Arachnoiditis

Template:Short description Template:Infobox medical condition Arachnoiditis is an inflammatory condition of the arachnoid mater or 'arachnoid', one of the membranes known as meninges that surround and protect the central nervous system. The outermost layer of the meninges is the dura mater (Latin for hard) and adheres to inner surface of the skull and vertebrae.<ref name="Neuroanatomy, Cranial Meninges">Template:Citation</ref> The arachnoid is under or "deep" to the dura and is a thin membrane that adheres directly to the surface of the brain and spinal cord.<ref name="Neuroanatomy, Cranial Meninges"/>

Signs and symptoms

Arachnoid inflammation can lead to many painful and debilitating symptoms which can vary greatly in each case, and not all people experience all symptoms.<ref name="Peng-2023"/><ref name="Rice-2004a">Template:Cite journal</ref><ref name="Rice-2004b">Template:Cite journal</ref> Chronic pain is common, including neuralgia, while numbness and tingling of the extremities can occur with spinal cord involvement, and bowel, bladder, and sexual functioning can be affected if the lower part of the spinal cord is involved.<ref name="Peng-2023" /><ref name="Rice-2004a" /><ref name="Rice-2004b" /> While arachnoiditis has no consistent pattern of symptoms, it frequently affects the nerves that supply the legs and lower back.<ref name="Peng-2023" /><ref name="Rice-2004a" /><ref name="Rice-2004b" /> Many patients experience difficulty sitting for long (or even short) periods of time due to discomfort or pain.<ref name="Rice-2004b" /><ref name="Peng-2023" />

Etiology

Arachnoiditis has been described as having many different etiologies. As an infectious source, tuberculosis,<ref name="Shah-2001">Template:Cite journal</ref><ref name="Safi-2021">Template:Cite journal</ref> syphilis,<ref name="Shah-2001" /><ref name="Safi-2021" /> candida,<ref name="Safi-2021" /> mycosis,<ref name="Safi-2021" /> and HIV.<ref name="Peng-2023"/> As a mechanical source, spinal and cranial surgery,<ref>Template:Cite journal</ref> trauma,<ref name="Wright-2003">Template:Cite journal</ref> and disc herniation.<ref name="Wright-2003" /> Prior disease including ankylosing spondylitis,<ref name="Shah-2001"/><ref>Template:Cite journal</ref> autoimmune vasculitis,<ref name="Peng-2023">Template:Citation</ref> and Guillain-Barré syndrome<ref name="Peng-2023"/> have been known to cause arachnoiditis. Chemical causes include morphine,<ref name="Davies 123–125">Template:Cite journal</ref> myelograms with oil-based radiographic contrast agents,<ref name="Davies 123–125"/> phenolic solutions,<ref>Template:Cite journal</ref> chlorhexidine,<ref>Template:Cite journal</ref> epidural injection of steroids and antibiotics,<ref name="Shah-2001"/> blood in subarachnoid hemorrhage,<ref>Template:Cite journal</ref> epidural blood patches and anesthetics.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

Oftentimes, the precise cause of arachnoiditis is not known due to the variable latency from cause to symptom onset. With growing incidence of spine surgery, a common cause of arachnoiditis is lumbar spine procedures.<ref>Template:Cite journal</ref>

Pathogenesis

The above etiologies can cause inflammation of the arachnoid, leading to arachnoiditis. This inflammation is enough to cause pain and even potentially neurological deficits - symptoms caused by nerves not communicating properly with the body's mechanisms for sensation and movement.<ref name="Rice-2004a"/><ref name="Killeen-2012">Template:Cite journal</ref> The inflammation can lead to the formation of scar tissue and adhesion that can make the spinal nerves "stick" together, a condition where such tissue develops in and between the leptomeninges - between dura and arachnoid or pia and arachnoid.<ref name="Killeen-2012" /> This condition can be very painful, especially when progressing to adhesive arachnoiditis. Adhesive arachnoiditis occurs when inflammation leads to recruitment of cells to the area and fibrous exudate, and ensuing deposition of collagen forms bands that could cause ischemia or even atrophy of the spinal cord or nerve roots.<ref name="Killeen-2012" /><ref name="Stacey M 2018">Template:Cite journal</ref> Chronic inflammation could lead to arachnoiditis ossificans, in which the inflamed arachnoid becomes ossified, or turns to bone, and is thought to be a late-stage complication of the adhesive form of arachnoiditis.<ref>Template:Cite journal</ref> More serious complications can occur, including spinal cord swelling, myelomalacia, cauda equina syndrome, and hydrocephalus.<ref name="Stacey M 2018"/><ref>Template:Cite journal</ref>

Diagnosis

Diagnosis is based on a combination of clinical findings, patient examination, and imaging evaluation.<ref>Template:Cite journal</ref> The most common affected area is the lumbar region of the back, and includes the classic symptomatic triad of back pain, neurological deficits, and MRI with notable adhesions.<ref>Template:Cite journal</ref> For the ossificans form of the condition, unenhanced CT may better show the presence and extent of arachnoid ossifications, and is complementary to MRI, as MRI can be less specific and findings can be confused with regions of calcification or hemosiderin.<ref name="SteelAbrames2015">Template:Cite journal</ref><ref name="MaulucciGhobrial2014">Template:Cite journal</ref>

Treatment

Arachnoiditis can be difficult to treat and treatment is generally limited to alleviation of pain and other symptoms.<ref name="ninds">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> While arachnoiditis may not yet be curable with the potential to be life-altering, management including medication, physical therapy, and if appropriate, psychotherapy, can help patients cope with the difficulties it presents.<ref name="ninds" />

Medications that have been used to treat arachnoiditis include nonsteroidal anti-inflammatory drugs,<ref name=cegm>Template:Cite journal</ref> pulse steroid therapy with methylprednisolone,<ref name=cegm/><ref name="Peng-2023"/><ref>Template:Cite journal</ref> and multi-modal pain regimens.<ref name="Peng-2023"/> Surgical intervention generally has a poor outcome and may only provide temporary relief,<ref name="ninds" /> but some cases of surgical success have been reported.<ref name="TachibanaMoriyama2014">Template:Cite journal</ref> Epidural steroid injections to treat sciatic pain have been linked as a cause of the disease by the U.S. Food and Drug Administration as well as in other research, and are therefore discouraged as a treatment for arachnoiditis as they will most likely worsen the condition.<ref name="nelson">Template:Cite journal</ref><ref name="shaw">Template:Cite journal</ref><ref name="NealKopp2015">Template:Cite journal</ref>

Prognosis

Arachnoiditis is a chronic disorder with no known cure,<ref name="ninds" /> and prognosis may be difficult to determine because of an unclear correlation between the beginning of the disease or source and the appearance of symptoms. For many, arachnoiditis is a disabling disease that causes chronic pain and neurological deficits,<ref name="SteelAbrames2015" /> and may also lead to other spinal cord conditions, such as syringomyelia.<ref name="Brammah">Template:Cite journal</ref><ref name="IbrahimKamali-Nejad2010">Template:Cite journal</ref>

Further reading

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External links

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