|
What is “Chiari”?
Arnold Chiari Malformation is named after a German Pathologist, Professor Hans Chiari who first described these abnormalities of the brain at the junction of the skull with the spine in 1890. Later, another Doctor, Dr. Arnold, added to the “type II” description, hence the name “Arnold-Chiari Malformation.” Of the four classifications of Chiari, only two types of the malformation have practical importance, commonly referred to as Chiari type I and Chiari type II. The most common type is Chiari Type 1 Malformations (CM1). These occur in the region where the brain and the spinal cord join. When the rear base of the skull (Posterior Fossa) is not correctly shaped or is not fully developed and is smaller than necessary for proper protection and cushioning of the brain, part of the cerebellum known as the cerebellar tonsils can be pushed downward (herniated) and protrude out of the base of the skull into the spinal canal. This protrusion causes pressure in the brain which can result in some degree of blockage of cerebrospinal fluid (CSF) which surrounds and protects the brain and spinal cord. This blockage is often a contributing factor to the various and in many cases multiple symptoms people with “Chiari” experience. It used to be typically that a displacement had to be greater than 5 mm below the foramen magnum in order for a patient being diagnosed with Arnold-Chiari Malformation. Today, the 5mm guideline is not as much the “measuring stick” as it once was when considering diagnosing a patient. There are references to a “Chiari Type 0” Malformation but unfortunately and somewhat controversially, not all physicians who treat Chiari Malformations have accepted this name. Chiari Malformation may be associated with many other anomalies including Syringomyelia, and Spina Bifida. Hydrocephalus (increased intracranial pressure) may also occur. In simpler terms: Sometimes, the brain is actually too big for the skull to contain it fully inside and the cerebellum extends to the bottom and is pushed in that hole where the spine is and puts pressure on the fluids and messes stuff up. Symptoms The brainstem, cranial nerves, and the lower portion of the cerebellum may be stretched or compressed. Therefore, any of the functions controlled by these areas may be affected. Chiari is often associated with major headaches, sometimes mistaken for migraines. Chiari headaches usually include intense pressure in the back of the head, aggravated by laughing, coughing, sneezing or straining, the presence of “brain fog” or the inability to focus or concentrate are also common. Chiari also includes extreme muscle soreness, facial pain, hearing problems, and low energy levels. It also can cause insomnia cycles of sleep deprivation followed by inabilities to remain awake cycling between them. Research says that 15% of patients with adult Chiari Malformation are asymptomatic. List of Chiari Symptoms May Include (but are not limited to): · Severe head and neck pain · Fainting, sometimes mini seizures · Difficulty swallowing (Dysphalgia) · Frequent gagging and choking · Dizziness and vertigo, confusion · Balance problems · Muscle weakness · Poor hand coordination · Blurred or double vision · Hypersensitivity to bright lights · involuntary eye movements (Nystagmus) · Difficulty in tracking objects · Buzzing or ringing in the ear (Tinnitus) · Hearing loss · Vocal cord paralysis · Sleep apnea and MANY more, Treatment Once symptomatic onset occurs, and after a thorough Neurological examination of a variety of films, tests and physical presentation of the patient to the Doctor which, sometimes can be over a 2 day period to complete the examination, a common treatment is decompression surgery, in which a neurosurgeon usually removes the first and part of the second and sometimes third cervical vertebrae and part of the occipital bone of the skull to allow the flow of spinal fluid and may be accompanied by a shunt. This treatment is well recognized and accepted with many studies published (involving a total of hundreds of patients) in well-respected peer-reviewed medical journals showing that about 80% of patients obtain improvement. Some authors advocate performing a transoral clivus-odontoid resection in cases with ventral brain-stem compression, as they feel these patients may potentially deteriorate with posterior fossa decompression alone. A small number of neurological surgeons believe that de-tethering the spinal cord as an alternate approach relieves the compression of the brain against the skull opening (foramen magnum), obviating the need for decompression surgery and associated trauma. However, this approach is significantly less documented in the medical literature, with reports on only a handful of patients. It should be noted that the alternative spinal surgery is also not without risk. Syringomyelia Syringomyelia (IPA: /sɪˌrɪŋgoʊmaɪˈiːliə/) is a generic term referring to a disorder in which a cyst or cavity forms within the spinal cord. This cyst, called a syrinx, can expand and elongate over time, destroying the spinal cord. Since the spinal cord connects the brain to nerves in the extremities, this damage may result in pain, weakness, and stiffness in the back, shoulders, arms, or legs. Syringomyelia may also cause a loss of the ability to feel extremes of hot or cold, especially in the hands. Each patient experiences a different combination of symptoms. These symptoms typically vary depending on the extent and, often more critically, to the location of the syrinx within the spinal cord. Other, more common disorders share the early symptoms of syringomyelia. In the past, this has made diagnosis difficult. The advent of one diagnostic test, however, called magnetic resonance imaging or MRI, has significantly increased the number of syringomyelia cases diagnosed in the beginning stages of the disorder. Syringomyelia has a prevalence estimated at 8.4 cases per 100,000 people, or about 21,000 Americans, with symptoms usually beginning in young adulthood. Signs of the disorder tend to develop slowly, although sudden onset may occur with coughing, straining, or myelopathy. If not treated surgically, syringomyelia may lead to progressive weakness in the extremities, loss of hand sensation, chronic pain and potentially total paralysis. Spina Bifida (Latin: "split spine") is a developmental birth defect involving the neural tube: incomplete closure of the embryonic neural tube results in an incompletely formed spinal cord. In addition, the vertebrae overlying the open portion of the spinal cord do not fully form and remain un-fused and open. This allows the abnormal portion of the spinal cord to stick out through the opening in the bones. There may or may not be a fluid filled sac surrounding the open spinal cord. Other neural tube defects include anencephaly, a condition in which the portion of the neural tube which will become the cerebrum does not close, and encephalocele, which results when other parts of the brain remain un-fused. Spina bifida malformations fall into four categories: Spinal bifida occulata, spina bifita cystica (myelomeningocele), meningocele and lipomeningocele. The most common location of the malformations is in the lumbar and sacral areas of the spinal cord. Myelomeningocele is the most significant form and it is this that leades to disability in most affected individuals. The terms spina bifida and myelomeningocele are usually used interchangeably. Spina bifida can be surgically closed after birth, but nerve damage is permanent and this does not restore normal function to the affected part of the spinal cord. An individual with this condition will have dysfunction of the spinal cord and associated nerves from the point of the open defect and below. Intrauterine surgery for spina bifida has also been performed and the safety and efficacy of this procedure is currently being investigated. The incidence of spina bifida can be decreased up to 75 percent when daily folic acid supplements are taken prior to conception. **The contents of this site such as text, graphics, images, and other material ("Content") are for informational purposes only. The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on the ChiarisAngels web site! |
