Letters to the Editors: Arachnoiditis, Pituitary Adenoma
Arachnoiditis is Not A Rare Disease
While I am aware that there are many causes for arachnoiditis, a reference to arachnoiditis as a rare disease is misleading.1
The <1% incidence often cited is from a study of the first x-ray dye ever manufactured—iodized oil (Lipiodol), which was found to cause arachnoiditis. Lipiodol was replaced by the oil-based dye Pantopaque, which was promoted to be “safe.” The fact is that there were no requirements for end-users to
report any adverse reaction to the FDA. We now know that Pantopaque dye is a major cause of arachnoiditis worldwide.
Derek Morrison, BCW, Behavioural Scientist (Community Welfare)
While your conclusion that arachnoiditis is no longer “rare” is one I now support, your information needs some clarification. When magnetic resonance imaging entered clinical practice in the late 1980’s, the use of Pantopague dye coincidentally disappeared. Although there may be residual cases involving the dye, any data concerning the use of this toxic dye is simply out-dated.
PPM’s article on arachnoiditis was published a year ago, and we used the best data we could find and we remarked that the incidence was up 400% in the past decade.1 In the past year, we have received so many anecdotal reports about new cases of arachnoiditis that we no longer consider it "rare".
First, the term “arachnoiditis” is applied to inflammation of either the arachnoid layer of the dura or thecal sac, which surrounds the spinal cord or the nerve roots in the cauda equina below T12-L1. Like any other inflammatory condition, it can be acute, mild, and resolve—or it can be severe and progressive. These severe cases include patients who clearly show clumped nerve roots that are attached to the arachnoid lining. This condition is usually referred to as “adhesive” arachnoiditis.
Now that we know microglial activation causes neuroinflammation, it certainly appears proper to refer to these patients as having a spinal cord or cauda equina inflammatory disorder, regardless of whether the nerve roots are actually adhered to the arachnoid lining.
Cauda equina inflammatory disorder, including those that show adhesion to the arachnoid, can no longer be called “rare” or “uncommon”. In fact, cauda equina inflammation may actually be a major underlying cause of severe, chronic back pain and be epidemic, in nature.
In the past, arachnoiditis has been thought to be a “hopeless, untreatable” condition. We now have emerging, therapeutic measures to deal with neuroinflammation whether it be in the brain or spinal cord, and I encourage all pain practitioners to make a New Year’s Resolution to begin to better understand and treat it.
—Forest Tennant, MD, DrPH
I have a patient that has recently been diagnosed with arachnoiditis (via magnetic resonance imaging [MRI]). My practice is in a rural location, so pain management options are very limited—the closest legitimate clinic is 2 hours away by car.
I have sent my patient to a pain management clinic, but they have insisted that my patient undergo epidural steroid injections. I am not an expert on this subject, but I have read that steroid injections will have limited, if any, benefit.
I am looking for any guidance on pain medications, particularly opioid medications. My patient is currently on a fentanyl patch and short-acting oxycodone.
Lynn Hartman, DO, UPHS-Doctors Park Family Physicians, Escanaba, Michigan
As noted in the previous letter, you are encountering a condition that is dramatically increasing in incidence and prevalence. Unfortunately, I believe every clinician will now have to become familiar with this condition.1
The pain and disability of adhesive arachnoiditis is profound. Your patient is on fentanyl and oxycodone, which is most appropriate. A short-acting fentanyl preparation (buccal film, lozenge, or nasal spray) or even an injectable opioid may be required for the severe pain flares of arachnoiditis.
Epidural injections and any procedure that brings a potential irritant or contaminant close to the inflamed arachnoid layer or inflamed nerve roots is strictly contraindicated except in life-threatening situations. I’ve encountered many arachnoiditis patient who worsened following epidural injections, spinal taps, facet injections, or surgery. Once the arachnoid layer and/or the nerve roots in the cauda equina becomes inflamed, the inflammation may spread to the dura and even to the epidural space.
There are 2 major pain treatment goals: provide enough pain relief to function and stop the progression of neuroinflammation.
Unless controlled, the neuroinflammation progressively leads to a host of predictable complications that may include:
- bladder and bowel dysfunction
- sexual impairment
- burning feet
- blurred vision
- leg jerks or tremors
- episodes of heat and sweating
- inability to stand very long.
Arachnoiditis patients often can be observed sitting in your office on pillows or even laying on the floor.
In an initial attempt to stop the progression of nerve root inflammation, I start a 5-day course of methylpredinisolone. I prefer the Depo-Medrol Dose Pak (alternative corticosteroids are acceptable) for convenience. After this course, I give a 5-day course of oral ketorolac (Toradol) 10 mg three times a day.
Once the course of corticosteroids and ketorolac are finished, I develop an ongoing regimen of low-dose corticosteroid maintenance and periodic courses of ketorolac. I have found that the old anti-inflammatory agent, choline-magnesium-trisalicylate to sometimes be helpful. The standard NSAID’S haven’t been of much help.
The best analogy I can give is that treating arachnoiditis is like dealing with rheumatoid arthritis. We can’t cure it, but we can stop the destructive progression of inflammation, relieve pain, and give the patient an improved quality of life. Unfortunately, the inflammation in the central nervous system doesn’t respond well, if at all, to the usual anti-inflammatory, immunologic agents that are effective in the periphery. The control of neuroinflammation is very difficult, and we are in the early stages of developing effective treatments for it.2
The basic treatment of arachnoiditis is aggressive anti-neuroinflammatory measures and potent analgesia. Reasonable pain relief, stretching exercises, and walking are a must. Once these are in place there are a number of neuropathic agents, microglial modulators, topical agents, and neurohormones that I am using and are helpful in selected cases, but space here doesn’t allow description of these alternatives.
—Forest Tennant, MD, DrPH