A chiari malformation type 1 occurs when the cerebellum extends into the spinal canal and causes pressure on the brain and spinal cord. The cerebellum coordinates movement, balance, and posture. A small or misshapen skull can cause pressure on the brain and spinal cord, disrupting normal cerebrospinal fluid flow. The cerebrospinal fluid (CSF) surrounds and protects the brain and spinal cord as well as carries nutrients and wastes.
The exact cause of chiari malformation type 1 is not known. It is thought to be a congenital defect, meaning that it is present at birth, but it may not be detected until later in life. Some factors that may contribute to the development of chiari malformation type 1 are:
Genetic factors. Some people may inherit a tendency to have a small or misshapen skull, or a large or elongated cerebellum.
Environmental factors. Some factors that may affect the growth and development of the skull and brain during pregnancy, such as maternal nutrition, exposure to toxins, infections, or trauma, may increase the risk of chiari malformation type 1.
Other conditions. Some conditions that affect the bones, muscles, or connective tissues of the head and neck, such as craniosynostosis, hydrocephalus, or Ehlers-Danlos syndrome, may also cause or worsen chiari malformation type 1.
Many people with chiari malformation type 1 have no symptoms and do not need treatment. They may discover they have the condition after undergoing imaging tests for an unrelated reason. The severity and frequency of symptoms for people with chiari malformation type 1 vary based on the amount of pressure on the brain and spinal cord and the disruption of CSF flow. Chiari malformation type 1 symptoms include:
Headaches. These are the most typical symptom of chiari malformation type 1. They usually occur at the back of the head, and are triggered or worsened by coughing, sneezing, straining, or bending over.
Neck pain. This may radiate to the shoulders, arms, or upper back.
Dizziness and balance problems. These may cause difficulty walking, standing, or performing daily activities.
Numbness and tingling. These may affect the hands, feet, face, or other parts of the body.
Muscle weakness. This may affect the arms, legs, or facial muscles, and may cause difficulty with fine motor skills, such as writing, typing, or buttoning clothes.
Difficulty swallowing. This may result in gagging, choking, or vomiting, and may increase the risk of aspiration, which is when food or liquid enters the lungs.
Speech problems. This may include hoarseness, slurred speech, or changes in voice quality.
Vision problems. This may include blurred vision, double vision, or sensitivity to light.
Hearing problems. This may include ringing or buzzing in the ears, known as tinnitus, or hearing loss.
Sleep problems. This may include difficulty falling asleep, staying asleep, or breathing during sleep, known as sleep apnea.
It is important for a doctor to review the patient's medical history and symptoms as well as perform a physical examination in order to diagnose chiari malformation type 1. In order to confirm the diagnosis and determine the extent of the condition, the doctor will order imaging tests. Magnetic resonance imaging (MRI) is the most common imaging test used to diagnose chiari malformation type 1. It can be used to create detailed images of the brain and spinal cord by using powerful magnets and radio waves, including the cerebellum's size and location, as well as the amount of cerebral spinal fluid flowing through it. CT scans, which produce cross-sectional images of the body using X-rays, and X-rays, which reveal the skull and spine's shape and structure, are other imaging tests that may be used to diagnose chiari malformation type 1.
There are different treatment options for chiari malformation type 1 based on the severity of the symptoms and the patient's quality of life. It is possible for some people with chiari malformation type 1 to be monitored with regular examinations and MRIs without any treatment. Pain and other symptoms may be managed with medication, including anti-inflammatory drugs, muscle relaxants, and anticonvulsants. The main treatment option for chiari malformation type 1 that causes significant symptoms or complications is surgery. The goal of surgery is to relieve the pressure on the brain and spinal cord, and restore the normal flow of CSF. The most common surgery for chiari malformation type 1 is posterior fossa decompression, which involves removing a small piece of bone at the back of the skull, and sometimes part of the spine, in order to create more space for the cerebellum. Also, the doctor may sew a patch to enlarge the dura mater, which covers the brain, to prevent it from pressing on the cerebellum. If there is a condition called hydrocephalus or syringomyelia, which is the accumulation of fluid in the brain or spinal cord, a tube, called a shunt, may be inserted into the brain or spinal cord to drain excess fluid. Chiari malformation type 1 can be stabilized or improved with surgery, but it may not cure it completely. Even after surgery, some people may still experience some symptoms or develop new ones. Infection, bleeding, nerve damage, or CSF leakage are some of the risks associated with surgery.
There is no known way to prevent chiari malformation type 1, as it is a congenital defect that occurs before birth. However, some steps that may reduce the risk of developing or worsening the condition are:
Avoiding activities that increase the pressure on the head and neck, such as lifting heavy objects, playing contact sports, or diving.
Seeking medical attention for any head or neck injuries, infections, or other conditions that may affect the skull and brain development.
Getting regular check-ups and imaging tests to monitor the condition and detect any changes or complications.
Following the doctor’s advice and treatment plan to manage the symptoms and improve the quality of life.
