HTLV-I associated myelopathy in Porto Alegre (Southern Brazil)

Proposal for diagnostic criteria of tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM)

After the first description of TSP/HAM in 1985 and the elaboration of WHO's diagnostic criteria in 1988, the experience of the professionals in this field has increased so that a critical reappraisal of these diagnostic guidelines was considered timely. Brazilian neurologists and observers from other countries met recently to discuss and propose a modified model for diagnosing TSP/HAM with levels of ascertainment as definite, probable, and possible, according to myelopathic symptoms, serological findings, and/or detection of HTLV-I DNA and exclusion of other disorders.

Possible etiologies for tropical spastic paraparesis and human T lymphotropic virus I-associated myelopathy

The epidemiology of tropical spastic paraparesis/human T lymphotropic virus I (HTLV-I)-associated myelopathy (TSP/HAM) is frequently inconsistent and suggests environmental factors in the etiology of these syndromes. The neuropathology corresponds to a toxometabolic or autoimmune process and possibly not to a viral disease. Some logical hypotheses about the etiology and physiopathology of TSP and HAM are proposed. Glutamate-mediated excitotoxicity, central distal axonopathies, cassava, lathyrism and cycad toxicity may explain most cases of TSP. The damage caused to astrocytes and to the blood-brain barrier by HTLV-I plus xenobiotics may explain most cases of HAM. Analysis of the HTLV-I/xenobiotic ratio clarifies most of the paradoxical epidemiology of TSP and HAM. Modern neurotoxicology, neuroimmunology and molecular biology may explain the neuropathology of TSP and HAM. It is quite possible that there are other xenobiotics implicated in the etiology of some TSP/HAMs. The prevention of these syndromes appears to be possible today.

HTLV-I associated myelopathy in the northern region of Brazil (Belém-Pará): serological and clinical features of three cases

Three patients (males, black, ages 37, 40 and 57) attended a university clinic with a progressive paraparesis of obscure origin. One patient who referred disease duration of more than 16 years, showed diminished deep reflexes, bilateral Babinski's sign, diminished sensation of vibration, abnormal bladder function and back pain. The other two patients (with one and six years of disease duration) complained of weakness in one leg, increased deep reflexes and back pain. Babinski's sign and bladder disturbance were also present in the patient with six years of disease. Blood samples tested by an enzyme immune assay and a discriminatory Western blot were positive for HTLV-I. The familial analysis of one patient showed a possible pattern of sexual and vertical transmission of the virus. To the best of our knowledge, these are the first cases of a proven association between HTLV-I and TSP/HAM in Belem, Para, and emphasize the need to actively look for cases of neurological disease associated to the virus.

HTLV-I-associated myelopathy: are ferritin, S100beta protein, or guanine nucleotides CSF markers of disease?

In southern Brazil, there is an endemic high prevalence foci of HTLV-I and HTLV-II infection. HTLV-infected individuals may develop HAM/TSP. Little is known about HAM/TSP pathogenesis and there is a lack of disease progression markers. This study investigated ferritin, S-100beta protein, and guanine nucleotides (GN) concentrations in the CSF of 18 patients with HAM/TSP. In HAM/TSP patients, concentrations of ferritin and S100beta were increased, whereas GMP was reduced. CSF ferritin, S100beta, and GN are potential markers for HAM/TSP.

[Tropical spastic paraparesis/HTLV-I associated myelopathy. Report of 2 cases diagnosed in Cuiabá, Mato Grosso, Brazil]

We describe two cases of tropical spastic paraparesis/HTLV-I associated myelopathy, according to the criteria of World Health Organization-1989. These are the first cases diagnosed in Cuiabá (Mato Grosso State, Brazil). One of them had a good response with the treatment with prednisone.

On the etiology of tropical spastic paraparesis and human T-cell lymphotropic virus-I-associated myelopathy

The purpose of this review is to present some concepts on the etiology of tropical spastic paraparesis or human T-cell lymphotropic virus-I (HTLV-I)-associated myelopathy (TSP/HAM). The large number of syndromes that have been associated with HTLV-I (60 to date), the existence of TSP/HAM cases associated with other retroviruses (human immunodeficiency virus-2 [HIV-2], HTLV-II), the existence of many TSPs without HTLV-I, and the evidence of clear epidemiologic contradictions in TSP/HAM indicate that the etiopathogenesis of TSP/HAM is not yet clear. Tropical spastic paraparesis/HAM affects patients of all human ethnic groups, but usually in well localized and relatively isolated geographic regions where HTLV-I has been endemic for a long time. Environmental factors and geographic locations appear to be critical factors. Because the neuropathology of TSP/HAM suggests a toxometabolic, rather than a viral cause, it is proposed that an intoxication similar to neurolathyrism could account for some of TSP/HAM cases, mainly in tropical and subtropical countries. If this were the case, HTLV-I could be a cofactor or act as a bystander. it is possible that co-infection with another agent is necessary to produce TSP/HAM and most of the syndromes associated with HTLV-I.

[HTLV-I-associated myelopathy/tropical spastic paraparesis: report of 2 cases diagnosed in Florianópolis, Santa Catarina, Brazil]

We describe two cases of tropical spastic paraparesis/HTLV-I associated myelopathy, according to the criteria of World Health Organization-1989. These are the first cases diagnosed in Florianópolis (Santa Catarina State-Brazil). One of them had a good response with the treatment with methylprednisolone.