Transverse Myelitis (TM) is a neurological disorder caused by inflammation across one level, or segment, of the spinal cord. The term myelitis refers to inflammation of the spinal cord; transverse simply means the position of the inflammation occurs across the width of the spinal cord. These inflammatory attacks can damage or destroy myelin- the insulating substance that covers nerve cell fibers. The damage that occurs creates scars on the nervous system that interrupt communications between the nerves in the spinal cord and the rest of the body.
TM occurs in both adults and children, in all races and both genders equally. There appears to be no genetic or familial predisposition for those affected by TM. It is estimated that the rate of diagnosis of new cases of TM is 1.3 cases/1,000 000 people per TM has been shown to have incidence rates that peak between the ages of 10-19 years and 30-39 years 1.
The signs and symptoms of acute TM usually develop rapidly over a few hours to several days. Less commonly; subacute TM, the signs and symptoms progress gradually over several days to weeks. In most cases, but not all, both sides of the body are affected.
Typical signs and symptoms include:
- Initial symptoms usually include localized lower back pain, sudden paresthesias (abnormal sensations such as burning, tickling, pricking, or tingling) in the legs, sensory loss, and paraparesis (partial paralysis of the legs). Paraparesis often progresses to paraplegia (paralysis of the legs and lower part of the trunk)
- Many patients also report experiencing muscle spasms, a general feeling of discomfort, headache, fever, and loss of appetite. Depending on which segment of the spinal cord is involved, some patients may experience respiratory problems as well..
- Patients who experience sensory disturbances often use terms such as numbness, tingling, coldness, or burning to describe their symptoms. Other patients report areas of heightened sensitivity to touch and even a light touch with a finger causes significant discomfort or pain (a condition called allodynia). Many also experience heightened sensitivity to changes in temperature or to extreme heat or cold. Patients often may feel as if the skin of their chest, abdomen or legs is being wrapped tightly by something.
- Weakness in your arms or legs.Some people with mild weakness notice that they’re stumbling or dragging one foot or that their legs feel heavy as they move. Others may develop severe paralysis.
- Bladder and bowel problems.These problems may include an increased urinary urge, urinary incontinence, difficulty urinating and constipation.
Generally, prognosis for complete recovery from TM is not good. Although recovery usually begins between 2 and 12 weeks after onset and may continue for up to 2 years, most individuals are left with considerable disability. Some individuals may have minor or no deficits, while others may have significant motor, sensory, and bowel deficits. Some individuals show no recovery at all. About 1/3 of patients recover, 1/3 retain some weakness and urinary urgency, and 1/3 are bedridden and incontinent.
The majority of people with this disorder experience only one episode although in rare cases recurrent or relapsing TM does occur. Some patients recover completely and then experience a relapse. Others begin to recover, then they suffer worsening of symptoms before recovery continues. In all cases of relapse, physicians will likely investigate possible underlying causes such as MS or systemic lupus erythematosus since most people who experience relapse have an underlying disorder.1
Diagnosis requires a neurological examine, MRI and sometimes cerebrospinal fluid analysis (CSF).
- Magnetic Resonance Imaging (MRI) scans may show the extent of the inflammation in the brain and help differentiate encephalitis from other conditions. Brain scans can exclude stroke, brain tumours and aneurysms. In the early stages brain scans may show nothing abnormal with significant inflammatory changes only occurring later in the illness.A brain MRI may also rule out a diagnosis of MS.
- Lumbar puncture (LP) allows a doctor to sample the CSF, that surrounds the brain and spinal cord. CSF is produced within the brain and flows out at the base of the brain to surround and cushion the brain and spinal cord. It contains substances essential for normal activity of the brain but also takes waste products back to blood.A lumbar puncture involves passing a needle, under local anaesthetic, between two of the back bones at the base of the spine. In an adult, several tablespoons full of fluid can be collected safely. Usually blood tests are taken at the same time as the LP in order to compare blood contents with that in CSF.Approximately 10% of adult patients suffer a mild headache after a LP. This headache is typically worse upon being upright and better lying flat. It usually improves with simple pain killers and good hydration.A variety of laboratory tests are performed on CSF. Some tests give results within hours whereas others often take days.Immediate tests performed on CSF include analysis under the microscope to assess the number and type of white blood cells present. A raised number of white blood cells in CSF are indicative of inflammation within the brain, spinal cord, or lining of the brain (meninges). The types of white blood cell found help differentiate between viral or bacterial infections.More complicated tests on CSF include culture for bacteria, antibody studies, or molecular tests to detect the genetic footprint of viruses or bacteria. The latter molecular tests include the polymerase chain reaction (PCR), which when applied to CSF is used most frequently to identify genetic material from herpes simplex virus, varicella zoster virus (chickenpox virus), and enteroviruses. PCR has significantly advanced the ability to diagnose viral encephalitis. LP may have to be repeated during an individual’s illness.
