Role of return migration in the emergence of multiple sclerosis in the French West Indies

The emergence of multiple sclerosis in island societies has been investigated only in a few Caucasian populations living in temperate regions. The effect of human migration on the risk of developing this disease is still an open question because of possible genetic selection. We conducted an epidemiological study of the multiple sclerosis population in the French West Indies (Martinique and Guadeloupe), a population which includes large numbers of West Indians who have returned after emigrating to metropolitan France. Standardized incidence ratios (SIRs) for multiple sclerosis among migrants were calculated and their genetic characteristics were compared to those of non-migrants. The crude prevalence of multiple sclerosis was 14.8/10(5) on December 31, 1999 (95% CI: 11.9-17.7); and its crude mean annual incidence for the period July 1, 1999 to June 30, 2002 was 1.4/10(5) (95% CI: 1.0-1.8), confirming its emergence in the French West Indies. Recurrent neuromyelitis optica, which is virtually the only form of multiple sclerosis in black African populations in tropical regions, represented not >17.8% of these cases. During the 1,440,000 person-years of follow-up, 33 incidence cases were identified in migrants. Since the number of expected cases was 19.3, the overall SIR was 1.71 (95% CI: 1.19-2.38; P < 0.01) among migrants. The increase in the SIR was more marked if the stay was made before the age of 15 years (4.05, 95% CI: 2.17-6.83; P < 0.0001). European ancestry in the two migrating and non-migrating populations was similar. Martinique, which has a higher rate of return migration, has a higher prevalence of multiple sclerosis (21.0/10(5) versus 8.5/10(5)) and a higher incidence (2.0/10(5) versus 0.7/10(5)) than Guadeloupe. The emergence of the disease in the French West Indies is of environmental rather than genetic origin. It may be explained either through the introduction by migrants of precipitating environmental factors that operate in a critical way before the age of 15 years, and/or by the recent disappearance from the French West Indies of protective environmental factors acting before this age.

Unusual form of neurocysticercosis associated with HIV infection

Concurrent infection with Taenia solium and HIV would be expected to occur more frequently because of the increasing frequency of HIV infection in endemic areas of cysticercosis. However, little is known about the influence of HIV infection on the frequency and the clinical course of cysticercosis. Giant cysts and racemose forms of neurocysticercosis seem to be more frequent in HIV-infected patients and may be secondary to an uncontrolled parasitic growth because of an impaired cell-mediated immune response. We report an unusual case of epidural spinal racemose neurocysticercosis revealed by compression of cauda equina in an HIV-infected man and discuss the potential interactions between T. solium and HIV infections.

[Steroid treatment in four cases of anti-GAD cerebellar ataxia]

INTRODUCTION

Few neurological diseases are linked with anti-glutamic acid decarboxylase antibodies (GAD-ab); stiff man syndrome is an example. Cerebellar ataxia is a new feature of this expanding spectrum. No therapeutic trial is yet available in these diseases. We here report on four patients suffering from cerebellar ataxia linked with GAD-ab and review the data in the literature on this recently described syndrome.

METHOD

We conducted an open trial with monthly pulsed steroids. Steroid pulses were given six months followed with placebo for another six months. Main clinical and biological parameters were monitored monthly (International Cooperative Cerebellar Ataxia Rating Scale [ICARS] and GAD-ab).

RESULT

The clinical response was found limited and inconstant. Transient decline in GAD-ab level was noted in two patients. Moreover, GAD-ab level was found highly variable and did not correlate with clinical parameters.

DISCUSSION

Cerebellar ataxia with GAD-ab is an increasingly described syndrome. Outcome can be severe, leading to definitive cerebellar atrophy. Diagnosis is supported by high level of serum GAD-ab with intrathecal secretion. Experimental data have suggested a direct excitotoxic effect of GAD-ab on Purkinje cells. Response to various treatments is often disappointing. Improvement has been obtained with veinoglobulins in individual patients. A weak clinical and biological response was associated with monthly steroid pulses.

Visual Phenotype of Multiple Sclerosis in the Afro-Caribbean Population and the Influence of Migration to Metropolitan France

PURPOSE

To describe the visual phenotype of multiple sclerosis (MS) in the Afro-Caribbean population living in Martinique (French West Indies) and to specify the influence of the migration to metropolitan France on ocular impairment.

DESIGN

Prospective consecutive observational case series.

METHODS

A complete ophthalmologic examination was performed.

PARTICIPANTS

A total of 112 patients of Afro-Caribbean origin with MS satisfying McDonald's diagnostic criteria, divided into 53 cases (47.3%), the non-migrant patients (group NM), who had never left the Caribbean basin, and 59 cases (52.7%), the migrant patients (group M), who had lived in metropolitan France for at least 1 year before age 15.

