Central Pain Syndrome

Central Pain Syndrome

National Organization for Rare Disorders, Inc.

Important

It is possible that the main title of the report Central Pain Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

Synonyms

  • CPS

Disorder Subdivisions

  • central post-stroke pain
  • central post-stroke syndrome
  • Dejerine-Roussy syndrome (obsolete)
  • thalamic pain syndrome (obsolete)
  • thalamic syndrome (obsolete)

General Discussion

Summary

Central pain syndrome is a neurological disorder caused by damage to the central nervous system (CNS). Common symptoms include pain and loss of sensation, usually in the face, arms and/or legs. Pain is often constant and can be mild, moderate, or severe in intensity. Affected individuals may become hypersensitive to painful stimuli. The specific type of pain experience can vary from one individual to another based, in part, upon the underlying cause of the disorder and the area of the central nervous system affected. Central pain syndrome can potentially disrupt an individual's daily routine. In severe cases, the pain can be agonizing and unrelenting and dramatically affect a person's quality of life. Central pain syndrome can develop following a variety of conditions including stroke, multiple sclerosis, spinal cord injury, or brain tumors.



Introduction

For years, it was believed that the majority of cases of central pain syndrome were due to damage of the thalamus most often caused by a stroke. The disorder was frequently referred to as thalamic pain syndrome or Dejerine-Roussy syndrome after two French neurologists who reported on the disorder in the early 1900s. In fact, to some degree central pain became synonymous with thalamic pain syndrome for many years. However, researchers now know that damage to other areas of the CNS can cause central pain syndrome, including cases following a stroke. Consequently, the preferred name for this group of disorders is central pain syndrome to acknowledge that damage to various areas of the CNS (and not predominantly the thalamus) can cause central pain and that a stroke is not necessarily the primary cause. The preferred term for the specific subtype of central pain syndrome caused by CNS damage due to a stroke is central post-stroke pain.

Symptoms

The onset of central pain syndrome can vary from days to weeks to months or more than a year after injury to the central nervous system. However, the disorder can also appear immediately after an injury or within a day. In most cases, central pain syndrome remains a lifelong condition.



Central pain syndrome can be limited to a specific area of the body such as the hands or feet or may be widespread over a large portion of the body. Some areas of the body may be more intensely affected than other areas. Pain can fluctuate during the day and can be affected by several factors including touch, emotions such as stress, certain movements or overall level of activity, and temperature changes, especially cold temperatures. Rest and distraction may lessen symptoms.



Central pain syndrome can vary greatly from one individual to another, in part, based upon the underlying cause of the condition. Central pain syndrome can be broken down into central pain of brain or brainstem origin or central pain of spinal cord origin.



In some cases, symptoms of central pain syndrome can be vague and difficult to characterize. Many different pain sensations including burning, stabbing, lacerating, pressing, aching, prickling or tingling (a feeling of being on "pins and needles") may occur. A constant burning sensation is in several cases the most prominent symptom. Pain can be constant and unrelenting or it may come and go (intermittent). In most cases, pain is constant and usually moderate or severe in intensity. In some cases, pain has been described as agonizing. Some affected individuals may experience short bursts of sharp, excruciating pain, which has been compared to the pain that occurs when a dental probe strikes an exposed nerve. In some cases, the constant pain associated with central pain syndrome can be debilitating and affect an individual's ability to perform daily tasks and significantly impair quality of life.



Pain sensations associated with central pain syndrome are generally spontaneous, which means they occur despite no apparent cause or trigger. People with this disorder may be extra-sensitive or have a heightened response to acute painful stimuli (hyperalgesia, hyperpathia), which means that pain that would normally be small or minimal is felt to a far greater degree. In addition, individuals may feel pain from stimuli that would normally not be painful (allodynia). For example, affected individuals may experience pain when touched, even when lightly touched. In severe cases, this can include pain caused by a strong breeze, the weight of a blanket, or even the clothes a person is wearing.



Some individuals with central pain syndrome may initially experience impairment or distortion of sensation, especially of touch (dysesthesia). Dysesthesia is described as vague, unpleasant sensations. Some individuals may experience a painful numbness, especially affecting the feet. Itching (pruritus) has also been reported in individuals with central pain syndrome.



Some individuals with central post-stroke pain may experience painful symptoms on one side of the body (from head to foot); other notable, accompanying symptoms include loss of sensation (hemihypesthesia), partial or complete muscle weakness (hemiparesis, hemiplegia), and , on occasion, abnormal, involuntary, irregular jerky motions and slow, writhing movements (hemichoreoathetosis).

