About Arachnoiditis

Summary for Patients 

Sarah Andreae-Jones MB BS (Smith)

SUMMARY
Arachnoiditis is a chronic, insidious inflammatory condition, involving the arachnoid (middle) layer of the meninges, the membranes surrounding the spinal cord. It typically causes debilitating, persistent back and limb pain and a range of other problems. This condition is substantially under-diagnosed and adverse drug reactions under-reported, so that the true incidence has yet to be established.

There are 3 subtypes of arachnoiditis:

1.Mechanically-induced: due to trauma (including surgical) which resembles post-spinal surgery scarring, with localised damage and symptoms. Other mechanical causes include multiple lumbar punctures (especially if there is a "bloody tap" with bleeding into the spinal fluid), stenosis (narrowing) or chronic degenerative disc disease.

2.Chemically-induced arachnoiditis, usually secondary to medical procedures such as myelograms or epidural injections (mostly steroid injections*), results in more widespread symptoms and may present with a toxic type picture and can be associated with other inflammatory conditions such as systemic lupus.

3.Miscellaneous causes include meningitis, subarachnoid bleed (may be termed a "stroke")

*these may contain preservatives that carry a risk of toxicity to nerves, especially if the injection is incorrectly sited in the subarachnoid space instead of the epidural space (inside the outer layer of meninges, the dura, instead of outside)

SYMPTOMS :
Predominant and most distressing symptom is chronic, persistent pain (causalgia) in lower back and lower limbs. (this may also occur throughout the body) 

Often centralised pain in widepread distribution: typically described as a background burning and intermittent severe shooting pains which may be likened to an electric shock sensation. The pain is often worst at night and thus considerably affects sleep, and typically may be felt in numb areas which can be confusing for the patient and doctor.

Other Sensory symptoms: tingling, numbness, bizarre sensations such as water trickling down the leg or insects crawling on the skin. 

• Loss of temperature sensation and balance. 
• Motor: weakness, muscle cramps, spasms and twitching.
• Autonomic: bladder/bowel/sexual dysfunction; excessive or reduced sweating; heat intolerance; difficulty swallowing (and sometimes related chest pain); limb swelling; blood pressure disturbance.
• Autoimmune type: intermittent low grade fever , swollen glands, 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. most commonly constipation and dry mouth.

Depression and anxiety: as in all chronic illnesses; exacerbated by sleep disturbance, experienced by most patients.

OTHER DIAGNOSES: Arachnoiditis may be diagnosed as one of the following:

1. Failed Back Surgery Syndrome
2. Epidural (peridural, post-surgical)fibrosis (scarring)
3. Multiple Sclerosis
4. Fibromyalgia
5.Reflex Sympathetic Dystrophy (Complex Regional Pain Syndrome CRPS)
6.Chronic Pain Syndrome
7. Lupus-like disorder
8. Depression
9. Psychosomatic disorder
10. Compensation neurosis/ Malingering

TREATMENT:
It is vital that a holistic approach be maintained: looking at various modalities: medication, physical (exercise within the constraints of the condition, hydrotherapy, massage, electronic pain relief devices), lifestyle (sleep patterns, diet, smoking, aids and devices to improve mobility etc.), psychological support (for patient and their partner/family), information. Of the well-established treatment regimes, opiates(narcotics) such as morphine are frequently used.

Contrary to widespread opinion amongst both lay and medical personnel, the risk of addiction is extremely low. Previously, it was thought that these drugs were ineffective against nerve-related pain, but it is now recognised amongst experts in palliative care that given in high enough doses, opiates may be beneficial. The more unpleasant adverse effects such as
sleepiness and nausea/vomiting tend to subside after a couple of weeks, constipation being the most persistent side-effect, but generally fairly easily managed.

Adjunctive treatment may also be necessary to combat nerve pain:

• Antidepressants such as amitriptyline given at low dose (not a dose for depression)
• Anticonvulsants such as tegretol, neurontin
• Muscle relaxants such as baclofen are helpful to combat muscle cramps
• Anti-inflammatory drugs(NSAIDS) are not generally effective against nerve pain but may help reduce joint and muscle pain.
  Invasive treatments such as epidural steroid injections carry potential risk of exacerbating the condition. However, some people may require an implanted device to provide electrical stimulation (this masks the pain signal): a spinal cord stimulator; or a pump to provide delivery of painkilling drugs directly to the spinal fluid (intraspinal pump)
• Surgery tends not be effective, except perhaps in the short term, as recurrence is fairly inevitable.
• 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 (as with patients with Rheumatoid arthritis etc.).
• Cognitive pain management techniques (using thought processes) may be of some help, but will generally not be sufficient alone.

Dr. S. A. Andreae-Jones MB BS, October 2000

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