| Tropical spastic paraparesis | |
|---|---|
| Other names | HTLV-I-associated myelopathy (HAM) orHTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP)[1] |
 | |
| HTLV-1 which causes TSP | |
| Specialty | Neurology  |
| Symptoms | Bowel dysfunction[2] |
| Causes | HTLV-1 retrovirus causes 80% of cases[3] |
| Diagnostic method | Lumbar puncture,MRI[2] |
| Treatment | Interferon alpha, corticosteroids[3] |
Tropical spastic paraparesis (TSP), is a medical condition that causes weakness,muscle spasms, and sensory disturbance byhuman T-lymphotropic virus resulting inparaparesis, weakness of the legs. As the name suggests, it is most common intropical regions, including theCaribbean.[4]Blood transfusion products are screened forhuman T-lymphotropic virus 1 (HTLV-1) antibodies, as a preventive measure.[5]
Some of the signs of Tropical spastic paraparesis are:[2]
Individuals with TSP may also exhibituveitis (inflammation of the uveal tract of the eye),arthritis (inflammation of one or more joints),pulmonary lymphocytic alveolitis (inflammation of the lung tissues),polymyositis (an inflammatory muscle disease),keratoconjunctivitis sicca (persistent dryness of the cornea and conjunctiva), andinfectious dermatitis (inflammation of the skin).[6]
HTLV-1 can be transmitted via breastfeeding (mother to child), sexual contact, via blood contact (transfusion orneedle sharing).[7]
In tropical spastic paraparesis, HTLV-1 shows elevated cellular acquired immune response as well as high production ofproinflammatory cytokines.Interferon overexpression has been demonstrated as well. Also the number ofNK cells (CD56+ andCD16+) is diminished.[8]
Among the methods of diagnosing tropical spastic paraparesis areMRI (magnetic resonance imaging) andlumbar puncture (which may show lymphocytosis).[2]
Often, the diagnosis process is based on symptoms and one's risk of exposure to the virus. A spinal tap or lumbar puncture may be used to obtain blood and CSF samples which can then be tested for parts of the virus or antibodies produced to combat the virus. MRI may be performed on the brain and spinal cord to check for abnormalities such as spinal cord degeneration and other potential causes of symptoms.[9]
Treatment of TSP involvescorticosteroids to help with inflammation. However, any success with corticosteroids is short-lived, with symptoms worsening as the dosage is reduced. A synthetic derivative,17-alpha-ethinyltestosterone, can be used to treat tropical spastic paraparesis, improvement in motor and bladder function was reported but not sustainable.[10]
Mogamulizumab, an anti-CCR4IgG1 monoclonal antibody, is also being researched as a possible treatment for tropical spastic paraparesis. The antibody reduces HTLV-1 proviral load and production of proinflammatorycytokines.Valproic acid has also succeeded in reducing the proviral load of HTLV-1 (though clinical benefits were minimal or none). A further combination of valproic acid andzidovudine has demonstrated a decrease in proviral loads (in animals).[11]
The prognosis for tropical spastic paraparesis indicates some improvement in a percentage of cases due to immunosuppressive treatment. A higher percentage will eventually lose the ability to walk within a ten-year interval.[12]
For several decades, the termtropical spastic paraparesis was used to describe a chronic and progressive clinical syndrome that affected adults living in equatorial areas of the world. This condition was initially thought to be associated with infectious agents (such asTreponema pertenue andTreponema pallidum, which cause inflammation of thecentral nervous system) and with chronic nutritional deficiencies (such asavitaminosis) or exposure to potentially toxic foods (such as bittercassava).[medical citation needed]
Tropical myeloneuropathies are classified as two separate syndromes:tropical ataxic neuropathy (TAN) and tropical spastic paraparesis (TSP). They are placed together because they are found in tropical countries, although tropical spastic paraparesishas occurred in temperate countries (e.g., Japan).[13]
