Hypertension (HTN) is a significant risk factor for cardiovascular disease and is characterized by persistently high arterial blood pressure. Long-term elevation of blood pressure can lead to end-organ damage to the eyes, kidneys, heart and nervous system.
In the eye, this is commonly seen in the form of retinopathy and can lead to retinal vascular occlusion. Hypertensive retinopathy is diagnosed based on certain fundoscopic appearances.
Malignant or accelerated hypertension is a sudden rise in blood pressure (above 180mmHg systolic and 120mmHg diastolic) which causes rapid end-organ damage. This manifests as swelling of the optic disc and a specific form of retinopathy.
Statistics show that in 2015, 31% of men and 26% of women in England had hypertension, with more than half of those over 60 years of age affected. 10% of the adult population had hypertensive retinopathy.
There are a few different types of hypertension: primary or essential (90%), secondary (caused by other medical issues), malignant or accelerated (sudden, severe increase in blood pressure), white-coat (only diagnosed during a medical consultation) and masked (only seen on home or ambulatory blood pressure measurements).
Hypertension is typically diagnosed by measuring a patient's blood pressure.
Further investigations may include tests to confirm end-organ damage (e.g. urinalysis, ECG and U&Es) and tests to determine the cause of hypertension.
HTN is the leading risk factor for cardiovascular disease and must be identified and managed appropriately.
Hypertensive retinopathy caused by chronic hypertension usually has no symptoms and is only detected on clinical examination. However, those with malignant or accelerated hypertension are usually symptomatic. Common symptoms include blurred vision, visual field defects, headache, nausea/vomiting, flushed face and sudden, painless vision loss.
Hypertensive retinopathy is a clinical diagnosis based on characteristic fundoscopic appearances.
There are numerous classification systems used to stage hypertensive retinopathy due to chronic hypertension.
The Keith-Wagener-Barker classification grades hypertensive retinopathy as follows:
Malignant hypertension typically presents with Grade 4 hypertensive retinopathy with evidence of papilloedema (optic disc swelling secondary to raised intracranial pressure).
Investigations to investigate hypertensive retinopathy can include optical coherence tomography (OCT) and intravenous fluorescein angiography (IVFA).
When considering hypertension, an important differential to consider is diabetic retinopathy due to many patients with hypertension having type one or type two diabetes mellitus. Differences between these conditions can be distinguished through clinical history and examination findings. Typical fundoscopic findings in diabetic retinopathy include microaneurysms, dot and blot haemorrhages, cotton wool spots, and neovascularisation (new vessels on the retina).
The treatment for hypertensive retinopathy primarily focuses on reducing blood pressure.
Chronic hypertension management may be split into conservative and medical management. Conservative measures include lifestyle changes (e.g. healthy diet, regular exercise, and reduced alcohol and smoking). Medical management includes oral antihypertensives (e.g. ACE inhibitors, angiotensin receptor blockers, and calcium channel blockers).
Malignant or accelerated hypertension is considered a hypertensive emergency. In a patient suspected of having this type of hypertension, same-day specialist assessment is recommended by NICE if there are signs of retinal hemorrhage and/or papilloedema on fundoscopy, life-threatening symptoms (e.g. confusion, chest pain, heart failure signs, acute kidney injury signs), etc. Medical management should be started immediately without waiting for ambulatory or home blood pressure monitoring to confirm. The aim is to reduce blood pressure over 24-48 hours, and an arterial line may be inserted to allow continuous blood pressure monitoring. Lowering the blood pressure too quickly could result in organ hypoperfusion.
Intravenous anti-hypertensives, such as nitroprusside, labetalol and nicardipine, may be used to further control blood pressure.
Fundoscopic appearances of retinal pathologies are used to identify and diagnose potential eye conditions. This article will explore three of the most commonly observed abnormalities seen through a fundoscope.
Retinal artery nipping, also known as 'arteriolar narrowing', is a condition which appears as a white crescent-shaped narrowing at the arteriovenous junction. It is a common sign of hypertensive retinopathy and is often seen in patients with high blood pressure.
Arteriovenous nipping is another sign of hypertensive retinopathy and appears as a crescent-shaped narrowing at the arteriovenous crossing. It is caused by increased vascular resistance of the retinal arterioles, which is a common feature of hypertensive retinopathy.
Acute retinal exudate is a sign of diabetic retinopathy and appears as white or gray patches of exudates located within the retina. It is caused by a disruption in the blood-retinal barrier, which is a common feature of diabetes.
These are some of the most common fundoscopic abnormalities which can be identified through a fundoscope. This article has discussed the appearance and causes of three of the most commonly observed retinal pathologies.
Hypertension increases a person's risk of other retinal vascular diseases, such as central or branch retinal vessel occlusion. This can lead to neovascularisation, vitreous haemorrhage and tractional retinal detachment. Uncontrolled hypertension can also contribute to the progression of pre-existing diabetic retinopathy.
If treated late, malignant hypertension can cause irreversible visual loss and changes, and carries a 90% mortality at one year. Most retinal changes due to malignant hypertension will improve within six months once hypertension is managed, but any arteriosclerotic changes in the retina will not regress.
