SN3 SHORT NOTE 5M ★ High-yield

Describe ocular tuberculosis and sarcoidosis.

Ophthalmology · 3rd Professional

Tuberculosis is among the most important causes of uveitis in INDIA, accounting for a substantial proportion of cases, and it must be considered in every granulomatous, chronic or recurrent uveitis
Mechanism — either direct infection by haematogenous spread of Mycobacterium tuberculosis, or a hypersensitivity response to tubercular protein without viable organisms in the eye. The two require different treatment in principle, and cannot reliably be separated in practice — which is the central difficulty of the subject
Ocular tuberculosis is frequently isolated: the chest radiograph is often normal and there may be no systemic symptoms at all, so a normal chest film does not exclude it

Manifestation	Features
Anterior uveitis	Chronic granulomatous iridocyclitis with mutton-fat KPs, Koeppe and Busacca nodules, broad posterior synechiae and iris granulomas
Choroidal tubercles	Small, discrete, yellowish-white choroidal lesions, at the posterior pole, seen in miliary tuberculosis — and their presence is a valuable bedside sign of disseminated disease.
Choroidal tuberculoma	A large solitary subretinal mass with exudative detachment.
Serpiginous-like choroiditis	Multifocal choroiditis spreading in a serpiginoid manner.
Retinal vasculitis — EALES disease	An idiopathic obliterative periphlebitis of young adult males, characteristically in INDIA, widely attributed to hypersensitivity to tubercular protein. Presents with recurrent vitreous haemorrhage and floaters; progresses through inflammation, ischaemia and neovascularisation to tractional detachment. Treated with steroid in the inflammatory stage, laser photocoagulation to ischaemic retina, and vitrectomy for non-clearing haemorrhage
Others	Scleritis, interstitial keratitis, orbital and lacrimal gland involvement, and optic neuropathy

Sarcoidosis is a multisystem non-caseating granulomatous disease of unknown cause; the eye is involved in 25 to 50%, and uveitis may be the presenting feature
Ocular features — granulomatous anterior uveitis with mutton-fat KPs and iris nodules; candle-wax drippings (taches de bougie) — segmental perivenous exudates along the retinal veins, which are characteristic; vitreous snowballs in a "string OF pearls"; multifocal choroiditis; optic disc granuloma; and conjunctival nodules, which are easily biopsied and give a high yield
Systemic features — bilateral hilar lymphadenopathy, pulmonary infiltration, erythema nodosum, lupus pernio, arthralgia, hypercalcaemia, and cranial nerve palsy

Think of tuberculosis in every granulomatous uveitis in India, and do not be reassured by a normal chest radiograph; ocular disease is frequently isolated
Examine the fundus in suspected miliary tuberculosis; choroidal tubercles are a quick bedside confirmation of disseminated disease
Give steroid alongside antitubercular therapy, not instead of it; the hypersensitivity component worsens paradoxically when the organisms are killed

All questions in Diseases of the Uveal Tract