Arachnoiditis is a painful condition of the spine. It involves inflammation of the arachnoid, which is the middle of three membranes that surround and protect the brain and the nerves of the spinal cord.

Inflammation in the arachnoid can start after surgery, spinal cord injury, infection, or irritation from chemicals injected into the spine. This inflammation damages spinal nerves, causing them to scar and clump together. Inflammation can also affect the flow of cerebrospinal fluid. This is the fluid that bathes and protects the brain and spinal cord.

Damage to the nerves can lead to neurological symptoms such as severe pain, intense headaches, numbness and tingling, and difficulty moving. Keep reading to learn more.

Your symptoms depend on which nerves or areas of the spinal cord are damaged by inflammation. Arachnoiditis often causes intense pain in the injured area, which can include the lower back, legs, buttocks, or feet.

The pain may feel like an electric shock or a burning sensation. It can spread across your back and down your legs. The pain may get worse when you move.

Other common symptoms of arachnoiditis include:

  • numbness, tingling, or a pins-and-needles feeling
  • crawling sensation on the skin, as if ants are walking up and down your back
  • muscle cramps or spasms
  • weakness
  • trouble walking
  • severe headaches
  • vision problems
  • hearing problems
  • dizziness
  • nausea
  • bladder or bowel problems
  • trouble sleeping
  • fatigue
  • joint pain
  • loss of balance
  • sexual dysfunction
  • depression
  • ringing in the ears (tinnitus)
  • inability to sweat normally (anhidrosis)

In the most severe cases, the legs can become paralyzed.

Arachnoiditis often starts after surgery, injury, or epidural injection into the spine.

Causes include:

  • epidural steroid injections used to treat disk problems and other causes of back pain
  • epidural anesthesia, which is often used during labor and delivery
  • chemotherapy drugs, such as methotrexate (Trexall), that are injected into the spine
  • injury or complications during spinal surgery
  • spinal cord injury
  • bleeding in the spine due to injury or surgery
  • spinal tap (lumbar puncture), which is a test that removes a sample of cerebrospinal fluid from your spine to look for infections, cancer, and other nervous system conditions
  • myelogram, which is an imaging test that uses contrast dye and X-rays or CT scans to look for problems in your spinal cord
  • disk prolapse, which occurs when the inner part of a disk in your spinal cord bulges out
  • meningitis, which is a viral or bacterial infection that causes inflammation of the membranes around the brain and spinal cord
  • tuberculosis, which is a bacterial infection that can affect the lungs, brain, and spine

Arachnoiditis can be difficult to diagnose because its symptoms are similar to those of other nerve problems in the back. Knowing that you’ve recently had spinal surgery, an injury, or an epidural injection can help your doctor focus in on arachnoiditis.

To diagnose this condition, your doctor might do a neurological exam. They’ll check your reflexes and look for any areas of weakness.

To confirm the diagnosis, doctors perform an MRI of the lower back. An MRI uses powerful magnets and radio waves to create detailed pictures of the inside of your body. Contrast dye can help highlight the injury more clearly on the pictures.

There isn’t a cure for arachnoiditis, and the condition can be difficult to treat. A few therapies can help relieve your pain and other symptoms. Some of the treatments for this condition include:

Opioids: These medications can help relieve severe pain, but they should be used with caution. Opioids can cause side effects and may become addictive.

Physical therapy: Working with a physical therapist can help you regain movement in the affected parts of your body. Your physical therapist may use interventions such as exercise, massage, heat and cold treatment, and water therapy.

Talk therapy: Therapy can help with any mood changes related to arachnoiditis. Many people with this condition also experience depression. Therapy can help you cope with the emotional and physical pain of the disorder.

Surgery usually isn’t recommended to treat arachnoiditis. That’s because it relieves pain only temporarily, and it may cause more scar tissue to form.

Arachnoiditis causes chronic pain and neurological problems like numbness and tingling. Some people have very mild symptoms. Others have severe symptoms. Most people with the condition are in between mild and severe.

The progression of arachnoiditis can be hard to predict. In some people, the symptoms can get worse over time. Others find that their symptoms remain stable for many years.

Although there isn’t a cure for this condition, treatments can help you manage pain and other symptoms.