A series of 86 black, Indian and white patients with motor neuron disease were analysed retrospectively. Although the material does not allow statistically valid conclusions, there are sufficient cases among blacks to allow two prima facie observations in this population group: (i) motor neuron disease has an earlier age of onset than in whites and Indians; and (ii) more patients come from peripheral and rural areas than would be expected in prevailing circumstances.S Af Med J 1989; 76: 155-15

Bhigjee, AI

Bill, PLA

Cosnett, JE

English

AJOL - African Journals Online

SAMT VOL. 76 19 AUG 1989 155Motor neuron disease in blacksEpidemiological observations in NatalJ. E. COSNETT, P. L. A. BILL, A. I. BHIGJEESummaryA series of 86 black, Indian and white patients with motorneuron disease were analysed retrospectively. Although thematerial does not allow statistically valid conclusions, thereare sufficient cases among blacks to allow two prima facieobservations in this population group: (~ motor neuron diseasehas an earlier age of onset than in whites and Indians; and (it)more patients come from peripheral and rural areas thanwould be expected in prevailing circumstances.S Air Med J 1989; 76: 155-157.We reported earlier that motor neuron disease occurs morecommonly among blacks than Parkinson's disease, which isrelatively rare in this race group.! The hypothesis that theseconditions, and other neuronal abiotrophies, are the result ofprevious subclinical neuronal insult and subsequent age-relatedneuronal attrition2 adds pertinence to epidemiological obser-vations. For this reason we have examined the occurrence ofmotor neuron disease more ClOSely.Patients and methodsCase summaries of 95 patients diagnosed as having motorneuron disease were collected over 9Y2 years. These patientswere of all races and had been admitted at least once to one ofthe four major public hospitals in Durban - King EdwardVIII, Addington, R.K. Khan and Wentworth. Before 1984patients were seen during neurological consultation in generalwards. Since then most have been admitted to the NeurologyUnit at Wentworth Hospital for assessment. After excluding 9patients with doubtful diagnosis, there were 86 patients inwhom the diagnosis of motor neuron disease was reasonablycertain - 59 were black (36 men and 23 women), 16 whiteand 2 coloured (9 men and 9 women) and 9 Indian (8 men and1 woman) and the mean age at onset, estimated from age atpresentation and duration of symptoms, was 47,45 years inblacks and 54 years in whites and Indians. The patients hadfull clinical assessment and laboratory and radiological in-vestigations, including myelography when necessary. After1984 most patients had electromyographic studies, these wereperformed in 45,3% of the total series (39 patients). Because ofgeographical and socio-economic factors, and the unavailabilityof specific treatment, only 25 patients (29%) were seen afterdischarge from hospital. This lack of follow-up places certainrestrictions on diagnosis in some cases.It must be emphasised that this report does not profess toindicate the total prevalence of motor neuron disease in thisNeurology Unit, Department of Medicine, University ofNatal and Wentworth Hospital, DurbanJ. E. COSNETT, M.D. F.R.C.P.P. L. A. BILL, F.C.P. (S.A.), F.R.C.P.A. 1. BHIGJEE, M.MED. (NEUROL.), F.C.P. (S.A.), M.R.C.P.Accepted 9 Nov 1988area. However, because the patients were collected randomly,without any selection, and diagnosed by the same group ofdoctors, they broadly reflect the prevalence in the various racegroups. The 86 patients in whom there was little doubt of thediagnosis were classified retrospectively according to theirdominant features, into three types of motor neuron disease.'Those black patients with a combination of upper motorneuron (UMN) and lower motor neuron (LMN) signs, with alesser degree of bulbar involvement in some, were classified asamyotrophic lateral sclerosis (ALS) - 27 men (75%), 12women (52%). Those with predominant affection of bulbarmuscles, including those of LMN type, were classified asprogressive bulbar palsy (BP - 5 men, 6 women) and thosewith predominant LMN involvement of limb and trunkmuscles were