Chapter 23: Hypertensive Retinopathy

PATIENT STORY

A 37-year-old man comes in for a physical examination and is noted to have a blood pressure of 198/142 mm Hg. He has no symptoms at the time. The physician performs a dilated funduscopic examination and notes optic disc edema, cotton wool spots, flame hemorrhages, dot-blot hemorrhages, arteriovenous nicking, and exudates (Figure 23-1). Fortunately, the remainder of the neurologic exam and the ECG are normal. The patient is sent to the emergency department to be evaluated further and treated for a hypertensive emergency.

INTRODUCTION

Hypertensive retinopathy (HR) develops from elevated blood pressure. HR is diagnosed clinically by the presence of classic retinal findings seen on funduscopic examination or digital retinal photographs in a patient with hypertension. HR can result in vision loss. Treatment is control of blood pressure.

EPIDEMIOLOGY

• Prevalence of 7.7% (black) versus 4.1% (white) in a population study of men and women between 49 and 73 years of age without diabetes.¹

• Patients with moderate HR are 2 to 3 times more likely to have a stroke than those without HR at the same level of blood pressure control independent of other risk factors.²

ETIOLOGY AND PATHOPHYSIOLOGY

High blood pressure results in these retinal findings³:

• Retinal vessels become narrow and straighten at diastolic blood pressure (DBP) of 90 to 110 mm Hg.

• Arteriovenous "nicking" (white oval in Figure 23-1) occurs when the arteriolar wall enlarges from arteriosclerosis, compressing the vein. Patients with hypertension are at risk for central and branch retinal vein occlusions, which can result in significant vision loss.

• Microaneurysms and flame hemorrhages (Figures 23-1 and 23-2) result from the increased intravascular pressure. Cotton-wool spots (dashed arrow in Figure 23-2) represent ischemia of the nerve fiber layer. Hard exudates indicate vascular leakage (white arrowheads in Chapter 22, Figure 22-1).

• DBP 110 to 115 mm Hg causes leakage of plasma proteins and blood products resulting in retinal hemorrhages and hard exudates (Figures 23-1, 23-2, 23-3, 23-4).

• Optic nerve swelling occurs at DBP of 130 to 140 mm Hg (Figure 23-3).