In the 1890s, a German pathologist, Professor Hans Chiari, first described brain abnormalities at the junction of the skull and spine. He categorized these in order of severity; types I, II, III and IV. This condition is called Chiari malformation .
Definition
Chiari malformation, formerly called Arnold-Chiari malformation, is where the bottom of the brain presses into the spinal canal. This condition occurs when the cerebellum (the part of the brain that controls muscle coordination and movement) pushes down through a hole at the bottom of the skull. This hole is called the foramen magnum. Normally, only the spinal cord passes through the foramen magnum.
Doctors categorize Chiari malformations into three types, depending on the anatomy of the brain tissue that is displaced into the spinal canal and whether there are any problems with brain or spinal development. Type 1 Chiari malformations develop as the skull and brain grow. As a result, signs and symptoms may not occur until late childhood or adulthood. The pediatric forms, type 2 and type 3 Chiari malformations, are present at birth (congenital).
Chiari malformation is a structural defect in the cerebellum. That’s the part of the brain that controls balance.
Symptom
Many people with Chiari malformations have no signs or symptoms and do not require treatment. Their condition is only detected when tests are performed for unrelated disorders. However, depending on the type and severity, Chiari malformations can cause a number of problems.
Chiari Malformation Type 1
In Chiari malformation type 1, signs and symptoms usually appear in late childhood or adulthood.
Headaches, often severe, are a classic symptom of Chiari malformation. They generally occur after a sudden cough , sneeze or strain. Children with type 1 Chiari malformation may also experience:
- Neck pain
- Unsteady gait (problems with balance)
- Poor hand coordination (fine motor skills)
- Numbness and tingling in the hands and feet
- Dizzy
- Difficulty swallowing, sometimes accompanied by choking and vomiting
- Speech problems, such as hoarseness.
Less commonly, people with Chiari malformation may experience:
- Ringing or buzzing in the ears (tinnitus)
- Weakness
- Slow heart rhythm
- Curvature of the spine (scoliosis) associated with spinal cord disorders
- Breathing problems, such as central sleep apnea, which is when a person stops breathing while sleeping.
Chiari Malformation Type 2
In Chiari malformation type 2, the amount of tissue extending into the spinal canal is greater than in Chiari malformation type 1.
Signs and symptoms may include those related to a form of spina bifida called myelomeningocele that almost always accompanies Chiari malformation type 2. In myelomeningocele, the spine and spinal canal do not close properly before birth.
Signs and symptoms may include:
- Changes in breathing patterns
- Problems swallowing, such as choking
- Rapid downward eye movement
- Weakness in the arms
Chiari malformation type 2 is usually noted by ultrasound during pregnancy. It can also be diagnosed after birth or in early infancy.
Chiari Malformation Type 3
In the most severe form of the condition, type 3 Chiari malformation, part of the lower back part of the brain ( cerebellum ) or brain stem extends through a hole in the back of the skull. This form of Chiari malformation is diagnosed at birth or with an ultrasound during pregnancy.
This type of Chiari malformation has a higher mortality rate and can also cause neurological problems.
Chiari Malformation Type 4
Type 4 involves an incomplete or underdeveloped cerebellum. It is usually fatal in infancy.
Reason
According to WebMD , Chiari malformation is usually caused by structural defects in the brain and spinal cord. This defect develops during fetal development.
Due to genetic mutations or a mother’s diet lacking certain nutrients, the bony space at the base of the skull becomes very small. As a result, pressure is placed on the cerebellum. This blocks the flow of cerebrospinal fluid. That’s the fluid that surrounds and protects the brain and spinal cord.
Most Chiari malformations occur during fetal development. Much less commonly, Chiari malformations can occur later in life. This can occur when excessive amounts of cerebrospinal fluid are drained due to:
- injury
- infection
- exposure to toxic substances
Risk Factors
There is evidence that Chiari malformations run in some families. However, research into the possibility of a hereditary component is still in its early stages.
Other risk factors are, according to the Healthline page :
- Lack of proper vitamins and nutrients during pregnancy, such as folic acid, can affect fetal development.
- Infection or high fever during pregnancy can affect fetal development.
- Chiari malformation affects girls more often than boys.
Frequency of Occurrence
Scientists once believed that Chiari malformation occurred in only 1 in every 1,000 births. However, the increasing use of diagnostic imaging techniques such as CT scans and MRIs suggests that the condition may be much more common.
Accurate estimates are difficult to make. That’s because some children who are born with the condition never develop symptoms or don’t develop symptoms until they reach adolescence or adulthood.
