|Year : 2012 | Volume
| Issue : 3 | Page : 229-232
Routine retinal examination in patients with acute stroke in Ahmadu Bello University Teaching Hospital, Shika-Zaria, Nigeria
Emmanuel R Abah1, OR Obiako2, AF Mahmoud-AJeigbe1, O Audu3
1 Department of Ophthalmology, Ahmadu Bello University, Shika-Zaria, Nigeria
2 Department of Medicine, Ahmadu Bello University, Shika-Zaria, Nigeria
3 Department of Community Medicine, Ahmadu Bello University, Shika-Zaria, Nigeria
|Date of Web Publication||8-Aug-2012|
Emmanuel R Abah
Department of Ophthalmology, Ahmadu Bello University Teaching Hospital, Shika-Zaria
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: There is high prevalence of hypertension and diabetes in patients with stroke, and these are also major risk factors for potentially blinding retinal diseases. This study was conducted to determine the prevalence and types of retinal abnormalities in patients with acute stroke in Ahmadu Bello University Teaching Hospital, Shika-Zaria, Nigeria. Materials and Methods: A prospective study of 297 consecutive patients with acute stroke was carried out. All the patients recruited had dilated fundoscopy and those who had retinal abnormalities were referred to the eye clinic for follow-up on discharge. Data analysis was by use of statistical package for social sciences (SPSS version 17), with statistical significance set at a P-value of 0.05. Results: Out of the 275 patients examined, 57.4% (n = 158) had retinal abnormalities. Age-related Macular Degeneration (AMD) predominated (36.7%), followed by cotton wool spots (22.2%) and retinal hemorrhage (16.5%). Hard exudates constituted 12.7%. Neovascularization and microaneurysms formed 5% each, while branch retinal vein occlusion constituted only 1.9%. Sixty-four percent were hypertensive and 24% were diabetic. Conclusion: The prevalence of retinal abnormalities among stroke patients is quite remarkable (57.4%). Routine retinal examination in such patients cannot be overemphasized because it may help to detect potentially vision-threatening retinal disorders.
Keywords: Acute stroke, retinal, routine examination
|How to cite this article:|
Abah ER, Obiako O R, Mahmoud-AJeigbe A F, Audu O. Routine retinal examination in patients with acute stroke in Ahmadu Bello University Teaching Hospital, Shika-Zaria, Nigeria. Int J Nutr Pharmacol Neurol Dis 2012;2:229-32
|How to cite this URL:|
Abah ER, Obiako O R, Mahmoud-AJeigbe A F, Audu O. Routine retinal examination in patients with acute stroke in Ahmadu Bello University Teaching Hospital, Shika-Zaria, Nigeria. Int J Nutr Pharmacol Neurol Dis [serial online] 2012 [cited 2020 Aug 15];2:229-32. Available from: http://www.ijnpnd.com/text.asp?2012/2/3/229/99475
| Introduction|| |
Acute stroke is a significant economic, social, and medical problem all over the world. The incidence of acute stroke is increasing worldwide and it is the third leading cause of death in most industrialized countries. ,, Patients with acute stroke have a high prevalence of hypertension and diabetes,  which are risk factors for potentially blinding retinal diseases such as diabetic retinopathy, retinal arteriolar emboli, and age-related macular degeneration (AMD). Recent studies also show that patients with diabetic retinopathy, retinal arteriolar emboli, and AMD may have a higher risk of stroke, suggesting that a retinal examination may be useful for stroke risk stratification. ,,,, Many studies have shown that hypertensive ocular fundoscopic abnormalities are clearly related to stroke, even after controlling for blood pressure and other vascular risk factors.  Retinal abnormalities indicative of a breakdown of the blood retinal barrier confer a greater increase in risk for stroke than sclerotic retinal changes. Similar retinal changes also have a positive relationship to stroke mortality. In addition, hypertensive ocular fundus abnormalities are reported to be associated with an increased risk for cognitive impairment, cerebral atrophy, progression of magnetic resonance imaging defined white matter lesions, and subclinical infarction.  Evaluating the ocular fundus for signs of hypertensive retinopathy, in combination with an assessment of the presence or absence of other known risk factors, may allow clinicians to further individualize a risk profile for stroke to each individual patient, thus permitting more accurate risk stratification.  After adjusting for the age, sex, race, blood pressure, diabetes, and other stroke risk factors, most retinal microvascular abnormalities are predictive of stroke. There is an increased risk of 2.6 with any abnormality being present, 3.1 for retinal deposits, 2.6 for blot-like hemorrhages, and 2.3 for flame-shape hemorrhages. So, retinal microvascular abnormalities are related to stroke. 