labelled progressive muscular atrophy (PMA -4 men, 5 women). For whites and Indians combined thedistribution was as follows: ALS - 15 males, 6 females;PMA - 1 male, 2 females; BP - 1 male, 2 females. Therewas, of course, considerable overlap between these types insome cases. Patients with clinical signs of pure UMN affection,who might have been considered to have primary lateralsclerosis, were not included in this series. This clinical pictureis very similar to that of the hitherto unexplained myelopathy'that prevails in this region and may be associated with HTLV-I infection.s A few patients with pure localised LMN affection,who might have had early motor neuron disease, were excludedbecause it was not possible to perform follow-up studies.ResultsThe principal findings are shown in Fig. 1. All races showed apreponderance of men, which accords with world experience.6, 7The male/female ratio was 3:2 in the case of blacks, and inwhites and Indians combined. No specific effort was made toelicit a history of injury or antecedent illness. The relativelyhigh incidence of trauma (stab wounds 3 cases, fracture orother trauma 9 cases), hypertension (7 cases) and pulmonarytuberculosis (3 cases), which was recorded routinely in thecase summaries, reflects the frequency of these conditions inthe black population. Table I shows an attempt to relate thesecases to the total population from which they are drawn8 inorder to provide a standard for comparison. The areas con-cerned - KwaZulu (8 cases), Transkei (8 cases), and otherperipheral and rural areas of Natal (17 cases) - usually drainto Durban for specialist neurological services. Some blackpatients do not seek medical attention, and many with chronicneurological disease are probably not referred to large centres.The number of cases among whites and Inqians is reduced bysome who receive private medical attention. What these figuresshow is that motor neuron disease is by no means unknownamong blacks and, allowing for failure to reach specialistmedical centres, the disease may be as common among blacksas among whites and Indians.The most remarkable feature revealed by this series is theearlier age of onset of motor neuron disease among blacks,with a peak in the 4th decade, whereas the greatest incidencein most other countries and among our white and Indianpatients (Fig. 1) is 2 decades later. A further unexpected.156 SAMJ VOL 76 19 AUG 198910-19 20-29 30-39 40-49 50-59 60-69 70-79YearsFig. 1. Distribution of cases of motor neuron disease accordingto race, sex and age of onset (cross-hatched = men; stippled =women; M = case of PMA; B = case of BP; all other cases wereclassified as ALS.finding is that 33 black patients (56%) were referred from areasoutside the greater Durban area. These were from Transkei,KwaZulu and peripheral hospitals in Natal. This indicatesdistinct bias towards rural domicile, particularly since somepatients who gave metropolitan addresses may have come fromthe country. This finding is not in keeping with the averagehospital population or with the common assumption that ruralpatients seldom reach metropolitan hospitals. TO evidence ofclustering or familial incidence was found, but this would bedifficult to establish without a field survey. Regarding the typeof motor neuron disease, Fig. I shows the expected pre-Discussionponderance of ALS in all race groups. There is, however, arelatively greater proportion of BP and PMA among women,especially blacks.The most striking finding is the early age of onset of mostcases of motor neuron disease among blacks. The asymmetricaldistribution of age incidence (Fig. I), with a bias towardsyouth, is unlike any condition in which advancing age plays apart in its aetiology. The pattern for whites is more in keepingwith this concept, and is more in accord with world expe-rience. 