Secondary Acute Transverse Myelitis

A rare disorder characterized by focal inflammation within the spinal cord due to a known cause, usually an inflammatory disease.

Epidemiology

Exact incidence is unknown as there are many potential causes.

Clinical description

The age of onset, signs and symptoms, severity and clinical course (monophasic or relapsing) vary depending on the associated disease. The signs and symptoms of secondary acute transverse myelitis (ATM) may be similar to those of idiopathic ATM and also depend on the size and site of the inflammation. Common signs and symptoms include motor involvement (limb weakness, stiffness and muscle spasms with impaired respiratory function in some cases), sensory manifestations (back pain, paraesthesia, numbness and neuropathic pain) and autonomic findings (sexual dysfunction, urinary urge/retention, bowel urgency/retention and autonomic dysreflexia). However, other parts of the nervous system may be involved in secondary ATM, depending on the associated disease: the optic nerves in patients with multiple sclerosis (MS) and neuromyelitis optica (NMO), and the peripheral nerves in patients with systemic lupus erythematosus (SLE; see these terms).

Etiology

Secondary ATM may also occur as a result of direct bacterial, parasitic or viral invasion of the spinal cord, and in patients with Sjögren's syndrome (see this term).

Diagnostic methods

Diagnosis requires MRI of the spinal cord to confirm the presence of myelitis: for example, long lesions in patients with NMO, short and multifocal lesions in patients with MS. Laboratory tests are also essential for identifying the cause of secondary ATM: analysis of the cerebrospinal fluid may reveal the presence of oligoclonal bands (commonly seen in MS) or bacterial/viral/parasitic infections; serology may reveal the presence of autoantibodies to aquaporin-4 (NMO), anti-double-stranded DNA antibodies (SLE) or anti-Ro/SS-A antibodies (Sjögren's syndrome). Visual evoked responses may be abnormal.

Differential diagnosis

The differential diagnosis should include idiopathic ATM which is thought to be due to a late immune response to a recent infection, as well as acute transverse myelopathy associated with arteriovenous fistulae, tumors, trauma, spinal cord infarcts and compression.

Management and treatment

Treatment approaches depend on the underlying cause with acute treatment options including administration of steroids and plasma exchange in steroid-resistant patients. Long-term care should include symptomatic management, rehabilitative therapy and long-term maintenance treatments to prevent future relapses or slow disease progression.

Prognosis

The prognosis is variable and depends on the response to treatment, the associated disease and the prevention of further episodes.