larachnoïdite

Larachnoïdite, known in English as arachnoiditis, is an inflammatory condition affecting the arachnoid mater, one of the membranes that surround the brain and spinal cord. The inflammation can lead to scarring and adhesions of the arachnoid, with entrapment or distortion of nerve roots. The condition can affect the spinal canal or the cranial subarachnoid space.

Most cases are iatrogenic or post-traumatic. Procedures involving the spinal canal, such as spinal surgery, repeated punctures, intrathecal injections, spinal anesthesia, and myelography with oil-based contrast, have been linked to arachnoiditis. Infections (bacterial, tuberculous), inflammatory diseases, or chemical irritation from agents used during procedures can also play a role. In many patients, the exact cause remains unknown.

Symptoms are typically chronic and include severe back or limb pain, often described as burning or electric shock-like. Sensory changes, numbness, tingling, muscle weakness, gait disturbances, and reduced reflexes may occur. Autonomic symptoms such as bladder or bowel dysfunction can appear with extensive involvement. The course is often persistent and may be progressive.

Diagnosis is based on clinical presentation and imaging. MRI is the preferred method and may show clumped or adherent nerve roots, scarring, and cauda equina distortion; CT myelography can reveal adhesions or calcifications. Lumbar puncture is not diagnostic but may be performed to exclude infection. The condition is sometimes misdiagnosed as failed back surgery syndrome.

Treatment is aimed at symptom relief and functional improvement. There is no cure. A multidisciplinary approach may include analgesics, anticonvulsants, antidepressants, physical and occupational therapy, and interventional procedures such as nerve blocks or spinal cord stimulation in selected cases. Surgical adhesiolysis has limited success and carries a high risk of recurrence. Prevention centers on minimizing intrathecal procedures and using non-irritating agents.