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Arachnoiditis is a condition that can cause stinging, burning pain feelings, and muscle cramps and spasms. 

It results from inflammation of the one of the membranes – the arachnoid - that surrounds the nerves of the spinal cord.

Symptoms of arachnoiditis

Arachnoiditis has no consistent pattern of symptoms, but in many people it affects the nerves connecting to the lower back and legs. The most common symptom is pain, but arachnoiditis can also cause:

  • Tingling, numbness or weakness in the legs
  • Sensations that may feel like insects crawling on the skin or water trickling down the leg
  • Severe shooting pain that can be similar to an electric shock sensation
  • Muscle cramps, spasms and uncontrollable twitching
  • Bladder, bowel and/or sexual dysfunction

As the disease progresses, the symptoms may become more severe or even permanent. Many people with arachnoiditis are unable to work and suffer significant disability because they are in constant pain.

Causes of arachnoiditis

Inflammation of the arachnoid can lead to the formation of scar tissue and can cause the spinal nerves to stick together and malfunction. The arachnoid may become inflamed for one of the following reasons:

  • Direct injury to the spine
  • Chemicals: Dye used in myelograms - diagnostic tests in which a dye called a radiographic contrast medium is injected into the area surrounding the spinal cord and nerves - have been blamed for some cases of arachnoiditis. The radiographic contrast medium held responsible for this is no longer used, however. Also, there is concern that the preservatives found in epidural steroid injections may cause arachnoiditis.
  • Infection by bacteria or viruses: Infections such as viral and fungal meningitis or tuberculosis can affect the spine.
  • Chronic compression of spinal nerves: Causes of this compression include chronic degenerative disc disease or advanced spinal stenosis (narrowing of the spinal column).
  • Complications from spinal surgery or other invasive spinal procedures: These may include multiple lumbar (lower back) punctures.

Making the diagnosis

Diagnosing arachnoiditis can be difficult, but tests such as the CT scan (computerised tomography) or MRI (magnetic resonance imaging) have helped with diagnosis. A test called an electromyogram (EMG) can assess the severity of the ongoing damage to affected nerve roots by using electrical impulses to check nerve function.

Myelograms with radiographic contrast medium currently in use, combined with CT scanning, are not considered to be responsible for arachnoiditis or causing it to worsen.

Treating arachnoiditis

There is no cure for arachnoiditis. Treatment options are similar to those for other chronic pain conditions. Most treatments focus on relieving pain and improving symptoms that impair daily activities.

Often, healthcare professionals recommend a programme of pain management, physiotherapy, exercise and psychotherapy. Surgery for arachnoiditis is controversial because outcomes can be poor and may provide only short-term relief.

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WebMD Medical Reference

Medically Reviewed by Dr Rob Hicks on May 19, 2016

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