Arachnoiditis is a rare pain disorder caused by inflammation of the arachnoid, one of the membranes that surrounds the nerves of your spinal cord. It can cause severe pain and neurological symptoms, such as muscle weakness. Arachnoiditis has several possible causes, and treatment is aimed at managing symptoms.


Anatomy of a section of the spine, showing the spinal cord, pia mater, inflamed arachnoid mater and the dura mater.
Arachnoiditis is a rare pain disorder caused by inflammation of the arachnoid, one of the membranes that surround and protect your spinal cord.

What is arachnoiditis?

Arachnoiditis is a rare pain disorder caused by inflammation (swelling) of the arachnoid, one of the membranes that surrounds and protects the nerves of your spinal cord.

Arachnoiditis causes severe stinging, “burning” pain and neurological problems. It most commonly affects the nerves of your lumbar (low back) and thoracic spine (middle back). It rarely affects your entire spine.

The course of this condition remains highly variable since arachnoiditis can be either a static (stays the same) or progressive (gets worse over time) disease.


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What happens to the arachnoid in arachnoiditis?

The arachnoid mater is part of the meninges, which are three layers of membranes that cover and protect your brain and spinal cord (your central nervous system). The arachnoid mater is the middle layer. The other two layers are the dura mater and pia mater.

There are three spaces within the meninges:

  • The epidural space is between your skull and dura mater and the dura mater of your spinal cord and the bones of your vertebral column.
  • The subdural space is a potential space between your dura mater and your arachnoid mater. It can open when the arachnoid mater separates from the dura mater as a result of trauma, a pathologic process or a lack of cerebrospinal fluid. This can happen with arachnoiditis.
  • The subarachnoid space is between your arachnoid mater and pia mater. It’s filled with cerebrospinal fluid. Cerebrospinal fluid cushions and protects your brain and spinal cord.

Arachnoiditis affects the arachnoid layer somewhere along your spinal cord, not your brain.

In arachnoiditis, damage to and inflammation of the arachnoid (subarachnoid or subdural space) leads to a cascade of events, including:

  • Collagen deposits.
  • Scar tissue that encloses nerve roots.
  • Fibrosis (thickening or scarring of tissue).
  • Decreased cerebrospinal fluid flow.
  • Clumping of nerve roots.
  • Impaired blood supply to the affected nerves.
  • Nerve atrophy (wasting).
  • Nerve damage and possibly tethered nerves.

Due to these changes in the arachnoid and nerve roots, arachnoiditis frequently results in pain and possible neurological deficits, such as muscle weakness and sensory issues.

What is adhesive arachnoiditis?

As arachnoiditis progresses, it can lead to the formation of scar tissue and cause the spinal nerves to stick together and malfunction (not work properly). This leads to a condition called chronic adhesive arachnoiditis.

Adhesive arachnoiditis can potentially lead to disability. Many people with the condition eventually need to use a wheelchair due to paraparesis, which occurs when you're partially unable to move your legs.


How common is arachnoiditis?

Arachnoiditis is rare, but researchers don’t know exactly how widespread it is. Since the presentation of arachnoiditis ranges from very mild to severe, many mild cases of arachnoiditis will either never be diagnosed or aren’t reported.

Recent studies show that the frequency of lumbar arachnoiditis appears to be increasing due to an increasing amount of lumbar spine surgeries.

Is arachnoiditis serious?

While it’s not life-threatening, the chronic pain and neurological issues associated with arachnoiditis can greatly affect your quality of life. It’s important to find a healthcare provider who’s familiar with arachnoiditis to receive the best treatment.


Symptoms and Causes

What are the symptoms of arachnoiditis?

Arachnoiditis has no consistent pattern of symptoms, though the most common symptom is pain. The symptoms can vary based on which part of your spine (which spinal nerve) is affected and can range from mild to severe.

Arachnoiditis most commonly affects the nerves connecting to your lower back and legs (lumbar spine).

Arachnoiditis can cause many symptoms, including:

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

What causes arachnoiditis?

In many cases of arachnoiditis, healthcare providers aren’t able to determine the exact cause. This is because it’s a rare condition with multiple possible causes, and the symptoms can appear a while after the incident that caused it.

The arachnoid can become inflamed because of irritation from one of the following sources:

  • Complications from spinal surgery or multiple lumbar punctures: Up to 90% of cases of arachnoiditis have been linked to lumbar spine surgeries, though arachnoiditis is a rare complication of these procedures.
  • Direct injury to your spine: In rare cases, direct trauma or injury to your spine, such as from a fall or vehicle accident, can lead to arachnoiditis.
  • Chemicals: Dye used in myelograms has been blamed for some cases of arachnoiditis. Myelograms are diagnostic tests in which a dye called radiographic contrast media is injected into the area surrounding your spinal cord and nerves. The radiographic contrast media responsible for this (iofendylate) is no longer used, however. Also, there’s concern that the preservatives found in epidural steroid injections may cause arachnoiditis.
  • Infection from bacteria or viruses: Infections such as viral and fungal meningitis, tuberculosis or HIV can affect your spine and cause arachnoiditis.
  • Chronic compression of spinal nerves: Chronic compression of your spinal nerves due to degenerative disc disease or advanced spinal stenosis (narrowing of your spinal column) can cause arachnoiditis.

