SUMMARY

A review of 154 black African patients with stroke checked with C.T. scan of the head over a period of five years shows that the ischemic attack is more frequent than the haemorrhagic one. The stroke involves mainly the territory of the middle cerebral artery and the lenticulo-pallido- strate arteries. The arterial hypertension is the most common aetiologic factor, followed by sickle cell disease, diabetes and some cardiovascular diseases.

Keywords : Africa, Stroke, Black African, C.T. scan

RESUME

Dans une revue des 154 cas d’ AVC explores en tomodensitométrie sur une période de cinq ans dans une population noire urbaine, les auteurs notent que I’accident ischémique est plus fréquent que l’hémorragique. Les territoires de l’artère cérébrale moyenne et des artères lenticulo-pallido-striales sont les plus intéressés. L’HTA est le facteur predictif Ie plussouvent retrouve, suivi de l’anémie à cellules falciformes, du diabète et d’autres maladies cardio-vasculaires.

Mots cles: Afrique, CT scan, tomodensotométrie

INTRODUCTION

The cerebio-vascular stroke is responsible for the 6 per cent of morbidity and 12 per cent of adult mortality at the Kinshasa Hospital (11) and has become a real public health problem. (1, 11, 14, 17)
The diagnosis, based in the past on physical examination only, has greatly improved after the advent of the C.T. scan used as a routine diagnostic procedure in this cases. (2, 4, 5, 6, 9, 12, 16,17, 19).
Therefore a review of five years experience of C.T. scan in the black african urban patients with strokes is carried out, and the results discussed.

MATERIALS AND METHODS

From 1988 to 1993, 286 patients have been referred to the Radiological Department of the Kinshasa University Hospital to be investigated with C.T. scan for presumptive stroke. Out of 286 patients, ’54 were selected on the following criteria:

1) Black Africans.

2) Clinical evidence of stroke

3) C.T. scan performed not later than ten days from the stroke

4) C.T. scan examination excluding other conditions (tumours, abscesses etc.) All scans were performed with a third generation C.T. scan machine. Contiguos 10 mm. thick axial slieces parallel to the Om – line without contrast enhancement were carried out.

The following parameters were considered in our study:

1) Age and sex,

2) Aetiological factors,

3) Vascular area involved,

4) Type of stroke (haemorrhagic, ischemic),

5) Hemispheric incidence,

6) Associated signs.

RESULTS

The age and sex distribution in relation to the type of stroke is shown in table 1:

Table 1: Age and sex distribution in relation of type of stroke

The incidence of age was from 2 years to 92 years with an average age of 44 years( 43 years for men and 47 years for women). The highest incidence was in the fifth decade of life (41 to 50 years). The sex ratio was of one women for two men showing a high incidence in males. The incidence of the type of stroke shows a ratio of one haemorrhagic stroke to two ischemic strokes. It is interesting to note that in the first two decades of life the strokes were all ischemic in this series and that in the haemorrhagic 6 cases had a ventricular bleeding.

Table 2 shows the hemispheric side and the vascular area involved in percent:

Table 2 : Hemispheric side and vascular are involved in ischemic and haemoragic stroke

As shown in table 2 the ischemic strokes involve predominantly the left hemisphere (3 left to 1 right): there is no hemispheric difference in the haemorrhagic strokes.
The ischemic strokes are more frequent in the left middle cerebral artery (47.5 per cent). The anterior cerebral artery is involved in the ischemic stroke with an incidence of 25 per cent (10% right, 15 % left side) and the lenticulo-striate arteries are involved in the 27,5 per cent (17.5% right, 10% left side) showing no relevant differences between right and left sides. No ischemic lesions occurred in the posterior cerebral arteries area in our series, (see Fig. 2a).

Fig 2a. Distribution of vascular area involved in ischemic strokes.

The haemorrhagic strokes are more frequent in the lenticulo-pallido-striate areas (44,9 per cent) and in the territory of the middle cerebral artery (34,7 per cent). The anterior cerebral artery and the posterioe cerebral artery are involved with the same incidence (10,2 per cent). A ventricular bleeding is associated in 10 per cent of cases of haemorrhages of the middle cerebral and lenticulo-pallido-striates arteries, ( see Fig. 2b).

Fig 2b. Distribution on vascular areas involved in haemorrhagic strokes

Table 3 shows the age related aetiological factors in the patients of our series.

Table 3 : Age related aetiological factors in stroke

() = Associate to HTA

Hypertension is the commonest aetiological factor in 85.7 per cent ofcases( 83.8 per cent alone and 1,9 per cent in association with diabetes mellitus). Sickle cell anaemia in the commonest aetiological factor in teenagers (87.5 per cent); Diabetes mellitus is present in 5.8 per cent of cases (3.9 per cent alone and 1.9 per cent of cases associated with hypertension); cardiovascular diseases are present in 1.9 per cent of cases, whilst in two cases no aetiological factor could be found.

DISCUSSION

In accordance with other Authors (LABAUGE et all (7), VALLAT et all (17), GAUTHIER et all (4), this study shows that in our population the most common stroke is ischemic. The majority of our patients had the stroke between the age of 30 and 60 years with an avarage age of 44 years, age that is lower than in the overseas studies (2, 4, 6, 12, 18) but in accordance with the african studies (10, 11, 14, 15, 16) and seems to affect more the population with no medical facilties and low socio-economic status.
The sex ratio of one woman to two men is similar to the one reported by NJOH (15) in Liberia, but higher to the ones reported by other Authors of 1 woman to 1,3 men (4, 7,17,1B, 19).

Haemorrhagic strokes are present in all vascular area but predominantly in the territory of the middle cerebral artery (34 per cent) and in the territory of the lenticulo-pallido-striate arteries (44 per cent) with a total of almost 80 per cent of stroke in this particular areas.

Although prevalent in the left hemisphere, and this should be investigated in larger series, the ischemic stroke involves also the areas of the middle cerebral and lenticulo-pallido-striate arteries in 75 per cent of cases. Several other studies confirms the high indicence of stokes in these arterial territories (1,4, 18, 19). Another research should try to understand the poor involvement of the territories of the posterior cerebral arteries in stroke.

The arterial hypertension is the commonest aetiological factor in stroke also for BOUDOURESQUES et all (1) who finds an incidence of 67 -90 per cent of cases. NJOH (15) finds that hypertension is the second aetiological cause in stroke and MATUJA et all (10) in Tanzania finds that hypertension is responsible only for 43 – 45 per cent of strokes. COOPE et all (3) reported the beneficial effect of antihypertensive drugs on the control of stroke incidence.
Sickle cell anaemia is responsible for 7.2 per cent of strokes in our series higher than the incidence of 2 per cent reported by LAMBOTTE et all (ADELOYE and ODEKU reported an incidence of 4 per cent of strokes due to sickle cell anemia in Nigeria). The high incidence of strokes in teenager ( 87.5 per cent) due to sickle cell anaemia recognises the pathogenesis in the thrombosis and hemolysis due to this disease.

Diabetes mellitus has an incidence of 5.8 per cent similar to the incidence of diabetes in the general population of 5 per cent. This should be further investigated because macroangiopathy seems to be rare in the African (13)
Cardiovascular diseases as cause of stroke are less frequent in our series compared with the European ones.
Further studies are needed to understand the arterial and side distibution of stroke.

A policy of control of hypertension should be suggested to prevent the devastating effect of stroke mainly in the young population.