Arachnoiditis

Definition

Arachnoiditis literally means "inflammation of the arachnoid," which is the middle of the three membranes (meninges) surrounding the brain and spinal cord. The term more generally refers to several rare neurologic disorders caused by inflammation of a portion of the arachnoid and subarachnoid space, affecting the neural tissue that lies beneath. Symptoms of arachnoiditis are quite variable, and may include anything from a skin rash to moderate or severe pain, to paralysis. The condition is often progressive, can only rarely be cured, and existing treatments vary in their effectiveness.

Description

Three membranes, including the dura mater, arachnoid, and pia mater, and a layer of cerebrospinal fluid (CSF) surround, protect, and cushion the brain and spinal cord. The pia mater adheres to the brain and spinal cord, and is separated from the arachnoid membrane by the subarachnoid space, which contains the circulating CSF. Arachnoiditis always involves inflammation in one or several restricted areas, but the entire membrane is never affected. Fibrous (scar) tissue growth along the affected section of the membrane usually occurs, projecting down through the subarachnoid space and encompassing neural tissue of the brain (cerebral arachnoiditis) and/or nerve roots of the spinal cord (spinal arachnoiditis). Nerve damage occurs through restricted blood flow (ischemia), compression from accumulated fluids (edema), and secondary effects of the inflammatory process itself.

Other terms used less frequently for arachnoiditis include arachnitis, chronic adhesive arachnoiditis (CAA), and spinal fibrosis. Other conditions that may be associated with or mimic arachnoiditis include syringomyelia (cyst near the spinal cord), cauda equina (lower spinal cord) syndrome, and spinal tumor. Several different types of arachnoiditis have been described, including adhesive (fibrous attachments), ossifying (bony tissue growth), neo-plastic (tumor growth), optochiasmatic (optic nerve and chiasm), and rhinosinusogenic (olfactory nerve and area above the sinuses).

Demographics

The true incidence of arachnoiditis is not known, but it is rare. It affects males and females equally, and seems to be less frequent in children than in adults. Rare cases of familial arachnoiditis have been documented, but no particular ethnic groups seem to be at higher risk.

Causes and symptoms

The causes of arachnoiditis are varied, but fall into the following four categories:

• trauma to the membrane due to spinal surgery (often multiple procedures), cranial or spinal injury, or needle insertion to remove CSF for testing
• external agents such as anesthesia, corticosteroids, medications, or medical dyes/chemicals injected near the spinal cord (epidural) or directly into the CSF
• infection of the arachnoid/CSF (meningitis)
• blood in the CSF caused by trauma, spontaneous bleeding, or infection

For reasons that are not entirely clear, different areas of the arachnoid have differing sensitivities to the causative agents. Spinal arachnoiditis due to infection most often occurs in the cervicothoracic (neck and upper back) region, while cases due to external agents most often occur in the lumbosacral (lower back) area. Likewise, spinal arachnoiditis of any type is more common than the cerebral/cranial variety.

Symptoms of cerebral arachnoiditis may include severe headaches, vision disturbances, dizziness, and nausea/vomiting. Vision disturbances are especially pronounced in optochiasmatic arachnoiditis. If inflammation and tissue growth in specific areas of the cranial arachnoid membrane divert or obstruct normal flow of the CSF, the result is hydrocephalus (increased fluid pressure within the brain).

Typical symptoms of spinal arachnoiditis include back pain that increases with activity, pain in one or both legs or feet, and sensory abnormalities of some type, usually involving decreased reflexes. Patients may also exhibit decreased range of motion of the trunk or legs, and urinary sphincter dysfunction (urgency, frequency, or incontinence). In more severe cases, partial or complete paralysis of the lower extremities may occur.

Diagnosis

The most reliable method of establishing the diagnosis of arachnoiditis is a positive computed tomography (CT) or magnetic resonance imaging (MRI) scan, combined with one or more of the symptoms. Testing for certain cell types and proteins in the CSF may prove helpful only in the early stages of the inflammation. On the other hand, imaging studies may be negative or equivocal early on, and only later be more definitive as inflammation and tissue growth becomes more pronounced. In some cases, a definitive diagnosis may not be possible.

