Dictionary:
sy·rin·go·my·e·li·a (sə-rĭng'gō-mī-ē'lē-ə)  |
[New Latin sȳringomyelia : Greek sūrinx, sūring-, spinal cavity + Greek muelos, marrow (from mūs, mouse, muscle).]
syringomyelic sy·rin'go·my·el'ic (-ĕl'ĭk) adj.| 5min Related Video: syringomyelia |
| Britannica Concise Encyclopedia: syringomyelia |
For more information on syringomyelia, visit Britannica.com.
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Neurological Disorder:
Syringomyelia |
Definition
The term syringomyelia refers to a collection of differing conditions characterized by damage to the spinal cord that is caused by a formation of abnormal fluid-filled cavities (syrinx) within the cord. In 1827, French physician Charles-Prosper Ollivier d'Angers (1796–1845) suggested the term syringomyelia after the Greek syrinx, meaning pipe or tube, and myelos, meaning marrow. Later, the term hydromyelia was used to indicate a dilatation of the central canal, and syringomyelia referred to cystic cavities separate from the central spinal canal.
Description
The cavities may be a result of spinal cord injury, tumors of the spinal cord, or congenital defects. An idiopathic form of syringomyelia (a form of the disorder without known cause) is also described in medical literature. The fluid-filled cavity, or syrinx, expands slowly and elongates over time, causing progressive damage to the nerve centers of the spinal cord due to the pressure exerted by the fluid. This damage results in pain, weakness, and stiffness in the back, shoulders, arms, or legs. People with syringomyelia experience different combinations of symptoms. In many cases, the disorder is related to abnormal lesions of the foramen magnum, the opening in the occipital bone that houses the lower portion of the medulla oblongata, the structure that links the brain and spinal cord. An additional cause of syringomyelia involves a Chiari malformation, a condition in which excess cerebral matter extends downward towards the medulla oblongata, crowding the outlet to the spinal canal. Some familial cases of syringomyelia have been observed, although this is rare. Types of syringomyelia include:
Demographics
Syringomyelia occurs in approximately eight of every 100,000 individuals. The onset is most commonly observed between ages 25 to 40. Rarely, syringomyelia may develop in childhood or late adulthood. Males are affected with the condition more often than females. No geographic difference in the prevalence of syringomyelia is known, and the occurrence of syringomyelia in different races is also unknown. Familial cases have been described.
Causes and symptoms
Most people with syringomyelia experience headaches, along with intermittent pain in the arms or legs, usually more severe on one side of the body. The pain may begin as dull or achy and slowly increases, or may occur suddenly, often as a result of coughing or straining. Pain in the extremities frequently becomes chronic. Additionally, numbness and tingling in the arm, chest, or back is often reported. The inability to feel the ground under the foot, or tingling in the legs and feet is also frequently experienced. Weakness of an extremity, leading to clumsiness in grasping objects or difficulty walking may also occur in individuals with syringomyelia. Eventually, functional use of the limb may be lost.
The cause of syringomyelia remains unknown. Not a single clear theory at the present can properly explain the basic mechanisms of cyst formation and enlargement. One theory proposes that syringomyelia results from pulsating CSF pressure between the fourth ventricle of the brain and the central canal of the spinal cord. Another theory suggests that syrinx development, particularly in people with Chiari malformation, occurs after a difference in intracranial pressure and spinal pressure. A third theory contends that syrinx formation is caused by the cerebellar tonsils acting as a piston to produce large pressure waves in the spinal subarachnoid space, and this action forces fluid through the surface of the spinal cord into the central canal. Syringomyelia usually progresses slowly; the course may extend over many years. Infrequently, the condition may have a more acute course, especially when the brainstem is affected.
Diagnosis
Examination by a neurologist may reveal loss of sensation or movement caused by compression of the spinal cord. Diagnosis is usually reached by magnetic resonance imaging (MRI) of the spine, which can confirm syringomyelia and determine the exact location and extent of damage to the spinal cord. The most common place for a syrinx to develop is in the cervical spine (neck), with the second most common in the thoracic spine (chest and rib areas). The least likely place for a syrinx is in the lumbar spine (lower back). MRI of the head can be useful to determine the presence of any additional lesions present, as well as the presence of hydrocephalus (excess CSF in the ventricles of the brain). As the syrinx grows in size, it may cause scoliosis (abnormal curvature of the spine), which is best determined by x ray of the spine.
