Retinal Vasculitis

What is retinal vasculitis?

The retina has its own network of small arteries and veins. In retinal vasculitis, immune cells cluster around and inside these vessel walls. On examination, the eye doctor sees white sheathing or "cuffing" along the vessels, sometimes with hemorrhages, cotton-wool spots and inflammatory cells floating in the vitreous gel.

It is usually part of posterior or intermediate uveitis. It can affect:

• Veins mostly (periphlebitis): the most common pattern, seen with sarcoidosis, MS, TB and Eales disease
• Arteries mostly (arteritis): seen with lupus, viral retinitis and Susac syndrome
• Both: typical of Behçet's disease

The inflammation can make vessels leak fluid (causing swelling of the macula) or close off completely (occlusive vasculitis), starving areas of retina of oxygen. Starved retina releases growth signals that cause fragile new vessels to grow, which can bleed.

Symptoms

• Floaters: dots, cobwebs or strands drifting across vision
• Blurred or hazy vision
• Blind spots or patchy vision, or reduced side vision
• Distortion if the macula swells
• Sudden vision loss from vessel blockage or bleeding into the eye
• Sometimes eye redness, pain or light sensitivity if the front of the eye is also inflamed

Many cases affect both eyes, though often unevenly. Mild peripheral vasculitis may cause no symptoms and be found on a routine exam.

Causes

Systemic inflammatory diseases

Infections

Infection must be excluded before treating with steroids, which can make an infection much worse.

• Tuberculosis (and Eales disease, a vein-predominant occlusive vasculitis in young adults, often linked to TB exposure)
• Syphilis
• Toxoplasmosis
• Viruses: herpes simplex, varicella zoster (acute retinal necrosis), cytomegalovirus in people with weakened immunity
• Others: Lyme disease, Bartonella (cat scratch disease), rickettsial infections

Other causes

• Medicines: rare reactions to some eye injections and other drugs
• Idiopathic: no cause is found in a substantial share of cases, sometimes as an isolated eye disease

How it is diagnosed

1. Dilated eye exam with a slit lamp and ophthalmoscope to see vessel sheathing, hemorrhages and vitreous inflammation.
2. Fluorescein angiography: a dye is injected into an arm vein and photographed as it passes through the retinal vessels. It shows leakage from inflamed vessels and areas where vessels have closed. Wide-field imaging captures the far periphery, where disease often starts. This is the key test for retinal vasculitis.
3. Optical coherence tomography (OCT): checks for macular swelling.
4. Workup for the cause, guided by symptoms: - Blood tests: syphilis serology, TB blood test (interferon-gamma release assay), ACE and lysozyme for sarcoidosis, ANA, ANCA, antiphospholipid antibodies, HLA-B51 or HLA-A29 - Chest X-ray or CT for sarcoidosis and TB - Brain MRI if MS or Susac syndrome is suspected - Eye fluid sampling (PCR) if viral or parasitic infection is suspected

Treatment

Treatment is usually shared between a uveitis or retina specialist and a rheumatologist or infectious disease doctor.

Infectious retinal vasculitis

Specific antibiotics, antivirals or antiparasitic drugs, sometimes with steroids added once the infection is controlled.

Noninfectious retinal vasculitis

• Corticosteroids: oral, injected around or into the eye, or as long-acting implants, to bring inflammation under control quickly.
• Steroid-sparing immunosuppressants: methotrexate, mycophenolate, azathioprine or cyclosporine, to allow steroids to be reduced.
• Biologic drugs: TNF inhibitors such as adalimumab or infliximab, particularly effective in Behçet's disease and refractory uveitis.
• Treating the systemic disease in coordination with other specialists.

Treating complications

• Laser photocoagulation to areas of retina without blood supply, to prevent or shrink abnormal new vessels
• Anti-VEGF injections for new vessels or macular swelling
• Vitrectomy for non-clearing vitreous hemorrhage or traction on the retina

Complications

• Macular edema, the commonest cause of reduced vision
• Retinal vein occlusion or artery occlusion
• Abnormal new vessels and bleeding into the vitreous
• Tractional retinal detachment
• Neovascular glaucoma
• Cataract and glaucoma from inflammation or long-term steroids

Outlook

Outlook depends on the cause, how much retina is starved of blood, and how quickly treatment starts. Mild, nonocclusive vasculitis often responds well. Occlusive disease, especially in Behçet's, can cause lasting vision loss, although biologic drugs have greatly improved results. Regular monitoring with angiography helps catch silent activity before vision is affected.

Frequently asked questions

What are the symptoms of retinal vasculitis?

Typical symptoms are painless floaters, blurred or hazy vision, blind spots and reduced side vision. Some people notice distorted vision from macular swelling, or sudden vision loss if a vessel closes or bleeds. Mild disease can cause no symptoms and only be found on an eye exam.

What causes retinal vasculitis?

Common causes include Behçet's disease, sarcoidosis, multiple sclerosis, lupus and other forms of vasculitis, and infections such as tuberculosis, syphilis, toxoplasmosis and herpes viruses. In many people no cause is found. Ruling out infection is essential before starting steroids.

How is retinal vasculitis treated?

Infections are treated with the appropriate antimicrobial drugs. Noninfectious retinal vasculitis is treated with corticosteroids, followed by immune-suppressing drugs or biologics such as adalimumab for long-term control. Laser and eye injections treat complications like abnormal blood vessel growth and swelling.

Can retinal vasculitis cause blindness?

It can cause serious vision loss if untreated, through macular swelling, blocked vessels, bleeding or retinal detachment. Total blindness is uncommon with modern treatment. Early diagnosis, control of inflammation and regular follow-up greatly reduce the risk of permanent vision loss.