Treatment team

A neurologist is the primary specialist involved in monitoring and treating arachnoiditis. Occupational/physical therapy (OT/PT) might also be suggested to assist with treatment for pain and adaptation to sensory deficits and/or muscular weakness in the back and lower limbs. A neurosurgeon performs any elected surgeries to address the various effects of the inflammation. Many individuals with chronic pain attend pain clinics staffed by physicians (usually anesthesiologists) and nurses who specialize in pain management. Neuropsychiatrists and neuropsychologists specialize in treating the psychological problems specific to individuals who have an underlying neurologic condition.

Treatment

Treatment for arachnoiditis is mostly done with medications, and is geared toward reducing the inflammation and alleviating pain. Medications may include both nonsteroidal and steroidal anti-inflammatory drugs, along with non-narcotic and narcotic pain medications. Other possible treatments include epidural steroid injections, transcutaneous electrical nerve stimulation (TENS), topical analgesics, and alternative medical therapies.

Direct spinal cord stimulation is a newer pain management method that involves placement of tiny electrodes under the skin, directly on the affected nerve roots near the spine. Mild current application inhibits pain signals, and is provided by a small, battery-powered unit that is placed under the skin by a surgeon.

Surgery to remove fibrous or ossified tissue at the site of the inflammation is used only if more conservative methods do not provide sufficient relief. Surgical removal of a small portion of one or more vertebrae at the area of the nerve root is called a laminectomy. A neurosurgeon treats hydrocephalus by placing a shunt (plastic tube) from the brain to the abdominal cavity to relieve increased pressure. Microsurgical techniques to remove scar tissue from around the nerve roots themselves are a more recent development.

Prognosis

Given the lack of effective treatments for arachnoiditis, the prognosis in most instances is poor, with the neurologic symptoms remaining static or worsening over time. It is not uncommon for people who undergo surgery for the condition to improve at first, but eventually regress within several years.

Resources

BOOKS

Bradley, Walter G., et al., eds. Neurology in Clinical Practice, 3rd ed. Boston: Butterworth-Heinemann, 2000.

Victor, Maurice, and Allan H. Ropper. Adam's and Victor's Principles of Neurology, 7th ed. New York: The McGraw-Hill Companies, Inc., 2001.

Wiederholt, Wigbert C. Neurology for Non-Neurologists, 4th ed. Philadelphia: W.B. Saunders Company, 2000.

PERIODICALS

Chin, Cynthia T. "Spine Imaging." Seminars in Neurology 22 (June 2002): 205–220.

Faure, Alexis, et al. "Arachnoiditis Ossificans of the Cauda Equina: Case Report and Review of the Literature." Journal of Neurosurgey/Spine 97 (September 2002): 239–243.

Rice, M. Y. K., et al. "Obstetric Epidurals and Chronic Adhesive Arachnoiditis." British Journal of Anaesthesia 92 (2004): 109–120.

Wright, Michael H., and Leann C. Denney "A Comprehensive Review of Spinal Arachnoiditis." Orthopaedic Nursing 22 (May/June 2003): 215–219.

ORGANIZATIONS

American Paraplegia Society. 75-20 Astoria Boulevard, Jackson Heights, NY 11370-1177. (718) 803-3782. http://www.apssci.org.

American Syringomyelia Alliance Project, Inc. P.O. Box 1586, Longview, TX 75606-1586. 800-272-7282. http://www.asap.org.

NIH/NINDS Brain Resources and Information Network. PO Box 5801, Bethesda, MD 20824. (800) 352-9424. http://www.ninds.nih.gov/.

National Organization for Rare Disorders (NORD). 55 Kenosia Ave, PO Box 1968, Danbury, CT 06813-1968. (800) 999-6673; Fax: (203) 798-2291. http://www.rarediseases.org.

National Spinal Cord Injury Association. 6701 Democracy, Bethesda, MD 20817. (800) 962-9629. http://www.spinalcord.org.

Spinal Cord Society. 19051 County Hwy 1, Fergus Falls, MN 56537. (218) 739-5252.

Scott J. Polzin, MS, CGC

Inflammation of the arachnoid membrane and subarachnoid space.

Inflammation of the arachnoid.