Diagnosis
To diagnose Chiari malformation , the doctor will review the child’s medical history and symptoms and perform a physical examination. The doctor will also order imaging tests to diagnose the condition and determine its cause. Tests may include:
Magnetic resonance imaging (MRI)
MRI is often used to diagnose Chiari malformation. MRI uses radio waves and powerful magnets to create detailed images of the body.
This safe, painless test produces detailed 3D images of structural differences in the brain that may be contributing to symptoms. It can also provide images of the cerebellum and determine whether it extends into the spinal canal.
MRI can be repeated over time, and can be used to monitor the progression of the disorder.
CT scan
Your doctor may recommend other imaging tests, such as a computed tomography scan. A CT scan uses X-rays to create cross-sectional images of the body. It can help reveal brain tumors, brain damage, bone and blood vessel problems, and other conditions.
Handling
Treatment for Chiari malformation depends on the severity and characteristics of the child’s condition. If the child has no symptoms, the doctor will likely not recommend treatment other than monitoring with regular exams and MRIs. When headaches or other types of pain are the main symptom, the doctor may recommend painkillers.
Here are some treatments for children who experience Chiari malformation .
Reducing Pressure with Surgery
Doctors usually treat symptomatic Chiari malformations with surgery. The goal is to stop the progression of anatomical changes to the brain and spinal canal and to relieve or stabilize symptoms.
Surgery usually results in significant symptom relief and prolonged periods of remission. According to Boston Children’s Hospital , which specializes in the treatment of Chiari malformations, surgery virtually eliminates symptoms in 50% of pediatric cases. Surgery substantially reduces symptoms in another 45% of cases. Symptoms are stable in the remaining 5%.
If successful, surgery can relieve pressure on the cerebellum and spinal cord and restore normal flow of spinal fluid.
In the most common surgery for Chiari malformation, called posterior fossa decompression, the surgeon removes a small piece of bone at the back of the skull, relieving pressure by giving the brain more room.
In many cases, the covering of the brain, called the dura mater, can be opened. Also, a patch can be sewn in place to enlarge the covering and provide more space for the brain. This patch may be an artificial material, or it may be tissue taken from another part of the body.
The doctor may also remove a small section of the spine to reduce pressure on the spinal cord and provide more space for the spinal cord.
Surgical techniques can vary, depending on whether there is a fluid-filled cavity (syrinx), or if the child has fluid on the brain ( hydrocephalus ). If the child has a syrinx or hydrocephalus, the child may need a tube ( shunt ) to drain the excess fluid.
Surgical Risks and Follow-up
According to Kid’s Health , for children with severe symptoms, doctors often recommend an operation called posterior fossa decompression. This surgery creates more space for the cerebellum and reduces pressure on the spinal cord.
Children with associated problems (such as syringomyelia, hydrocephalus, sleep apnea , or scoliosis) may need medical treatment for the condition. Some doctors recommend that children with Chiari I malformation avoid certain activities, such as gymnastics, wrestling, and contact sports.
Surgery carries risks, including possible infection, fluid on the brain, cerebrospinal fluid leaks or problems with wound healing. Discuss the pros and cons with your doctor when deciding whether surgery is the most appropriate treatment for your child.
Surgery relieves symptoms in most people, but if nerve injury in the spinal canal has already occurred, this procedure will not reverse the damage.
After surgery, your child will need regular follow-up checkups with the doctor, including periodic imaging tests to assess the results of the surgery and the flow of cerebrospinal fluid.
Possible Complications
In some people, Chiari malformation can be a progressive disorder and cause serious complications. In others, there may be no associated symptoms, and no intervention is needed. Complications associated with this condition include:
Hydrocephalus
Accumulation of excess fluid in the brain (hydrocephalus) may require placement of a flexible tube (shunt) to divert and drain cerebrospinal fluid to another area of the body.
Spina bifida
Spina bifida, a condition in which the spinal cord or its covering is not fully developed, can occur in Chiari malformations. Part of the spinal cord is exposed, which can lead to serious conditions such as paralysis. People with type 2 Chiari malformations usually have a form of spina bifida called myelomeningocele.
Syringomyelia
Some people with Chiari malformation also develop a condition called syringomyelia, in which a cavity or cyst (syrinx) forms inside the spine.
Curvature of the spine
This includes conditions such as:
- scoliosis (curvature of the spine to the left or right)
- kyphosis (forward curvature of the spine).
Tethered cord syndrome
In this condition, the spinal cord attaches to the spine and causes the spinal cord to stretch. This can cause serious nerve and muscle damage in the lower body.
Prevention
This condition is caused by a genetic mutation, so it cannot be prevented. However, pregnant women can avoid some possible causes of Chiari malformation by getting the right nutrition, especially folic acid, and avoiding exposure to harmful substances, illegal drugs, and alcohol.
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Republished with permission from theAsianParent Indonesia
