Prevalence of multiple sclerosis in Buenos Aires, Argentina using the capture-recapture method.

BACKGROUND: Scarce data exist about multiple sclerosis (MS) prevalence in South America. The objective of the study is to determine the prevalence of MS in a high populated area from Argentina (Greater Buenos Aires Metropolitan area) using the capture-recapture methodology. METHODS: Greater Buenos Aires is the generic denomination that refers to the megalopolis comprised by the autonomous city of Buenos Aires and the surrounding conurbation of the province of Buenos Aires. The study was carried out taking July 1996 as the prevalence month. We used capture-recapture method to estimate the prevalence of MS cross matching registries from four MS Centers. RESULTS: A total of 803 registries were obtained from the four lists. Log-linear model for capture-recapture method was used to analyze the data. The population of the area based on the 1990 census was 12,594,974; the number of MS cases estimated amongst sources interactions were between 1833 and 2359; the prevalence estimated ranged from 14 to 19.8 cases per 100,000 inhabitants. CONCLUSIONS: This is the first study to provide epidemiological data on the prevalence of MS in a large population in Argentina (Greater Buenos Aires Metropolitan area). Further epidemiological studies will clarify the true prevalence of MS in South America.

Argentine Patagonia: prevalence and clinical features of multiple sclerosis.

There are few studies reporting multiple sclerosis prevalence rates in the Buenos Aires region, Argentina (latitude 34 degrees S) (between 12-18.5/100 000 inhabitants), and no studies have been performed in the larger region between parallels 36 degrees and 55 degrees S. The aim of this study is to determine the prevalence rates and clinical features of multiple sclerosis in residents of the Argentine Patagonia. Four cities from the region were selected for this study, giving a sample population of 417 666 inhabitants (approximately 24% of the total Patagonia population). 1(st) March 2002 was determined as prevalence day. Patients were ascertained using multiple case-finding methods. The point prevalence rate was 17.2/100 000 (17.2 age-adjusted to the world population). Prevalence rates were higher for women than for men, 22.1 versus 12.2/100 000 inhabitants (21.4 versus 12.7 sex-adjusted to the world population). The study population was mainly of European descent and mestizoes. Clinical features were similar to those reported in other countries. This study shows that Argentine Patagonia is a medium-risk area with no south-north gradient between parallels 55 degrees and 36 degrees S. The Patagonia population shows recent internal migration that makes it difficult to determine whether the exposure to potential risk factors has been long enough to modify the disease incidence.

[Data base for patients with balance disorders]. / Base de datos para pacientes con trastornos del equilibrio.

INTRODUCTION: With the aim of integrating clinical thinking and obtaining epidemiological and biostatistical results in long series of patients who present balance disorders, we have developed a neuro otological protocol and its corresponding database. This offers answers to the questions of how to assess the patient, how to conduct a clinical interview correctly, and which complementary studies should be requested and how. RESULTS: The information from the protocol is stored and analysed in our database, which was designed in the Epi Info software application, produced by CDC (NIH, USA), in collaboration with the WHO Global Program on AIDS. The application, which we call ENO LK, has already been used to store data concerning 1,100 patients whose average age is 54.5 years old and 62.8% of which were females (SD 18, range 4 93). 69.1% were diagnosed as suffering from vertigo, 12.7% displayed instability, 1.9% syncope and 16.3% had other causes (37% psychogenic and 28% disorders affecting the central integrator). Of the 760 patients with vertigo, in 55% it was positional (60% of these were idiopathic benign), 6.3% were sustained (peripheral causes accounted for 74% and a vascular aetiology was predominant in the central causes), 26.6% were recurring and 12.1% otolithic (in this series the vertigos all had a central aetiology). CONCLUSIONS: With this application the user has the possibility of obtaining epidemiological and diagnostic conclusions efficiently and effectively, as well as aiding to follow up all patients who present balance disorders.

[A statistical analysis of 1300 patients with dizziness-vertigo. Its most frequent causes]. / Análisis estadístico de 1.300 pacientes con mareo vértigo. Causas más frecuentes.

PATIENTS AND METHODS: We analysed the records of the individuals who were attended because of dizziness or vertigo in the vestibular sector, with the aim of describing the epidemiological clinical profile of a group of patients with such symptoms. 1300 patients were systematically evaluated according to our neuro otological examination protocol. Diagnoses were ordered, according to the international classification reported by Drachman and later modified by Bahlo, in four categories: 1. Vertigo, 2. Instability, 3. Pre syncope and 4. Miscellaneous. Each of these classes was organised according to the topography of the lesion and these were in turn grouped by aetiologies (viral, vascular, tumoural, demyelinating, post traumatic, idiopathic, autoimmune, etc.). The data were stored and analysed in a computer database, Epi info 6.02 (OMS 1994), which was especially adapted by the researchers for the purpose. RESULTS: 63.1% were women. The average age was 55.5 years old (SD: 17.5, interval: 4 93). Vertigo was diagnosed in 68.9%, instability was found in 12.4%, 1.8% presented syncope and miscellaneous disorders occurred in 16.9% (of these, 64.1% had disorders of the central integrator and 16.4% were of a psychogenic origin). Of the 1300 patients, 896 presented vertigo; the positional type was seen in 54%, sustained in 6.5%, recurrent in 27.7% and 11.8% were found to have the otolithic type. CONCLUSIONS: The relevance of the epidemiological work based on clinical evaluation and the thorough neuro otological examination in our medium must be highlighted. These findings were similar to those reported in the international literature in more delimited series.

