurological problem that affects the nerves and brain.

It is known as the Stiff Baby Syndrome, hyperekplexia, or startle reflex.

This is a hereditary disease that is quite rare. In fact, to date there has only been 150 reported cases.


This condition is hereditary in nature, and is caused when there are mutations in a specific genetic sequence.

The details of which will sound like medical jargon, but if you are interested in some deep reading about the technicalities of the condition you can check the info out here.

The laymen’s synopsis is here:

The mutation in the genes can affect the glycine production in the body. Glycine is an inhibitor transmitter. It actually helps in diminishing the action of the nerve cells, brain, and spinal cord.

To put it simply, it helps control the way we react to stimuli.

When something interferes with the functioning of Glycine or if it is damaged, the body is going to lose its ability to control the way it responds to stimulus and when that happens, our body will respond to outside triggers faster and quite excessively.

The condition can also be brought on by circumstantial causes that can damage the signals going from the spinal cord to the brain:

  • Traumatic birth
  • Infant stroke
  • Other ganglia disorders

Signs & Symptoms

Muscle Stiffness

This is the most visible sign that your child may suffer from this condition. The arms and legs appear tense, and it is difficult for them to raise their arms overhead.

As your baby grows, you will notice that they do not have the increasing freedom of movement you would expect. They will have trouble rotating their body, or bend naturally.

This tense state may visibly relax when your baby is asleep.

Extreme Startled Reactions

Babies can have a noticeably startled reaction to unexpected sounds or noise, movement, and touch.

This is characterized by excessive arching of the head and jerky movements of the arms and legs. Sometimes a severe startle episode can lead to a very stiff looking fall.

Babies remain conscious while this is happening and it can be very unpleasant for a concerned parent to watch.

Delayed Motor Development

The jerking movements will discourage a baby from moving much at all.

When they do, it is done slowly.

As a result their mobility development can be delayed and may not progress to crawling and walking until a much later stage.

Unstable Gait

The involuntary jerking movements can lead to unstable walking patterns in toddlers.

Their legs are often placed further apart than what would be considered normal due to the body trying to compensate for its center of gravity.

The wide base of support, and the reduced movement control the child has can lead to wobbly gait patterns.


The child may also exhibit excessive reflexes such as knee jerk when stimulated.

Interrupted Breathing

This occurs primarily because of muscle stiffness and tightening. When the muscles for breathing are tense, it cannot assist the lungs and diaphragm when breathing.

Hip Dislocation

This is usually present at birth, and the result of underdeveloped muscles that support the hips.

It is important to note that babies with minor hyperekplexia may only exhibit symptoms in certain conditions such as when sick, or under stress.

Diagnosis Of Stiff Baby Syndrome

This condition is most often thought of as an epilepsy or even a seizure.

To determine if your child indeed has hypereklesia you need to do the following together with your doctor:

Prepare A Detailed Family History

This is of great relevance given the fact that this is a genetic disorder.

Tell your doctor if any other family members have been affected with the disease.

Examine The Symptoms

It is likely that you have been watching your baby very closely… and probably losing sleep as a result.

Keep a log of the symptoms that your child is exhibiting such as stiffness, and the startle response.

The more detail you can provide your doctor on timing and circumstances around each episode will assist with the diagnosis.

stiff baby syndromeFurther Testing

There are a number of tests that can be performed that your child indeed has hyperekplesia such as:

  • Electromyography (EMG) – This will record the electrical impulses that are being produced by the muscles.
  • Electroencephalography (EEG) – This will record brain activity and the impulses that it emits.
  • Molecular Genetic Testing – Genetic testing that will look for specific mutations on GLRA1 and SLC6A5 gene sequence.


Drug Therapy

Your doctor may prescribe a combination of anti-anxiety drug and anti-spasmodic drugs.

Examples of such drugs are: carbamazepine, phenobarbital, phenytoin, and diazepam.

It can also include 5-hydroxytryptophan, piracetam, clonazepam and sodium valproate.

Physical Therapy

This type of therapy can help supplement the drugs.

It will help train the patient on how to control their movements as well.

Preventative Therapy – Genetic Counselling

This is a proactive step that can be taken for those who have a family history of hyperekplexia.

Genetic counselling can help determine the probability of offspring being affected.

Differential Diagnosis

There are a number of conditions that can show similar symptoms to hyperekplexia.

It is best to know it to make sure that your child is going to get the right diagnosis and treatment.

Jumping Frenchmen Of Maine

This condition is characterized by extreme startled reactions, just like hyperekplexia.

Patients with this condition are prone to involuntarily raising their head, jumping, and involuntarily repeating words.

They are responsive to commends where those with hyperekplexia are not.

Startle Epilepsy

Those with the condition will also startle, but are also subject to seizure like symptoms.

Tips For Dealing With Hypertonicity

Start Therapy Early

Your child’s brain can be retrained, and this process will be easier the earlier you start. Children have previously had therapy sessions from as early as two-months old.

Learning how to handle the emotions of frustration and being able to stay calm will be an important skill to develop.

As your child grows they will understand more of what is going on, and will be capable of handling the process better. It will seem far more normal to them than if they started later in life.

Assist With Stretching

Ask your child’s therapist to teach you how to assist your child to stretch properly.

Improper stretching can lead to muscle and ligament tears and injuries so you should not attempt this without that initial guidance on the techniques to use, and frequency that will work best for your child.

Massage Your Child

Again, proper training is imperative. The physical state of your child can be painful, and the massage can provide some relief from the symptoms.

Massages can help relax muscles if done correctly, but can also worsen the pain.

So again seek professional guidance before attempting to do so.

Final Word

Through education and training your child will be able to cope with any limitations that hyperekplexia can impose and lead a full life.

Being a positive and encouraging parental influence will be the key to making this happen, along with good quality medical help.

Educating the whole family on how to handle these limitations will ensure that aggravations are minimized in the long run.

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