6•7 Possible explanations for this unusual distributionamong blacks are that a causative factor becomes operative atan earlier age, that we are dealing with a different condition orthat the graph represents the superimposition of two con-ditions, one of which is motor neuron disease as seen amongother races. In a population in which poliomyelitis has beenvery prevalent, the suspicion may arise that this early onsetmotor neuron disease is of the post-poliomyelitis type. Recentevidence from Britain has shown a relationship between pastnotification rates for poliomyelitis (1931-1939) and recentmortality from motor neuron disease (1969-1978).9 Most ofour young black patients with motor neuron disease showedthe classic features of ALS with UMN involvement. They alsotended to present at an advanced stage, unlike the benignappearance of those cases that have been reported after polio-myelitis. '0 Other virus infections may also be incriminated.HTLV-I appears to be associated with some of the unexplainedspastic paraparesis that is prevalent in this region, but evidencehas not shown that it is responsible for motor neuron disease,either here or elsewhere."A further observation is that, among blacks, motor neurondisease appears to be more prevalent in rural and peripheralareas than would be expected from relative population densityand the composition of average hospital population. Surveys inother parts of the world have not shown excess of motorneuron disease among farm workers but there has been asuggestion that exposure to animal carcasses and consumptionof large quantities of milk may be influential in the aetiologyof motor neuron disease. 7 The only consistent.association thathas been shown is one with mechanical injury. However, thehigh rate of trauma among our patients is probably notunusual for this ethnic group.These observations are offered in the full realisation thatthey will not stand close methodological scrutiny. The materialsuffers from the defects inherent in any random collection ofhospital admissions. Nevertheless, it is felt that they shouldnot be ignored on this account. They may provide pointerstoward avenues for more definitive research into the cause andpathogenesis of this mysterious and tragic disease.We 'are grateful to Phyllis Enstrom and Trish Kuhn for secre-tarial assistance.BlackIndian5551510TABLE I. RELATION OF MOTOR NEURON DISEASE TOTOTAL POPULATIONTotal MND Rate/Race population cases 100000Blacks 6750000 59 0,88Whites,coloureds 662000 18 2,7Indians 659000 9 1,4MND = motor neuron disease.REFERE~CESI. Co'n"n JE, Bill PLA. Parkinson's disease in blacks: observations on epide-miology in Natal. S Afr Med] 1988; 73: 281-283.2. Calne DB, Eisen A, McGreer E, Spencer P. Alzheimer's disease, Parkinson'sdisease, and motoneuron disease: abiotrophic interaction between ageing andenvironment. Lancet 1986; 2: 1067-1070.3. Rowland LP. Diverse forms of human motor neuron disease. Adv Neural1982; 36: 1-13.4. Cosnen JE. Unexplained spastic myeloparhy: 41 cases in a non-Europeanhospital. S Afr Med] 1965; 39: 592-595.5. Roman JGc. Retrovirus-associated myelopathies. Arch Neural 1987; 44:659-663.6. Mulder DW. Clinical limits of ALS. Adv Neural 1982; 36: 15-22.SAMT VOL 76 19 AUG 1989 1577. Kuruke JP. Epidemiology of ALS. Adv Neuro11982; 36: 281-302.8. Central Statistical Services. SOlllh African S,atiSlics, 1986. PretOria:Government Printer, 1987.9. Martyn eN, Barker DJP, Osmond C. MotOneuron disease and pastpoliomyelitis in England and Wales. Lancer 1988; 1: 1319-1321.10. Campbell AMG, Williams ER, Pearce J. Late motor neuron degenerationfollowing poliomyelitis. Neurology 1969; 19: 1101-1106.11. Mora CA, GarrutO RM, Brown P er al. Seroprevalence of antibodies toHTLV-I in patients with chronic neurological disorders other than tropicalspastic paraparesis. Ann Neurol 1988; 23: suppl., S192-S 195.measles immunisationgrowing peri-urban areaof a massa rapidlyEvaluation• •campaIgn InMAUREEN KEARNEY, D. YACH, H. VAN DYK, S. A. FISHERSummaryA mass measles immunisation campaign, with a targetcoverage rate of 85 - 90%, was launched in Khayelitsha, arapidly growing urban township in the Cape Town area.Cross-sectional surveys of the measles immunisation statusof resident 6 - 23-month-old infants were conductedimmediately before, immediately after, and approximately 2months after the campaign in order to determine the effec-tiveness of a mass campaign in boosting coverage in an areawith a high influx rate. Immunisation coverage rates were55% in the first survey, 76% in the