What is arachnoiditis?

Arachnoiditis is a pain disorder caused by the inflammation of the arachnoid, one of the membranes that surround and protect the nerves of the spinal cord. Severe stinging, a “burning” pain, and neurological problems characterize the condition. Inflammation (swelling) of the arachnoid can lead to the formation of scar tissue and can cause the spinal nerves to stick together and malfunction (not work properly).

Symptoms and Causes

What causes arachnoiditis?

The arachnoid can become inflamed (swollen) because of an irritation from one of the following sources:

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

What are the 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 and its most common symptom is pain. Arachnoiditis can cause many symptoms including the following:

  • 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

Symptoms may become more severe or even permanent if the disease progresses. Many people with arachnoiditis are unable to work and have a significant disability because of constant pain.

Diagnosis and Tests

How is arachnoiditis diagnosed?

Difficulty in diagnosing arachnoiditis has been compounded by a lack of awareness about the problem. Diagnosing arachnoiditis can be difficult, but tests such as the CT scan (computerized axial 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 the radiographic contrast currently in use, combined with CT scanning, are not considered to be responsible for causing arachnoiditis or causing it to worsen. Sometimes a lumbar puncture, in which spinal fluid is withdrawn for testing is important if arachnoiditis may be due to infections or other processes in the spinal fluid.

Management and Treatment

How is arachnoiditis treated?

There is no cure for arachnoiditis. Treatment options for arachnoiditis are similar to those for other chronic pain conditions. Most treatments for arachnoiditis focus on relieving pain and improving symptoms that impair daily activities. Often, healthcare professionals recommend a program of pain management, physiotherapy, exercise and psychotherapy. Surgery for arachnoiditis is controversial because outcomes can be poor and can provide only short-term relief. Clinical trials of steroid injections and electrical stimulation are needed to determine whether those treatments are effective.

Last reviewed by a Cleveland Clinic medical professional on 06/10/2019.


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  • National Institute of Neurological Disorders and Stroke. Arachnoiditis Information Page. ( Accessed 6/14/2019.
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