Causes

The exact underlying cause of central pain syndrome is being elucidated. The disorder develops following damage to the central nervous system – the brain, brainstem or spinal cord. Such damage is most often associated with a stroke, multiple sclerosis, spinal cord injury or brain tumors. Central pain syndrome can also develop after neurosurgical procedures involving the brain or spine.



Central pain syndrome results from damage to the pain-transmission pathway from the level of the spinal cord up to the cortex, the gray matter that covers the cerebral hemispheres. Recent studies revealed that central pain syndrome is due to a disturbed communication between the thalamus and the sensory cortex. The thalamus is a structure within the brain that extensively processes sensory signals and together with the cortex is fundamental in creating all sensory experiences we become aware of.



More research is necessary to translate the latest advancements into effective therapeutic strategies.

Affected Populations

Central pain syndrome is estimated to affect several million people worldwide. Approximately, 8-10% of individuals who suffer a stroke develop central post-stroke pain. Approximately one third (or more) of individuals who suffer a spinal cord injury develop pain.

Standard Therapies

Diagnosis

A diagnosis of central pain syndrome is based upon identification of characteristic symptoms, a detailed patient history, a thorough clinical evaluation and a variety of specialized tests. Central pain syndrome is suspected in individuals who complain of pain or other abnormal sensations following injury to the central nervous system. Other conditions that cause pain may need to be excluded before a diagnosis of central pain syndrome is made.



Clinical Testing and Workup

Imaging techniques such as computerized tomography (CT) scanning and magnetic resonance imaging (MRI) are used to visualize tumors, infarcts, cerebral hemorrhage and other causal lesions. During CT scanning, a computer and x-rays are used to create a film showing cross-sectional images of certain tissue structures. An MRI uses a magnetic field and radio waves to produce cross-sectional images of particular organs and bodily tissues. MRI is the preferred technique in the work-up of CPS.



Treatment

Treatment for central pain syndrome can be challenging. Most therapies that have been used for individuals with central pain syndrome are based on anecdotal reports or small case series. Additionally, therapies that have proven beneficial in some individuals may have no benefit in others.



Traditional pain medications generally provide little to no relief for individuals with central pain syndrome. However, drug therapy remains the first-line therapy for most affected individuals. Two drugs, lamotrigine and amitriptyline, have proven beneficial, especially for individuals with central pain of brain origin. Lamotrigine is an anti-seizure drug (anticonvulsant). Amitriptyline is an antidepressant. Few individuals find significant relief with gabapentin, another type of anti-seizure medication, and pregabalin is not advised by the Scottish Medicinal Agency. Antiarrhythmics (mexiletine) and local anesthetics such as lidocaine, can be effective. Opioids such as morphine or levorphanol are not effective in the vast majority of cases. In several cases, the effectiveness of drug therapies are limited due to associated side effects.



Some affected individuals may find temporary relief from sedation and/or stress reduction techniques. Supportive care, rehabilitation, and psychotherapy are recommended as well.

Investigational Therapies

Individuals with central pain of brain origin who do not respond to drug therapy may be treated with extradural cortical stimulation of the sensory-motor area (MCS/PCS), a procedure that has been used to treat refractory, chronic pain. During this procedure, a stimulating paddle or plate is placed extradurally on the primary motor cortex and/or primary sensory cortex to deliver electrical stimulation. Extradurally means that the paddle is placed on the dura mater, the outermost layer of the membranes (meninges) that line the brain and spinal cord. The paddle is inserted through two burr holes or via the temporary removal of a small piece of the skull (craniotomy). According to the medical literature, more than half of individuals have seen a pain reduction of greater than 50% with no significant morbidity. More research is necessary to determine the long-term safety and effectiveness of this procedure for individuals with central pain syndrome.



Controlled studies showed that deep brain stimulation is not indicated for the treatment of individuals with central pain syndrome, with few exceptions, and only after a trial of CS. During this surgical procedure, an electrode is placed into the thalamus and a thin wire is passed under the skin is connected to a small battery pack (which is also placed underneath the skin). The risk of lethal brain hemorrhage is small, but real.



Some individuals experience pain relief through the direct injection of drugs into the cerebrospinal fluid that surrounds the brain and spinal cord (intrathecal administration). Drugs such as baclofen or midazolam have been used in this manner. A few individuals have experienced pain relief through the insertion of a morphine pump that delivers drugs intrathecally. Intrathecal drug delivery is not always effective for the treatment of individuals with central pain syndrome. However, much more research is necessary in this area.



