Hypotonia: Causes, Symptoms, Diagnosis, and Treatment.

hypotonia medical definition

Also called Floppy Baby Syndrome, is a condition that features decreased muscle tone.

Muscles Tone refers to the amount of muscle-fiber tension in individual muscles or muscle groups.

Hypotonia (also known as Poor Muscle Tone or Floppy Baby Syndrome) is a term used to describe a reduction in muscle tone.

The muscles of those who suffer from this condition display a remarkably low resistance to movement and stretching

It usually manifests in children and sometimes adults too as a result of different diseases and disorders, but it can also appear on its own.

Kids with this problem will feel “floppy” when held, and they tend to rest with their elbows and knees loosely extended, which is odd because infants with normal muscle tone would typically flex elbows and knees.

Hypotonia is not a synonym of muscle weakness. This condition can make it harder to use the muscles, but muscle weakness can come either before, during, or after the appearance of Hypotonia.

For those who developed this condition during their childhood, the effects can last until their adulthood.

Hypotonia causes

Given Hypotonia is more of a symptom than a disease of its own, there are several conditions and underlying health issues capable of causing Hypotonia.

Some of these issues affect the nerves and the nervous system, elements essential for muscles to properly function. While others are non-neurological problems, more often than not, inherited conditions.

Neurological conditions

Cerebral palsy: it is an inherited movement disorder that appears in early childhood and features impaired muscle coordination, also known as “spastic paralysis,” as well as others disabilities.

When this condition damages the peripheral nervous system, the muscles of a particular area of the body become flaccid and unresponsive to most sensations or stimuli.

This peripheral paralysis can cause muscle weakness, complete or partial immobility, and Hypotonia.

Spinal Cord Injury: It refers to damage to any part of the spinal cord or nerves that causes changes in their function

Usually, such changes are permanent, but in some cases, they can be temporary. Still, it negatively impacts muscle strength, sensation, and other bodily functions.

Months after the injury, spasticity gradually appears. The Spinal Cord Injury can cause loss of tendon reflexes, muscle paralysis, as well as flaccid muscle tone.

Traumatic Brain Injury: some people know it as intracranial injury. It happens when an external force causes damage to the brain, disrupting its standard functions.

This injury results in a wide-range of effects. From memory problems, confusion, and fatigue to the uncontrolled tightening of skeletal muscles.

Usually, the nervous system allows for groups of muscles to work in a coordinated way so that when one muscle flexes, its opposing muscle relaxes. This process keeps the muscle tone at a stable level.

But after a Traumatic Brain Injury, the nerves fail to send and deliver the signals needed for this process to happen. That results in muscles needlessly staying tight or contracted.

Meningitis: It is the inflammation of the tissues that cover the brain and spinal cord.

This condition negatively impacts the central nervous system, causing severe headaches, remarkable lack of physical coordination, increasingly poor blood circulation, stiff neck, and muscle pain.

In some cases, it can even cause opisthotonos, which features painfully rigid and arched neck and spine. Muscle spasms, body aches, and generalized weakness could happen due to this condition.

Encephalitis: It is an acute inflammation of the brain, which occurs because of a viral infection. But in some cases, it’s the result of an autoimmune response.

It is rarely a life-threatening condition. Still, it can cause muscle spasms, seizures, and even coma. As if that isn’t enough, there are several types of Encephalitis.

One type of this condition, commonly known as West Nile Encephalitis, usually produces non-itchy rashes, loss of muscle tone, and generalized weakness.

Muscular Dystrophy: It is a term that refers to a group of muscular disorders, which is the result of a genetic mutation that hampers the production of muscle proteins that needed to keep muscles healthy.

One kind of Muscular Dystrophy called Myotonic Dystrophy features a gradual muscle wasting and weakness. That causes a delayed muscle relaxation known as Myotonia, as well as weak muscle tone

The progressive weakening process typical of this disease makes people unable to relax some muscles after using them.

Myasthenia Gravis: It is a chronic neuromuscular disease, the possible result of an autoimmune response that breaks down the communications between muscles and nerves.

This condition causes varying degrees weakness, as well as the rapid fatigue of any of the skeletal muscles under the sufferer’s voluntary control.

The children born with Myasthenia Gravis are prone to developing Hypotonia.