Despite the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC) recommendation, many physicians do not examine the fundus of their patients. 
The need for fundus examination is re-emphasized for all patients at risk. We examined the fundi of patients with acute stroke to enable us determine the prevalence and types of retinal diseases in these patients within our own environment. This will help us to appreciate the need for ophthalmology referral in these patients and also create a platform for stroke risk stratification in our setting.
| Materials and Methods|| |
This was a prospective study of consecutive patients with stroke admitted to the Ahmadu Bello University Teaching Hospital Medical Wards between October 2010 and September 2011. A standardized study protocol designed by the authors was used to collect data on patients' demographics, medical history, physical examination, and radiological findings. Approval was obtained from the Ethics and Research Committee of Ahmadu Bello University Teaching Hospital Shika-Zaria, and informed oral and written consent were obtained from the participants. Those who were uncooperative and those who refused to participate were excluded from the study. Pupillary dilatation was achieved with the instillation of 1% Cyclopentolate and 2.5% Phenylepherine, 1-2 drops each, into both eyes. They were encouraged to close their eyes for about 10 minutes. Direct and indirect ophthalmoscopy were done by two ophthalmologists to identify pre-specified retinal abnormalities and diseases such as microaneurysm, hemorrhage, hard exudates, cotton wool spots, neovascularization, AMD, retinal artery and vein occlusion. Stroke was diagnosed by the neurologist based on clinical presentation and brain imaging. Hypertension was defined as prior diagnosis by a physician, previous or current use of antihypertensives, or by blood pressure criteria.  Diabetes was defined as prior diagnosis of diabetes by a physician, previous or current treatment with oral hypoglycemic agents or insulin.  Standard statistical tests were used to determine associations. Chi-square and Student's "t" tests were used for discontinuous and continuous variables, respectively. Significance level was set at 5% probability.
| Results|| |
From October 2010 to September 2011, 297 patients were admitted with stroke. Twenty patients could not participate because they were in critical condition. Two patients declined. So, 92.6% participated (N = 275). Their age ranged between 19 and 86 years, with a mean of 58.8 years (SD ±7.7). Males constituted 59.6% (n = 164) and females formed 40.4% (n = 111) [Table 1]. The prevalence of any pre-specified retinal abnormality was 57.4% (n = 158). Of this, 63.9% (n = 101) were males and 36.1% (n = 57) were females [Table 2]. Sixty-four percent were hypertensive and 36.0% were diabetic. ARM constituted 36.7% (n = 58), while cotton wool spots were found in 22.2% (n = 35). Retinal hemorrhage and hard exudates were quite close, i.e. 16.5% (n = 26) and 12.7% (n = 20), respectively. Others were neovascularization and microaneurysm which made up 5.0% (n = 8) each and branch retinal vein occlusion was the least [1.9% (n = 3)] [Table 3]. Retinal abnormalities were significantly associated with hypertension and diabetes (P < 0.05), but not age and gender (P > 0.05) [Table 4].
| Discussion|| |
There are no present guidelines on the usefulness of a retinal examination in patients with stroke,  although previous studies suggest that many retinal diseases, including hypertensive retinopathy, diabetic retinopathy, and AMD, are the risk markers of stroke. ,,
The prevalence of retinal abnormalities including potentially blinding diseases was found to be high in the stroke patients studied (57.4%). This is quite close to the findings in stroke patients of Singapore (59%). 
Similar to the findings in Singapore (AMD = 30%),  AMD was the commonest retinal abnormality in our patients also (36.7%). However, retinal hemorrhage was more in their study (27%) compared to ours (16.5%), probably because the population of diabetics was 22% higher in their study. For similar reasons, microaneurysms were 8% higher in the Singapore study. Other retinal abnormalities detected in our patients include cotton wool spots (more in our study by 11%, probably because we had more young patients with uncontrolled/poorly controlled hypertension), neovascularization, and branch retinal vein occlusion.