RESULTS

MS first manifested as an impairment of the optic nerve in 41 cases (36.6%): 25 cases (47.1%) in group NM and 16 cases (27.1%) in group M. Visual function was recovered in 13/25 cases (52%) in group NM compared to 13/16 cases (81%) in group M. Two-thirds of patients presented with a clinical ocular impairment, which was bilateral in 58.5% of cases in group NM. Fourteen cases (12.5%) met the criteria of neuromyelitis optica, nine cases (17%) in group NM and five cases (8.5%) in group M. In group NM, when the initial visual attack did not regress, the visual Expanded Disability Status Scale (EDSS) score was 5+/-1.5 ; 75% of patients had monocular blindness and 50% binocular.

CONCLUSIONS

In the non-migrants (group NM), MS manifested more frequently with an optical neuropathy, the ocular impairment was more severe, and corresponded to neuromyelitis optica in 17% of the cases; a visual presentation and the absence of complete recovery from the first attack represented a factor of poor prognosis. This series is the largest description of the visual phenotype of MS in patients of African origin. The results confirm the preferential impairment of the optic nerve in the black population in the course of the disease. The migration towards an area of high prevalence of MS influences the visual phenotype in terms of a lower incidence and less severe prognosis of ocular impairment.

La neuromyélite optique rémittente: données neuroradiologiques

INTRODUCTION

Neuromyelitis optica (NMO) is a rare inflammatory and demyelinating disorder of the central nervous system, restricted to optical nerves and spinal cord. The main neuroradiological aspects, now summarized into a complete set of diagnosis criteria, are a normal cerebral MRI at onset and longitudinal involvement of the spinal cord concerning more than 3 vertebral segments. The clinical course and frequency of typical lesions remain unknown.

OBJECTIVE

We here report neuroradiological data from patients suffering from NMO.

METHODS

Brain and spinal cord MRI were systematically reviewed for 32 afro-Caribbean patients.

RESULTS

A typical longitudinal spinal lesion was seen in 44.7 percent with or without edema; a lesion involving less than 3 vertebral segments in 26.3 percent and no lesion in 21.1 percent. Longitudinal study of a few bouts suggested a progressive normalisation of spinal cord appearance. Atrophy was negatively correlated with immunosuppressive treatment. Cerebral lesions usually absent at onset were correlated to the follow-up. In a non-recursive condition, patients completed diagnostic criteria for encephalic and spinal lesions in 82.8 percent and 48.1 percent.

CONCLUSION

Radiology of spinal bouts showed multiple aspects besides the typical form. The notion of multiple bouts must be added to the spinal criteria to achieve good sensitivity. A typical extensive spinal lesion is usual in the follow-up, but seen after less then half of the bouts. Requiring such a lesion would delay the diagnosis.

Magnetic resonance imaging characteristics of ischemic stroke in an Afro-Caribbean population: A 1-year prospective MRI study on 534 consecutive patients

PURPOSES

Few population-based MRI studies on stroke, particularly in African-descent populations, are available. Based on a 1-year Afro-Caribbean population-based study MRI, ischemic stroke characteristics were extensively analyzed.

METHODS

All strokes occurring in Martinique (390,371 inhabitants) were prospectively included. Ascertainment was based, whenever possible, on MRI. All patients were categorized as single- (subclassified as cortical, cortical-subcortical, subcortical, lacunar) or multiple-lesion pattern, and vascular (single, multiple or junctional) territory. Brain parenchyma was evaluated, based on visualization of macrobleeds, microbleeds, white-matter hyperintensities or stroke sequelae. Etiology was classified according to TOAST criteria.

RESULTS

Among 596 ischemic stroke patients included, 534 (295 men, 239 women; mean age, 71 [range 23-110] years) underwent MRI (median delay 1 day). Four hundred and eighty-eight had single-type lesion (14.8% cortical, 42.4% cortical-subcortical, 14.5% subcortical, 16.6% lacunar), involving anterior cerebral (4%), middle cerebral (63.7%), posterior cerebral artery (10.4%) or basilar trunk (11.7%) territories, with 10.3% simultaneously involving multiple territories and 4.9% junctional infarction. Etiologies were LAA (11.2%), SVD (10.7%), CE (29.6%), rare (4.5%) or undetermined (44.1%).

CONCLUSION

Our prospective, consecutive, ischemic stroke series gives a comprehensive description of ischemic stroke imaging patterns and etiologic distributions in an Afro-Caribbean population with high socio-economic status. Our patients' stroke characteristics are close to those of European-descent populations.