diabetes mellitus, hypertension, hyperlipidemia, thy in primary care: diabetes melli- tus and Type 2 diabetes mellitus is more common than type 1 …
Review of Clinical Signs
Series Editor: Bernard Karnath, MD
Retinal Manifestations of Diabetes Mellitus and Hypertension
Charlise A Gunderson, MD Bernard Karnath, MD
T
he ophthalmoscope Figure 1, which was invented in 1850 by Hermann von Helmholtz,1 allowed for the clinical correlation of retinal findings with many systemic diseases, such as diabetes mellitus, hypertension, hyperlipidemia, thyroid disease, vascular disease, and systemic infections Although ocular signs are not necessarily disease specific eg, signs seen in hypertensive patients also appear in diabetic patients, early recognition of these signs can help prevent unnecessary vision loss2 Additionally, these signs in combination can help the physician determine which systemic disease is responsible for the patients retinopathy A comprehensive discussion of all systemic diseases with ocular manifestations is beyond the scope of this article Hence, this review focuses on retinal findings associated with two of the most common diseases seen in primary care: diabetes mellitus and hypertension A brief review of the technique for ocular examination with the ophthalmoscope also is included OCULAR EXAMINATION A systematic
routine should be used when examining the eyes and surrounding tissues2,3 Generally, it is best to examine the eyes in the following sequence: visual acuity, extraocular muscle function, visual field testing, and then finally ophthalmoscopy4,5 For optimum retinal examination, a mydriatic agent is used to dilate the pupil2 Both tropicamide 1 Mydriacyl and phenylephrine hydrochloride 25 Mydfrin dilate the pupils in approximately 30 minutes Once the patients eyes are dilated, the ophthalmoscope is held approximately 12 to 15 cm away from the patients eye For examining the patients right eye, the examiner holds the ophthalmoscope in close proximity to his or her own right eye using the right hand For examining the patients left eye, the examiner uses the left hand and left eye The examiner then moves in closer to the patients eye while adjusting the lens settings for opti-
RETINAL SIGNS OF DIABETES AND HYPERTENSION
Microaneurysms Dot and blot hemorrhages Hard exudates Macular edema Cotton-wool spots Neovascularization Retinal edema Optic disc edema
mal focus The physician also should keep his or her nonexamining eye open during this procedure DIABETES MELLITUS Diabetes mellitus is
the leading cause of new cases of blindness in middle-aged Americans6,7 Timely detection and treatment of diabetic retinopathy can substantially reduce the likelihood of blindness Approximately half of adult diabetics in the United States, however, do not receive yearly eye examinations8 Type 2 diabetes mellitus is more common than type 1 diabetes, and the prevalence of type 2 diabetes increases with age Type 2 diabetes may remain undetected for a long time It has been estimated that 5 to 10 years of sustained hyperglycemia are needed to develop retinal manifestations6 A high degree of correlation exists between glycemic control as measured by glycosylated hemoglobin levels and presence of early retinopathic
Dr Gunderson is as Assistant Professor of Medicine and Director of Pediatric Ophthalmology and Adult Strabismus, University of Texas Medical Branch, Galveston, TX Dr Karnath is an Assistant Professor of Internal Medicine, University of Texas Medical Branch
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Gunderson Karnath : Retinal Manifestations : pp 15 18
Figure 1 A drawing of Hermann von Helmholtzs original ophthalmoscope Reprinted with permission from Ravin JG
Sesquicentennial of the ophthalmoscope Arch Ophthalmol 1999;117:1636
Table 1 Subdivisions and Characteristic Lesions of Diabetic Retinopathy
Nonproliferative retinopathy Microaneurysms Hemorrhages Hard exudates Cotton-wool spots Macular edema Proliferative retinopathy Neovascularization Figure 3 The arrow indicates hard exudates Dot and blot hemorrhages also are visible
Figure 2 The arrow indicates dot and blot hemorrhages Hard exudates also are visible