Treatment team
Diagnosis and treatment of syringomyelia require specialized physicians, including neurologists, radiologists, neurosurgeons, and orthopedists, along with specialized nurses. Physical therapy is often useful to maximize muscular function and assist with gait (walking).
Treatment
Treatment, usually surgery, is aimed at stopping the progression of spinal cord damage and maximizing functioning. Surgical procedures are often performed if there is an identifiable mass compressing the spinal cord. Additional surgical options to minimize the syrinx include correction of spinal deformities and various CSF-shunting procedures. Fetal spinal cord tissue implantation has recently been used in an attempt to obliterate syrinx. Surgery results in stabilization or modest improvement in symptoms for most patients. Many physicians advocate surgical treatment only for patients with progressive neurological deterioration or pain. Delay in treatment when the condition is progressive may result in irreversible spinal cord injury, and post-traumatic syringomyelia remains difficult to manage.
Medications (vasoconstrictors) are often prescribed to help reduce fluid formation around the spinal cord. Avoiding vigorous activity that increases venous pressure is often recommended. Certain exercises such as bending the trunk so the chest rests on the thighs may reduce the risk of syrinx expansion. People with progressive symptoms of syringomyelia, whether or not surgically treated, usually are monitored by their physician and have MRI scans completed every six to 12 months.
Recovery and rehabilitation
Despite reports of neurological recovery following surgery, most people achieve stabilization or only mild improvement in symptoms. Syringomyelia in children has a much lower incidence of sensory disturbance and pain than occurs with adolescents and adults, and is associated with a high incidence of scoliosis that is more favorable to surgical treatment. Additionally, all cases of syringomyelia do not progress at the same rate. Some people, usually with milder symptoms, experience stabilization in their symptoms for a period of years. A frequent complication of symptom progression is the person's ongoing need to adjust to evolving functional losses that accompany syringomyelia. These adjustments may result in loss of independence and loss of personal privacy. Rehabilitation may focus on maintaining functionality for as long as practically possible with the use of exercises and adaptive equipment, or, especially in the case of children, may focus on recovery from scoliosis caused by the syringomyelia.
Clinical trials
As of February 2004, the National Institute of Neurological Disorders and Stroke (NINDS) was sponsoring three trials for the study of syringomyelia, including the physiology of syringomyelia, study and surgical reatment of syringomyelia, and genetic analysis of the Chiari I malformation.
Prognosis
The prognosis for persons with syringomyelia depends on the underlying cause of the syrinx and on the type of treatment. Untreated syringomyelia is compatible with long-term survival without progression in 35–50% of cases. In patients treated by shunting for syringomyelia due to spinal cord injury, long-lasting pain relief and improved strength are usually observed. Recent studies have revealed an unsatisfactory long-term prognosis due to high rates of syrinx recurrence in other forms of syringomyelia. Surgery (posterior fossa decompression) in syringomyelia associated with a Chiari malformation is described as a surgically safe procedure with a considerable chance of clinical improvement. In pediatric syringomyelia, surgery is effective in improving or stabilizing scoliosis.
Resources
BOOKS
Anson, John A., Edward C. Benzel, and Issam A. Awad. Syringomyelia & the Chiari Malformation. Rolling Hills, IL: American Association of Neurological Surgeons, 1997.
Icon Health Publications Staff. The Official Patient's Sourcebook on Syringomyelia: A Revised and Updated Directory for the Internet Age. San Diego: Icon Group International, 2002.
Klekamp, Joerg. Syringomyelia: Diagnosis & Treatment New York: Springer-Verlag, 2001.
PERIODICALS
Brodbelt, A. R., and M. A. Stoodley. "Post-traumatic Syringomyelia: A Review." J Clin Neurosci. 10, no. 4 (July 2003): 401–408.
Todor, D. R., T. M. Harrison, and T. H. Milhorat. "Pain and Syringomyelia: A Review." Neurosurg Focus 8, no. 3 (2000): 1–6.
OTHER
"Syringomyelia Fact Sheet." National Institute of Neurological Disorders and Stroke. February 10, 2004 (April 4, 2004). http://www.ninds.nih.gov/health_and_medical/pubs/syringomyelia.htm.
ORGANIZATIONS
American Syringomyelia Alliance Project (ASAP). P.O. Box 1586, Longview, TX 75606-1586. (903) 236-7079 or (800) ASAP-282 (272-7282); Fax: (903) 757-7456. info@asap.org. http://www.asap.org.
National Institute for Neurological Disorders and Stroke. P.O. Box 5801, Bethesda, MD 20824. (301) 496-5761 or (800) 352-9424. http://www.ninds.nih.gov.
