The brain and spinal cord are covered with protective membrane called the meninges. The meninges are made of three layers – the innermost layer known as the pia mater, the middle layer as the arachnoid and the outermost layer as the dura mater. The space between the pia and arachnoid is called as the subarachnoid space and contains cerebrospinal fluid (CSF), which provides nutrition and oxygen to the brain and spinal cord. It also helps to remove invasion and responds to inflammation.
Arachnoiditis is a condition when the arachnoid membrane inflames. The most severe type of arachnoiditis is adhesive arachnoiditis where there is scar formation in the membrane.
What is Adhesive Arachnoiditis?
Arachnoiditis means inflammation of the arachnoid membrane of the meninges. Adhesive Arachnoiditis is the most severe type of arachnoiditis. It is a very rare medical condition. Inflammation is caused due to infection of the meningeal coverings of spinal cord by bacteria, tuberculosis, syphilis and fungi. Adhesive Arachnoiditis is also caused due to adverse reactions to direct injury to spine, epidural cortisone injection, local anesthetics injection in to cerebrospinal fluid, complications from spinal surgery or accidental injection in the spine. The chronic or long standing inflammation leads to formation of a scar tissue, which compresses nerve roots and makes their ends sticky. The scarring causes formation of compartment within subarachnoid space resulting in compromised or restricted blood supply and the flow of cerebrospinal fluid.(1)
Adhesive Arachnoiditis is a chronic extreme painful condition. In additions to pain, Adhesive Arachnoiditis manifests a number of symptoms and shows a complex clinical picture. It is characterized by unremitting pain and disability. It often ends up as a chronic noncurable and progressive disease. The advanced form is known as arachnoiditis ossificans where the arachnoid becomes ossified or changes into a bone. Hence, the prompt and appropriate treatment of Adhesive Arachnoiditis is extremely important to prevent a disabling advance disease of arachnoiditis ossificans.
Causes of Adhesive Arachnoiditis
The causes (2) of adhesive arachnoiditis include:
Chemically Induced Injury Causing Adhesive Arachnoiditis
- Spinal Injections- Chemicals such as local anesthetics or antibiotics when injected in to subarachnoid space rarely causes inflammation resulting in adhesive arachnoiditis.
- Corticosteroid Injections in the epidural space- Corticosteroids like Depo-Medrol and Kenalog are frequently injected into epidural space for treatment of radicular pain and backache. The particles of corticosteroid preparation is a common cause of new cases of iatrogenic chemically-induced arachnoiditis.
- Injection of Myelogram- Myelogram is a radiological dye study of spinal cord and subarachnoid space. The chemical particle of dye, which is injected in to cerebrospinal fluid rarely causes inflammation of arachnoid space in few patients who may have hypersensitivity to the chemical in dye.
- Chemotherapy Medications- Anti-cancer medications are often injected into cerebrospinal fluid in a patient suffering with spinal cord or vertebral column cancer. The particles of drugs may induce inflammation of subarachnoid membrane resulting in adhesive arachnoiditis.
Mechanically Induced Injury Causing Adhesive Arachnoiditis
- Spinal injury due to surgery.
- Chronic spinal stenosis.
- Accidental trauma.
- Multiple lumbar punctures due to spinal taps.
- Spinal injections misplaced and delivered into the intrathecal region.
- Bleeding into the spinal fluid due to the invasive procedures.
Adhesive Arachnoiditis Caused Due to Infection:
- Bacterial and viral infection leading to cerebral and spinal meningitis.
- Tuberculosis infection of the thoracic region of the spinal cord.
- Parasitic infections.
Symptoms of Adhesive Arachnoiditis
Adhesive arachnoiditis does not show typical symptoms and has a number of features, majority of which are shown by the patients as:
- Chronic Low Back Pain- The inflammation of spinal membrane causes severe low back pain during initial phase. Burning or tingling sensation in the feet. This may be accompanied by feeling of walking on broken glass.
- Radicular Pain- The scarring of arachnoid membrane causes pinch of spinal nerve. The superficial strangulation of entrapped spinal nerve within scarred spinal membrane causes moderate to severe pain. The spinal nerve pain radiates to section of arm, chest abdomen or leg, which depends on injury of level of spinal nerve. Such pain that radiate to arm or leg is known as radicular pain.
- Tingling and Numbness- As the pinch become severe, the pain often follows with symptoms of tingling and numbness. The compression of sensory nerve causes symptoms like tingling and numbness.
- Weakness- The weakness in arms, abdominal muscles and leg muscles is seen during advanced stages of adhesive arachnoiditis. The motor nerve strangulation results in muscle weakness and follows paralysis.
Other Symptoms of Adhesive Arachnoiditis Include:
- Bowel dysfunction.
- Bladder dysfunction.
- Sexual dysfunction.
