Enhanced Depth Imaging-Spectral Domain-Optical Coherence Tomography imaging of choroidal tubercles with multiple pigment epithelial detachments in a case of miliary tuberculosis

Mudaliar Ashwini Elango; Arokiam John Bosco; S Thanikachalam; R Josephine Kavitha

doi:10.4103/IJO.IJO_2803_22

CASE REPORT

Year : 2023 | Volume : 3 | Issue : 2 | Page : 388-392

Enhanced Depth Imaging-Spectral Domain-Optical Coherence Tomography imaging of choroidal tubercles with multiple pigment epithelial detachments in a case of miliary tuberculosis

Mudaliar Ashwini Elango¹, Arokiam John Bosco², S Thanikachalam², R Josephine Kavitha³
¹ Senior Resident, Department of Ophthalmology, Indira Gandhi Government General Hospital and Post Graduate Institute, Puducherry, India
² Senior Administrative Grade, Department of Ophthalmology, Indira Gandhi Government General Hospital and Post Graduate Institute, Puducherry, India
³ Chief Medical Officer, Department of Ophthalmology, Indira Gandhi Government General Hospital and Post Graduate Institute, Puducherry, India

Date of Submission	25-Oct-2022
Date of Acceptance	09-Jan-2023
Date of Web Publication	28-Apr-2023

Correspondence Address:
Mudaliar Ashwini Elango
Senior Resident, Department of Ophthalmology, Indira Gandhi Government General Hospital and Post Graduate Institute, No: 1, Rue Victor Simmonal Street, Puducherry - 605 001
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJO.IJO_2803_22

Abstract

Choroidal tubercles in miliary tuberculosis have been rarely reported. A 65-year-old male diagnosed with miliary tuberculosis was started on antitubercular therapy (ATT) and referred for fundus screening, which revealed lesions suggestive of choroidal tubercles and pigment epithelial detachments (PEDs), confirmed by optical coherence tomography (OCT) and fundus fluorescein angiography (FFA). Choroidal tubercles were identified in Enhanced Depth Imaging-Spectral Domain-Optical Coherence Tomography (EDI-SD-OCT) as nodular hyperreflective lesions with thickening of overlying choriocapillaris– Retinal Pigment Epithelium (RPE)–Bruch's complex, myoid–ellipsoid junction disruption, and increased choroidal thickness. Choroidal thickening and PED decreased following ATT. EDI-SD-OCT is the investigative tool of choice to identify choroidal tubercles and inflammation. EDI-SD-OCT can be utilized as a biomarker in choroidal studies. PED may result due to choroidal inflammation.

Keywords: Choroidal tubercles, miliary tuberculosis, pigment epithelial detachments

How to cite this article:
Elango MA, Bosco AJ, Thanikachalam S, Kavitha R J. Enhanced Depth Imaging-Spectral Domain-Optical Coherence Tomography imaging of choroidal tubercles with multiple pigment epithelial detachments in a case of miliary tuberculosis. Indian J Ophthalmol Case Rep 2023;3:388-92

How to cite this URL:
Elango MA, Bosco AJ, Thanikachalam S, Kavitha R J. Enhanced Depth Imaging-Spectral Domain-Optical Coherence Tomography imaging of choroidal tubercles with multiple pigment epithelial detachments in a case of miliary tuberculosis. Indian J Ophthalmol Case Rep [serial online] 2023 [cited 2023 Jun 10];3:388-92. Available from: https://www.ijoreports.in/text.asp?2023/3/2/388/374991

Miliary tuberculosis is a rare fatal form of disseminated tuberculosis which constitutes 2% of all new cases of tuberculosis and approximately 20% of all cases of extrapulmonary tuberculosis.^[1] The most common intraocular manifestation of tubercular posterior uveitis includes choroidal tubercles, choroidal tuberculoma, subretinal abscess, and serpiginous-like choroiditis.^[2] Choroidal tubercles have been reported in 13% of the cases of disseminated tuberculosis.^[3] Choroidal tubercles appear as yellow to white nodules and usually are no more than five in number.^[2] We report a case of miliary tuberculosis with choroidal tubercles and multiple pigment epithelial detachments (PEDs). Our report details on the pathognomonic features of choroidal tubercles in EDI-SD-OCT.

Case Report

A 65-year-old male presented with low-grade fever and cough with expectoration for 1 month and a family history of pulmonary tuberculosis. Patient was a known diabetic for 15 years. Chest X-ray revealed mottling pattern [Figure 1]. High-resolution computed tomography (HRCT) thorax showed diffuse reticulonodular opacities in both lungs and sputum Cartridge Based-Nucleic Acid Amplification Test (CB-NAAT) positive for tubercular antigen. Sputum microscopy, Mantoux test, and human immunodeficiency virus (HIV) antibodies were negative. Contrast-enhanced computerized tomography (CECT) abdomen and magnetic resonance imaging (MRI) brain were normal. Based on these, the case was diagnosed by pulmonologist as miliary tuberculosis and antitubercular therapy (ATT) regimen was initiated.

Figure 1: Chest X-ray showing miliary mottling pattern suggestive of miliary tuberculosis

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He was referred to the ophthalmology department for fundus screening. On examination, his best corrected visual acuity was 20/30 right eye (RE) and 20/20 left eye (LE). Anterior segment examination was normal, except for posterior synechiae in the right eye, suggesting a previous attack of uveitis. On fundus examination, multiple ill-defined yellowish subretinal lesions were noted [Figure 2]a and [Figure 2]b. FFA examination of the lesions discerned early hypofluorescence and late hyperfluorescence, suggesting the lesions were choroidal. In addition to ill-defined subretinal lesions, multiple yellow orange lesions were noted [Figure 2]c, [Figure 2]d, [Figure 2]e, [Figure 2]f. Homogenous progressive pooling pattern on FFA confirmed the lesions were PEDs. Clinical fundus and FFA findings were corroborated with EDI-SD-OCT. Nodular lesions in the inner choroidal layer beneath RPE associated with elevation, thickening of the RPE–Bruch's complex, breaks in the RPE–Bruch's complex and focal loss involving the myoid–ellipsoid zone were noticed, indicative of probable choroidal tubercles [Figure 3].

