Rare presentation of definitive ocular tuberculosis in an immunocompetent young patient

Abstract

Ocular tuberculosis is not uncommon ocular presentation in our community nowadays. Rare presentations described mainly in the immunocompromised patients. The diagnosis of ocular TB is presumed in the vast majority of the cases of the intraocular TB. We are presenting a very rare presentation of definitive intraocular TB in a healthy 24-year-old male.

1. Introduction

Tuberculosis (TB) is one of the major systemic diseases causing mortality and morbidity in developing countries. However, migration from these countries to developed countries, widespread drug abuse, predisposition of AIDS patients to the mycobacterial infections, and development of multiple drug-resistant strains of the pathogen have aroused interest throughout the world (Bodaghi and LeHoang, 2000; Sarvanantthan et al., 1998). TB may affect any ocular or orbital tissue with diverse clinical manifestations, either by an active infection or an immunological reaction, related to delayed hypersensitivity and an aseptic reaction (Bodaghi and LeHoang, 2000). The ocular manifestation of tuberculosis are diverse and depend on the immunological, bacteriological, and epidemiological variables (Dunn et al., 1996). Individuals with compromised immune status usually present with atypical presentations (Helm and Holland, 1993). Here we report a case with a large ciliary body and limbal lesion diagnosed as a definitive intraocular TB.

2. Case report

A healthy 24-year-old male, presented to the emergency room with a history of redness and gradual loss of vision in his right eye for one year duration. There was no history of any medical illness or ocular surgery or trauma. His youngest brother (2 years old) died recently because of chronic cough. Ocular examination of the right eye revealed VA 20/70, IOP 17 mmHg, large limbal lesion with anterior synechiae, mutton fat keratic precipitate, +3 cells reaction in the anterior chamber, and vitritis (Fig. 1). Left eye examination was unremarkable with 20/20 VA.

Figure 1.

Limbal mass (TB granuloma).

B-scan ultrasound of the posterior segment of the involved eye showed only vitreous haze, UBM ultrasound showed large mass arising from the ciliary body and involving the limbus and the sclera (Fig. 2). PPD skin testing was positive with 11 mm induration, CT chest showed lesions typical of pulmonary tuberculosis.

Figure 2.

(a and b) Ciliary body involvement by TB granuloma.

The limbal mass was excised with sclera patch graft, the histopathological study of the scleral biopsy showed acid-fast bacilli, the cultures from the mass have grown mycobacterium tuberculosis, also the PCR testing for the samples was positive for mycobacterium tuberculosis.

We investigated this patient thoroughly for his immune status including HIV screening and he was immunocompetent. We started him on full anti-TB treatment with systemic and topical steroids.

3. Discussion

Tuberculosis is the leading infectious cause of morbidity and mortality worldwide (Maher and Raviglione, 1999; Dye et al., 1999). Although ocular complications are less common than systemic involvement but still well recognized (Biswas and Badrinath, 1995–96; Rosenbaum and Wernick, 1990). Virtually any ocular tissue and ocular adnexa may be affected by TB, intraocular inflammation includes mutton- fat keratic precipitates, iris granulomas, posterior synechiae, vitritis, vasculitis, retinal ischemia, macular edema choroidal tubercles, retinal involvement, endophthalmitis, and panophthalmitis (Bodaghi and LeHoang, 2000; Scheu et al., 2001), of these presentations the most common clinical findings of intraocular TB are solitary or multiple choroidal nodules, choroiditis and retinal vasculitis (Rosen et al., 1990; Ishihara and Ohon, 1998; Cangemi et al., 1980; Biswas et al., 1995). Individuals with compromised immune status usually present with atypical presentations (Helm and Holland, 1993; Rajesh et al., 2006). The patient we are presenting is immunocompetent which makes this type of presentation very rare. Tuberculoma in the sclera is a rare presentation of ocular tuberculosis with very few reports in the literature (Biswas et al., 1995). The diagnosis of ocular tuberculosis is often problematic (Bodaghi and LeHoang, 2000; Helm and Holland, 1993). There are no specific findings for ocular TB, culture or direct histopathological examination of the infected tissue can provide definitive proof of ocular infection (Sarvanantthan et al., 1998; Biswas et al., 1995; Bowyer et al., 1999) but is often impractical given the risks of intraocular biopsy, particularly in the setting of active inflammation. In typical presentation, TB is usually included in the differential diagnosis but the challenge is to recognize the atypical presentations, which are not uncommon nowadays and can only be picked up with an index of suspicion. The diagnosis of ocular TB is presumptive in majority of the cases in the literature (Bodaghi and LeHoang, 2000). Definitive diagnosis relies on demonstration of tubercle bacilli. The widely accepted approach to the diagnosis of ocular TB is based on the clinical findings consistent with TB, positive tuberculin skin testing, and absence of any other systemic disease to account for ocular signs (Bodaghi and LeHoang, 2000; Morimura et al., 2002). Diagnosing ocular TB is especially important, as TB is one of the few causes of uveitis with a definitive effective treatment and where the standard treatment of uveitis with steroids in the absence of anti-TB treatment could by sight or life threatening. The case we are presenting is from the rare situations where uveitis and ciliary body granuloma having an associated extension to the ocular surface (sclera) where biopsy could be taken for a definitive diagnosis of ocular TB rather than presumptive type of diagnosis.