Chiari malformation, also called Arnold-Chiari syndrome, is a rare congenital condition that occurs when the skull forms abnormally, creating pressure on the brain. This pressure pushes part of the brain downward toward the spinal canal, affecting the cerebellum, brainstem, and spinal cord. As a result, it can cause symptoms such as headaches, balance problems, loss of coordination, and vision issues.
This condition usually develops during in utero but can also appear later in life, though rarely. In adults, it may occur due to factors that reduce cerebrospinal fluid (CSF) levels, such as infections, head trauma, or exposure to toxic substances.
Treatment for Chiari malformation is managed by a multidisciplinary team that may include a pediatrician, neurologist, or neurosurgeon, depending on the type and severity of the condition. It may involve medications to relieve symptoms or, in some cases, surgery to correct the malformation.
Chiari malformation symptoms
The most common symptoms of Chiari malformation include:
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Headaches or neck pain;
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Muscle weakness or balance problems;
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Poor hand coordination;
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Loss of sensation or numbness in the hands and feet;
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Vision changes or rapid, involuntary eye movements;
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Dizziness or vertigo;
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Hoarseness, difficulty swallowing, choking, or vomiting;
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Ringing in the ears (tinnitus);
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Scoliosis;
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Sleep apnea;
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Slowed heart rate.
Symptoms can vary depending on the extent of nervous system involvement. Some children born with this malformation may have no symptoms until adolescence or adulthood, with most cases appearing after age 30.
Confirming a diagnosis
Diagnosis of Chiari malformation is made by a pediatrician or a neurologist based on an evaluation of symptoms, medical history, and a physical and neurological exam. These exams help assess motor function, sensation, and balance.
To confirm the diagnosis, a doctor may order imaging tests such as magnetic resonance imaging (MRI) or computed tomography (CT) scans.
Chiari malformation types 2, 3, and 4 can sometimes be detected by an obstetrician during prenatal care using an obstetric ultrasound in the second or third trimester of pregnancy.
Main types
Chiari malformation is classified into different types based on the development of the cerebellum. The main types include:
- Chiari malformation type 1: This is the most common form, usually found in children. It occurs when the cerebellum extends into an opening at the base of the skull called the foramen magnum, through which only the spinal cord should normally pass;
- Chiari malformation type 2: In this type, both the cerebellum and the brainstem extend into the foramen magnum. It is often seen in children with spina bifida, a birth defect in which the spinal cord and surrounding structures do not fully develop;
- Chiari malformation type 3: This is a rare and severe form in which the cerebellum and brainstem extend beyond the foramen magnum and into the spinal canal;
- Chiari malformation type 4: Also rare and typically incompatible with life, this type occurs when the cerebellum does not develop or develops incompletely.
The specific type of Chiari malformation is identified by a doctor through imaging tests, based on the shape and severity of the structural abnormalities.
Treatment options
Treatment for Chiari malformation depends on the symptoms and their severity. The main goal is to relieve discomfort and prevent the condition from progressing. If symptoms are mild or absent, treatment may not be necessary.
When symptoms are present, a neurologist may prescribe pain relievers such as ibuprofen to manage headaches or neck pain.
If symptoms are more severe and affect quality of life, surgery may be recommended to decompress the spinal cord and restore normal cerebrospinal fluid flow.
Physical therapy or occupational therapy may also be recommended to help improve coordination, speech, and motor skills.