Antonio Farina, MD, PhD
| Veterinary Dictionary: syringomyelia |
The presence of fluid-filled cavities in the substance of the spinal cord, with destruction of nervous tissue. Clinical signs are posterior paralysis, or if the animal is able to stand the posture is a wide spacing of the feet and overextension of the legs when walking. An inherited trait in Weimaraner dogs. See also spinal dysraphism.
| Wikipedia: Syringomyelia |
| Syringomyelia | |
|---|---|
| Classification and external resources | |
 An idiopathic syrinx. See the thin light grey shape inside the spinal column, placed at centre in the bottom half of the above image. |
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| ICD-10 | G95.0, Q06.4 |
| ICD-9 | 336.0 742.53 |
| OMIM | 272480 186700 |
| DiseasesDB | 12769 |
| MedlinePlus | 001398 |
| eMedicine | neuro/359 |
| MeSH | D013595 |
Syringomyelia (pronounced /sɪˌrɪŋɡɵmaɪˈiːliə/) (archaically known as "Morvan's disease"[1]:67) 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. This damage may result in pain, weakness[2], and stiffness in the back, shoulders, and extremities. Syringomyelia may also cause a loss of the ability to feel extremes of hot or cold, especially in the hands. The disorder generally leads to a cape-like loss of pain and temperature sensation along the back and arms. 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.
Syringomyelia has a prevalence estimated at 8.4 cases per 100,000 people,[3] 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.
Contents |
A watery, protective substance known as cerebrospinal fluid normally flows in a pulsatile manner throughout the subarachnoid space which envelopes the spinal cord and brain, transporting nutrients and waste products. The cerebrospinal fluid also serves to cushion the brain. Excess cerebrospinal fluid in the
The pulsatile movement of the cerebrospinal fluid within the subarachnoid space is a result of the phase difference in influx and outflow of blood within the cranial vault. The total fluid pulsation per cardiac cycle is approximately 1 cc in a healthy adult. Since the brain is contained within the nearly rigid cranial cavity, the cerebrospinal fluid pulsation moves into the more compliant spinal canal having nearly zero net flow during each cardiac cycle.
It has been observed that obstruction of the cerebrospinal fluid pulsation in the subarachnoid space can result in syrinx formation. A number of pathological conditions can cause an obstruction of the normal cerebrospinal fluid pulsation. These include Chiari malformation, spinal arachnoiditis, scoliosis, spinal vertebrae misalignment, spinal tumors, spina bifida, and others. For reasons that are not understood, blockage of the cerebrospinal fluid pulsation within the subarachnoid space can result in syrinx formation. It is unclear if syrinx fluid originates from bulk movement of cerebrospinal fluid into the spinal cord, from bulk transmural movement of blood fluids through the spinal vasculature into the syrinx, or from a combination of both. Once a syrinx has formed, pressure differences along the spine have been proposed to be one mechanism causing fluid movement within the cyst, possibly resulting in damage to the spinal cord.
Generally, there are two forms of syringomyelia: congenital and acquired. (In addition, one form of the disorder involves a part of the brain called the brainstem. The brainstem controls many of our vital functions, such as respiration and heartbeat. When syrinxes affect the brainstem, the condition is called syringobulbia.)
The first major form relates to an abnormality of the brain called an Chiari malformation, named after the physician who first characterized it. This is the most common cause of syringomyelia, where the anatomic abnormality causes the lower part of the cerebellum to protrude from its normal location in the back of the head into the cervical or neck portion of the spinal canal. A syrinx may then develop in the cervical region of the spinal cord. Because of the relationship that was once thought to exist between the brain and spinal cord in this type of syringomyelia, physicians sometimes refer to it as communicating syringomyelia. Here, symptoms usually begin between the ages of 25 and 40 and may worsen with straining or any activity that causes cerebrospinal fluid pressure to fluctuate suddenly. Some patients, however, may have long periods of stability. Some patients with this form of the disorder also have hydrocephalus, in which cerebrospinal fluid accumulates in the skull, or a condition called arachnoiditis, in which a covering of the spinal cord—the arachnoid membrane—is inflamed.
Some cases of syringomyelia are familial, although this is rare.
The second major form of syringomyelia occurs as a complication of trauma, meningitis, hemorrhage, a tumor, or arachnoiditis. Here, the syrinx or cyst develops in a segment of the spinal cord damaged by one of these conditions. The syrinx then starts to expand. This is sometimes referred to as noncommunicating syringomyelia. Symptoms may appear months or even years after the initial injury, starting with pain, weakness, and sensory impairment originating at the site of trauma.
