Most commonly resulting from direct injury to the spine, arachnoiditis is caused by the inflammation of the arachnoid, which is one of the membranes that surround and protect the nerves of the spinal cord.
The arachnoid can also become inflamed due to an irritation from chemicals, infection from bacteria or viruses, chronic compression of spinal nerves, or complications from spinal surgery or other invasive spinal procedures.
Inflammation can sometimes lead to the formation of scar tissue and adhesions, which cause the spinal nerves to “stick” together. If arachnoiditis begins to interfere with the function of one or more of these nerves, it can cause a number of symptoms, including numbness, tingling, and a characteristic stinging or burning pain in the lower back or legs.
The most common symptom of this condition is pain, but arachnoiditis can also cause:
- Sensations that may feel like insects crawling on the skin or water trickling down the leg
- Severe shooting pain that can be similar to an electric shock sensation
- Muscle cramps, spasms, and uncontrollable twitching
- Bladder, bowel, and sexual problems
In very extreme cases, arachnoiditis has also been known to cause paralysis of the lower limbs.
Arachnoiditis remains a difficult condition to treat, and long-term outcomes are unpredictable. Most treatments for arachnoiditis are focused on pain relief and the improvement of symptoms that impair daily function.
A regimen of pain management, physiotherapy, exercise, and psychotherapy is often recommended. Surgical intervention is controversial since the outcomes are generally poor and provide only short-term relief. Clinical trials of steroid injections and electrical stimulation are needed to determine the efficacy of these treatments.
Arachnoiditis appears to be a disorder that causes chronic pain and neurological deficits and does not improve significantly with treatment. Surgery may only provide temporary relief. Aging and pre-existing spinal disorders can make an accurate prognosis problematic. The outlook for someone with arachnoiditis is complicated by the fact that the disorder has no predictable pattern or severity of symptoms.