What is Chiari Malformation by Celia Beabout

Chiari Malformation is a defect with the cerebellum and the shape of the skull, there is a part of the brain (cerebellum) that protrudes out of the foramen magnum (or attempts to) which causes the majority of the clinical signs associated with this disorder. This is a most commonly a congenital malformation that occurs during development of the brain and skull. However there are other types, in fact there are four different types of Chiari Malformation.


Type I is the most common type of Chiari Malformation and will most likely go unnoticed until individuals are adults or close to it and results in the base of the skull and upper spinal area not being formed correctly. Type II is a congenital abnormality where the brain starts to shift through the foramen magnum. The type II Chiari Malformation is more commonly seen in infants born with spina bifida. Type III is a condition where the cerebellum attempts to squeeze out of the opening in the back of the skull. Type IV is where the back of the brain develops abnormally.

The cause of Chiari Malformation is unknown, but it is thought that a problem arose in fetal development causing the abnormal brain/skull formation. It also can occur when the part of the skull containing the cerebellum is too small or shaped incorrectly, resulting in too much pressure being put on the brain. As a result the cerebellum is pushed downward into the upper spinal canal and in the majority of cases will interfere with the flow of the cerebrospinal fluid. This fluid helps protects your brain and spinal cord. If you’re cerebrospinal fluid is too low it will mess with your neurological signals that are transmitted from your brain to your body, other neurological signs can occur as well if the fluid level is too high.

Symptoms of Chiari Malformation can include headaches, stiffness and pain in neck or back of head area, poor feeding and swallowing (mainly infants), decreased strength in the arms, decreased sensation in the arms and legs, rapid back and forth eye movement, developmental delays, weak cry and breathing problems. These will vary with the type of Chiari Malformation that is present.

Some of the major medical complications secondary to Chiari Malformation are:

Hydrocephalus: the excess fluid that builds up in the brain may require a stent or shunt to be placed and will aid in diversion of this fluid to other body cavities.

Paralysis: This may happen after the crowding and subsequent trauma from the pressure on the spinal cord; this can be permanent in some cases even after surgery.

Syringomyelia is condition where a cavity or cyst structure is formed within the spinal cord. It’s unknown how the two are connected, but is thought that it could have something to do with injury or trauma in the spinal cord, most specifically the nerve fibers. If this type of a cavity were to form it could fill with fluid and also impair some functions of the spinal cord.

Death: This occurs when an infant is born with Chiari Malformation type IV. The infant would die not long after being born. Diagnosing: when you go to your physician he/she will start off with taking your medical history and ask questions as to what symptoms you are presenting with. They would ask if you pain or aches in your head and for you to describe them. They would also check your motor skills and how well you are able to swallow. If your doctor is not sure what is going on they are most likely going to do a magnetic resonance imaging (MRI) this will tell them if you have Chiari Malformation.

Treatment: This would depend how severe your Chiair Malformation is. If you do not have any symptoms you will just have to have regular examinations to make sure everything is stable and non-progressive. If you only have headaches or some pain your doctor may prescribe anti-inflammatory medication. For some this will relieve head aches and pain and may decrease your chances of having surgery. However, for cases that are severe, surgery is required to stop the changes in the anatomy of the brain and spinal canal as well as to reduce symptoms. When the surgery is successful it can reduce the amount of pressure that is put on the cerebellum and spinal cord and the flow of the spinal fluid can return to normal. As always there are risks with having any type of surgery and one of the most common risks is post-surgical infection in the wound as it is trying to heal. The operation does reduce the symptoms of quite a few people. However, if there is nerve damage to spinal canal the surgery will not reverse that damage that is already done. After the surgery regular follow ups and diagnostic imaging or other testing will need to be done to see how the surgery went and to see how the flow of the cerebrospinal fluid has been altered with this surgical corrections.

“Chiari Malformation” Home. Web 10 Apr. 2012
http://www.columbiaeurosurgery.org/conditions/chiari-malformation/
Staff, Mayo Clinic. “Definition.” Mayo Clinic. Mayo Foundation for Medical Education and Research, 13 Nov. 2010. Web. 12 Apr. 2012.
<http://www.mayoclinic.com/health/chiari-malformation/DS00839/DSECTION%3Dtreatments-and-drugs>.