The primary symptom of post-traumatic syringomyelia (often referred to using the abbreviation of PTS)[4] is pain, which may spread upward from the site of injury. Symptoms, such as pain, numbness, weakness, and disruption in temperature sensation, may be limited to one side of the body. Syringomyelia can also adversely affect sweating, sexual function, and, later, bladder and bowel control. A typical cause of PTS would be a car accident or similar trauma involving a whip-lash injury.
What can make PTS difficult to diagnose is the fact that symptoms can often first appear long after the actual cause of the syrinx occurred, e.g. a car accident occurring and then the patient first experiencing PTS symptoms such as pain, loss of sensation, reduced ability on the skin to feel varying degrees of hot and cold, a number of months after car accident.
Syringomyelia causes a wide variety of neuropathic symptoms due to damage of the spinal cord. Patients may experience chronic pain, abnormal sensations and loss of sensation particularly in the hands. Some patients experience paralysis or paresis temporarily or permanently. A syrinx may also cause disruptions in the parasympathetic and sympathetic nervous systems, leading to abnormal body temperature or sweating, bowel control issues, or other problems. If the syrinx is higher up in the spinal cord or affecting the brainstem as in syringobulbia, vocal cord paralysis, ipsilateral tongue wasting, trigeminal nerve sensory loss, and other signs may occur.[5] Rarely, bladder stones can occur in the onset of weakness in the lower extremities.[6] Classically, syringomyelia spares the dorsal column/medial lemniscus of the spinal cord, leaving pressure, vibration, touch and proprioception intact in the upper extremities.
Physicians now use magnetic resonance imaging (MRI) to diagnose syringomyelia. The MRI radiographer takes images of body anatomy, such as the brain and spinal cord, in vivid detail. This test will show the syrinx in the spine or any other conditions, such as the presence of a tumor. MRI is safe, painless, and informative and has greatly improved the diagnosis of syringomyelia.
The physician may order additional tests to help confirm the diagnosis. One of these is called electromyography (EMG), which measures muscle weakness. The doctor may also wish to test cerebrospinal fluid pressure levels and to analyze the cerebrospinal fluid by performing a lumbar puncture. In addition, computed axial tomography (CT) scans of a patient's head may reveal the presence of tumors and other abnormalities such as hydrocephalus.
Like MRI and CT scans, another test, called a myelogram, uses radiographs and requires a contrast medium to be injected into the subarachnoid space. Since the introduction of MRI this test is rarely necessary to diagnose syringomyelia.
The possible causes are trauma, tumors and congenital defects. It is most usually observed in the part of the spinal cord corresponding to the neck area. Symptoms are due to spinal cord damage and are: pain, decreased sensation of touch, weakness and loss of muscle tissue. The diagnosis is confirmed with a spinal CT, myelogram or MRI of the spinal cord. The cavity may be reduced by surgical decompression.
Furthermore, evidence also suggests that impact injuries to the thorax area highly correlate with the occurrence of a cervical-located syrinx.
The first step after diagnosis is finding a neurosurgeon who is experienced in the treatment of syringomyelia. Surgery is the only viable treatment for syringomyelia, and a neurosurgeon is the only specialist qualified to provide a fully informed recommendation. Not all patients will advance to the stage where surgery is needed. Evaluation of the condition is often difficult because syringomyelia can remain stationary for long periods of time, and in some cases progress rapidly.
Surgery of the spinal cord has certain, characteristic risks associated with it and the benefits of a surgical procedure on the spine have to be weighed up against the possible complications associated with any procedure. Surgical treatment is aimed at correcting the condition that allowed the syrinx to form. It is vital to bear in mind that the drainage of a syrinx does not necessarily mean the elimination of the syrinx-related symptoms, but rather is aimed at stopping progression. In cases involving an Arnold-Chiari malformation, the main goal of surgery is to provide more space for the cerebellum at the base of the skull and upper cervical spine without entering the brain or spinal cord. This often results in flattening or disappearance of the primary syrinx or cavity, over time, as the normal flow of cerebrospinal fluid is restored. If a tumor is causing syringomyelia, removal of the tumor is the treatment of choice and almost always eliminates the syrinx.
Surgery results in stabilization or modest improvement in symptoms for most patients. Delay in treatment may result in irreversible spinal cord injury. Recurrence of syringomyelia after surgery may make additional operations necessary; these may not be completely successful over the long term.
