Neurological Disorders: Arachnoiditis

Arachnoiditis means inflammation of the arachnoid membrane of the meninges. The meninges are the coverings of the brain and the spinal cord and these coverings protect the brain & spinal cord and are made of 3 layers; dura, arachnoid & pia from out side to inside. So it is the middle layer or arachnoid membrane that gets inflamed and produces the condition mentioned above.

Although it can occur related to both brain & spinal cord generally this term is used for the occurrence of this condition in the spine. An advanced form of this condition called as adhesive-arachnoiditis can produce lot of scar tissue and make the spinal nerve roots clump together and this could be severely disabling to the patient.

This condition occurs commonly in the lower areas of the spine, the lumbosacral area.

There are multitudinous causes for this condition including;

• Infections
• Traumas
• Post surgical
• Chemical reaction due to contrast dyes, medications etc

Back pain is very common and the severity varies. If the spinal nerve roots are irritated then radiculopathy (pain shooting down to the limbs) features are seen. A cauda equina or conus medularis syndrome can take place when this condition is severe and occurs in the lumbosacral spine area. These conditions are due to irritation of multiple spinal roots or pressure effect on the lower portion of the spinal cord called as conus medullaris.

When spinal roots and/or lower spinal cord is involved the following manifestations are usually seen;

• Limb weakness
• Numbness and/or tingling sensation (pins & needles)
• Loss of sensation
• Bowel and /or bladder manifestations
• Gait difficulties etc

A picture of the spine in the form of MRI is highly recommended. CT, CT myelogram, basic x-ray myelogram are also helpful but less compared to MRI.

An electromyography and nerve conduction studies (EMG & NCS) is helpful when radiculopathy features are present.

A Spinal tap & spinal fluid analysis is required when you suspect infections and certain inflammatory causes for the irritation of the arachnoid tissue. Any additional tests would depend upon the individual case.

Most of these patients complain of lot of pain in the lower back and radiating to the legs and good pain management is of paramount significance. Medications like duloxetine gabapentin, pregabalin are recommended often. Epidural steroid injections are necessary sometimes. Spinal cord stimulators are tried in come patients.

Surgery is an option too however only in advanced cases and when patients are having severe manifestations.

A neurologist and a neurosurgeon are frequently involved in the care of patients with arachnoiditis.