29th December 2023

Hypertensive retinopathy

Background & Epidemiology

Systemic hypertension is the leading modifiable risk factor for cardiovascular disease worldwide, with a global age-adjusted prevalence of 31%. Risk factors include older age, male gender, and Afro-Caribbean origin. The vast majority of cases are chronic, although ‘malignant’ hypertension may sometimes occur if there is an acute severe elevation of blood pressure associated with end organ damage. Both types may be essential (idiopathic) or secondary to other underlying causes, such as renal artery stenosis and phaeochromocytomas.

Hypertension can affect various end organs, including the heart, brain, kidney and eyes. Both acute and chronic ocular abnormalities may result. These can be classified according to the ocular structure affected: retinopathy, choroidopathy, and optic neuropathy. Risk factors for developing hypertensive retinopathy include older age, duration of hypertension, and elevated systolic blood pressure levels.

Clinical Features

The Keith-Wagener-Barker classification is one of the most common grading systems in use:

Hypertensive retinopathy presents with retinal arteriolar constriction or focal narrowing, with arteriovenous nipping, ‘silver-wiring’ of arterioles, flame-shaped haemorrhages, and cotton wool spots. Hard exudates and macular oedema may be present. Hypertensive optic neuropathy presents with optic disc swelling with or without macular star formation; disc swelling tends to reflect malignant hypertension.

Hypertensive choroidopathy may rarely occur due to malignant hypertension. This may manifest as Elschnig spots (small black spots representing focal choroidal infarcts), Siegrist streaks (streaks indicating fibrinoid necrosis along choroidal vessels), or exudative or serous retinal detachment such as that seen in some patients with pre-eclampsia.

Patients tend to be asymptomatic, except in cases where serous retinal detachment or macular oedema affect the macula. These patients may report blurred vision or scotomas.

Image Source: Wikimedia Commons (2009). Hypertensiveretinopathy, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Hypertensiveretinopathy.jpg (Accessed on: 27 May 2022).

Management

Blood pressure optimisation is key to reducing excess mortality and cardiovascular disease.

In patients with chronic hypertension, a blood pressure of < 140/90 mmHg is appropriate for the majority of patients under 80 years of age and < 150/90mmHg for those 80 years old and above. A lower target of < 130/80 mmHg is ideal for diabetic patients. The target blood pressure should be individualised according to the patient’s clinical circumstances, taking frailty and multi-morbidity into account. Management includes lifestyle changes (diet, exercise, smoking cessation) and antihypertensive treatment according to NICE guidelines.

Patients with malignant hypertension also require urgent intervention to reduce their blood pressure. However, their blood pressure should not be lowered too rapidly or significantly due to the risk of severe multi-organ dysfunction and ischaemia. Antihypertensives should, therefore, be carefully titrated to achieve this. An underlying cause should be sought and managed appropriately.