biology

Tropical spastic paraparesis

Tropical spastic paraparesis is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tropical spastic paraparesis rather than just read about it. In short: Tropical spastic paraparesis (TSP), is a medical condition that causes weakness, muscle spasms, and sensory disturbance by human T-lymphotropic virus resulting in paraparesis, weakness of the legs. As the name suggests, it is most common in tropical regions, including the Caribbean.

Key takeaways

Tropical spastic paraparesis belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tropical spastic paraparesis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tropical spastic paraparesis from memory before moving on to harder problems.

Reference excerpt

Tropical spastic paraparesis (TSP), is a medical condition that causes weakness, muscle spasms, and sensory disturbance by human T-lymphotropic virus resulting in paraparesis, weakness of the legs. As the name suggests, it is most common in tropical regions, including the Caribbean. Blood transfusion products are screened for human T-lymphotropic virus 1 (HTLV-1) antibodies, as a preventive measure.

Signs and symptoms Some of the signs of Tropical spastic paraparesis are:

Leg instability Urinary dysfunction. Bowel dysfunction Back pain Erectile problems Psoriasis Individuals with TSP may also exhibit uveitis (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), and infectious dermatitis (inflammation of the skin). HTLV-1 can be transmitted via breastfeeding (mother to child), sexual contact, via blood contact (transfusion or needle sharing).

Pathogenesis In tropical spastic paraparesis, HTLV-1 shows elevated cellular acquired immune response as well as high production of proinflammatory cytokines. Interferon overexpression has been demonstrated as well. Also the number of NK cells (CD56+ and CD16+) is diminished.

Diagnosis Among the methods of diagnosing tropical spastic paraparesis are MRI (magnetic resonance imaging) and lumbar puncture (which may show lymphocytosis). 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.

Treatment

Treatment of TSP involves corticosteroids 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. Mogamulizumab, an anti-CCR4 IgG1 monoclonal antibody, is also being researched as a possible treatment for tropical spastic paraparesis. The antibody reduces HTLV-1 proviral load and production of proinflammatory cytokines. 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 and zidovudine has demonstrated a decrease in proviral loads (in animals).

Prognosis 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.

History For several decades, the term tropical 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 as Treponema pertenue and Treponema pallidum, which cause inflammation of the central nervous system) and with chronic nutritional deficiencies (such as avitaminosis) or exposure to potentially toxic foods (such as bitter cassava). 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 paraparesis has occurred in temperate countries (e.g., Japan).

See also Treponema pallidum Myelopathy Lymphatic system Neuropathy

References

Further reading Machigashira, N.; Yoshida, Y.; Wang, S.-y.; Osame, M. (2001). "HTLV-1-associated myelopathy/tropical spastic paraparesis with pseudohypoparathyroidism". Neurology. 56 (1): 104–6. doi:10.1212/WNL.56.1.104. PMID 11148245. Nagamine, Yuito; Hayashi, Takeshi; Kato, Yuji; Horiuchi, Yohsuke; Tanahashi, Norio (2015). "Human T Lymphotropic Virus Type-1-associated Myelopathy Manifesting Shortly after Living-donor Renal Transplantation". Internal Medicine. 54 (1): 75–8. doi:10.2169/internalmedicine.54.2950. PMID 25742898.

External links

Illustrations

Worked examples

Example 1 — a first encounter with Tropical spastic paraparesis

Start with the simplest possible case. Write down what Tropical spastic paraparesis claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tropical spastic paraparesis before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tropical spastic paraparesis ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tropical spastic paraparesis

In research: Tropical spastic paraparesis appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tropical spastic paraparesis in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tropical spastic paraparesis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Viral diseases, so understanding it makes those chapters shorter.
In everyday life: Look for Tropical spastic paraparesis outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tropical spastic paraparesis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tropical spastic paraparesis means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tropical spastic paraparesis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tropical spastic paraparesis in simple terms?

Why does Tropical spastic paraparesis matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tropical spastic paraparesis?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tropical spastic paraparesis.