In most cases of transverse myelitis, the cause of the spinal inflammation is never found
Transverse myelitis is a rare inflammation that spreads across the full cross-section of the spinal cord, disrupting movement, sensation and bladder control below the damaged level. Infections, immune disorders and loss of nerve insulation have all been linked to it, yet for about 60 percent of patients no cause is identified.
The word transverse signals that the inflammation runs horizontally through the cord's entire width; when only part is affected, clinicians speak of partial myelitis. That sets it apart from leukomyelitis, which touches only white matter. Symptoms usually build over hours to a few weeks and can include limb weakness and numbness, pins and needles climbing from the feet, and a sensory level below which light touch or pain feels dulled. Damage to the autonomic system can also produce bouts of high blood pressure.
Where the lesion sits largely determines what happens. The thoracic segment is the most common site, so leg weakness with spasticity is the typical picture. Lesions in the neck account for roughly 20 percent of cases; high in the cervical cord they can affect all four limbs and threaten breathing, because nerves from C3 to C5 form the phrenic nerve that drives the diaphragm. Lumbar lesions make up about 10 percent.
Known triggers are diverse. Viruses linked to the condition include herpes zoster, Epstein-Barr, Zika and West Nile; bacterial associations include Mycoplasma pneumoniae and the Borrelia species behind Lyme disease, which turns up in about 4 to 5 percent of acute cases. When it accompanies neuromyelitis optica, it is attributed to NMO-IgG autoimmunity, and alongside multiple sclerosis it is often misdiagnosed as MS. Unlike MS, which scatters patchy damage, it usually strikes the cord centrally and symmetrically.
A proposed variant, longitudinally extensive transverse myelitis, involves a lesion stretching over three or more vertebral segments, and MOG auto-antibodies have been suggested as a marker for it. Diagnostic criteria for the idiopathic acute form were put forward in 2002 by the Transverse Myelitis Consortium Working Group. High-dose corticosteroids are often given early in the hope of reducing swelling, though whether they genuinely help is still debated.
Source: Transverse myelitis
