Etiology (Causes) of Myelitis
Myelitis, inflammation of the spinal cord, can arise from a diverse range of causes. It's crucial to understand these origins for accurate diagnosis and targeted treatment. The etiology is broadly categorized into infectious, autoimmune, idiopathic, and vascular causes.
- Infectious Causes: Viruses (Herpes simplex virus, Varicella-zoster virus, Cytomegalovirus, Epstein-Barr virus), Bacteria (Streptococcus pneumoniae, Neisseria meningitidis), Fungi.
- Autoimmune Diseases: Multiple sclerosis, Rheumatoid arthritis, Systemic lupus erythematosus.
- Idiopathic Myelitis: Cases with no identifiable cause – often referred to as NSAID-induced or acute disseminated encephalomyelitis (ADEM).
- Vascular Causes: Vasculitis, spinal artery occlusion.
- Other causes: Trauma, toxins, medications.
Recent research suggests a growing understanding of the role of molecular mimicry in some autoimmune-related myelitis cases – where an immune response against one pathogen inadvertently attacks the nervous system.
Diagnosis of Myelitis
Diagnosing myelitis involves a thorough clinical evaluation and often requires specialized tests. There isn’t a single definitive test; instead, physicians rely on a combination of findings.
- Neurological Examination: Assessing reflexes, motor strength, sensation, coordination, and spinal cord function.
- Magnetic Resonance Imaging (MRI): The gold standard for visualizing the spinal cord and identifying inflammation or lesions.
- Lumbar Puncture (Spinal Tap): Analyzing cerebrospinal fluid (CSF) for signs of infection, inflammation, or autoimmune activity.
- Blood Tests: Ruling out infections, assessing autoimmune markers (e.g., rheumatoid factor, ANA), and checking for other systemic conditions.
- Evoked Potentials: Measuring the speed and accuracy of nerve signals to assess spinal cord function.
The diagnostic process can be complex, particularly in cases of idiopathic myelitis where no clear etiology is identified. A detailed patient history and careful clinical correlation are critical.
Treatment of Myelitis
Treatment for myelitis focuses on managing symptoms, addressing the underlying cause, and preventing complications. The approach varies depending on the diagnosis and severity of the condition.
- Supportive Care: Maintaining adequate hydration, nutrition, and respiratory support.
- Medications: Antiviral drugs (for viral myelitis), corticosteroids (to reduce inflammation), immunosuppressants (for autoimmune myelitis).
- Intravenous Immunoglobulin (IVIG): Used in some cases of ADEM to modulate the immune system.
- Rehabilitation Therapy: Physical therapy, occupational therapy, and speech therapy to improve function and mobility.
Early intervention is often crucial for improving outcomes. In severe cases, hospitalization and intensive care may be required.
Prognosis of Myelitis
The prognosis of myelitis varies greatly depending on the underlying cause, severity of inflammation, and individual patient factors. Some cases resolve completely with conservative management, while others lead to long-term disability.
- Viral Myelitis: Often self-limiting, with full recovery expected in many cases.
- Autoimmune Myelitis: Prognosis can be variable, ranging from complete remission to chronic disability.
- ADEM: Prognosis is generally good, with most patients recovering within weeks or months.
Close follow-up and ongoing rehabilitation are often necessary to optimize long-term outcomes.
Potential Complications of Myelitis
Myelitis can lead to a range of complications, depending on the extent of spinal cord damage. Early recognition and management are key to minimizing these risks.
- Paralysis: Weakness or paralysis in the legs or arms.
- Spasticity: Increased muscle tone and stiffness.
- Autonomic Dysfunction: Problems with blood pressure regulation, bowel/bladder control, and sexual function.
- Chronic Pain: Persistent pain in the back, legs, or other areas.
- Respiratory Failure: In severe cases, respiratory muscles can be affected.