Rifabutin-induced uveitis with inflammatory vitreous infiltrate

The Impact of Systemic Medications on Retinal Function

This study will provide a thorough review of systemic (and select intravitreal) medications, along with illicit drugs that are capable of causing various patterns of retinal toxicity. The diagnosis is established by taking a thorough medication and drug history, and then by pattern recognition of the clinical retinal changes and multimodal imaging features. Examples of all of these types of toxicity will be thoroughly reviewed, including agents that cause retinal pigment epithelial disruption (hydroxychloroquine, thioridazine, pentosan polysulfate sodium, dideoxyinosine), retinal vascular occlusion (quinine, oral contraceptives), cystoid macular edema/retinal edema (nicotinic acid, sulfa-containing medications, taxels, glitazones), crystalline deposition (tamoxifen, canthaxanthin, methoxyflurane), uveitis, miscellaneous, and subjective visual symptoms (digoxin, sildenafil). The impact of newer chemotherapeutics and immunotherapeutics (tyrosine kinase inhibitor, mitogen-activated protein kinase kinase, checkpoint, anaplastic lymphoma kinase, extracellular signal-regulated kinase inhibitors, and others), will also be thoroughly reviewed. The mechanism of action will be explored in detail when known. When applicable, preventive measures will be discussed, and treatment will be reviewed. Illicit drugs (cannabinoids, cocaine, heroin, methamphetamine, alkyl nitrite), will also be reviewed in terms of the potential impact on retinal function.

Pharmacologic management of Mycobacterium chimaera Infections: A Primer for Clinicians

Mycobacterium chimaera, a member of the Mycobacterium avium complex, can cause infections in individuals after open heart surgery due to contaminated heater-cooler units. The diagnosis can be challenging, as the incubation period can be quite variable, and symptoms are nonspecific. In addition to aggressive surgical management, combination pharmacologic therapy is the cornerstone of therapy, which should consist of a macrolide, a rifamycin, ethambutol, and amikacin. Multiple second-line agents may be utilized in the setting of intolerances or toxicities. In vitro susceptibility of these agents is similar to activity against other species in the Mycobacterium avium complex. Drug–drug interactions are frequently encountered, as many individuals have chronic medical comorbidities and are prescribed medications that interact with the first-line agents used to treat M. chimaera. Recognition of these drug–drug interactions and appropriate management are essential for optimizing treatment outcomes.

Rifabutin-Associated Panuveitis with Retinal Vasculitis in Pulmonary Tuberculosis

INTRODUCTION

Rifabutin-associated uveitis has been reported frequently in AIDS patients and more rarely in immunocompetent patients. It is characterized clinically by anterior acute uveitis. Only a few poorly documented cases of rifabutin-induced panuveitis with retinal vasculitis have been reported. Here, we report four cases of rifabutin-associated panuveitis with retinal vasculitis.

CASE REPORTS

We describe four patients with active tuberculosis, treated with a multidrug regimen including rifabutin for at least 1.5 months before presentation. The first patient was immunocompetent, the three others had AIDS and were undergoing triple anti-HIV therapy. Three patients were women with a low body weight. All four patients presented with panuveitis and retinal vasculitis. Interruption of the drug rapidly reduced the ocular inflammation in all cases.

CONCLUSION

Four cases of rifabutin-associated panuveitis with retinal vasculitis are reported in patients with active pulmonary tuberculosis. Immunogenicity of Mycobacterium tuberculosis as well as the very low weight of the patients might be implicated in the development of this unusual form of rifabutin-associated uveitis.

Anterior Segment and External Ocular Disorders Associated with Human Immunodeficiency Virus Disease

The eye is a common site for complications of human immunodeficiency virus (HIV) infection. Although cytomegalovirus retinitis remains the most prevalent of the blinding ocular disorders that can occur in individuals with the acquired immunodeficiency syndrome (AIDS), several important HIV-associated disorders may involve the anterior segment, ocular surface, and adnexae. Some of these entities, such as Kaposi sarcoma, were well described, but uncommon, before the HIV epidemic. Others, like microsporidial keratoconjunctivitis, have presentations that differ between affected individuals with HIV disease and those from the general population who are immunocompetent. The treatment of many of these diseases is challenging because of host immunodeficiency. Survival after the diagnosis of AIDS has increased among individuals with HIV disease because of more effective antiretroviral therapies and improved prophylaxis against, and treatment of, opportunistic infections. This longer survival may lead to an increased prevalence of anterior segment and external ocular disorders. In addition, the evaluation and management of disorders such as blepharitis and dry eye, which were previously overshadowed by more severe, blinding disorders, may demand increased attention, as the general health of this population improves. Not all individuals infected with HIV receive potent antiretroviral therapy, however, because of socioeconomic or other factors, and others will be intolerant of these drugs or experience drug failure. Ophthalmologists must, therefore, still be aware of the ocular findings that develop in the setting of severe immunosuppression. This article reviews the spectrum of HIV-associated anterior segment and external ocular disorders, with recommendations for their evaluation and management.

Anti-inflammatory activity of ansamycins

Inflammation represents a complex biologic and biochemical process involving cells of the immune system and a plethora of biologic mediators in response to mechanical, chemical or infectious injuries. When mobilization of effector cells and molecules becomes excessive, the beneficial aspect of this response--to limit damage and promote healing, can be overriden, resulting in host-cell and tissue dysfunction. Based on the hypothesis that chronic infections underly some inflammatory diseases, antibacterial therapy has long been assessed in various inflammatory settings. Recently, the anti-inflammatory activity of some antibacterial agents has also been suspected. Of these duel-action drugs, ansamycins represent an interesting family. Although their therapeutic use is restricted to potentially infectious inflammatory diseases, many experimental data suggest that these drugs also possess direct inhibitory activity on some crucial proinflammatory effectors. To date, the potent antimycobacterial activity of the therapeutically useful ansamycins precludes their widespread use in inflammatory diseases. However, biosynthetic manipulation remains an attractive route for the generation of pharmacologically useful analogs.

Appearance of Retinal Hemorrhages in Patients on Daily-Dose Anti-Tubercular Therapy

Objective:

To report 2 patients who presented with retinal hemorrhages while being treated with a continuous regimen of anti-tuberculous drugs.

Case Summaries:

Two women, one suffering from tuberculous infection of the lungs and the other from disseminated Koch's, were treated with a daily regimen of anti-tuberculous therapy consisting of rifampin, isoniazid, pyrazinamide, and ethambutol. On initiation of treatment, these patients did not have any systemic or ocular disease, and hematologic investigations, kidney function tests, and liver function tests were normal. Within 2 weeks of initiation of anti-tuberculous therapy, both women had transient renal function deterioration. Additionally, each had a single episode of retinal hemorrhage. While the patients remained under treatment with the same drugs, both of these adverse effects resolved spontaneously within a short period. According to the Naranjo probability scale, this reaction was probable.

Discussion:

The renal dysfunction and retinal hemorrhages in both of our patients were most probably due to anti-tuberculous drug-induced antibodies. A continuous mode of anti-tuberculous drug administration causes immunologic tolerance due to simultaneous neutralization of drug-induced antibodies. As the antibodies were short-lived, renal impairment, thrombocytopenia, and retinal hemorrhages in both of our patients were transient.

Conclusions:

The continuous regimen of anti-tuberculous drug administration is safer than intermittent therapy. In patients receiving treatment with these drugs, hepatic, hematologic, renal, and ocular parameters should be regularly monitored.