Acute Hypertension: Cotton Wool Spots, Optic Disc Edema
Cotton wool spots
These reflect microinfarcts of the retinal nerve fiber layer caused by fibrinoid occlusion of nutrient arterioles. They are usually found within a few disc diameters of the optic disc.
Vision is not affected unless the tiny infarcts are very numerous or located near the fovea.
Optic disc edema
Swelling of the optic nerve head is usually a sign of acute and very high blood pressure (diastolic pressures above 120 mm Hg). In the early phases, the edema reflects leakage of optic disc arterioles; vision is probably normal. If the blood pressure is not normalized, the disc vessels may become occluded and infarct the optic disc. Then vision fails permanently.
By the way, optic disc edema alonewithout cotton wool spots in the retinais not a sign of malignant hypertension. Think of other causes such as giant cell arteritis or optic neuritis.
What to do?
Finding a combination of optic disc edema and retinal cotton wool spots and hemorrhages is highly suggestive of severely elevated blood pressure. But be careful about normalizing it too quicklythat can cause infarction of the optic disc.