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Tropical Spastic Paraparesis/HTLV-1–Associated Myelopathy

by Michael Rubin, MDCM

Tropical spastic paraparesis/HTLV-1–associated myelopathy is a slowly progressive disorder of the spinal cord caused by the human T-lymphotropic virus 1 (HTLV-1).

  • The virus is spread through sexual contact, use of illegal intravenous drugs, exposure to blood, or breastfeeding.

  • People have weakness, stiffness, and muscle spasms in the legs, making walking difficult, and many have urinary incontinence.

  • To diagnose the disorder, doctors ask about possible exposure to the virus and do magnetic resonance imaging, a spinal tap, and blood tests.

  • Drugs, such as corticosteroids, may help, and spasms are treated with muscle relaxants.

The human T-lymphotropic virus 1 (HTLV-1) virus is similar to the human immunodeficiency virus (HIV), the virus that causes AIDS. The HTLV-1 virus can cause certain kinds of leukemia and lymphoma (cancers of the white blood cells).

The HTLV-1 virus is transmitted through

  • Sexual contact

  • Use of illegal intravenous drugs

  • Exposure to blood

It can be transmitted from mother to child through breastfeeding. It is most common among prostitutes, IV drug users, people undergoing hemodialysis, and people from certain areas such as those near the equator, southern Japan, and parts of South America.

A similar disorder can result from infection with a similar virus, human T-lymphotropic virus 2 (HTLV-2).

The virus resides in white blood cells. Because the cerebrospinal fluid contains white blood cells, the spinal cord can be damaged. Damage to the spinal cord results more from the body’s reaction to the virus than from the virus itself.

Symptoms

The muscles in both legs gradually become weak. People may not be able to feel vibrations and may lose the sense of where their feet and toes are (position sense). Their limbs feel stiff, movements become clumsy, and walking may become difficult. Muscle spasms in the legs are common, as is loss of bladder control (urinary incontinence).

The disorder usually progresses over several years.

Diagnosis

  • Assessment of the person's risk of being exposed

  • Magnetic resonance imaging

  • Tests to check for the virus in blood and cerebrospinal fluid

The diagnosis is usually based on symptoms and the person’s risk of being exposed to the virus. Thus, a doctor may ask people about their sexual contacts and use of illegal intravenous drugs.

Magnetic resonance imaging (MRI) of the spinal cord is done.

Samples of blood and cerebrospinal fluid, obtained by a spinal tap (lumbar puncture—see How a Spinal Tap Is Done), are tested for parts of the virus or antibodies to the virus.

Treatment

  • Interferon alfa, immune globulin, and/or corticosteroids

  • For spasms, muscle relaxants

Interferon alfa, immune globulin (given intravenously), and corticosteroids (such as methylprednisolone, given by mouth) may help, although their usefulness has not been established.

Spasms can be treated with muscle relaxants such as baclofen or tizanidine.

Drugs Mentioned In This Article

  • Generic Name
    Select Brand Names
  • LIORESAL
  • MEDROL
  • ZANAFLEX