MB BS (Smith)
Arachnoiditis is a chronic, insidious inflammatory condition that
typically causes debilitating, intractable neurogenic back and limb pain
and a range of other neurological problems. This condition is substantially under-diagnosed and adverse drug reactions
under-reported, so that the true incidence has yet to be established. It remains an
incurable condition at this time.
There are 2 main subtypes of arachnoiditis:
1.Mechanically-induced: which resembles epidural fibrosis, with
localised pathology and symptoms.
2.Chemically-induced arachnoiditis, often iatrogenic, which results in a
systemic, toxic type picture, and may be associated with autoimmune disorders.
1. Of mechanically-induced arachnoiditis (MIA) Spinal surgery (especially multiple)
Multiple lumbar punctures
Trauma Spinal stenosis (congenital/degenerative) Chronic disc prolapse/ degenerative disc disease
2.Of Chemically-induced arachnoiditis (CIA) Myelographic dyes (especially oil-based such as Myodil (Pantopaque))
Epidural steroid injections (e.g. Depo-Medrol) Epidural anaesthesia Other intraspinal drugs such as amphotericin B and methotrexate
Chemonucleosis with chymopapain
Subarachnoid haemorrhage Infection e.g. meningitis
Predominant and most distressing symptom is chronic, persistent deafferentation pain (causalgia) in lower back and lower limbs. (this
may also occur throughout the body) Often central pain, allodynia, dyesthesia, hyperpathia, in widepread
distribution. Tends to be worse at night and pain felt in numb areas is pathognomonic of neurogenic pain. Sensory symptoms: parasthesiae, numbness, bizarre sensations. Loss of
temperature sensation and proprioception.
Motor: weakness, muscle cramps, spasms and fasciculation.
Autonomic: bladder/bowel/sexual dysfunction; hyperhidrosis/anhydrosis;
heat intolerance; dysphagia (possibly with non-cardiogenic chest pain);limb oedema (c.f. RSD/CRPS); autonomic dysreflexia (c.f. spinal
cord injury) Autoimmune type: intermittent low grade fever; raised ESR, lymphadenopathy, malaise, joint pains, skin rashes, dry eyes. New drug(
and other) allergies. Miscellaneous: osteoporosis; weight gain; low potassium; dental
problems; visual problems.
Side-effects of medication. Depression and anxiety: as in all chronic illnesses; exacerbated by
sleep disturbance, experienced by most patients.
Other types of failed back surgery syndrome e.g. epidural fibrosis, recurrent disc herniation etc. Also, arachnoiditis may mimic Multiple
Sclerosis, Cauda Equina Syndrome, Systemic Lupus Erythematosus. Some patients are diagnosed with fibromyalgia, but these symptoms are likely
to occur as a secondary feature due to the altered spinal dynamics. Often, patients are considered to have psychosomatic problems or may be
diagnosed with Chronic Pain Syndrome, depression or even to be malingering for compensation purposes.
Generally speaking, this complex neurogenic pain syndrome is best treated at a specialist pain clinic, with a multidisciplinary approach.
As it is a chronic, incurable condition, it is vital that a sustained multimodal approach is maintained: using medication, physical modalities
(hydrotherapy, gentle exercise, massage, stretching), lifestyle measures
(e.g. diet, smoking etc), psychological support (especially establishing
a strong therapeutic alliance).
Medication: of the well-established treatment regimes, opiates are
frequently used, often as part of a triad with antidepressant at low dose(tricyclic group are best) and anticonvulsant such as
tegretol/gabapentin. Risk of addiction to opiates is very small. Muscle relaxants such as baclofen may be necessary to combat painful
NSAIDS may be useful for musculoskeletal pain or during "flare-ups"
Invasive treatments carry potential risk of exacerbating the condition, but patients who have not responded to oral treatment may require a
spinal cord stimulator or intraspinal narcotic device (the pump).
Epidural steroids are of little benefit and are implicated in causing
Surgery is generally not effective in
the long-term, due to recurrence.
Non pharmacological treatment such as hydrotherapy may be useful but
arachnoiditis is essentially an inflammatory condition and physiotherapy
must be tailored accordingly to prevent flare-ups (c.f. Rheumatoid
Cognitive pain management techniques may be of some help, but will
generally not be sufficient alone.
Dr. S. A. Andreae-Jones MB BS