Spinal Muscular Atrophy: It refers to a genetic neuromuscular disorder that affects the nervous system, more specifically, the control of voluntary muscle movement.

According to medical experts, the cause of this disease is the loss of motor neurons (nerve cells transmit signals from the brain to particular groups of muscles).

That is why this condition often results in Hypotonia and muscular weakness.

Charcot-Marie-Tooth disease: It is a group of inherited disorders that damage the peripheral nervous system. This condition features the gradual loss of muscle tissues, as well as sensory loss.

This damage occurs because the disease directly impacts the myelin sheath that covers and protect the nerves.

Multiple Sclerosis: It is a demyelinating disease, in which the immune system attacks the myelin sheath disrupting the communication between the brain and several parts of the body.

Two common symptoms of Multiple Sclerosis are muscle spasms and stiffness. Female patients who suffer from this condition are likely to develop Hypotonia due to cerebellar degeneration.

Motor Neurone Disease: It is a rare neurodegenerative disorder that affects the brain and the nerve cells that send the brain’s signals to the muscles.

This condition affects the muscles’ ability to function and results in diminished limb movements, lack of tendon reflexes, and loss of muscle tone.

Non-neurological problems

Down’s Syndrome: It is an inherited disorder in which a child is born with an extra chromosome

Some of the most recognizable signs of this syndrome are intellectual impairment, poorly developed motor skills, small stature, and low muscle tone.

Prader-Willi Syndrome: It refers to a weird genetic multisystem disorder which causes a wide range of symptoms that affects a child’s physical and psychological development.

The cause of this condition is a disruption of the SNRPN gene, a protein that helps to build a part of the molecular mechanisms that shape the development of the brain.

It features decreased muscle tone, feeding problems, delayed growth, and it eventually leads to obesity.

Tay-Sachs Disease: It is a rare and deadly neurodegenerative disorder that gradually destroys nerve cells in the brain and the spinal cord.

People who suffer from this condition lack a specific protein called hexosaminidase. That results in an excessive accumulation of certain fats that leads to the dysfunction of the central nervous system.

This disorder usually causes myoclonic jerks, muscle weakness, and low muscle tone.

Congenital Hypothyroidism: It is a condition that consists of an inadequate thyroid hormone production at birth.

Most babies born with this disorder show very few clinical manifestations, so it’s pretty hard to predict when a child will get affected by this condition.

The typical signs of Congenital Hypothyroidism are excessive sleeping, infrequent bowel movements, poor feeding, weight gain, small stature, and poor muscle tone.

In the United Kingdom, babies get screened for this condition so healthcare providers can treat them earlier.

Marfan Syndrome: It refers to a rare genetic disorder that affects the connective tissues that hold all the body’s cells and organs together.

It features several skeletal malformations (sometimes that includes scoliosis), subcutaneous fat, and Hypotonia.

Aside from these diseases and disorders, a baby that’s born prematurely might have low muscle tone too because their muscles are still underdeveloped.

Hypotonia symptoms

Those who suffer from Hypotonia experience loss of voluntary muscle control. They may find it difficult to speak, chew and swallow food.

When the underlying condition is way too severe, the patient might be unable to walk or perform any physical activity.

And it can get worst if medical experts don’t treat the cause of the problem soon enough, especially in the cases of babies.


Since this condition mostly affects children, people tend to look for a pediatrician with expertise in disorders of the nervous system or nerve cells. In other cases, some prefer to ask a neurologist.

The specialist will likely need details about the pregnancy and delivery, as well as whether there have been issues (such as seizures or feeding difficulties) since the birth of the child.

Experts can perform any or most of the following tests:

  • Full Physical Examination
  • Blood Tests
  • Computerized Tomography (CT)
  • Electroencephalogram (EEG)
  • Electromyography (EMG)
  • Nerve conduction studies
  • Muscle Biopsy
  • Genetic Testing


The first step to take is fighting the underlying condition causing Hypotonia. If healthcare providers can’t cure the disease or disorder responsible for the problem, the procedures will focus on alleviating the symptoms.

Treatments for Hypotonia may include physiotherapy, and for those who suffer from impaired speech, doctors recommend speech and language therapy.

In the best case scenario, when medical experts manage to cure the underlying cause of Hypotonia, the muscle tone should gradually go back to normal on its own.