In the past, surgery has been used to treat individuals with central pain syndrome. This includes invasive, drastic surgeries such as the surgical removal or destruction of targeted parts of the brain such as thalamus (thalamotomy). However, most of these surgeries were generally associated with low success rates and a high risk of complications and morbidity. Such invasive surgeries are rarely used for individuals with central pain syndrome anymore.



According to the medical literature, a surgical procedure known as subparietal leucotomy/capsulotomy has the potential to eliminate pain associated with central pain syndrome. During this procedure, a small lesion is made in certain areas of the white matter of the brain in order to interrupt the descending arm of the corticothalamic loop. In one case reported in the medical literature, this procedure immediately and completely relieved pain in the affected individual. However, more research is necessary to determine the long-term safety and effectiveness of this procedure as a potential therapy for individuals with central pain syndrome.



Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.



For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:



Toll-free: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov



For information about clinical trials sponsored by private sources, in the main, contact:

www.centerwatch.com



Contact for additional information about central pain syndrome:



Sergio Canavero, M.D.

Turin Advanced Neuromodulation Group

Cso Einaudi 2, 10128

Torino, Italy

Email: sercan@inwind.it

References

TEXTBOOKS

Canavero Sergio, Vincenzo Bonicalzi. Central Pain Syndrome: pathophysiology, diagnosis and management. 2nd edition. Cambridge: Cambridge University Press, 2011.



Canavero Sergio (editor). Textbook of therapeutic cortical stimulation. New York: Nova Science, 2009



JOURNAL ARTICLES

Canavero S, Bonicalzi V. Central pain syndrome: elucidation of genesis and treatment. Expert Rev Neurother. 2007;7:1485-1497. http://www.ncbi.nlm.nih.gov/pubmed/17997698



Canavero S, Bonicalzi V. Extradural cortical stimulation for central pain. Acta Neurochir Suppl. 2007;97:27-36. http://www.ncbi.nlm.nih.gov/pubmed/17691286



Frese A, Husstedt IW, Ringelstein EB, Evers S. Pharmacologic treatment of central post-stroke pain. Clin J Pain. 2006;22:252-260. http://www.ncbi.nlm.nih.gov/pubmed/16514325



INTERNET

National Institute of Neurological Disorders and Stoke. Central Pain Syndrome Information Page. January 13, 2011. Available at: http://www.ninds.nih.gov/disorders/central_pain/central_pain.htm Accessed On: May 4, 2012.



Brenman EK. WebMD. Pain Management: Central Pain Syndrome. March 1, 2007. Available at: http://www.webmd.com/pain-management/guide/central-pain-syndrome Accessed On: May 4, 2012.

Resources

American Chronic Pain Association

P.O. Box 850

Rocklin, CA 95677

USA

Tel: (916)632-0922

Fax: (916)652-8190

Tel: (800)533-3231

Email: ACPA@theacpa.org

Internet: http://www.theacpa.org



NIH/National Institute of Neurological Disorders and Stroke

P.O. Box 5801

Bethesda, MD 20824

Tel: (301)496-5751

Fax: (301)402-2186

Tel: (800)352-9424

TDD: (301)468-5981

Internet: http://www.ninds.nih.gov/



American Pain Society

4700 West Lake Avenue

Glenview, IL 60025

Tel: (847)375-4715

Fax: (866)574-2654

Email: info@ampainsoc.org

Internet: http://www.ampainsoc.org



Pain.com

c/o Dannemiller, Inc.

5711 Northwest Parkway

San Antonio, TX 78246

Tel: (210)641-8311

Fax: (210)641-8329

Email: editor@pain.com

Internet: http://www.pain.com



International Association for the Study of Pain

IASP Secretariat

1510 H Street NW

Suite 600

Washington, DC 20005-1020

Tel: (202)524-5300

Fax: (202)524-5301

Email: IASPdesk@iasp-pain.org

Internet: http://www.iasp-pain.org



Genetic and Rare Diseases (GARD) Information Center

PO Box 8126

Gaithersburg, MD 20898-8126

Tel: (301)251-4925

Fax: (301)251-4911

Tel: (888)205-2311

TDD: (888)205-3223

Internet: http://rarediseases.info.nih.gov/GARD/



Irish Chronic Pain Association

Coleraine House, Coleraine St.

Dublin, 7

Ireland

Tel: 35318047567

Fax: 35318047567

Email: info@chronicpain.ie

Internet: http://www.chronicpain.ie



For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into myCigna.com. For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html.

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