Less commonly reported causes of arachnoiditis include:

Diagnosis and Tests

How is arachnoiditis diagnosed?

Arachnoiditis can be difficult to diagnose since it’s rare and not all healthcare providers are familiar with it. There are also no reliable laboratory tests or imaging test findings to definitively diagnose arachnoiditis. Providers base the diagnosis on clinical presentation and symptoms, along with supporting MRI or CT myelography.

What tests will be done to diagnose arachnoiditis?

If you have symptoms of arachnoiditis, your healthcare provider may order the following tests to help diagnose it:

  • Magnetic resonance imaging (MRI): MRI is a painless test that produces very clear images of the organs and structures within your body. It uses a large magnet, radio waves and a computer to produce detailed images. Your provider will look for certain signs of arachnoiditis, such as nerve root thickening and clumping, in an MRI of your spine.
  • Computed tomography (CT) myelogram: A myelogram is an imaging procedure that examines the relationship between your vertebrae and discs, through your spinal cord, nerves and nerve roots. Your provider will look for certain signs of arachnoiditis.
  • Lumbar puncture: Sometimes a lumbar puncture, in which spinal fluid is withdrawn with a needle for testing, is important if arachnoiditis may be due to infections in the spinal fluid.
  • Electromyogram (EMG): An EMG can help your provider assess the severity of the damage to the affected nerve roots by using electrical impulses to check nerve function.

Management and Treatment

How is arachnoiditis treated?

Unfortunately, there’s no cure for arachnoiditis. Treatment mainly focuses on alleviating pain, improving quality of life and managing symptoms.

Treatment options for arachnoiditis are similar to those for other chronic pain conditions. Often, healthcare professionals recommend a program of the following:

  • Pain management.
  • Physical therapy, such as hydrotherapy and massage.
  • Stretching and range-of-motion exercises.
  • Psychotherapy (talk therapy).
  • Adaptive equipment or technology to help with mobility and comfort.

Specific types of treatment include:

  • Spinal cord stimulation: A spinal cord stimulator is a device that transmits an electrical signal to your spinal cord for pain relief.
  • Medications: Your provider may recommend medications, such as NSAIDs or stronger medications, to help manage pain. They may also prescribe other drugs, such as duloxetine, gabapentin, pregabalin, and muscle relaxants, such as baclofen.


Can arachnoiditis be prevented?

Unfortunately, there’s no known way to prevent arachnoiditis.

Outlook / Prognosis

What is the prognosis (outlook) for arachnoiditis?

Arachnoiditis is usually chronic (lifelong) and may be progressive, meaning it gets worse over time. While there are therapies and treatments that can help manage symptoms, there’s no cure.

The quality of life of people with severe arachnoiditis is often poor due to significant neurological symptoms and pain.

Arachnoiditis may cause disability in some people, and they may be unable to work full time due to constant pain and various neurological issues. Many people with arachnoiditis, however, can walk and drive a car without significant limitations.

Living With

How can I take care of myself if I have arachnoiditis?

Besides following your healthcare provider’s plan for managing your symptoms, such as medications and therapy, it’s important to take care of yourself. The following actions can help you cope with chronic pain and improve your overall health:

  • Avoid smoking.
  • Don’t try to do too much. Create a daily schedule that includes a few priorities and time for rest and self-care.
  • Eat a healthy diet.
  • Exercise regularly, if possible.
  • Get enough sleep.
  • Manage your stress.
  • Join a support group for chronic pain and/or arachnoiditis to learn from other people with similar conditions.
  • Limit alcohol, which can cause more problems with sleep and pain.
  • Try to think positively.
  • Use healthy methods for coping with pain, such as meditation, aromatherapy, biofeedback and mindfulness training.

If you have chronic pain and depression and/or anxiety, it’s important to seek treatment for your mental health condition(s) as well. Having depression or anxiety can make your chronic pain worse. For example, if you have depression, the fatigue, sleep changes and decreased activity may worsen your chronic pain.

When should I see my healthcare provider about arachnoiditis?

If you’ve been diagnosed with arachnoiditis, you’ll need to see your healthcare provider regularly to monitor your symptoms and treatment plan.

A note from Cleveland Clinic

It’s never easy to live with chronic pain. Since arachnoiditis can affect both your physical and mental health, it’s essential to seek proper treatment and advocate for yourself. Joining a support group — whether online or in-person — or finding other healthy, therapeutic outlets to manage your stress can help lighten the load. Be sure to seek out a healthcare provider who’s familiar with arachnoiditis. They can help determine the best treatment plan for you to manage your symptoms.

Medically Reviewed

Last reviewed on 08/09/2022.

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