Figure 2: Fundus examination revealed choroidal tubercles (yellow arrows) and PEDs (red arrows) in both eyes (a and b). FFA of RE showing hypofluorescent lesions in the early phase (c) and hyperfluorescent lesions in the late phase (d), suggestive of choroidal tubercles, and well-demarcated pooling of lesions, suggesting PEDs. FFA of LE in the early (e) and late phases (f). FFA = fundus fluorescein angiography, LE = left eye, PED = pigment epithelial detachment, RE = right eye

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Figure 3: EDI-SD-OCT revealed nodular structure in the inner choroidal layer beneath RPE, suggestive of choroidal tubercles in both eyes (a = RE, c = LE). Elevation of the RPE–Bruch's complex, focal loss involving the ellipsoid–myoid zone, and breaks in the RPE- Bruch's complex suggest inflammatory process in the choroid (magnified 2.5× = b and d). SD-OCT showing multiple PEDs in RE (e) and LE (f). LE = left eye, PED = pigment epithelial detachment, RE = right eye

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Subfoveal choroidal thickness (SFCT) was 545 μm in RE and 351 μm in LE, signifying choroidal inflammation in both eyes. PED was confirmed by EDI-SD-OCT as serous elevations beneath RPE with an average height of 57 μm in RE and 119 μm in LE.

ATT regimen consisted of isoniazid (75 mg), rifampicin (150 mg), pyrazinamide (400 mg), and ethambutol (275 mg) for 2 months followed by isoniazid (75 mg) and rifampicin (150 mg) for 4 months, along with pyridoxine (25 mg) daily. Following ATT therapy for 6 months, visual acuity and clinical findings remained same, while SFCT reduced to 476 μm in RE and 261 μm in LE and the average PED height reduced to 33 μm in RE and 95 μm in LE [Figure 4]. Reduction in SFCT and decrease in PED height denoted favorable response to ATT therapy. No adverse effect with ATT therapy was noted.

Figure 4: Fundus photographs of right eye (a) and left eye (b) at 6-month follow-up visit. Comparison of EDI-SD-OCT of initial visit and 6-month follow-up visit of right eye (c and d) and left eye (e and f), respectively, showing reduced subfoveal choroidal thickness and decreased height of PED. PED = pigment epithelial detachment

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Discussion

Choroidal granuloma in tuberculosis has been widely reported. Salman et al.^[4] described that on SD-OCT, overlying tuberculous choroidal granulomas, there is an area of localized adhesion between the choriocapillaris–RPE layer and the overlying neurosensory retina, tagging the finding as contact sign. Chhablani et al. suggests the contact sign may be present in other similar inflammatory disorders; nevertheless, the authors observed choroidal granulomas generated an increased transmission of OCT signals toward sclera.^[2] Wang et al.,^[5] in their study of choroidal granulomas, reported sub-RPE drusenoid changes in a case of choroidal granulomas.

Choroidal tubercles in miliary tuberculosis and the associated EDI-SD-OCT findings have been rarely reported. Evaluation of choroidal tubercles in our case revealed increase in SFCT, choriocapillaris thickening adjacent to tubercles, adhesions of RPE–choriocapillaris complex, elevated RPE–Bruch's complex, and focal disruptions in the myoid–ellipsoid zone. These findings are comparable to the published literature on EDI-SD-OCT analysis of tuberculous granulomas. Underlying immune-mediated mechanisms are similar in both clinical entities and exhibit similar EDI-SD-OCT findings. Hence, we believe EDI-SD-OCT findings applicable to choroidal tuberculous granuloma may be applicable to choroidal tubercles in miliary tuberculosis.

Previous studies in literature have reported decrease in the choroidal lesion height following ATT.^[6],[7] In our case, we observed reduction in SFCT and height of PED following 6 months of ATT therapy. From our observation, we surmise ATT therapy reduces immune-mediated hypersensitivity reactions with subsequent reduction in SFCT and PED height. We believe this characteristic finding of reduction in choroidal thickness post-therapy can be utilized as a biomarker in studies on choroidal tuberculosis.

Presence of multiple PEDs along with tubercles in our case offers a different ophthalmic picture of miliary tuberculosis. Zhang et al.,^[8] in their study, suggested PED results due to changes in choroidal thickness and permeability. We hypothesize that in miliary tuberculosis, immune-mediated inflammatory process can cause increased choroidal thickness, leading to compression of choriocapillaris, disrupting overlying RPE functions and resulting in PED formation. In our case, we believe the reduced height of PED is due to decrease in inflammation of the choroid following ATT therapy. However, this concept needs to be studied further.

Conclusion

In conclusion, we report a rare case of miliary tuberculosis with choroidal tubercles associated with increased SFCT, pigment epitheliopathy, and inflammatory changes in RPE–Bruch's complex, as evaluated by EDI-SD-OCT. Our report supports that EDI-SD-OCT is an effective tool for studying choroids, particularly in tubercular disease. Evaluation of choroid and SFCT measurements should be routinely employed to identify choroidal tubercles and inflammation. EDI-SD-OCT may be utilized as a biomarker in the detection of asymptomatic disease and can also be utilized to study the efficacy of ATT.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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