This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (February 2007)

Arachnoiditis
Classification and external resources
ICD-10	G03.9
ICD-9	320-322
DiseasesDB	22543
eMedicine	radio/49
MeSH	D001100

Arachnoiditis is a neuropathic disease caused by the inflammation of the arachnoid, one of the membranes that surround and protect the nerves of the central nervous system, including the brain and spinal cord. The arachnoid can become severely inflamed because of adverse reactions to chemicals, blood, and/or steroids, infection from bacteria or viruses, as the result of direct injury to the spine, chronic compression of spinal nerves, or complications from spinal surgery or other invasive spinal procedures such as epidural steroid injections. Lumbar patches (also known as blood patches), which are often useful in relieving painful headaches associated with spinal taps and epidural anesthesia, have been found to be significant potential causative agents in some cases and may warrant avoidance of the procedure where possible. Multiple blood patches may amplify the probability of contracting arachnoiditis. It is also noteworthy that blood has been found to be a significant inflammatory agent in the nervous system. Inflammation can sometimes lead to the formation of scar tissue and adhesions which can cause the spinal nerves to "stick" together.

Contents 1 Symptoms 2 Prognosis 3 Treatment 4 Current research 5 External links

Symptoms

The swollen arachnoid can lead to a host of painful and debilitating symptoms. Chronic pain is common, including neuralgia. Numbness and tingling of the extremities is frequent in patients due to spinal cord involvement. Bowel, bladder, and sexual functioning can be affected if the lower part of the spinal cord is affected. While arachnoiditis has no consistent pattern of symptoms, it frequently affects the nerves that supply the legs and lower back. Many sufferers find themselves unable to sit for long (or even short) periods of time, often due to severe pain as well as efferent neurological symptoms, such as difficulties controlling limbs. This can be particularly problematic for those patients who exhibit difficulties standing or walking for protracted periods, as wheelchairs are not helpful for this group. Some sufferers benefit from relatively new inventions, such as the Segway or the less expensive Stand'n'Ride alternative. Standing wheelchairs are also available, although often quite expensive and limited compared to these alternatives. However, standing endurance and vibration tolerance should be taken into account before a motorized assistance device is selected.

It is critical for patients to realize that the symptoms of arachnoiditis are highly varied and are not all experienced by all sufferers. Consequently, while typically significantly life-altering, the outcome, especially with physical therapy, appropriate psychotherapy, and medication, may be better than many patients fear upon receiving the diagnosis.

Prognosis

Arachnoiditis is a chronic disorder and there is no known cure at this time. Pain management techniques may provide some relief to patients. Prognosis may be hard to determine because of the lack of correlation between the beginning of the disease and the start of symptoms. For many, arachnoiditis is a disabling disease that causes chronic pain and neurological deficits. It may also lead to other spinal cord conditions, such as syringomyelia.

Treatment

Arachnoiditis is a difficult condition to treat. Treatment is limited to alleviation of pain and other symptoms. Surgical intervention generally has a poor outcome and only provides temporary relief. Steroid injections administered either intrathecally or epidurally have been linked as a cause of the disease, therefore they are generally discouraged as a treatment and may even worsen the condition.

Current research

Recent research has indicated that a group of chemicals called cytokines that are produced by various cells in the body may be responsible for generating the pain response. Medications that affect the release of cytokines or block the action of cytokines may reduce the pain response. Various anti-cytokine medications are now being used to treat painful disease states such as Rheumatoid Arthritis and Crohn's Disease. In a recent study the anti-cytokine medication, Thalidomide, is being evaluated for its effect in treating pain associated with Arachnoiditis.

