Retinal Vasculitis

B.K.S. Pannu, Rajeev Gupta & Sunandan Sood
(Department of Ophthalmology, Govt. Medical College, Sector 32-B, Chandigarh.)

Introduction
Retinal vasculitis is a sight threatening inflammatory eye disease affecting the retinal vasculature. It may present as a:-

a. Periphlebitis: when veins are affected

b. Periarteritis: when arteries are affected or

c. Angitis: as a combination of both

More common picture is that of periphlebitis

Clinical Presentation
Patients may present with mild to moderate blurring of vision, floaters or sudden decrease of vision due to vitreous haemorrhage. Vasculitis is usually detectable in about fifty percent of eyes showing significant cells, flare and exudates in the vitreous body. Anterior segment reaction is mild, although condition where concomitant ocular inflammation is present keratic precipitates andposterior synechiae may occur. Posterior segment findings show a vitirits, which is always more marked than the anterior reaction. Vascular sheathing is diagnostic and may be associated with other features like vascular occlusions, intra-retinal haemorrhage, neo-vascularization and vitreous haemorrhages. The condition is usually bilateral with the features being more prominent in one eye.

Aetiology
Although the underlying clinico-pathological process of inflammation and damage to the blood vessels is same, aetiology may vary.

1. Infective aetiology: Tuberculosis, Syphilis, viral, CMV retinitis, HIV, toxoplasmosis

2. Systemic disease : Sarcoidosis, Behcet's disease, Systemic lupus erythematosus, Wegner's granulomatosis, Polyarteritis nodosa

3. Ocular inflammatory disease : Pars planitis, Birdshort retino choroidopathy

4. Isolated retinal vasculitis/Primary retinal vasculitis : Eales disease, a common form of idiopathic primary periphlebitis seen in India may also be considered to represent a similar disease process

5. Idiopathic retinal vasculitis with aneurysms and neuroretinitis (IRVAN)

1. Tubercular vasculitis : In India, the most common infective aetiology responsible for retinal vasculitis is tuberculosis. The usual presentation is either of a focal periphlebitis or of a severe periphlebitis with marked perivenous cuffing and accompanying vitritis. As a result of excessive exudation candle wax drippings or periphlebitic nodules may be seen along the vessels. Snowball opacities may be present in the vitreous. Progression of the disease results in complications like vascular occlusions, intra-retinal haemorrhages, neovascularization and vitreous haemorrhage. Tuberculosis has also been implicated in the aetiology of Eales disease, an entity to be discussed separately. Syphilis is a great mimicer, but the vasculitis may be associated with a patch of accompanying retinitis.

2. Eales disease : It is an idiopathic obliterative vasculopathy that usually involves the peripheral retina of young adults, with a peak age of onset between 20-35 years. Bilateral involvement is evident in 80-90% of patients. Vascular sheathing, tortuosity, with adjacent nerve fibre haemorrhages is seen in most patients. The sheathing manifests as thin white lines limiting the blood column on both sides. Heavy exudative sheathing can cause vascular occlusion. Although, primarily the veins are affected, some reports have shown the same prevalence for both venules and arterioles. Anterior chamber may also show some cells and flare with keratic precipitates, but vitreous cells are often seen, even in absence of vitreous haemorrhage. Macular oedema if seen with vascular sheathing is usually cystoid in nature.

Branch vein occlusion (BRVO) in presence of Eales disease can be differentiated from isolated BRVO in presence of Eales disease by the more extensive peripheral involvement in Eales disease. BRVO alone is usually confined to a single affected quadrant and respects the anataomical distribution of the horizontal raphe, unlike Eales disease. New vessels at the disc and elsewhere have been reported in upto 80% of patients with Eales disease.

Systemic abnormalities reported in association with Eales disease are mostly neurological. Myelopathy, ischemic stroke, hemiplegia and multifocal white matter abnormalities have been reported. A higher incidence of vestibulo-auditory dysfunction is seen in patients with Eales disease as compared to the general population of the same age group. It is presumed that a similar mechanism of vascular occlusion and hypoxia leads to these systemic findings.

Actiology of Eales disease is unknown, and is thought to be idiopathic. No causative drugs, environmental factors or infectious agents have been identified. Although a hypersensitivity to tuberculin protein has been reported, no clear relationship to tuberculosis has been found. The association of Eales disease with both ocular inflammation and sensitivity to tubercular protein suggests that this disease may be associated with immunologic phenomenon whose mechanism is still unknown.

C Isolated Retinal Vasculitis : Inflammation of the retinal vasculature in absence of an infective etiology, underlying systemic disease or a concomitant ocular disease is termed as primary retinal vasculitis.