changes As a rule, retinopathy precedes nephropathy Therefore, early detection of the ocular manifestations of diabetes Table 1 is important9 The initial stage of retinal changes in the diabetic patient is called nonproliferative diabetic retinopathy9,10
and includes the appearance of dot and blot hemorrhages which are caused by intraretinal blood and/or microaneurysms Figure 2 Microaneurysms are seen as scattered red spots in the retina caused by weakened arterioles and capillaries leading to outpouching of the vessel walls Dot and blot hemorrhages represent blood in the retina The differentiation between a microaneurysm and a dot and a blot hemorrhage is based on size and is somewhat subjective Distinguishing between a dot and
blot hemorrhage and microaneurysm on direct ophthalmoscopy may be difficult Several years may pass before other lesions, such as retinal hemorrhages and exudates, develop10,11 Hard exudates caused by leakage of proteins and lipids from the damaged arterioles appear as small white or yellow areas with sharp margins, often with a glistening appearance on the retina Figure 3 As the disease progresses further, retinal changes occur, including macular edema and cotton-wool spots Figure 4 Cotton-wool spots result from microinfarctions of nerve fibers caused by focal ischemia after occlusion of terminal retinal arterioles occurs These spots appear as white fluffy spots on the retina Macular edema is the principal mechanism of visual loss in nonproliferative retinopathy Macular edema results from leakage from microaneurysms Proliferative diabetic retinopathy is a late stage of disease and is characterized by neovascularization ie, new blood vessel formation, which is a response to continued retinal ischemia9 Neovascularization results in vision loss due to vitreous hemorrhages and retinal detachment
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Gunderson Karnath : Retinal
Manifestations : pp 15 18
Figure 4 The arrow indicates a cotton-wool spot
Figure 6 The arrow indicates retinal hemorrhages Hard exudates also are visible
Figure 5 Hypertensive retinopathy showing arteriovenous nicking arrow Reprinted with permission from Bradford CA Basic ophthalmology for medical students and primary care residents 7th ed San Francisco: American Academy of Ophthalmology; 1999:135
Figure 7 Malignant hypertension showing optic disc edema Also seen are flame-shaped hemorrhage, 
hard exudates, arterial constriction, and cotton-wool spots Reprinted with permission from Bradford CA Basic ophthalmology for medical students and primary care residents 7th ed San Francisco: American Academy of Ophthalmology; 1999:135
HYPERTENSION The funduscopic changes in the eye noted with hypertension were first described in 189812 Since that time, little has changed in the terminology describing these characteristic retinal abnormalities These characteristic retinal changes included arteriolar narrowing, arteriovenous crossing changes, alterations of light reflexes on arterioles, cotton - wool spots, microaneurysms, retinal hemorrhages, retinal edema, and blurred disc margins13 The
first and most widely used grading system for hypertensive retinopathy was proposed by Keith et al14
The classification system consists of 4 grades as follows:
Grade I: mild narrowing of the retinal arterioles Grade II: arteriovenous nicking ie, venous compression at arteriovenous crossings Figure 5 Grade III: cotton-wool spots, hemorrhages Figure 6, retinal edema Grade IV: optic disc edema Figure 7
A newer more simplified grading system was recently proposed and divides the features, according to
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Gunderson Karnath : Retinal Manifestations : pp 15 18
REFERENCES
1 Ravin JG Sesquicentennial of the ophthalmoscope Arch Ophthalmol 1999;117:16348 2 Bradford CA Basic ophthalmology for medical students and primary care residents 7th ed San Francisco: American Academy of Ophthalmology; 1999 3 Frith P, Gray R, Maclennan S, Ambler P The eye in clinical practice 2nd ed Malden MA: Blackwell Science; 2001 4 Seidel HM, Ball JW, Dains JE, Benedict GW Mosbys guide to physical examination 4th ed St Louis: Mosby; 1999 5 Bickley LS Bates guide to physical examination and history taking 7th ed Philadelphia: Lippincott, Williams