second, and 72% in thethird. In the first survey, coverage rates for children born inCape Town were 1,4 times higher than those born elsewhere.This trend continued throughout the survey. Duration of stayin Cape Town also influenced coverage, with rates for therecently arrived children being considerably lower than thosefor the more established Cape Town residents. The influx ratebetween the second and third survey (over the Christmasperiod) was 9,1% per month. Failure to reach the targetedrate is attributed to the influx rate, campaign design andimplementation, and factors related to child and career mobi-lity. Alternative immunisation strategies, with social awarenessplaying a key role, are being urgently investigated.S Air Med J 1989; 76: 157-159.Measles became a notifiable disease in the RSA in 1979. 1Measles notification rates per 100000 population were 105 and14 for blacks and whites respectively in 1987.2 There was amarked downward trend in the incidence of measles in thewestern Cape from 1980 to 1984, but in the mid-summermonths of 1985 and 1986 it once again reached epidemicproportions. 3.4 The summer peaks were in contradistinction toWestern Cape Regional Services Council, Cape TownMAUREEN KEARNEY, M.B. B.CH., D.e.M. (S.A.) (Deceased)S. A. FISHER, M.B. CH. B., M.MED. (COMM. HEALTH), D.CH. (S.A.), F.F.CH.(CM.) (S.A.)Centre for Epidemiological Research in Southern Africa,South African Medical Research Council, Parowvallei, CPD. YACH, M.B. CH.B., B.SC HO~S (EPIDE.\-\lOL.), M.P.H.Department of Paediatrics, University of Stellenbosch andTygerberg Hospital, Parowvallei, CPH. VAN DYK, 5lh-year medical slUdem.-\cccptcd 9 Mar 1989.previous experience where measles incidence reached peaks inthe winter months. 5 It was suggested that this change inpattern was related to increased population movement fromthe rural areas of Transkei and Ciskei (±1500 km from theCape) to the western Cape, predominantly over the Christmasperiod.Although not entirely restricted to the black population, byfar the greatest problem was centred around the rapidlygrowing new township of Khayelitsha, with its large proportionof squatters in two areas known as Site B and Site C. In thesetwo areas there is site-and-service provision with plots of 60-90 m2, piped water, waterborne or bucket sewerage and garbageremoval. People build their own shacks. Khayelitsha was firstsettled in late 1983 and at present (mid-1988) has an estimatedpopulation of 250 000.Since these two areas were most affected by the recentincrease in the occurrence of measles, an intensive measlescontainment strategy was initiated. The World HealthOrganisation's Expanded Programme on Immunisation (EPI)served as a guide.6 The key elements of the Khayelitshaprogramme consisted of a mass measles immunisation cam-paign, over and above the routine child health clinics (runthree times a week in both areas). This was done a monthbefore Christmas, with the object of preventing the expectedmeasles outbreak over the 1987 Christmas/New Year periodby increasing herd immunity.The methods and results of evaluation of the mass measlesimmunisation campaign are presented.Subjects and methodsA mass immunisation campaign was conducted in Site BandSite C from 16 November to 2 December 1987. A team of 19health workers (trained staff, clerks and a driver) with 4vehicles worked for a total of 13 working days to cover theentire area. An attempt was made to administer measlesvaccine to all children between 6 months arid 6 years of age andit was hoped to attain 85 - 90% coverage.Site B was selected for the cluster sample surveys since itwas considered to be more unstable than Site C in respect ofinflux into the area. An estimated 73000 people lived in Site Bat the time of the first survey - 55000 in shacks and 18000 intents.A cross-sectional survey following EPI guidelines forimmunisation surveys7 was conducted immediately before thestart of the immunisation campaign, immediately thereafter

Motor neuron disease in blacks

https://www.ajol.info/index.php/samj/article/download/159845/149411

Motor neuron disease in blacks

Abstract

Similar works

Full text

Available Versions

AJOL - African Journals Online