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Myelitis – A Comprehensive Medical Guide

Overview

Myelitis refers to inflammation of the spinal cord. The term is a blanket description that includes several specific disorders, the most common being:

• Acute transverse myelitis (ATM) – a rapid‑onset inflammation that typically affects a segment of the cord.
• Neuromyelitis optica spectrum disorder (NMOSD) – an autoimmune condition that attacks the spinal cord and optic nerves.
• Multiple sclerosis (MS) – spinal cord lesions – although MS is a separate disease, spinal cord involvement is a form of myelitis.

Myelitis can occur at any age, but the epidemiology varies by type:

• Acute transverse myelitis incidence is roughly 1–4 cases per million persons per year worldwide (Mayo Clinic, 2022).
• NMOSD affects 0.5–4 per 100,000 individuals, with a higher prevalence among Asian and African‑descent populations (WHO, 2023).
• Spinal cord lesions in MS affect about 15–20 % of people with MS during the disease course (National Multiple Sclerosis Society, 2021).

Both sexes are affected, though NMOSD shows a female predominance (≈ 9 : 1). Myelitis is a medical emergency because spinal cord inflammation can cause irreversible neurologic damage if treatment is delayed.

Symptoms

Symptoms depend on the level and length of the inflamed spinal segment. Below is a complete list with brief explanations.

Motor Symptoms

• Weakness or paralysis – typically one side (hemiparesis) or both sides (paraparesis) of the body.
• Spasticity – increased muscle tone causing stiffness and involuntary muscle contractions.
• Difficulties with coordination – clumsiness or trouble walking (ataxia).

Sensory Symptoms

• Numbness or tingling (paresthesia) – often described as “pins and needles.”
• Loss of proprioception – inability to sense limb position, leading to a “walking on air” feeling.
• Altered pain perception – can be heightened (hyperalgesia) or reduced.

Autonomic Symptoms

• Bladder dysfunction – urgency, frequency, retention, or inability to empty the bladder.
• Bowel dysfunction – constipation or loss of control (fecal incontinence).
• Sexual dysfunction – erectile dysfunction in men, decreased lubrication in women.
• Sweat and temperature regulation problems below the level of inflammation.

Other Common Features

• Back pain – often localized to the level of the lesion.
• Fever, chills, or recent viral illness – suggest an infectious trigger.
• Visual disturbances – seen in NMOSD where optic neuritis co‑occurs.

Symptoms usually develop over hours to days for acute forms, whereas autoimmune or chronic myelitis may progress more slowly.

Causes and Risk Factors

Myelitis is not a single disease; its etiology is heterogeneous.

Infectious Triggers

• Viral: West Nile virus, Enteroviruses (e.g., poliovirus, coxsackie), herpesviruses, influenza, SARS‑CoV‑2.
• Bacterial: Mycoplasma pneumoniae, Borrelia burgdorferi (Lyme disease), syphilis.
• Parasitic: Angiostrongylus cantonensis (rare).

Autoimmune/Inflammatory

• Neuromyelitis optica spectrum disorder (NMOSD) – antibodies against aquaporin‑4 (AQP4‑IgG) or myelin oligodendrocyte glycoprotein (MOG‑IgG).
• Multiple sclerosis – demyelinating plaques involving the cord.
• Systemic lupus erythematosus, Sjögren’s syndrome, sarcoidosis – systemic inflammation that can involve the spinal cord.

Post‑Vaccination or Post‑Infection Autoimmunity

Rarely, myelitis follows immunizations (e.g., influenza, COVID‑19) or a documented infection, likely due to molecular mimicry. The absolute risk remains <0.1 % of vaccinated individuals (CDC, 2022).

Other Risk Factors

• Age: Acute transverse myelitis peaks in the 20–40 year age group.
• Sex: NMOSD is strongly female‑predominant.
• Genetic predisposition: Certain HLA alleles (e.g., HLA‑DRB1*03) increase susceptibility to autoimmune myelitis.
• Pre‑existing autoimmune disease.

Diagnosis

Because myelitis can mimic other neurologic emergencies, a systematic approach is essential.

Clinical Evaluation

• Detailed history – recent infections, vaccinations, systemic disease, and the timeline of symptom onset.
• Neurologic exam – level of sensory loss, motor strength (Medical Research Council scale), reflexes, and coordination.

Imaging

• MRI of the spine with and without gadolinium – the gold standard. Findings may include:
  • Hyperintense T2 signal spanning one or more vertebral segments.
  • Contrast‑enhancing lesions indicating active inflammation.
  • “H‑shaped” or “bagel” sign in NMOSD.
• Brain MRI – recommended to assess for concomitant MS plaques or optic nerve involvement.

Laboratory Tests

• CSF analysis (lumbar puncture) – typically shows mild pleocytosis (<50 cells/µL), elevated protein, and sometimes oligoclonal bands (MS) or absent bands (NMOSD).
• Serum autoantibodies:
  • AQP4‑IgG (highly specific for NMOSD).
  • MOG‑IgG (associated with a distinct demyelinating syndrome).
• Infectious work‑up – PCR or serology for suspected viruses/bacteria.

