Chiari Malformation

What is a Chiari Malformation?

Chiari malformations (CMs) are structural defects in the cerebellum, the part of the brain that controls balance. Normally the cerebellum and parts of the brain stem sit in an indented space at the lower rear of the skull, above the foramen magnum (a funnel-like opening to the spinal canal). When part of the cerebellum is located below the foramen magnum, it is called a Chiari malformation. CMs may develop when the bony space is smaller than normal, causing the cerebellum and brain stem to be pushed downward into the foramen magnum and into the upper spinal canal. The resulting pressure on the cerebellum and brain stem may affect functions controlled by these areas and block the flow of cerebrospinal fluid (CSF)— the clear liquid that surrounds and cushions the brain and spinal cord—to and from the brain.

 

Individuals with CM may complain of neck pain, balance problems, muscle weakness, numbness or other abnormal feelings in the arms or legs, dizziness, vision problems, difficulty swallowing, ringing or buzzing in the ears, hearing loss, vomiting, insomnia, depression, or headache made worse by coughing or straining. Hand coordination and fine motor skills may be affected.

Symptoms may change for some individuals, depending on the buildup of CSF and resulting pressure on the tissues and nerves. Persons with a Type I CM may not have symptoms. Adolescents and adults who have CM but no symptoms initially may, later in life, develop signs of the disorder. Infants may have symptoms from any type of CM and may have difficulty swallowing, irritability when being fed, excessive drooling, a weak cry, gagging or vomiting, arm weakness, a stiff neck, breathing problems, developmental delays, and an inability to gain weight.

 

Chiari malformations (CMs) are structural defects in the cerebellum, the part of the brain that controls balance. Normally the cerebellum and parts of the brain stem sit in an indented space at the lower rear of the skull, above the foramen magnum (a funnel-like opening to the spinal canal). When part of the cerebellum is located below the foramen magnum, it is called a Chiari malformation. CMs may develop when the bony space is smaller than normal, causing the cerebellum and brain stem to be pushed downward into the foramen magnum and into the upper spinal canal. The resulting pressure on the cerebellum and brain stem may affect functions controlled by these areas and block the flow of cerebrospinal fluid (CSF)— the clear liquid that surrounds and cushions the brain and spinal cord—to and from the brain.

 

Individuals with CM may complain of neck pain, balance problems, muscle weakness, numbness or other abnormal feelings in the arms or legs, dizziness, vision problems, difficulty swallowing, ringing or buzzing in the ears, hearing loss, vomiting, insomnia, depression, or headache made worse by coughing or straining. Hand coordination and fine motor skills may be affected. Symptoms may change for some individuals, depending on the buildup of CSF and resulting pressure on the tissues and nerves. Persons with a Type I CM may not have symptoms. Adolescents and adults who have CM but no symptoms initially may, later in life, develop signs of the disorder. Infants may have symptoms from any type of CM and may have difficulty swallowing, irritability when being fed, excessive drooling, a weak cry, gagging or vomiting, arm weakness, a stiff neck, breathing problems, developmental delays, and an inability to gain weight.

 

 

Individuals who have a Chiari malformation often have the following related conditions:

Hydrocephalus is an excessive buildup of CSF in the brain. A CM can block the normal flow of this fluid, resulting in pressure within the head that can cause mental defects and/or an enlarged or misshapen skull. Severe hydrocephalus, if left untreated, can be fatal. The disorder can occur with any type of CM, but is most commonly associated with Type II.

 

Spina bifida is the incomplete development of the spinal cord and/or its protective covering. The bones around the spinal cord don’t form properly, leaving part of the cord exposed and resulting in partial or complete paralysis. Individuals with Type II CM usually have a myelomeningocele, a form of spina bifida in which the bones in the back and lower spine don’t form properly and extend out of the back in a sac-like opening.

 

Syringomyelia, or hydromyelia, is a disorder in which a CSF-filled tubular cyst, or syrinx, forms within the spinal cord’s central canal. The growing syrinx destroys the center of the spinal cord, resulting in pain, weakness, and stiffness in the back, shoulders, arms, or legs. Other symptoms may include headaches and a loss of the ability to feel extremes of hot or cold, especially in the hands. Some individuals also have severe arm and neck pain.

 

Tethered cord syndrome occurs when the spinal cord attaches itself to the bony spine. This progressive disorder causes abnormal stretching of the spinal cord and can result in permanent damage to the muscles and nerves in the lower body and legs. Children who have a myelomeningocele have an increased risk of developing a tethered cord later in life.

 

Spinal curvature is common among individuals with syringomyelia or CM Type I. Two types of spinal curvature can occur in conjunction with CMs: scoliosis, a bending of the spine to the left or right; and kyphosis, a forward bending of the spine. Spinal curvature is seen most often in children with CM, whose skeleton has not fully matured.

 

For more information visit The Chiari & Syringomyelia Foundation http://www.csfinfo.org

 

Source: http://www.ninds.nih.gov/disorders/chiari/detail_chiari.htm

Image source: Mayfield clinic, http://www.mayfieldchiaricenter.com/chiari_overview.php