- Intolerance to heat.
- Dryness in mouth.
- Heat burn.
Less Commonly Observed Symptoms of Adhesive Arachnoiditis Include:
- Ringing in ears.
- Dental problems.
- Menstrual cycle problems.
Epidemiology of Adhesive Arachnoiditis
Adhesive Arachnoiditis is usually uncommon in the population. Its exact prevalence and incidence in every country and globally is not known. It is estimated that nearly 11,000 new cases of Adhesive Arachnoiditis are diagnosed in United States of America. However, this number may be underestimated since there are an increasing number of patients undergoing surgical and anesthetic spinal procedures. In addition, some cases are undiagnosed or misdiagnosed. Thus, the actual frequency cannot be determined. Generally, the females are more affected than the males. Since during delivery, the more number of females receive spinal and epidural injections.
Prognosis of Adhesive Arachnoiditis
The successful treatment of initial chemical and infectious inflammation of spinal membrane resulting in zero symptoms depends on prompt diagnosis and rapid initiation of treatment. The treatment become difficult to achieve resulting in zero pain once the scarring of spinal membrane is occurred. The advanced Adhesive Arachnoiditis is not a curable condition. The prognosis of Adhesive Arachnoiditis is poor since it is a very painful condition with neurological problems.
Diagnosis of Adhesive Arachnoiditis
The prompt diagnosis depends on physical examination and appropriate radiological as well as blood examination studies. Physical examination is performed by neurologist or primary care physician. This procedure enables to define the extent and severity of the illness.
- The radiological study helps to conclude diagnosis are MRI and CT scan of vertebral column and spinal cord as well as myelogram study. MRI and CT scan should be done using high resolution and should be able to assess the contents of thecal sac. MRI or CT scan results may not always be positive, which does not mean that arachnoiditis does not exist. Myelogram dye study may be a valuable study to diagnose adhesive arachnoiditis.
- The physical examination includes detecting changes in reflexes, sensory deficits and any alterations in balance because of muscle weaknesses.
- Nerve damage is assessed by using Electromyogram (EMG) or Nerve conduction velocity (NCV) tests.
- Urodynamic studies are conducted to check for the loss of bladder control.
Treatment of Adhesive Arachnoiditis
Adhesive arachnoiditis is noncurable. Hence, it’s symptoms can be only managed. The treatment strategy for Adhesive Arachnoiditis is palliative.
- Medications to Treat Adhesive Arachnoiditis: Pain relievers, antidepressants, muscle relaxants and membrane stabilizers such as gabapentin are given for symptomatic treatment. Non-steroidal anti-inflammatory drugs are given to decrease the musculoskeletal pain and reduce impact of the inflammation.
- Antibiotics- The bacterial or viral infection is treated with antibiotics or anti-viral medications.
- Alternative Therapies to Treat Adhesive Arachnoiditis: Along with the medicines, alternative therapies are also highly advised, so that the patients can cope with the difficulties.
- Physical therapy- Physical therapy is recommended to treat complications such as numbness and weakness, which are observed during advanced phase of adhesive arachnoiditis. Physical therapy is often combined with adjuvant therapy like chiropractic treatment, acupuncture, massage, and myofascial release techniques.
- Stretching- Stretching of back is achieved by stretching exercises, which helps to release the nerve pinch caused by scarring of spinal membrane. In few cases if stretching causes pain then hydrotherapy and isometric exercises are often beneficial.
- Bladder Therapy- Autonomic dysfunction causes bladder incontinence. Bladder incontinence is treated with pelvic muscle treatment.
- Lifestyle Changes- Symptoms like pain are exaggerated in patient who are either chronic smoker or consume frequent alcohol. The pain and other symptoms are less severe in patient who stopped smoking and drinking alcohol.
- Psychotherapy- Psychological consultation and meditation helps to increase tolerance of pain. Most patients suffering with Adhesive Arachnoiditis are in emotional distress and frustrated because lack of relief from symptoms like pain, numbness, weakness and bladder incontinence. Individual counseling or group therapy sessions or cognitive behavior therapy may be helpful.
- Surgery– Several surgical treatments are available, but outcome often are not helpful. Surgery is rarely performed and is not of much help in treating Adhesive Arachnoiditis.
Adhesive arachnoiditis is a rare medical condition. It has a debilitating effect on the quality of life of the person suffering from it. It is mainly due to the presence of severe intractable pain which is unbearable and could many a times be traumatic enough that a person does suicidal attempt. Since it is uncommon, hence not much research is done to understand how to tackle this problem. The doctors too have limited knowledge of drugs, which can provide relief from the severe unbearable pain. Thus, the future of adhesive arachnoiditis is not very clear. However, to prevent incidence of iatrogenic cases, there is a need to increase the awareness of the risks associated with these procedures.
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