Additional Tests

• Evoked potentials – assess conduction speed in sensory pathways.
• Urodynamic studies – evaluate bladder dysfunction when needed.
• Blood work – CBC, metabolic panel, vitamin B12, thyroid studies to rule out mimics.

Treatment Options

Treatment goals are to stop inflammation, protect neural tissue, and promote functional recovery.

Acute Management (first 24–48 hours)

• High‑dose intravenous corticosteroids – methylprednisolone 1 g daily for 3–5 days (Cleveland Clinic, 2023). Reduces edema and hastens neurological improvement in ~ 70 % of patients.
• Consider plasmapheresis (PLEX) if no response to steroids within 5 days, especially for NMOSD or severe ATM.

Immunomodulatory/Immunosuppressive Therapies

• For NMOSD: Rituximab, eculizumab, satralizumab, or inebilizumab – shown to lower relapse rates by > 70 % (NEJM, 2021).
• For MS‑related myelitis: Disease‑modifying therapies (DMTs) such as interferon‑β, glatiramer acetate, dimethyl fumarate, or newer oral agents (ocrelizumab).
• For autoimmune myelitis without a defined antibody: Mycophenolate mofetil or azathioprine are commonly used.

Symptomatic & Rehabilitation Treatments

• Physical therapy – gait training, strength exercises, and stretching to prevent contractures.
• Occupational therapy – adaptive equipment for activities of daily living (ADLs).
• Bladder management – intermittent catheterization, anticholinergics (oxybutynin), or timed voiding.
• Pain control – neuropathic agents (gabapentin, pregabalin), NSAIDs, or low‑dose tricyclic antidepressants.
• Psychological support – counseling, cognitive‑behavioral therapy, and support groups.

Lifestyle & Home Measures

• Maintain adequate hydration and a high‑fiber diet to aid bowel function.
• Monitor skin integrity – frequent repositioning if wheelchair‑bound.
• Avoid smoking and limit alcohol, which can worsen neuro‑inflammation.

Living with Myelitis

Adjusting to life after a myelitis event often requires a multidisciplinary approach.

Daily Management Tips

• Mobility aids – canes, walkers, or powered wheelchairs based on functional level.
• Home modifications – grab bars, stair lifts, non‑slip flooring.
• Assistive technology – voice‑activated smart devices for those with hand weakness.
• Schedule regular follow‑up MRI scans (typically every 6–12 months) to monitor lesion activity.
• Keep a symptom diary – note changes in strength, sensation, bladder/bowel patterns, and any new pain.

Psychosocial Considerations

• Depression and anxiety occur in up to 30 % of patients with chronic spinal cord inflammation (NIH, 2022). Early mental‑health referral is recommended.
• Connect with disease‑specific support groups (e.g., NMOSD UK, Transverse Myelitis Association).

Work & School

• Discuss reasonable accommodations with employers or educational institutions (e.g., flexible schedules, remote work).
• Occupational therapists can provide ergonomic assessments.

Prevention

Because many triggers are not preventable, the focus is on reducing modifiable risks.

• Vaccination – despite rare cases of post‑vaccine myelitis, the benefits of influenza, COVID‑19, and other recommended vaccines far outweigh the risk (CDC, 2022).
• Infection control – hand hygiene, safe food handling, and avoiding tick‑borne diseases (use repellents in endemic areas).
• Prompt treatment of systemic autoimmune diseases – regular rheumatology follow‑up can lower the chance of spinal involvement.
• Smoking cessation – reduces overall inflammatory burden.
• Regular health maintenance – annual physicals, vitamin D level checks (deficiency linked to MS activity).

Complications

If inflammation is not halted or if recovery is incomplete, several complications may arise:

• Permanent motor deficit – chronic weakness or paralysis requiring lifelong assistive devices.
• Chronic neuropathic pain – can be severe and challenging to treat.
• Neurogenic bladder – leading to recurrent urinary tract infections, renal damage, or incontinence.
• Severe bowel dysfunction – constipation, overflow incontinence, and risk of fecal impaction.
• Spasticity and contractures – may require intrathecal baclofen pumps or orthopedic surgery.
• Depression, anxiety, and reduced quality of life.
• Secondary complications – pressure ulcers, deep‑vein thrombosis, and osteoporosis from reduced mobility.

When to Seek Emergency Care

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References:

1. Mayo Clinic. “Transverse Myelitis.” Updated 2022. https://www.mayoclinic.org
2. Centers for Disease Control and Prevention. “Vaccines and Myelitis.” 2022. https://www.cdc.gov
3. World Health Organization. “Neuromyelitis Optica.” 2023. https://www.who.int
4. Cleveland Clinic. “Acute Transverse Myelitis.” 2023. https://my.clevelandclinic.org
5. J. Wingerchuk et al., “Eculizumab in Aquaporin‑4 Positive NMOSD,” NEJM, 2021.
6. National Multiple Sclerosis Society. “Spinal Cord Involvement in MS.” 2021.
7. National Institutes of Health. “Psychiatric Comorbidities in Chronic Neurologic Disease.” 2022.

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