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Severe tuberculous retinal vasculitis in healthy adults

Ocular tuberculosis may be a presenting feature of tuberculous infection, especially with extensive occlusive retinal vasculitis among Asians. Being a curable disease, awareness of its presentation and high index of suspicion are paramount as prompt treatment can halt the disease progression and prevent visual loss. We presented three cases of ocular tuberculosis in young healthy adults who presented with progressive blurring of vision with florid retinal vasculitis seen on funduscopy. Two of them were with no bacillus Calmette-Guerin scar. Fundus fluorescein angiography confirmed the presence of occlusive vasculitis with extensive area of ischemia. All cases showed a raise in erythrocyte sedimentation rate and strongly positive Mantoux tests. Pan-retinal photocoagulation was given to all patients. Two cases responded well to anti-tubercular therapy followed by oral steroids and regained normal vision in both eyes. One patient was not started on anti-tubercular therapy as he requested to return to his native country for further treatment.


Tuberculosis (TB) is among the top 5 transmissible diseases in
Malaysia and the incidence of TB in Malaysia shows an increasing trend in the last decade [1]. It is a curable infectious disease caused by the acid-fast bacillus Mycobacterium tuberculosis. TB is spread through air-droplets, when infected individuals cough or sneeze. The World Health Organization estimated that one-third of the world population is infected with Mycobacterium tuberculosis and 10% of infected people have a lifetime risk of manifesting tuberculous disease [2].
Eye involvement is an uncommon presentation of extrapulmonary TB, seen in approximately 2.8%-11.4% of patients [3]. Retinal vasculitis is the commonest manifestation of intraocular TB [4].
TB mostly affects young adults especially immunocompromised individuals due to diabetes mellitus, malnutrition, HIV infection and tobacco smokers [2]. Ocular TB, as the presenting manifestation of extrapulmonary TB in young healthy adults, is however uncommon.
We report three cases of healthy young adults with ocular signs and symptoms as the first presenting features of intraocular TB.

Case 1
A 17-year-old healthy male of Indonesian parentage, presented with 1 week history of bilateral painless progressive blurring of vision. He had no prolonged fever, cough, night sweats or recent loss of weight. There was no history of exposure to TB patients. His visual acuity was counting fingers in the right eye (OD) and 6/36 in the left eye (OS). There were anterior chamber cells of 2 + with granulomatous keratic precipitates both eyes (OU). Funduscopy revealed an infero-temporal branch retinal vein occlusion with a partial macular star exudation OD ( Figure 1A). Both fundi showed extensive retinal vasculitis with periphlebitis and intra-retinal hemorrhages ( Figure 1A Fundus fluorescein angiography confirmed the presence of occlusive vasculitis with extensive area of ischemia. All cases showed a raise in erythrocyte sedimentation rate and strongly positive Mantoux tests. Pan-retinal photocoagulation was given to all patients. Two cases responded well to anti-tubercular therapy followed by oral steroids and regained normal vision in both eyes. One patient was not started on anti-tubercular therapy as he requested to return to his native country for further treatment. 1C  (Figure 2A, B). FFA showed peripheral vasculitis with large area of capillary fall-out (OS > OD), and new vessels OS ( Figure 2C). She had a BCG scar and the chest X-ray was normal.

Discussion
The overall cases of notified TB have shown an increasing trend in Malaysia from the year 2000 to 2012 [1] despite a decline in the incidence of TB in developed countries during the last century [2]. The three cases we reported here are healthy young adults with age ranging from 17 to 24 years. Two of the patients are immigrants without BCG vaccination, potentially being at a greater risk of developing active TB [5].
It is postulated that ocular TB occurs as a result of direct haematogenous spread after a primary infection or by hypersensitivity response [6]. and extensive capillary fall-out with a mild degree of vitreous cells [6], as seen in all three cases. Case 1 highlighted the rare presentation of retinal vein occlusion secondary to tuberculous retinal vasculitis [7].
It is postulated that the antibody-antigen complex reaction leads to hypersensitivity-like responses, resulted in occlusion of blood vessels, predominantly the retinal veins. Neovascularization may complicate the large area of capillary fall-out leading to vitreous haemorrhage (case 2 and case 3) and PRP has been shown to be successful in treating and preventing this complication [6,8].
The three reported cases here had no overt active pulmonary TB.
The diagnosis of intraocular TB was supported by the strongly positive Mantoux test which is relatively specific [9], and a raised ESR.