The Two Most Common Causes of Adhesive Arachnoiditis
/By Dr. Forest Tennant
Adhesive arachnoiditis (AA) doesn’t just happen out-of-the-blue or overnight. It is the tragic end result of sequential pathologic damage, over time, to multiple spinal tissues.
AA may develop from a direct spinal injury or from an inflammatory, autoimmune disease that originates outside the spine. The discovery that inflammatory-autoimmune diseases can originate outside the spine and spread into spinal tissue is a new medical concept.
Here are the two common pathologies that can cause AA, and the early symptoms that precede AA itself:
Pathology #1: Spinal Trauma
The first pathologic journey is accidental spine trauma or a medical procedure such as an epidural injection that damages the spinal canal cover, which consists of an outer layer (dura) and an inner layer (arachnoid).
Direct spinal injuries may occur to persons in good health. Examples are auto accidents or electrocution in an industrial accident. The arachnoid layer becomes inflamed after trauma, just like a finger that has been hit with a hammer. The inflammation may progress and then spread.
Eventually, the inflammation will contact cauda equina nerve roots and spread into them. After a time ranging from weeks to months, the inflammatory adhesions “glue” cauda equina nerve roots to the arachnoid, forming the disease called adhesive arachnoiditis.
Pathology #2: Degenerative Discs
Spinal discs degenerate when they become inflamed, due to a pathologic generator such as an infection, autoimmunity or trauma.
Persons who have a genetic connective tissue disease like Ehlers-Danlos, a spine anatomic abnormality, or an autoimmune disease are at high risk to develop degenerative disc disease. Once inflammation sets in, the disc softens, shrinks and slips out of its space, pressing against the spinal canal cover (dura and arachnoid layers).
The inflammation in the disc may spread to the arachnoid membrane and cauda equina nerve roots. As stated in Pathology #1, when inflammation produces sticky adhesions in the cauda equina nerve roots and arachnoid, they may glue together forming AA.
Early Symptoms
If the arachnoid becomes inflamed after trauma, epidural injection, spinal puncture or surgical procedure, there will be headaches, localized back pain, feverishness and dysphoria (a state of unease, depression and fatigue). This usually starts 7 to 10 days after the procedure or trauma.
When the cauda equina also becomes inflamed, the first early symptoms are shooting pains into the buttocks and legs, burning feet, and the tingling sensation of water or insects on the buttocks or legs.
Prevention of AA may be possible in these circumstances by use of one or more anti-inflammatory drugs that are effective inside the spinal canal. You can learn more about the symptoms and treatments for AA on our website.
Forest Tennant, MD, DrPH, is retired from clinical practice but continues his research on the treatment of intractable pain. Readers interested in learning more about his research should visit the Tennant Foundation’s website, Arachnoiditis Hope. You can subscribe to its research bulletins here.
The Tennant Foundation gives financial support to Pain News Network and sponsors PNN’s Patient Resources section.
