of Ocular Tuberculosis


Fig. 17.1

Anterior chamber color photograph showing circumcorneal congestion with chronic pigmented granulomatous keratic precipitates and iris granuloma



Intermediate uveitis of TB and sarcoidosis mimic each other as both are granulomatous and recurrent. Ciliary body tuberculoma can be demonstrated with ultrasonic biomicroscopy. Other findings include vitritis, pars plana snowballs, snow banking, peripheral granulomas, pigmented pars plana scars, and cystoid macular edema.


Posterior segment findings include focal or multifocal yellow choroidal granulomas (Fig. 17.2) or multifocal chorioretinal pigmented scars specifically along retinal vessels (Fig. 17.3) (Gupta et al. 2010). The retinitis may be seen with an associated choroiditis, although a direct retinal involvement is rare. Other signs include subretinal granuloma or abscesses, retinal vasculitis, optic neuritis, retrobulbar neuritis, neuroretinitis, optic disc granuloma, and disc edema. TB can cause serpiginous-like choroiditis (SLC) which sometimes mimic a classic serpiginous choroidopathy (SC). Tubercular SLC show multifocal, scattered, highly pigmented lesions with significant vitreous cells. Unlike classic SC, SLC do not respond to corticosteroid therapy, and inflammatory control is achieved only after anti-TB treatment (Vasconcelos-Santos et al. 2010).

../images/473014_1_En_17_Chapter/473014_1_En_17_Fig2_HTML.png

Fig. 17.2

(a) A 45-year-old woman presented with optic nerve granuloma, superficial hemorrhage, and multifocal choroidal granulomas. Her Mantoux test was necrotic positive. (b) Resolution of fundus findings and choroidal granulomas were observed after 3 months of antituberculous treatment. Edema is resolved leaving white proteinaceous material


../images/473014_1_En_17_Chapter/473014_1_En_17_Fig3_HTML.png

Fig. 17.3

Fundus photography of left eye showing healed multifocal choroiditis with highly pigmented scars along the blood vessels. Superior quadrant shows multiple hemorrhagic spots because of branch retinal vein occlusion


Rarely, an acute and robust inflammatory response may result in hypopyon in tubercular panuveitis. Yellowish subretinal abscess can rupture into the vitreous and result in endophthalmitis or panophthalmitis.


Latent TB


The term latent TB infection (LTBI) is used when an asymptomatic person presents with a positive tuberculin skin test (TST) with no clinical or radiographic signs of active TB. Usual interpretation is that they are infected but not diseased. Among these, 5–15% may progress to active disease in future when the environmental conditions are favorable. However, they cannot spread the disease to other people. Decision for prophylactic treatment for this population varies among countries.


Differential Diagnosis


Differential diagnosis includes other granulomatous uveitis such as sarcoidosis, Vogt–Koyanagi–Harada disease, sympathetic ophthalmia, herpetic infection, phaco-antigenic uveitis, syphilis, and leprosy. Other causes of choroidal granulomas include sarcoidosis, syphilis, and fungal lesions (Babu 2013; Vasconcelos-Santos et al. 2010).


Diagnostic Criteria and Laboratory Tests


Definitive diagnosis of ocular TB is possible only when the bacilli are isolated from the ocular tissues. As definitive evidence of Mycobacterium tuberculosis is rarely found in intraocular specimens, its diagnosis is usually clinical, supported by laboratory tests and favorable response to anti-tubercular therapy. The diagnosis is considered presumed ocular TB when the clinical picture is consistent with known clinical signs (broad-based posterior synechiae, retinal vasculitis with choroiditis, choroidal granuloma, or pigmented SLC) and supported by a positive tuberculin skin test or QuantiFERON TB Gold test or any other relevant anxillary tests, such as chest radiography and computed tomography. Inflammatory control after anti-tubercular treatment and absence of recurrence further supports the diagnosis of presumed ocular TB (Gupta et al. 2010).


The confirmation of etiological diagnosis of ocular tuberculosis remains a clinical challenge because of difficulty in getting a specimen from inflamed eye and paucibacillary tuberculosis. Ocular TB is diagnosed on the basis of a combination of clinical signs such as chronic granulomatous uveitis, choroidal granulomas, and multifocal pigmented chorioretinitis. Microbiological, histopathologic, or molecular evidences assist the confirmation of the diagnosis. Sometimes supportive evidences such as radiographic features (infiltrates, fibrosis, and cavitation in chest x-ray/computerized tomography (CT) chest) aid the diagnosis (Fig. 17.4).

../images/473014_1_En_17_Chapter/473014_1_En_17_Fig4_HTML.jpg

Only gold members can continue reading. Log In or Register to continue

Related posts:

  1. Ophthalmia
  2. Evanescent White Dot Syndrome
  3. Cysticercosis
  4. Scleritis

Stay updated, free articles. Join our Telegram channel
Tags:
Mar 22, 2020 | Posted by in OPHTHALMOLOGY | Comments Off on of Ocular Tuberculosis

Full access? Get Clinical Tree
Get Clinical Tree app for offline access