Further studies on HTLV-I associated myelopathy in Argentina.

We report 10 HTLV-I virus seropositive subjects, eight of them with HTLV-I associated myelopathy (HAM), two of them also infected with HIV as well as two asymptomatic HTLV-I+ relatives of two unrelated patients. HTLV-I is endemic in several tropical areas, where it causes different neurological diseases. Only few patients have been reported in our country since 1994. We studied 8 patients, who fulfilled the clinical criteria for chronic spastic paraplegia, and 2 other non-symptomatic HTLV-I seropositive relatives, with electromyography (EMG), motor and sensory conduction velocities (NCV), somatosensory, visual and brainstem auditory evoked potentials (SSEP, VEP and BAEP), Magnetic Resonance Images (MRI) and cerobrospinal fluid (CSF) analysis. The latter was carried out only in seven symptomatic patients. In every case positive ELISA tests for HTLV-I/II were confirmed by Western Blot. The two asymptomatic persons were clinically and electromyographically assessed, one of them was also submitted to SSEPs studies. Three patients were males. Patient's ages ranged from 5 to 65 years old. All symptomatic patients showed muscular weakness, spasticity with pyramidal signs and sphincter disturbances. Five of them had paresthesias and 2 had burning pain on their feet. The EMGs and the NCVs were normal in 7 patients and in the 2 asymptomatic ones. SSEPs, obtained by stimulating the posterior tibial nerves, were impaired in 7 patients and in the asymptomatic person who received the procedure. The 7 symptomatic patients who underwent lumbar puncture had positive tests for HTLV-I in CSF, 3 out of these 7 patients had also high protein levels and 4 had increased number of lymphocytes. In 2 patients intrathecal IgG production could also be demonstrated. MRI were normal in 7 patients and in the 2 asymptomatics, the exception being a female who had bilateral hyperintense lesions in cerebral white matter in T2. In conclusion, tropical spastic paraparesis is apparently a rare disorder in Argentina. However, some cases have been reported recently. Most probably, its prevalence is currently underestimated. Its diagnosis should be considered in every patient with progressive spastic paraplegia.

[Hemichorea associated with cerebral toxoplasmosis and AIDS]. / Hemicorea asociada a toxoplasmosis cerebral y SIDA.

Only 12 AIDS cases with hemichorea were reported in the literature. We report the first case of hemichorea associated with AIDS and cerebral toxoplasmosis in our country. A 26-year-old man had 3 episodes of focal seizures on the left side with subsequent loss of consciousness. A few weeks later, he noticed progressive left-sided weakness. Examination revealed a left hemiparesis. MRI of the head showed a round mass in the right frontal lobe and a smaller lesion in the left temporo-occipital area. Laboratory showed positive serum ELISA and Western Blot analysis for HIV antibodies. Serum tests for Toxoplasma showed elevated titers. He was treated with pyrimethamine and sulfadiazine. His weakness improved and he had no further seizures. Two weeks later, choreic movements appeared in the left foot, finally involving the entire left hemibody. A second MRI showed a new small lesion in the right cerebral peduncle. The patient completed 6 weeks of treatment, with further reduction in the size of the lesions. Nevertheless, the left hemichorea persisted. We believe that the hemichorea our patient had was caused by the contralateral peduncular lesion. Lesions involving the subthalamic nucleus or its connections may cause contralateral hemiballismus or hemichorea. In spite of the favorable response to antitoxoplasmic therapy, the hemichorea persisted. The present report illustrates an uncommon neurological complication in AIDS. We believe that a combination of a focal cerebral lesion and the HIV infection caused the movement disorder presented by the patient.

Hemicorea asociada a toxoplasmosis cerebral y SIDA / Hemichorea associated with cerebral toxoplasmosis and AIDS

Se observan complicaciones neurologicas en 40 por ciento de enfermos con SIDA. De estos, en 10 por ciento puede ser la manifestación inicial de la enfermedad. En otro 11 por ciento pueden aparecer trastornos del movimimiento. Comunicamos el primer caso de hemicorea asociada a toxoplasmose cerebral y SIDA en nuestro pais. Hombre de 26 anos, con diagnóstico de SIDA y toxoplasmosis cerebral. Habia comenzado con crisis motoras simples de hemicuerpo izquierdo, con generalización secundaria y luego perdida de fuerza progresiva en dicho hemicuerpo. La RMN de cerebro mostro una lesión frontal derecha y otra temporo-occiptal izquierda, con gran edema perilesional y efecto de masa. Las serologias para HIV y toxoplasmosis fueron positivas. Comenzo tratamiento con sulfadiazina y pirimetamina. Al duodecimo dia aparecieron movimientos involuntários del pie izquierdo, coreicos, que se extendieron mas tarde a todo ese miembro inferior y luego al hemicuerpo. Nueva RMN de cerebro mostro disminución del edema y efecto de masa de las lesiones. Sin embargo, se observó una nueva lesion a nivel peduncular derecho. Movimientos involuntarios en pacientes con toxoplasmosis cerebral la literatura mundial y el primero en nuestro pais de hemicorea asoicada a toxplasmosis y SIDA