Author: Satabdi Nanda (India)
Co-authors: Keerti Mukesh, Kalpana Babu Murthy, Krishna R. Murthy, Dhwani Shah, Vinay Kumar Konana
Purpose
To describe a presentation of retinitis due to atypical mycobacterium subspecies Mycobacterium abscessus in a patient with Retroviral disease.Atypical mycobacteria are Mycobacteria other than Mycobacterium tuberculosis.They are opportunistic free living pathogens.Group IV, the rapid growers(according to Runyon’s Classification) -Mycobacterium abscessus, M. chelonae and M. fortuitum have been reported to be responsible for majority of the ocular infections caused by atypical mycobacteria.Risk factors include trauma, previous corneal infection or surgery, corticosteroid use and systemic immunosuppression. Laboratory detection, clinical diagnosis and management of ocular infections caused by atypical mycobacteria are quite challenging. Our purpose is to highlight the importance of cytology and culture in the diagnosis of these cases especially in immunocompromised patients who are more likely to develop intraocular atypical mycobacterial infections, which are associated with a greater risk of loss of vision.
Setting/Venue
Clinical case report from a tertiary eye care hospital in South India. A 17 year old male was referred to us from a higher paediatric centre with complaints of progressive diminution of vision in both eyes,left more than right,since 6 months. He was under ATT (Isoniazid, Rifampicin, Pyrazinamide) since 2.5years and Anti-Retroviral therapy (Tenofovir, Lamivudine, Dolutegravir) since 1 year. Chest X-ray done at this point in time was clear. CSF analysis (microscopy, culture & PCR) for MTB was negative in presence of mild pleocytosis. Under the advice to continue ATT and ART, he was referred for ophthalmological evaluation.
Methods
At the time of presentation, his CD4 count was 280.BCVA was 6/18P in OD and 6/9 in OS. Anterior segment examination OU revealed medium sized keratic precipitates, grade 2+ AC cells and posterior subcapsular cataract. Fundus examination showed vitritis of grade 2+ and multiple confluent, creamy yellowish white lesions in the periphery suggesting retinitis. IOP was 14mm of Hg in OU. He was investigated to rule out syphilis, toxoplasmosis, viral and endogenous endophthalmitis.Antibodies to Toxoplasma in blood and CSF, HCV, HBSAg and VDRL were negative. CBNAAT for TB was negative. CSF culture was positive for Cryptococcus on Indian Ink preparation which was surprising given the decent CD4 counts. After receiving IV Amphotericin B for 12 days, Oral Fluconazole 225 mg/day and Oral TMP-SMX, along with topical steroids and homide, the retinitis remained status quo with increased vitritis in the left eye. BCVA was 6/12p(OD) and 6/18(OS). In view of increasing vitritis in OS, he was administered single intravitreal injection of amphotericin B(5mcg/0.1ml). The following day, there was a significant worsening of vision to 6/24P with hypopyon in AC, dense vitritis, and increased retinitis in OS, raising suspicion of toxic reaction to Amphotericin B or secondary bacterial endophthalmitis.
Results
Intravitreal injection of Vancomycin and Ceftazidime was given to OS. AC tap sample was sent for Gram’s stain, KOH stain, PCR to rule out bacterial(including mycobacteria) and viral pathology,which was inconclusive. 2 days following the injection,vision dropped to CFCF with worsening of vitreous haze.He underwent pars plana vitrectomy in OS with intravitreal injections of Vancomycin, Amikacin and Voriconazole.Vitreous aspirate was sent for cytology, PCR( eubacterial, panfungal, viral & mycobacterial species) and Culture( Bacterial, fungal & Mycobacterial). On Postoperative day 1, vision was 6/24 with resolution of hypopyon. Cytology revealed granulomatous picture with few AFB suggestive of tubercular etiology. Mycobacterium abcessus was isolated on culture, which was sensitive to Imipenem, Azithromycin, Clarithromycin, Amikacin, Tobramycin and Gatifloxacin. He was started on Tab Azithromycin 500mg per day. OU received Intravitreal Amikacin injection(125mcg/0.1ml) following which retinitis showed signs of gradual resolution and consolidation. He received further injections of intravitreal amikacin (total of five in each eye). Intravenous Meropenem 1g injections thrice a day was given for 6 weeks based on sensitivity profile. He was followed up over four months and is doing well with BCVA of 6/9 in OU. We plan to continue periodic follow ups with meticulous examination.
Conlusions
Atypical mycobacterial infections are rare but can lead to serious vision-threatening complications.Management is challenging as the retinitis is usually attributed to other causes such as viral or fungal infection.In this case, presentation of granulomatous KP’s with retinitis was unusual in an immunocompromised patient with decent CD4 counts. CSF culture was positive for Cryptococcus but vision and retinitis worsened with anti fungal treatment.Multiple PCR did not reveal the causative agent. Vitreous aspirate revealed AFB and culture detected Mycobacterium abcessus.Patient received multiple intravitreal Amikacin injections and IV Meropenem which caused a dramatic improvement in vision and resolution of retinitis. In 2015, Kheir et al reported that more than half of endogenous endophthalmitis cases were associated with immunodeficiency status.Pinitpuwadol, Warinyupa et al in 2020 reported that M.abscessus was associated with poor visual outcome with majority of cases ending up with visual impairment, evisceration or phthisis.High index of suspicion is necessary.Repeated vitreous and aqueous cultures are required to identify causative organism.Treatment includes combination of local and systemic antibiotics based on drug sensitivity. Anti tuberculosis drugs are commonly prescribed.Amikacin, clarithromycin and azithromycin are considered to be the best antibiotics for these infections.Intravenous Amikacin and Imipenem have been reported to be successful in the management.
Financial Disclosure
NIL
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