Retinal vein thrombosis

Published on 02/04/2015 by admin

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Last modified 22/04/2025

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205 Retinal vein thrombosis

Instruction

Examine these patient eyes, including the fundus.

Salient features

History

• Age: central retinal vein occlusions arise in 0·1–0·4% and branch retinal vein occlusions in 0·6–1·1% of adults aged ≥40 years

• Branched retinal vein occlusion: decreased vision, floaters suggest vitreal haemorrhage

• Central retinal vein occlusion: loss or decreased vision, headache (associated increase in intraocular pressure), floaters

• History of hypertension, diabetes, glaucoma, multiple myeloma or macroglobulinaemia.

Examination

Patient 1

Central retinal vein occlusion (Fig. 205.1), the occlusion is behind the cribriform plate:

• Multiple retinal and preretinal haemorrhages surround the optic nerve head. there is marked dilatation and tortuosity of the veins, hyperaemia or oedema of the nerve head and soft exudates: ‘blood and thunder’ appearance

• Visual acuity is only slightly reduced.

Fig. 205.1 Central retinal vein thrombosis.

Patient 2

• Branch vein occlusion (Fig. 205.2), the occlusion is in front of the cribriform plate:

• Occlusion occurs just distal to the arteriovenous crossing and haemorrhages can be seen surrounding the occluded vein; the superior temporal vein is most commonly involved

• May cause a quadrantic field defect.

Fig. 205.2 Branch retinal vein thrombosis.

For both patients, proceed as follows:

• Tell the examiner that you would like to check for the following conditions:

• Diabetes (urine sugar)

• Hypertension (participants with hypertension were five times more likely to have a branch retinal vein occlusion than those without hypertension)

• Chronic simple glaucoma

• Hyperviscosity syndromes (Waldenström’s macroglobulinaemia, multiple myeloma)

• Haematological syndromes: hyperhomocysteinaemia, anticardiolipin antibodies, protein S and C deficiencies, activated protein C resistance, and factor V Leiden mutation.

Diagnosis

Patient 1 has multiple retinal haemorrhages (lesions) caused by central retinal vein occlusion with underlying diabetes mellitus (aetiology).

Patient 2 has branch vein occlusion (lesion). (Note: Visual prognosis is good if the haemorrhages do not extend to the macula with accompanying macular oedema.)

Advanced-level questions

What are the usual sites of occlusion in branch retinal vein occlusion?

• At arteriovenous crossings, causing classical quadrantic or small macular occlusions

• Along the main veins, as in diabetes mellitus

• At the edges of the optic disc, resulting in occlusion of the hemisphere

• Peripherally, as in sickle cell disease.

What are the vascular responses to retinal vein occlusion?

• Dilatation of retinal capillaries

• Abnormal vascular permeability

• Retinal capillary closure.

What is the prognosis in branch retinal vein occlusion?

It varies from complete resolution with no residual visual deficits to a progressive deterioration resulting in permanent loss of vision.

What is the clinical course in central retinal vein occlusion?

• In mild cases, there is minimal dilatation of veins and haemorrhages with little or no oedema of the macula and no visual deficit.

• In severe instances, the vision may deteriorate to hand motions, with extensively deep and superficial haemorrhages with stagnation of blood in the markedly dilated veins and several cottonwool spots.

What are the complications of central retinal vein occlusion?

These include macular oedema, neovascularization of the retina, rubeosis iridis (usually visible by 1 month) and rubeotic glaucoma (usually by 3 months). Ophthalmic follow-up is needed to diagnose and prevent the two main complications of retinal vein occlusion: neovascularization and macular oedema.

How would you manage such eyes?

• Treat the underlying condition

• Fluorescein angiography to determine areas of retinal ischaemia

• Regular follow-up by the ophthalmologist as secondary neovascularization is a common sequel and may need laser therapy. Panretinal photocoagulation prevents the dreaded complications of neovascular glaucoma.

Randomized clinical trials have demonstrated that prophylactic panretinal laser treatment does not necessarily prevent neovascularization in ischaemic vein occlusions, and that laser treatment can be withheld unless the patient develops frank ocular neovascularization. Whereas, focal oedema from branch retinal vein occlusion, but does not seem to benefit macular oedema associated with central retinal vein occlusion.

What is the role of arteriovenous crossing sheathotomy?

Arteriovenous crossing sheathotomy is commonly used as an adjuvant to pars plana vitrectomy. Branch retinal vein occlusion typically occurs at arteriovenous crossings, where the artery and vein share a common adventitial sheath. Cutting the sheath around the vessels and physically separating them where they cross should improve blood flow through the vein.

Further reading

Weinstein R, Mahmood M. Case 6–2002: a 54-year-old woman with left, then right, central-retinal-vein occlusion. N Engl J Med. 2002;346:603.

JG Waldenström (1906–1996), Professor of Medicine, Uppsala University, Sweden.

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