Wilkins; 1999 6 Aschner P Current concepts of diabetes mellitus Int Ophthalmol Clin 1998;38:110 7 Brechner RJ, Cowie CC, Howie LJ, et al Ophthalmic examination among adults with diagnosed diabetes mellitus JAMA 1993;270:17148 8 Javitt JC, Aiello LP Cost-effectiveness of detecting and treating diabetic retinopathy Ann Intern Med 1996;124 1 Pt 2:1649 9 DAmico DJ Diseases of the retina N Engl J Med 1994; 331:95106 10 Feman SS The natural history of the first clinically visible features of diabetic retinopathy Trans Am Ophthalmol Soc 1994;92:74573 11 Doft BH, Kingsley LA, Orchard TJ, et al The association between long-term diabetic control and early retinopathy Ophthalmology 1984;91:7639 12 Walsh JB Hypertensive retinopathy Description, classification, and prognosis Ophthalmology 1982;89:112731 13 Wagener HP, Clay GE, Gipner JF Classification of retinal lesions in the presence of vascular hypertension Ophthalmol Trans Am Sci 1947;45:5773 14 Keith NM, Wagener HP, Barker NW Some different types of essential hypertension: their course and prognosis Am J Med Sci 1939;197:33243 15 Dodson PM, Lip GY, Eames SM, et al Hypertensive retinopathy: a review of existing classification systems and a
suggestion for a simplified grading system J Hum Hypertens 1996;10:938 16 Wall M Optic disk edema with cotton-wool spot Surv Ophthalmol 1995;39:5028 17 Lee AG, Beaver HA Acute bilateral optic disk edema with a macular star figure in a 12-year-old girl Surv Opthalmol 2002;47:429 18 Bock KD Regression of retinal vascular changes by antihypertensive therapy Hypertension 1984;66 Pt 2: III15862 19 Wong TY, Klein R, Couper DJ, et al Retinal microvascular abnormalities and incident stroke: the Atherosclerosis Risk in Communities Study Lancet 2001;358:113440 20 Browning AC, Mengher LS, Gregson RM, Amoaku WM Visual outcome of malignant hypertension in young people Arch Dis Child 2001;85:4013
prognosis, into 2 categories: nonmalignant and malignant hypertension15 Nonmalignant findings include arteriolar narrowing and arteriovenous nicking; malignant findings consist of hemorrhages, hard exudates, cotton-wool spots, and optic disc edema Hard exudates in the macula would suggest diabetic retinopathy versus hypertensive retinopathy in which the hard exudates would more likely appear in the peripheral retinal around a macroaneurysm Optic disc edema can be caused by other conditions eg,
increased intracranial pressure; however, the presence of cotton-wool spots is highly suggestive of malignant hypertension as the etiology of disc edema16,17 In the case of malignant hypertension, optic disc edema is caused by ischemic optic neuropathy16 Papilledema develops within days to weeks of increased blood pressure and resolves within weeks to months following lowering of blood pressure Retinal vascular abnormalities, such as arteriolar narrowing and arteriovenous nicking, are irreversible long-term markers of hypertension These nonmalignant hypertensive retinal vascular changes persist long term even after successful antihypertensive therapy18 Retinal vascular abnormalities are useful risk indicators for cerebrovascular disease and stroke19 Early detection of malignant hypertension is essential in reducing the likelihood of permanent visual damage20 Malignant hypertensive retinal changes such as papilledema, cotton-wool spots, and hemorrhages resolve if blood pressure is well controlled18 Malignant hypertensive retinal changes are likely findings in patients in hypertensive crisis, which is an abrupt elevation in blood pressure with a systolic blood pressure of greater
than 210 mm Hg and a diastolic blood pressure of more than 120 mm Hg Ischemic optic neuropathy is a common cause of visual loss Hypertension is the most frequently reported underlying disease Ischemic optic neuropathy is a direct complication of hypertension, which affects the small arterioles supplying the anterior part of the optic nerve Patients with ischemic optic neuropathy frequently report blurred vision, and funduscopic examination reveals optic disc edema CONCLUSION Hypertension and diabetes are commonly encountered systemic diseases in primary care A thorough eye examination can uncover retinal manifestations of these disease processes and thus prevent further damage leading to visual impairment A basic understanding of these common retinal manifestations is essential in primary care HP
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