Disseminated tuberculosis presenting as irido-ciliary granuloma in an immunocompetent patient

Abstract

Dear Editor,The diagnosis of extra-pulmonary tuberculosis can be chal-lenging, even in highly endemic countries. We report a caseof irido-ciliary granuloma, where initial screening for TBwas negative, but further investigations revealed multipleorgan involvement with acid-fast bacillus (AFB), confirmedas Mycobacterium tuberculosis (MTB) by polymerase chainreaction (PCR).Case report A17-year-oldboypresentedwithreducedvisionin the right eye for 2 months. Best corrected visual acuity(BCVA)wascountingfingers2mand6/6intherightandlefteyes, respectively. Intra-ocular pressures were in the right18 mmHg and left 16 mmHg. Slit lamp examination of theright eye showed mutton fat keratic precipitates and multipledensely vascularized granulomatous lesions on the anteriorsurface of iris that seemed to arise from angle of anteriorchamber (Fig. 1a). A vascularized scleral nodule, with sur-rounding ciliary congestion, was noted near the inferior lim-bus. The right fundus was not visible. The left eye showedoptic disc edema, but no other inflammatory signs. B scanultrasonography of the right eye showed disc edema, but notchoroidalthickeningorvitreousechoes.Ultrasoundbiomicro-scopy of the right eye showed the iris lesion extending intociliary body and then onto sclera (Fig. 1b).Systemic examination revealed left submandibular lymph-adenopathy(non-tender,matted,rubberyconsistency;Fig.1c).Based on the above findings, we diagnosed irido-ciliary gran-uloma with scleral extension in the right eye, associated withcervical lymphadenopathy of likely tubercular aetiology, andprobable raised intracranial pressure. However, the tuberculintest was negative (4 mm induration with 5TU) and chestradiogram was normal. Fine needle aspiration cytology of thesubmandibular lymphnodeshowed mixed population of reac-tivelymphoidcellswithscatteredhistiocytesandplasmacells.There was no evidence of epithelioid granulomas or caseousnecrotic material. Ziehl–Neelsen stain was negative for AFB.We therefore biopsied the scleral nodule that revealed well-formedgranulomascomposedofep ithelioidhistiocytes,chroniclymphomononuclear cells and plasma cells and on 20 % acid-fast staining showed scattered AFB in the tissue (Fig. 1d). PCRshowed positive for MTB with three different gene targets(IS6110, MPB64 and protein B).Subsequently,computedtomography(CT)ofheadshowedmultiple ring enhancing lesions in the brain parenchyma(Fig. 1e). CT thorax showed a small non-cavitatory lesionin the left lung (apical lobe, Fig. 1f). Sputum tested positivefor AFB. ELISA for HIV was negative. Based on neurolo-gist’s recommendation, we initially treated the patient withintravenous dexamethasone (to reduce risk of paradoxicalworsening of brain lesions) for 3 days, followed by five-drug ATT (anti-tubercular therapy —isoniazid, rifampicin,ethambutol,pyrazinamideandstreptomycin)andoralcortico-steroids(1mg/kg/day,tapered).Irido-ciliarygranuloma,opticdiscedema and cervicallymphadenopathy gradually resolvedover the next 2 months (Fig. 1g). BCVA of the right eyeimproved to 20/60. Thereafter, ATTwas changed to isoniazidandrifampicinforanother7months—rightBCVAwas20/50,andirislesionshadcompletelyresolvedwithminimalresidualfibrosis.Comment Disseminated TB refers to involvement of twoor more non-contiguous sites and is commonly associatedwith immune-compromised state [1]. This case illustrateswidespread dissemination of MTB (lung, eye, brain andlymph nodes) in animmunocompetent patient thatpresented