ARACHNOIDITIS OR EPIDURAL FIBROSIS?

A frequent question arises about the difference between these two terms. Arachnoiditis is chronic inflammation inside the dura, in the arachnoid layer of the meninges (see below) whereas epidural (peridural, extradural) fibrosis is scarring outside the dural sac. It may also be referred to as “adhesions” or “scar tissue”. Many doctors appear to regard epidural fibrosis as less clinically significant than arachnoiditis, but in essence the nerve root compression arising from epidural fibrosis may cause similar clinical problems in terms of lower limb pain, sensory disturbance and weakness. Epidural fibrosis differs from arachnoiditis in that it is more likely to be a localised problem and is generally a post-surgical phenomenon, although it may also be a sequela to invasive procedures such as chemonucleolysis.

In cases of arachnoiditis, there is often associated epidural fibrosis, but the reverse is not generally acknowledged, so that patients may be left with a diagnosis of epidural fibrosis and are unable to get a diagnosis of arachnoiditis even when the clinical picture fits. Arachnoiditis is an underdiagnosed condition.

Table of Contents

Introduction
THE SCALE OF THE PROBLEM
ARACHNOIDITIS OR EPIDURAL FIBROSIS?
NEXT: NOMENCLATURE
THE INFLAMMATORY NATURE OF ADHESIVE ARACHNOIDITIS
PATHOLOGY
CLASSIFICATION
CAUSES
THE IATROGENIC ASPECT OF ADHESIVE ARACHNOIDITIS
PRESERVATIVES IN SPINAL INJECTIONS
PROGNOSIS
THE SYNDROMIC NATURE OF SYMPTOMS IN ADHESIVE ARACHNOIDITIS (Warning: LONG)
COMPLICATIONS OF ADHESIVE ARACHNOIDITIS
DIFFERENTIAL DIAGNOSIS
CLINICAL ASSESSMENT
DIAGNOSTIC TESTS
TREATMENT OPTIONS (Warning: LONG)
MULTIPLE CHEMICAL SENSITIVITY
LOOKING TO THE FUTURE
APPENDIX I: AUTOIMMUNE ASPECTS
APPENDIX II: SYRINGOMYELIA
ADDENDUM - May 2000
REFERENCES