- Tests for causes that can be treated should also include chest x-ray; purified protein derivative ); serologic tests for mycoplasma, Lyme disease, and HIV; vitamin B12 and folate levels; antinuclear antibodies; and Cerebrospinal and blood Venereal Disease Research Laboratory (VDRL) tests.
Researchers are uncertain of the exact causes of TM. The inflammation that causes such extensive damage to nerve fibers of the spinal cord may result from viral infections, abnormal immune reactions, or insufficient blood flow through the blood vessels located in the spinal cord. TM also may occur as a complication of syphilis, measles, Lyme disease, and some vaccinations, including those for chickenpox and rabies. In cases of TM where a cause cannot be identified it is referred to as idiopathic TM.1
TM may be caused by viral infections, spinal cord injuries, immune disorders (including systemic lupus erythematosus, Sjogren’s syndrome, sarcoidosis and multiple sclerosis) or insufficient blood flow through the blood vessels in the spinal cord. It may occur as a complication of such disorders as optic neuromyelitis, multiple sclerosis, smallpox, and measles, or as a complication of chickenpox or rabies vaccinations.
Because some affected individuals also have autoimmune diseases such as systemic lupus erythematosus, Sjogren’s syndrome, and sarcoidosis, some scientists suggest that TM may also be an autoimmune disorder. In addition, some cancers may trigger an abnormal immune response that may lead to TM.1
An acute, rapidly progressing form of TM sometimes signals the first attack of multiple sclerosis (MS), however, studies indicate that most people who develop TM do not go on to develop MS. Patients with TM should nonetheless be screened for MS because patients with this diagnosis will require different treatments.1
Some cases of TM result from spinal arteriovenous malformations (abnormalities that alter normal patterns of blood flow) or vascular diseases such as atherosclerosis that cause ischemia, a reduction in normal levels of oxygen in spinal cord tissues. Ischemia can result from bleeding (hemorrhage) within the spinal cord, blood vessel blockage or narrowing, or other less common factors. Blood vessels bring oxygen and nutrients to spinal cord tissues and remove metabolic waste products. When these vessels become narrowed or blocked, they cannot deliver sufficient amounts of oxygen-laden blood to spinal cord tissues. When a specific region of the spinal cord becomes starved of oxygen, or ischemic, nerve cells and fibers may begin to deteriorate relatively quickly. This damage may cause widespread inflammation, sometimes leading to TM. Most people who develop the condition as a result of vascular disease are past the age of 50, have cardiac disease, or have recently undergone a chest or abdominal operation.1
There currently exists no care or effective cure for TM. Current treatments are designed to manage and alleviate symptoms and largely depend upon the severity of neurological system involvement .
The standard treatment is with high doses of corticosteroids and about half of all patients with TM will recover within six months. Corticosteroid medications are believed to work by reducing the activity of the immune system to prevent the immune system from attacking the myelin of the spinal cord. Of course, this treatment would only be selected by physicians who believe that TM is partially or fully autoimmune in nature.
In many cases pain killers will likely be prescribed for the pain as nerve impulses from the spinal cord are often scrambled and misinterpreted by the brain as pain. Bed rest is recommended during the initial days and weeks after onset of the disorder. Antidepressants or anticonvulsants may also help ease the symptoms due to the damaged spinal cord.
Plasma exchange therapy is generally chosen for those with moderate to severe TM who do not show much improvement after being treated with intravenous steroids. Plasma exchange removes harmful substances that are circulating in the liquid portion (the plasma) of the blood. In the case of TM, this is probably antibodies against the protein that makes up myelin, as well as T cells and possibly other immune cells that may target myelin.
Some patients have been treated with intravenous cyclophosphamide. Cyclophosphamide is a drug that is often used to treat lymphoma or leukemia.
Patients that experience recurrent TM are sometimes treated with chemical agents that modify the immune system’s response. These treatments can include methotrexate, azathioprine, and mycophenolate or oral cyclophosphamide.
- National Institute of Neurological Disorders and Stroke.