External links

• Life With Arachnoiditis (LWA), a group determined to develop techniques for overcoming the condition and for supporting fellow sufferers
• Circle Of Friends With Arachnoiditis (COFWA)
• American Chronic Pain Association (ACPA)
• National Chronic Pain Outreach Association (NCPOA)
• National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
• National Institute of Dental and Craniofacial Research (NIDCR)
• Arachnoiditis
• Arachnoiditis, if you have ever suffered from back pain or know anyone who has then this is where to find help and information.
• Support for those with disorders of the Arachnoid Membrane
• http://www.burtonreport.com/InfSpine/AdhesArachAnatomy.htm
• http://groups.msn.com/DepoMedrolDidItHarmYou Did Depo-Medrol Cause Your Arachnoiditis? (EDNC)
• Arachnoiditis; Familial spinal arachnoiditis (subtype); Spinal tuberculous arachnoiditis (subtype) at NIH's Office of Rare Diseases
  • Online 'Mendelian Inheritance in Man' (OMIM) Spinal arachnoiditis -182950
  • Duke RJ, Hashimoto SA (April 1974). "Familial spinal arachnoiditis. A new entity". Arch. Neurol. 30 (4): 300–3. PMID 4816834. 
  • Arachnoiditis Information Page at NINDS

v • d • e Diseases of meninges (G00–G03, 320–322) Meningitis/Arachnoiditis: Bacterial (Tuberculous, Haemophilus, Pneumococcal) · Viral (Herpesviral) · Fungal (Cryptococcal) · Aseptic (Drug-induced) Meningoencephalitis central nervous system navs: anat/physio/dev, noncongen/congen/neoplasia, symptoms+signs/eponymous, proc

v • d • e Inflammation Acute Plasma derived mediators Bradykinin · complement (C3, C5a, MAC) · coagulation (Factor XII, Plasmin, Thrombin) Cell derived mediators preformed: Lysosome granules · vasoactive amines (Histamine, Serotonin) synthesized on demand: cytokines (IFN-γ, IL-8, TNF-α, IL-1) · eicosanoids (Leukotriene B4, Prostaglandins) · Nitric oxide · Kinins Chronic Macrophage · Epithelioid cell · Giant cell · Granuloma Processes Traditional: Rubor · Calor · Tumor · Dolor (pain) · Functio laesa Modern: Acute-phase reaction/Fever · Vasodilation · Increased vascular permeability · Exudate · Leukocyte extravasation · Chemotaxis Specific types Nervous CNS (Encephalitis, Myelitis) · Meningitis (Arachnoiditis) · PNS (Neuritis) · eye (Dacryoadenitis, Scleritis, Keratitis, Choroiditis, Retinitis, Chorioretinitis, Blepharitis, Conjunctivitis, Iritis, Uveitis) · ear (Otitis, Labyrinthitis, Mastoiditis) Cardiovascular Carditis (Endocarditis, Myocarditis, Pericarditis) · Vasculitis (Arteritis, Phlebitis, Capillaritis) Respiratory upper (Sinusitis, Rhinitis, Pharyngitis, Laryngitis) · lower (Tracheitis, Bronchitis, Bronchiolitis, Pneumonitis, Pleuritis) · Mediastinitis Digestive mouth (Stomatitis, Gingivitis, Gingivostomatitis, Glossitis, Tonsillitis, Sialadenitis/Parotitis, Cheilitis, Pulpitis, Gnathitis) · tract (Esophagitis, Gastritis, Gastroenteritis, Enteritis, Colitis, Enterocolitis, Duodenitis, Ileitis, Caecitis, Appendicitis, Proctitis) · accessory (Hepatitis, Cholangitis, Cholecystitis, Pancreatitis) · Peritonitis Integumentary Dermatitis (Folliculitis) · Cellulitis · Hidradenitis Musculoskeletal Arthritis · Dermatomyositis · soft tissue (Myositis, Synovitis/Tenosynovitis, Bursitis, Enthesitis, Fasciitis, Capsulitis, Epicondylitis, Tendinitis, Panniculitis) Osteochondritis: Osteitis (Spondylitis, Periostitis) · Chondritis Urinary Nephritis (Glomerulonephritis, Pyelonephritis) · Ureteritis · Cystitis · Urethritis Reproductive female: Oophoritis · Salpingitis · Endometritis · Parametritis · Cervicitis · Vaginitis · Vulvitis · Mastitis male: Orchitis · Epididymitis · Prostatitis · Balanitis · Balanoposthitis pregnancy/newborn: Chorioamnionitis · Omphalitis Endocrine Insulitis · Hypophysitis · Thyroiditis · Parathyroiditis · Adrenalitis Lymphatic Lymphangitis · Lymphadenitis

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