Abstract
Tuberculosis once thought to be the most common cause of uveitis is now thought to be a relatively rare cause of ocular disease. Due to current increase in prevalence of tuberculosis because of immunodeficiency virus syndrome, one should always take into account as a possible aetiology when dealing with cases of orbital diseases. Tuberculoprotein hypersensitivity may have a role in the pathogenesis of ocular tuberculosis. Oliveira has stressed the importance of immunohistochemistry analysis as an marker for the diagnosis of ocular Tuberculosis.

Introduction

Tuberculosis, once thought to be the most common cause of uveitis, is now thought to be a relatively rare cause of ocular disease. This is because of a decreased incidence of tuberculosis as well as a lessened emphasis on its diagnosis.

However, the global incidence and prevalence of M tuberculosis infections is under control yet, and it has been a serious public health problem. Thus one must be aware of the possibility of tuberculosis among the orbital diseases.1

Following is a case of orbital tuberculoma presenting with proptosis and gross diminution of vision in a young female is reported.

Fig. 1 : Showing left orbital swelling

Fig. 2 : Showing non ionic contrast CT scan

Case Report

Mrs B, age 28 years presented with proptosis of left eye since 1 month. Gradual onset, swelling was painless Gradual diminishing vision (Fig. 1).

O/E Physical examination revealed no systemic abnormality.

Vn = PL/PR
Ocular movements in left eye absent.
Fundus examination of left eye - Papilloedema.
10P = 30 mm Hg
Investigation : The laboratory work up includes Hb 9.2 RBC 4.0 WBC 8,900 N 70 L 30
ESR 72 mm at the end of 1 hour
Mantoux test was showing 18 x 18 mm induration and erythema.
HIV was Positive. CD 4 count was 100/c.mm
P/H pulmonary tuberculosis MDR defaulter.
X-ray skull : NAD

CT scan - Computed tomography of head confirmed the extraconal, intraorbital, hyperdense, homogeneously enhancing mass separated from lateral rectus muscle and further revealed involvement of lacrimal gland without erosion of temporal bone (Fig. 2).

Discussion

Due to current increase in prevalence of tuberculosis because of immunodeficiency virus syndrome, one should always take into account as a possible aetiology when dealing with cases of orbital diseases.2 Ocular manifestation of fungal infection (Aspergillosis) is emerging as increasingly more atypical, with a wide spectrum of presentation in immunocompromised individuals. So is tuberculosis, the index of suspicion for this infection should always be accounted in D/D of orbital diseases.3 The most common manifestation of ocular tuberculosis in patients with pulmonary tuberculosis is choroiditis. Tuberculoprotein hypersensitivity may have a role in the pathogenesis of ocular tuberculosis, both ocular and orbital tuberculosis are usually unilateral.4

However, orbital tuberculosis has been reported in individuals who did not suffer from pulmonary tuberculosis but associated tuberculosis in some other areas like tubercular sinusitis and constrictive pericarditis.5 In our case the patient had pulmonary tuberculosis with seropositivity and probable opportunistic infection. The important corroborrative evidence was obtained from computed axial tomography and detection of acid fast bacilli by staining the secretion by modified ZNCF method as well as tuberculin test was showing induration and erythema of 18 x 18 mm in diameter. Fine needle aspiration was inconclusive. It is known fact that Acid fast bacilli are difficult to detect in the pathological specimens and the diagnosis is usually based on the following:

1. The positive tuberculin test
2. The caseating granulomatous inflammatory lesion on histopathology, which is highly suggestive of active tuberculosis
3. The positive culture for mycobacterium and
4. The complete resolution of the disease. With the specific antitubercular medication.6

Oliveira et al has stressed the importance of Immuno histochemistry analysis as an marker for the diagnosis of ocular tuberculosis.5

Lastly awareness of the many faces of tuberculosis is important for the Ophthalmologist.

References

1. Oliveira B, Takey FC, et al. Orbital tuberculosis diagnosed by immunochemistry case report. Rev Inst Med Trop Sao Paulo 2004 Sep-Oct; 46,5 : 291.
2. Romero Aroca, Castro Salano et al. Tuberculous retinitis with associated peribhlebitis. Arch Soc Esp of Talmol 2004 Feb; 79,2 : 81-4.
3. Hutnik CM, Nicolle DA, Muno DG. Orbital aspergilosis A fatal masquerader. J Neuro Ophthalmol 1997 Dec; 17,4 : 257-61.
4. Helm CJ, Holland GN. Ocular tuberculosis. Surv Opthalmol 1993 Nov Ree 38,3 : 229-56.
5. Oliveira B, Takay FC, et al. Orbital tuberculosis diagnosed by immunohistochemistry: case report. Rev Inst Med Trop Sao Paulo 2004 Sep-Oct; 46,5 : 291-4.
6. Khalil M, Lindley S, et al. Tuberculosis of orbit. Ophthalmology 1985 Nov; 92,11 : 1624-7.