Kiyotaro Kondo  ( Departments of Neurology, Tokyo Metropolitan Institute for Neurosciences, Tokyo, Japan. )
Akhter Ahmed  ( Dow Medical College, Karachi Pakistan. )
Toshiaki Takasu  ( Nihon University, School of Medicine, Tokyo, Japan. )

Relative frequency of neurologic diseases in Karachi, with special reference to inflammatory disorders has been estimated by using the compre­hensive data from the Deptt. of Neurology, Dow Medical College, Karachi,
The incidence of subacute scierosing pan­ encephalitis has been estimated to be approx. 10 per million. Figures for multiple sclerosis appear comparable to those from India, Turkey and Israel. Rates for active encephalitides and postencephalitic sequelae are unbelievably higher than in the developed countries (JPMA 36:169 1986).

This is a part of comprehensive collabora­tive studies on encephalitides in Karachi area. Its purposes include: 1) clinical patterns and the relative frequency of the diseases, 2) estimation of their prevalence rate, 3) morbidity and mor­tality patterns in Karachi area due to various neurological disorders, particularly encephalitides, 4) evaluation of the risk factors for SSPE.
Thrget diseases are inflammatory disorders of the cerebral parenchyma of all kinds.

Table I summarizes such diseases with the applicable codes in the 9th Revision, International Classification of Diseases (ICD-9).

Table II describes diagnostic criteria for SSPE.

Materials include ; 1) cases, their histories, and the outpatient (OPD) and discharge records of the Department of Neurology, Civil Hospital; 2) the death certificates in the Abbasi Shaheed Hospital in which death certification is well or­ganized according to the rules proposed by the World Health Organization.
Prevalence rate of various groups of the target diseases was measured indirectly based on the number of the OPD patients with the diseases relative to motor neuron disease (MND), assuming that the rate from MND is 3-5/100,000 uniformly throughout the world.
Patterns of the morbidity of the target diseases and other disorders were evaluated on the basis of statistics of the OPD and the discharged patients, based on a classification by ICD-9.
Patterns of the mortality were determined by indirectly calculating age-and-sex specific mortality rates due to the target diseases and various other causes. The Abbasi Shaheed Hospital material was used instead of the regional certificates which were unsatisfactory.
Risk factors for SSPE were evaluated on the pattern of an ongoing Case Control Study being done in Japan by one of the authors (K.K.). Design of the Study was similar to those of Detels et al¹ and Halsey et al.²

Collected materials and on-going surveys are:
1) Statistics of the neurological patients: The following three statistics have been collected: a) OPD, selected diagnoses, all patients, April 1974 -March 1984; b) OPD, all diagnoses 2,000 consecutive patients around 1980 and c) Inpatients, all discharge diagnoses, all patients, March, 1975-March 1984.


Table III shows the numbers of patients based on the statistics. They provide a basis for an indirect estimation of the prevalence rate of SSPE. Table III also discloses unusual male! female ratios in all diseases. Even in multiple sclerosis or myasthenia gravis, which are known for a female excess world wide, males are preponderant. It is possible that female patients are disadvan­taged in Pakistan in asking for a medical consul­tation.
2) Cases with SSPE
Table N summarizes cases. Suspected as SSPE by the second author either in the Civil Hospital or in his private clinic. Clinical diagnosis is tentative and the cases were classified by the criteria in Table II according to the nature of the evidences that support the diagnosis. The Defin­ites and the Serological probables meet inter­national diagnostic standards, but a category for the Clinical probables has been proposed to separate cases lacking in laboratory data, but satisfying clinical criteria from the rest of “SSPE­like” cases. In epidemiological studies, the possibles are not accepted as SSPE.
There are, based on the clinical case ascer­tainment as of 22 March 1984, and on the serolo­gical data subsequently reported, no Definite, 8 Serological probables, 9 clinical probables along with one possible case. Total of the cases in three Original diagnosis of SSPE includes suspected cases. 3 unadmitted cases in the first group were not classified for which adequate clinical records and EEGs were not available. Of 8 Serological probables, 6 cases (0014, 0086, 0090, 0130, 0132, 0134) were included in the clinical case series of the present collaborative study. One each of male and female cases were reported from the Department of internal medicine of CHK and the Abassi-Shaheed hospital, which were not included in this table. acceptable categories were 11 males and 6 females, indicating a striking male predominance. These numbers are preliminary and changable as new cases or new laboratory data emerge.
3) Prevalence rate of SSPE
An exhaustive case finding is necessary for a direct measurement of the prevalence rate of a given disease in a given community, which is not feasible in Karachi in this project. An indirect method, therefore, has been proposed to estimate the rate relative to that of MND based on the numbers of the OPD patients with the diseases. Excluding high risk foci in Guam or Kii peninsula of Japan, prevalence rates of MND range 0.8-6.7 in areas of the world, the average being 3.7 per 100,000³. As seen in Table Ill number of MND is 26 and the acceptable cases of SSPE in the first group of

Table IV is 7, pooling both the sexes. Prevalence rate of SSPE in Karachi is, simply multiplying 3.7 by 7/26, 1.0 per 100,000, or 10 per million. Cases in the first group only was used for this calculation, because other cases have different motivations in seeking consultation.

Table V summarizes available incidence rates of SSPE in 13 countries. Such rate is not directly available in Karachi, but may be about 7-10 per million, based on the equation that prevalence rate incidence rate X average duration the latter being 1-1.5 years in SSPE IN MOST COUNTRIES. A follow-up study is being planned to obtain the average duration in Karachi cases. Validity of these estimations is debatable, but if we accept this tentative figure, it justifies clin­ical impressions of the second author that SSPE is common in Karachi.
Incidentally, figures for multiple sclerosis range 3.4-4.2 X l0,⁵ being comparable to those reported from India, Turkey and Sephardim Israe­lis. Rates for active encephalitides range 6.4-8.0 for postencephalitic sequelae, 18.4-23.0 being un­believably higher than the values in developed countries.

Even at this preliminary stage of the study convincing data indicated that inflammatory afflictions of the central nervous system pre­dominate in the neurological diseases in urban Karachi. SSPE appeared to be frequent which is, at least in communities in the temperate count­ries, usually considered to occur one per million per year. Regional factors, particularly climatic and socioeconomic, may be responsible for such a pattern. Results of the case-control study are awaited to evalnate the factors.

This study was supported by the Japan Ministry of Education. Cordial thanks are due to the Medical Superintendent, Civil Hospital for permit­ting the use of clinical data, and to Mr. Aftab Ahmed, Department of Neurology, Civil Hospital, for secretarial help.

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