There are four types of Chiari malformations:
- Type I is the most commonly observed in children, where the lower part of the cerebellum extends into the foramen magnum at the base of the skull, but not the brain stem. Typically, only the spinal cord passes through this opening. Type I is the only Chiari malformation that can be acquired.
- Type II is usually seen in children born with spina bifida, which is the incomplete development of the spinal cord and/or its protective covering. In Type II Chiari malformation, both the cerebellum and the brain stem extend into the foramen magnum.
- Type III is the most serious and rare form, involving the protrusion or herniation of the cerebellum and brain stem through the foramen magnum and into the spinal cord, leading to severe neurological defects.
- Type IV entails an incomplete or undeveloped cerebellum and is a rare type, sometimes associated with exposed parts of the skull and spinal cord.
Other conditions sometimes linked with Chiari malformations include hydrocephalus, an excessive buildup of cerebrospinal fluid in the brain; syringomyelia, a disorder where a cyst develops in the spinal cord’s central canal; tethered cord syndrome, a progressive disorder where the spinal cord attaches itself to the bony spine; and spinal curvature, encompassing conditions like scoliosis (a bending of the spine to the left or right) and kyphosis (a forward bending of the spine).
Chiari malformations occur when the lower part of the brain extends into the spinal canal, exerting pressure on the brainstem and spinal cord while obstructing fluid flow. These malformations typically result from structural defects in the brain and spinal cord that emerge during fetal development.
The abnormal reduction of the bony space at the skull’s base, often caused by genetic mutations or a maternal diet lacking specific nutrients, leads to increased pressure on the cerebellum. This, in turn, hinders the flow of cerebrospinal fluid, the protective fluid surrounding the brain and spinal cord.
Most Chiari malformations manifest during fetal development. Less frequently, they can arise later in life due to factors such as excessive cerebrospinal fluid drainage resulting from injury, infection, or exposure to toxic substances. Chiari malformations tend to affect females more frequently than males.
Many individuals with Chiari I malformation may not exhibit any symptoms, and the condition is sometimes discovered incidentally during a brain MRI conducted for another purpose.
However, if symptoms do arise, they can encompass:
– Headaches: Typically located at the back of the head and potentially triggered or intensified by activities such as coughing, straining, sneezing, or bending over.
– Neck pain
– Dizziness and balance issues
– Muscle weakness
– Numbness or tingling in the arms or legs
– Blurred vision, double vision, and sensitivity to light
– Swallowing difficulties
– Hearing loss and tinnitus
– Nausea and vomiting
– Sleep difficulties (insomnia) and clinical depression
In cases where syringomyelia develops, additional symptoms may include challenges with hand use, difficulty walking, pain, and issues related to bladder or bowel control.
If you have received a Chiari malformation diagnosis, it is advisable to consult your doctor if you experience new symptoms or if existing symptoms worsen. Regular communication with a physician is crucial for monitoring and managing the condition effectively.
If a Chiari malformation is suspected, a doctor will perform a physical exam. The doctor will also check functions controlled by the cerebellum and spinal cord. These functions include:
- balance
- touch
- reflexes
- sensation
- motor skills
The doctor may order diagnostic tests, such as:
- X-ray
- CT scan
- MRI, that is a test most often used to diagnose Chiari malformations.
Chiari Malformation is linked to and can contribute to the development of various neurological conditions. These include:
– Hydrocephalus: Characterized by an abnormal accumulation of cerebrospinal fluid (CSF) in the brain.
– Spina bifida: Involves the incomplete closure of the backbone and the membranes surrounding the spinal cord.
– Syringomyelia:In this condition, a cyst filled with CSF, known as a syrinx, forms in the spinal cord.
– Tethered Cord Syndrome: Occurs when the movement of the spinal cord is restricted by the tissue around the bottom of the spine.
