Linezolid-induced photoreceptor dysfunction masquerading as autoimmune retinopathy

Infective pulmonary diseases and the eye: a narrative review

Several infectious pulmonary diseases affect the eye. An understanding of the association between infectious pulmonary and ocular diseases is pivotal to their successful management. We aimed to review the infections affecting both the lungs and the eye. The electronic database PubMed and the search engine Google Scholar were searched for relevant articles. Ocular tuberculosis (TB), usually not associated with clinical evidence of pulmonary TB, can affect almost all the ocular structures. Confirmation of the diagnosis of ocular TB requires demonstration of Mycobacterium tuberculosis in ocular fluids/tissues. Among the drugs used to treat TB, ethambutol, isoniazid, and linezolid may cause toxic optic neuropathy. Elderly, those with renal disease, diabetes mellitus, malnourished, alcoholics, and those who will receive ethambutol at doses greater than 15 mg/kg/day and for prolonged periods are at high risk of developing toxic optic neuropathy. These individuals should be referred to an ophthalmologist before initiating ATT for a baseline ophthalmic evaluation. Linezolid may also cause toxic retinal neuropathy. Rifampicin may cause yellowish-orange discoloration of tears and contact lenses. Adenovirus, coronavirus, influenza virus, respiratory syncytial virus, and rhinovirus exhibit both pulmonary and ocular tropism. Pneumocystis jirovecii choroiditis is rare and mainly seen when aerosolized pentamidine is used for pneumocystis pneumonia prophylaxis. Further research is needed to develop non-interventional strategies to diagnose ocular TB. Biomarkers for early detection of toxic optic neuropathy are a need of the hour. Genetic factors and mechanisms behind the development of ethambutol, isoniazid, and linezolid-induced toxic optic neuropathy need further study.

Linezolid optic neuropathy

PURPOSE OF REVIEW

In this article, we reviewed 67 reported cases of linezolid optic neuropathy and describe the common characteristics and expectations for recovery with an emphasis on recent findings in the literature.

RECENT FINDINGS

Linezolid classically causes a reversible, duration-dependent optic neuropathy. However, in our review, we found only 66.7% of patients recovered complete visual function. Vision loss most commonly affected visual acuity followed by visual field and color vision. We also found patients taking higher doses of linezolid experienced full recovery less often, suggesting a dose-dependent component of linezolid optic neuropathy. Linezolid use has increased in frequency and duration, especially in the treatment of drug-resistant tuberculosis, and data indicate that these patients experience lower rates of complete vision recovery compared with patients taking linezolid for other indications.

SUMMARY

Linezolid is an effective medication for treating drug-resistant infections; however, it may result in optic neuropathy. It is reasonable for patients on linezolid to undergo screening examinations, especially those on higher doses or for prolonged duration of therapy.

Pleiotropic effects of antibiotics on T cell metabolism and T cell-mediated immunity

T cells orchestrate adaptive and innate immune responses against pathogens and transformed cells. However, T cells are also the main adaptive effector cells that mediate allergic and autoimmune reactions. Within the last few years, it has become abundantly clear that activation, differentiation, effector function, and environmental adaptation of T cells is closely linked to their energy metabolism. Beyond the provision of energy equivalents, metabolic pathways in T cells generate building blocks required for clonal expansion. Furthermore, metabolic intermediates directly serve as a source for epigenetic gene regulation by histone and DNA modification mechanisms. To date, several antibiotics were demonstrated to modulate the metabolism of T cells especially by altering mitochondrial function. Here, we set out to systematically review current evidence about how beta-lactam antibiotics, macrolides, fluoroquinolones, tetracyclines, oxazolidinones, nitroimidazoles, and amphenicols alter the metabolism and effector functions of CD4+ T helper cell populations and CD8+ T cells in vitro and in vivo. Based on this evidence, we have developed an overview on how the use of these antibiotics may be beneficial or detrimental in T cell-mediated physiological and pathogenic immune responses, such as allergic and autoimmune diseases, by altering the metabolism of different T cell populations.

Linezolid-Induced Toxic Optic Neuropathy

To report a case of linezolid-induced toxic optic neuropathy. Clinical examination and imaging are presented over a 4-month interval from initial presentation to subsequent follow-up of 4 months after discontinuation of linezolid. The patient was found to have optic neuropathy as demonstrated by clinical presentation and examination. Upon discontinuation of linezolid, the patient's visual acuity, visual fields, and color vision significantly improved. Linezolid has previously been reported to cause toxic optic neuropathy and retinopathy. We hereby describe a tuberculosis patient with linezolid-associated toxic optic neuropathy. Our report aims to describe the ocular side effects of linezolid use to enhance awareness.