What are the other Names for this Condition? (Also known as/Synonyms)

• HAM/TSP (HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis)
• Human T-Cell Leukemia Virus Type 1 Associated Myelopathy/Tropical Spastic Paraparesis

What is HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis? (Definition/Background Information)

• HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) is a progressive disease of the nervous system that affects less than 2% of people with HTLV-1 infection.
• Signs and symptoms vary but may include slowly progressive weakness and spasticity of one or both legs, exaggerated reflexes, muscle contractions in the ankle, and lower back pain. Other features may include urinary incontinence and minor sensory changes, especially burning or prickling sensations and loss of vibration sense
• Why only some people with HTLV-1 infection develop HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis is not well understood. Treatment generally aims to control the specific symptoms, as there is no standard treatment available
• Interferon alpha may be beneficial over short periods, and some aspects of the disease may be improved with interferon beta. Other medication may include immune globulin, oral corticoids and muscular relaxes such as baclofen or tizanidine

(Source: HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis? (Age and Sex Distribution)

• HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis is a rare infectious disorder
• Approximately, 10-20 million individuals are infected by HTLV-1 worldwide, and anywhere between 0.25-2% of the infected individuals develop HAM/TSP
• The presentation of symptoms typically occurs in sexually-active adults 
• Although both genders may be affected, the condition is twice more common in females 
• Worldwide, individuals of all racial and ethnic groups may be affected. However, HTLV-1 is endemic to countries of the Middle East, South America, equatorial Africa, Caribbean, and Japan and Melanesia

What are the Risk Factors for HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis? (Predisposing Factors)

The risk factors for HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis may include:

• Unprotected sexual contact with infected individuals
• Use of contaminated needles or syringes (in drug users)
• Transfusion of infected blood
• Breastfeeding while infected

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis? (Etiology)

• The exact cause of HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis in a small percentage of HTLV-1 infected individuals is not clearly understood (HTLV-1 is human T-lymphotrophic virus)
• An autoimmune response of the body to HTLV-1 infection, or a direct effect of the virus on the central nervous system have been proposed as potential causative mechanisms

What are the Signs and Symptoms of HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis?

The signs and symptoms of HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis may vary among affected individuals in type and severity, and include:

• Slowly progressive weakness and spasticity of one or both legs
• Exaggerated reflexes (hyperreflexia)
• Stiff muscles
• Muscle contractions in the ankle (ankle clonus)
• Lower back pain
• A 'weak' bladder and/or urinary incontinence
• Minor sensory changes, especially burning or prickling sensations and loss of vibration sense

(Source: HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis Diagnosed?

HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis is diagnosed on the basis of the following information:

• Complete physical examination
• Thorough medical history evaluation
• Assessment of signs and symptoms
• Laboratory tests, including detection of antibodies against HTLV-1 in blood and/or cerebrospinal fluid
• Imaging studies
• Biopsy studies, if necessary

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis?

The complications of HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis may include:

• Secondary infections
• Progressive weakening of muscles resulting in confinement to a wheelchair
• Progressive worsening of urinary symptoms

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis Treated?

The treatment for HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis generally aims to control the specific symptoms, as there is no standard treatment available.

• Interferon alpha may be beneficial over short periods, and some aspects of the disease may be improved with interferon beta
• Stiff and spastic muscles may be treated with lioresal or tizanidine, and urinary dysfunction may be treated with oxybutynin
• Corticosteroids were reported to slow progression in one case series and reduce neurologic disability in another. However, others have reported no such benefit with corticosteroids and there have been no randomized clinical trials

(Source: HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How can HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis be Prevented?

HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis may be prevented by:

• Practicing safe sex
• Avoiding the reuse of needles and syringes, which may be contaminated

Regular medical screening at periodic intervals with tests and physical examinations are recommended.

What is the Prognosis of HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis? (Outcomes/Resolutions)

• The prognosis of HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis is dependent upon the severity of the signs and symptoms and associated complications, if any
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications
• Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis:

• HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis used to be formerly known only as Tropical Spastic Paraparesis

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/