INCIDENCE AND CHARACTERISTICS OF MYASTHENIA GRA VIS IN DAR ES SALAAM, TANZANIA

Abstract

Objective: To ascertain the annual incidence and characterise the clinical features of
Myasthenia gravis in Dar es Salaam, Tanzania during a ten-year period from 1st January
1988 to 31 December 1998.
Design: Prospective cumulative registration at a major urban hospital of all patients with
newly diagnosed Myasthenia gravis who were resident in Dar es salaam.
Setting: Muhimbili Medical Centre Teaching Hospital, Dar es Salaam, Tanzania.
Subjects: Forty seven patients, twenty males, twenty seven females satisfied the criteria for
the diagnosis of Myasthenia gravis (MG).
Results: The annual incidence of MG of both sexes was 3 per 1,000,000 population of all age
groups (95 % CI 2.0 to 3.6). The incidence per 1,000,000 population was lowest in those aged
below ten yean: 2.2 (95% CI 1.4 to3.4) which was statistically significant. The incidence per
1,000,000 per year was higher in females but this was not statistically significant. The clinical
presentation of MG in Tanzania was localised disease accounting for 47% ocular type and
53% was mild to moderately severe generalised type MG. Twenty per cent of patients with
generalised MG presented with bulbar features. Single fibre electromyography was the most
sensitive test.
Conclusion: Myastherliagravis is fairly rare in Tanzania as is in other sub-Saharan countries
and presents in similar way to European in terms of age, sex, and clinical features. Ocular
Myasthenia gravis was more prevalent in Tanzania than in Europe.