A Chiari malformation occurs when the skull is abnormally tiny or shaped, which pushes the brain and causes it to descend into the spinal canal. The cerebellum, a part of the brain that is in charge of maintaining balance, is often affected.
The Chiari malformation is typically present from birth. However in certain varieties, the symptoms don’t appear until later in life. Depending on the severity, the patient might require ongoing observation.
The first description of this brain anomaly was made in the 1980s by Austrian pathologist Hans Chiari. As a result, the illness bears his name.
When a portion of the skull containing the cerebellum (brain) is distorted or too tiny, it crowds or puts pressure on the brain, resulting in Chiari malformation type 1. The upper spinal canal is filled with the bottom portion of the cerebellum.
Myelomeningocele, a kind of spina bifida, and Chiari malformation type 2 are almost usually connected.
The condition is frequently inherited, as was already established. It may result in neurological symptoms, such as balance problems.
Other names for it include tonsillar ectopia, Arnold-Chiari malformation, and hindbrain herniation.
Experts have noted four types of Chiari malformation. They are as mentioned below:
Chiari Type 1: the most common form of Chiari malformation in children. Patients with this disorder do not show symptoms or develop symptoms during adolescence or adulthood. It affects the lower part of the cerebellum and not the brain stem. The cerebellum enters into a hole at the base of the brain known as the foramen magnum. Usually, the spinal cord passes through this passage. It is often accidentally found during the diagnosis of other health conditions.
Chiari Type 2 : typically develops in patients with severe Spina Bifida, known as myelomeningocele. It occurs in utero when the spinal cord and backbone do not correctly close before the child’s birth. Surgery is necessary soon after birth to close the spinal cord and the backbone, and the chances of paralysis are high. Chiari type 2 affects both the cerebellar and brain stem tissues, Chiari Type 2 is also known as classic Chiari Malformation or Arnold-Chiari malformation.
Chiari Malformation Type 3: It is rare and severe form of a Chiari malformation. In this, the cerebellum or the brain stem enters the spinal cord through an opening in the back of the skull – known as the foramen magnum. The abnormality leads to swelling at the back of the skull, known as encephalocele. Type 3 causes life-threatening complications and neurological symptoms, including learning delays and seizures. Patients with Chiari malformation type 3 may also suffer from hydrocephalus – the accumulation of cerebrospinal fluid in the brain. Typically, doctors diagnose this form of Chiari malformation during pregnancy through ultrasound or at birth.
Chiari malformation type 4: A rarity where the cerebellum is underdeveloped or certain parts are missing. However, the spinal cord and the skull are exposed . This type is severe and causes fatality.
Chiari malformation type 0: This form is controversial to some experts as there is little to no protrusion of the cerebellum into the foramen magnum. It is the rarest form of Chiari malformation. However, doctors may find significant crowding, causing abnormal cerebrospinal fluid flow at the base of the skull.
