I am sharing the below information with others to help raise awareness of Chiari Malformation. Although it is a rare condition more people are being diagnosed as a result of better technology. I was diagnosed several years ago, but as of late the condition has progressed and I am in the process of seeking a second opinion before proceeding with surgery. Learning to live with this condition along with a spinal cord injury has made daily life a challenge.
What are Chiari Malformations
Chiari malformation is a condition in which the cerebellum and part of the brain stem push through the lower part of the skull. Normally the cerebellum, part of the brain that controls balance, and parts of the brain stem sit in a designated space at the base of the skull above the foramen magnum.
Chiari malformations may occur when the space where the cerebellum and part of the brain stem is smaller than normal, thus causing them to protrude downward into the upper spinal canal. As a result the flow of cerebrospinal fluid (CSF) may become blocked. Cerebrospinal fluid is the clear liquid that surrounds and cushions the brain and spinal cord. When the pathways are blocked is can cause a buildup of fluid on the brain called hydrocephalus or in the spinal cord called syringomyelia.
These malformations are uncommon, yet with improved modern imaging techniques and comprehensive exams physicians are beginning to make more accurate diagnoses.
Chiari Malformation type 1 is the most common type of the four possible types of the condition. Type 1 is also the only type that can be acquired. All other types are congenital.
Patients with type 1 normally do not have symptoms until late childhood or adulthood. This is because the malformation does not develop until the skull and brain have developed. On the other hand, patients with types 2-4 are often diagnosed in utero (during pregnancy), during birth, or during the first stages of infancy.
Patients that have Chiari malformation type I may complain of neck pain, headaches, balance problems, muscle weakness, vision problems, numbness or abnormal feelings in the legs and/or arms, ringing of the ears (tinnitus),hearing loss, dizziness, nausea, difficulty swallowing, facial pain, insomnia, and depression. Fine motor skills and hand coordination may also be affected.
Symptoms may vary from person to person and some may have no symptoms at all. The difference in symptoms depends on the buildup of CSF and the change in pressure on the tissues and nerves. For example, adolescent and adults may have no symptoms initially then later in life may develop signs of the disorder. Infants may show symptoms of any type of malformations. Their symptoms maybe difficulty swallowing, irritability during feedings, gagging or vomiting, excessive drooling, arm weakness, breathing problems, developmental delay and inability to gain weight.
If Chiari malformation type 1 if untreated may also result in the development of fluid filled cavities in the brain (hydrocephalus) or spinal cord (syrinx) which may eventually lead to syringomyelia. This can lead to irreversible damage to the brain or spinal cord.
How common are Chiari malformations?
In the past it has been estimated the condition happens one in every 1,000 to 2,00 births. However, the development of better technology and the increase use of diagnostic imaging has shown that the malformations may be more common. The estimates of actual cases is difficult as people born with the condition do not display symptoms at all or may not display them until they are in adolescence or adulthood.
The most common method of diagnosis is the use of an MRI (Magnetic Resonance Imaging) in conjunction with the patient history, and a neurological examination. Sometimes a special MRI scan called CINE studies are needed to make the diagnosis. Additional imaging techniques may be used. Early diagnosis of Chiari malformation type 1 can lead to treatment before the formation of syrinx.
The treatment of Chiari type 1 varies on several factors such as the severity of symptoms, whether or not syrinx (CSF fluid filled areas on the spinal cord) exists. For example, if a patient has no symptoms or neurological findings, the doctor ill often just observe the patient and schedule periodic visits to manage the condition. If the patient displays mild symptoms that are manageable, the physician may prescribe medications to help reduce the pain.
If the patient has symptoms that progress in severity, such as a decline in neurological function and/or they develop an enlarging syrinx, surgery may become necessary.
If surgery is recommended, it typically begins by making an incision is the middle of the back of the skull , and extends to about midway down the back of the neck. All the muscles are separated from the base of the skull to the fist cervical vertebra.
Next, a surgical removal of a portion of the cranium called a craniectomy is performed. This is done to enlarge the opening at the base of the skull and create additional space next to the brain to allow better flow of CSF. The neurosurgeon uses a specialized surgical instrument to carefully shave a small piece of bone about the size of a silver dollar. Next, the first cervical vertebra is removed. This called a laminectomy. At times, removal of additional cervical vertebra may be necessary.
Most patients with Chiari malformation type 1 often have no symptoms. The patient only finds out they have the condition after it is found during an evaluation for other non-related conditions.
Once a Chiari malformation is diagnosed, it is important to get an evaluation by a neurologist who then can refer you to a neurosurgeon if further treatment is needed. Early diagnosis and treatment of this condition is critical as surgical intervention for symptomatic Chiari malformation type 1 is most often successful when done early on. Many patients experience significant reduction of their symptoms after surgery and are able to return to daily life without activity restrictions.