In these patients the most prevalent finding is sheathing of the peripheral retinal vessels. Neovascularization, intra retinal haemorrhaze, vascular occlusions and vitreous haemorrhage are also seen as a sequelae to the condition. In isolated retinal vasculitis there is a particular association between peripheral vascular sheathing, macular edema and diffuse capillary leakage.

Since Eales disease is also a diagnosis of exclusion and a form of primary periphlebitis like isolated or primary retinal vasculitis, it becomes hard to separate the two entities. But, currently Eales disease is considered to effect multiple quadrants of the retina with progression of capillary drop out from periphery towards the posterior pole, and more over increased frequency of vestibuloauditory findings are seen in patients of Eales disease. While most of the patients of primary retinal vasculitis have diffuse vasculins and capillary drop out of both peripheral and central retina. However, without a clear understanding of the pathophysiology of these two entities, it is certainly possible that they represent a continuation of a similar disease process. In these patients only basic investigations should be ordered. Usually in the absence of an underlying systemic disease and concomitant ocular disease, these patients are subjected to extensive diagnostic evaluations without any reward. HIV testing should be considered in patients of isolated retinal vasculitis.

D Pars planitis : Aetiology of pars planitis remains obscure, although occasional association with diseases like tuberculosis, sarcoidosis or multiple sclerosis has been seen. The condition is bilateral in 80% of patients. Though at presentation one eye is symptomatic the fellow eye usually has signs of the disease. On examination of vitreous cavity there are numerous snow ball opacities, cells and debris. Posterior vitreous detachments are common. The snowball opacities are usually pre-retinal and concentrated inferiorly. Exudation over the pars plana in form of inferiorly located snow bank is the hall mark of the disease. Periphlebitis is patchy and peripheral. Common cause for decreased vision is cystoid macular edema.

i. Serous form : Pars plana not involved;
ii. or Infiltrative form: Gray or white spots seen over pars plana.

Investigations

A  Lab investigations

1. Basic : Chest X-ray, Mantoux test, ESR, VDRL. These basic tests are carried out in all patients, especially keeping in mind the comparative higher infective aetiology of vasculitis secondary to tuberculosis or syphilis in our country.

2. Selective : These are to be considered if there is a positive medical history of an underlying disease.

For Collagen vascular disease	For infections disease
RH factor	Toxoplasma serology
ANA	CMV serology
Anti-DNA	FTA-ABS
C-reactive protein	Complete blood count
LE cells	Serum chemistries
	Serum ACE
	Elisa for HIV

Molecular Biologic Techniques : Recently polymerase chain reaction has been used to determine the DNA of the infective organisms specially in cases of presumed ocular tuberculosis without any systemic association.

B Ophthalmic Investigations

i. Visual acuity
ii. Setlamp examination
iii. Indian Ophthalmology
iv. Fundus fluorescein angiography

It is to be carried out where ever indicated. FFA shows leakage of dye from the affected vessels and late staining of vessels. The leakage may be focal or diffuse. It also helps in identifying areas of capillary non-perfusion and neovascularization. Early CME changes can also be appreciated. In patients, where photocoagulation is to be carried out, FFA helps in monitoring the progress.

Treatment

1. To treat the underlying systemic or infective aetiology if identified

2. To reduce inflammation

3. To prevent proliferative retinopathy

4. To clear visual axis and to salvage maximum vision if proliferative retinopathy develops

1. Specific treatment : ATT is given when tuberculosis is the underlying aetiology. Positive PCR testing for M. tuberculosis in a vasculitis patients is an indication for starting ATT. These patients when given ATT show resolution of inflammation without any recurrence. In cases of Eales disease with acute phlebitis and massive infilteration, nodule formation and complete obliteration of segments of veins, ATT is administered.

2. Corticosteroids : They are the main stay of treatment in patients of Eales disease/primary retinal vasculitis or those with underlying systemic inflammatory disease. oral steroids, eg. Prednisolone upto 2mg/kg body wt. is given initially and later tapered off depending upon the response. Periocular depot steroids are given as posterior sub-tenon injections in cases of active retinal vasculitis.

3. Other durgs : Azathioprine can be used in patients of vasculitis where the disease remains uncontrolled despite appropriate treatment with steroids. After azathioprine therapy, alongwith steroids, decreased relapse rate of retinal vasculitis has been noted. FK 506 has also been used in patients of Behcet's disease and idiopathic vasculitis.

4. Photocoagulation : Scatter treatment of areas of neovascularization has been found to have beneficial effects in patients. Regression of neovessels has been noted in 80% patients of Eales disease after photocoagulation.

5. Vitrectomy : Main indications are unresolving vitreous hemorrhage, tractional retinal detachment threatening the macula, multiple vitreous membrane, in presence or absence of tractional retinal detachment and combined tractional and rhegmatogenous retinal detachment.

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