Hypertensive Retinopathy
Signs and Symptoms
The patient with hypertensive retinopathy, as expected, suffers from
hypertension. However, the hypertension may be unknown to th e patient and the eye exam
may yield the first clue to this relative asymptomatic systemic disease. Most commonly,
the patient is middle age or older. In addition, hypertension is more common in
African-Americans than Caucasians. Patients with only hypertensive retinopathy are nearly
always visually asymptomatic.
Findings in hypertensive retinopathy include cotton wool spots and flame
shaped hemorrhages. Only rarely will there be retinal or macular edema. In advanced cases,
there will be a macular star (ring of exudates from the disc to the macula) and disc
edema. Arteriolosclerosis (arteriolar narrowing, arterio-venous crossing changes with
venous constriction and banking, arteriolar color changes, vessel sclerosis) is often
found concurrently.
Pathophysiology
The findings in hypertensive retinopathy all stem from hypertension-induced
changes to the retinal microvasculature. Hypertension leads to a laying down of
cholesterol into the tunica intima of medium and large arteries. This leads to an overall
reduction in the lumen size of these vessels. In arteriolosclerosis, hypertension leads to
focal closure of the retinal microvasculature. This gives rise to microinfarcts (cotton
wool spots) and superficial hemorrhages. In extreme cases, disc edema develops. The
mechanism behind this phenomenon is poorly understood, but it may be related to a
hypertension-related increase in intracranial pressure, and hence is considered true
papilledema.
Arteriolosclerotic changes in the retinal microvasculature persist even
with the reduction of systemic blood pressure. However, hypertensive retinopathy changes
resolve over time with the reduction of systemic blood pressure (BP). Cotton wool spots
develop in 24 to 48 hours with the elevation of BP, and resolve in two to 10 weeks with
the lowering of BP. A macular star develops within several weeks of the development of
elevated BP and resolves within months to years after the BP is reduced. Papilledema
develops within days to weeks of increased BP and resolves within weeks to months
following BP lowering.
Management
Management of hypertensive retinopathy involves appropriate treatment of
the underlying hypertension. Medical co-management with the primary physician is of
paramount importance. However, if a patient presents with papilledema from hypertension,
then the patient has malignant hypertension and should be considered to be in medical
crisis. This patient needs immediate consult with a primary care physician and, most
likely, immediate transport to a hospital emergency room.
It must be reiterated, however, that there are many causes of
papilledema. Other causes of papilledema, such as an intracranial mass lesion, must also
be considered in the patient with hypertension. However, in a case where blood pressure is
extremely elevated (e.g. 250/150mmHg) and there is disc edema with a macular star,
malignant hypertension is the likely cause.
Clinical Pearls
In order for cotton wool spots to develop from
hypertension, autoregulatory mechanisms must first be overcome. For this to happen, the
patient must have at least 110mmHg diastolic readings.
Patients who develop papilledema from hypertension have
malignant hypertension and typically have BP in the range of 250/150mmHg
Fluorescein angiography is not indicated in cases of
hypertensive retinopathy as it yields no diagnostic information.
Hypertensive retinopathy presents with a ‘dry’
retina (few hemorrhages, rare edema, rare exudate, and multiple cotton wool spots) whereas
diabetic retinopathy, in comparison, presents with a ‘wet’ retina (multiple
hemorrhage, multiple exudate, extensive edema, and few cotton wool spots).
Other reports in this section
|
|