There was a significant association between retinal abnormalities and diabetes in Singapore study,  but not with age, gender, or hypertension, while we found a significant association between retinal abnormalities and hypertension/diabetes.
In Britain, retinal abnormalities were found to be uncommon in hypertensive patients (3-21%),  unlike ours in which they constituted 64% of the patients with retinal abnormalities. This is likely to be related to the level of awareness, better control of blood pressure, or the aggressive nature of hypertension in Black patients. 
Since retinal microvascular abnormalities are associated with stroke (although more data are required to clarify the associations between specific types and stroke),  the retinal abnormalities in our stroke patients could be regarded as the risk markers for stroke in our environment. More so, to our knowledge, the data on retinal abnormalities in stroke patients in Nigeria are limited.
The limitations of this study include the likelihood that we must have underreported some of the retinal abnormalities because we did not use sensitive instruments like a digital retinal camera. Secondly, we examined the patients after papillary dilatation; this may not be feasible in all patients. Effort should be made to use modern methods that can give adequate information through undilated pupils.
In conclusion, the prevalence of retinal abnormalities in stroke patients in Nigeria is high. So, all stroke patients in our environment should have routine retinal examination. In addition, the retinal abnormalities found in these patients can be used as markers of stroke risk for other patients. Such patients should also be promptly referred to the neurologist before they develop a stroke.
| References|| |
|1.||Sudlow CM, Warlow CP. Comparing stroke incidence worldwide. What makes studies comparable? Stroke 1996;27:550-8. |
|2.||Wolf PA, Kannel W, Dawber T. Prospective investigations; the Framingham study and the epidemiology of stroke. Adv Neurol 1978;19:107-20. |
|3.||Warlow CP. Epidemiology of stroke. Lancet 1998;352:SIII1-4. |
|4.||Elkind MS, Sacco RL. Stroke risk factors and stroke prevention. Semin Neurol 1998;18:429-40. |
|5.||Cheung N. Is diabetic retinopathy an independent risk factor for ischaemic stroke? Stroke 2007;38:398-401. |
|6.||Wang JJ, Sudha Cugati MS, Michael D, Knudson MS, Elena R. Retinal arteriolar emboli and long-term mortality: Pooled data analysis from two older populations. Stroke 2006;37:1833-6. |
|7.||Wong TY, Mosley TH, Klein R, Klein BE, Sharett AR, Couper DJ. Arterosclerosis risk in communities study. Age-related macular degeneration and risk for stroke. Ann Intern Med 2006;145:98-106. |
|8.||Wong TY, Klein R, Klein BK, Tielsch JM, Hubbard LD, Neito FJ. Retinal microvascular abnormalities and incident stroke; the Artherosclerosis Risk in communities study. Lancet 2001;358:1134-40. |
|9.||Wong TY. Is retinal photography useful for evaluating stroke risk? Lancet Neurol 2004;3:179-83. |
|10.||Henderson AD, Bruce BB, Newman NJ, Biousse V. Hypertension-related eye abnormalities and the risk of stroke. Rev Neurol Dis 2011;8:1-9. |
|11.||Wong TY, Mitchel P. Hypertensive retinopathy. N Engl J Med 2004;351:2310-7. |
|12.||Joint National Committee of Prevention Detection, Evaluation and Treatment of High Blood Pressure.The sixth report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. Arc Intern Med 1997;45:360-72. |
|13.||Alberti KG, Zimmet PZ. Definition, diagnosis and classification of diabetes mellitus and its complications. Part 1: Diagnosis and classification of diabetes mellitus provisional report of a W.H.O consultation. Diabet Med 1998;15:538-53. |
|14.||De Silver DA, Wong TY, Chang H. Is routine retinal examination useful in patients with acute ischemic stroke? Stroke 2008;39:1352-4. |
|15.||Van den Born BJ, Caroline AA, Joost BL. Value of routine fundoscopy in patients with hypertention; systematic review. BMJ 2005;331:73-6. |
|16.||Mensah GA. Epidemiology of stroke and high blood pressure in Africa. Heart 2008;94:697-705. |
|17.||Doubal FN, Hokke PE, Wardlaw JM. Retinal microvascular abnormalities and stroke: A systematic review. J Neurosurg Psychiatry 2009;80:158-65. |
[Table 1], [Table 2], [Table 3], [Table 4]