In some patients it may also be necessary to drain the syrinx, which can be accomplished using a catheter, drainage tubes, and valves. This system is also known as a shunt. Shunts are used in both the communicating and noncommunicating forms of the disorder. First, the surgeon must locate the syrinx. Then, the shunt is placed into it with the other end draining cerebrospinal fluid (CSF) into a cavity, usually the abdomen. This type of shunt is called a ventriculoperitoneal shunt and is particularly useful in cases involving hydrocephalus. By draining syrinx fluid, a shunt can arrest the progression of symptoms and relieve pain, headache, and tightness. Without correction, symptoms generally continue.
The decision to use a shunt requires extensive discussion between doctor and patient, as this procedure carries with it greater risk of injury to the spinal cord, infection, blockage, or hemorrhage and may not necessarily work for all patients. Draining the syrinx more quickly does not produce better outcomes, but a shunt may be required if the fluid in the syrinx is otherwise unable to drain.
In the case of trauma-related syringomyelia, the surgeon operates at the level of the initial injury. The syrinx collapses at surgery but a tube or shunt is usually necessary to prevent re-expansion.
Surgery is not always recommended for syringomyelia patients. For many patients, the main treatment is analgesia. A typical treatment of syringomyelia involving severe chronic pain would involve two or more medications. One medication for "classical" back pain such as a weak or strong opioid (e.g. tramadol and Oxycontin respectively) combined with a medication to combat any neuropathic pain symptoms such as shooting and stabbing pains (e.g. Neurontin or Lyrica). In addition, paracetamol can be used to combat headaches. Such long term treatment of chronic pain should be monitored with blood tests to assess any adverse effects of the medication on the liver, with the dosages being then changed accordingly, depending on the outcome of such blood tests.
Drugs have no curative value as a treatment for syringomyelia. Radiation is used rarely and is of little benefit except in the presence of a tumor. In these cases, it can halt the extension of a cavity and may help to alleviate pain.
In the absence of symptoms, syringomyelia is usually not treated. In addition, a physician may recommend not treating the condition in patients of advanced age or in cases where there is no progression of symptoms. Whether treated or not, many patients will be told to avoid activities that involve straining.
Since the natural history of syringomyelia is poorly understood, a conservative approach may be recommended. When surgery is not yet advised, patients should be carefully monitored by a neurologist or neurosurgeon. Periodic MRI's and physical evaluations should be scheduled at the recommendation of a qualified physician.
The precise causes of syringomyelia are still unknown. Scientists at the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland, and at grantee institutions across the country continue to explore the mechanisms that lead to the formation of syrinxes in the spinal cord. For instance, Institute investigators have found that as the heart beats, the syrinx fluid is abruptly forced downward. They have also demonstrated a block to the free flow of cerebrospinal fluid that normally occurs in and out of the head during each heartbeat. Duke University is conducting research to see if syringomyelia might be genetic.[7]
Surgical techniques are also being refined by the neurosurgical research community. In one treatment approach currently being evaluated, neurosurgeons perform a decompressive procedure where the dura mater, a tough membrane covering the cerebellum and spinal cord, is enlarged with a graft. Like altering a suit of clothing, this procedure expands the area around the cerebellum and spinal cord, thus improving the flow of cerebrospinal fluid and eliminating the syrinx.
It is also important to understand the role of birth defects in the development of hindbrain malformations that can lead to syringomyelia. Learning when these defects occur during the development of the fetus can help us understand this and similar disorders, and may lead to preventive treatment that can stop the formation of many birth abnormalities. Dietary supplements of folic acid during pregnancy have already been found to reduce the number of cases of certain birth defects.
Diagnostic technology is another area for continued research. Already, MRI has enabled scientists to see conditions in the spine, including syringomyelia, even before symptoms appear. A new technology, known as dynamic MRI, allows investigators to view spinal fluid pulsating within the syrinx. CT scans allow physicians to see abnormalities in the brain, and other diagnostic tests have also improved greatly with the availability of new, non-toxic, contrast dyes. Patients can expect even better techniques to become available in the future from the research efforts of scientists today.
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This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
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 | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| Britannica Concise Encyclopedia. Britannica Concise Encyclopedia. © 2006 Encyclopædia Britannica, Inc. All rights reserved. Read more |
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| Neurological Disorder. Gale Encyclopedia of Neurological Disorders. Copyright © 2005 by The Gale Group, Inc. All rights reserved. Read more |
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| Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved. Read more |
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| Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Syringomyelia". Read more |
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