Retinal toxicity in human immunodeficiency virus-infected children treated with 2',3'-dideoxyinosine

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.

Didanosine-induced Retinopathy: New Insights with Long-term Follow-up

INTRODUCTION

Didanosine is an adenosine analog, part of the nucleoside reverse-transcriptase inhibitor family. Since the description of didanosine-induced retinopathy in the early 1990s, little is known about the progression of this toxic retinopathy and the putative underlying mitochondrial defect.

OBJECTIVES

We report long-term follow-up for cases of didanosine-induced retinopathy and discuss a new hypothesis for pathophysiology based on the alteration of endogenous adenosine on the photoreceptor outer segment turnover and phagocytosis by the retinal pigment epithelium.

METHODS

Ophthalmic data from six cases (12 eyes) of didanosine-induced retinopathy from a single institution were retrospectively analyzed.

RESULTS

All patients displayed bilateral retinal alterations in the mid-periphery. Despite didanosine discontinuation, patients with advanced areas of patchy chorioretinal atrophy appeared to have a faster progression than those with limited lesions. Full-field electroretinogram revealed generalized rod-cone dysfunction in most cases that remained stable over time.

CONCLUSION

We propose new guidelines including early screening and long-term observations.

Didanosine-Associated Retinal Toxicity in a Patient With a Mutation in the CRB1 Gene

Purpose:

This article describes a case of didanosine (DDI)-associated retinal toxicity in a patient with a heterozygous pathogenic variant in the CRB1 gene.

Methods:

Case report.

Results:

A middle-aged patient with HIV controlled on HAART therapy, and a remote 10-year year history of treatment with DDI and tenofivir, presented with external ophthalmoplegia and well-circumscribed, midperipheral patterns of bilateral pigmentary retinopathy and chorioretinal atrophy in both eyes. Genetic testing revealed a heterozygous pathogenic variant in the CRB1 gene that encodes a protein (Crumbs homolog 1) involved in regulation of cell polarity and junctions and is localized adjacent to mitochondria in the ellipsoid and myoid area.

Conclusions:

This case highlights a potential role for genetic susceptibility to retinal toxicity in DDI-associated retinal toxicity. Large, prospective pharmacogenomics studies may be informative to further elucidate the role of genetic risk factors in drug-induced retinal toxicity.

A Rare Case of Didanosine-Induced Mid-Peripheral Chorioretinal Atrophy Identified Incidentally 11 Years after the Drug Cessation

Objective: This article aims to describe a unique case of didanosine-induced retinal degeneration that was discovered 11 years after the drug withdrawal. Case report: The patient is a 42-year-old woman with a medical history of HIV and hepatitis C virus since 2004. She has been prescribed antiretroviral therapy since then. For the first seven years (2004–2011), the patient was prescribed a combination therapy consisting of didanosine, efavirenz, and lamivudine. The protocol was changed to atripla (efavirenz, emtricitabine, and tenofovir) from 2011 to 2021. Recently (October 2021–January 2021), the patient was prescribed eviplera (rilpivirin, emtricitabine, and tenofovir). In addition, her past medical history revealed Gougerot-Sjogren syndrome and rheumatoid arthritis. She was prescribed hydroxychloroquine (HCQ) (2009–2021) at a dose of 400 mg daily. She had no vision complaint. Results: During her routine HCQ screening at the eye clinic, University Hospital Bretonneau, Tours, France, the widefield colour fundus photograph showed well-defined symmetric mid-peripheral areas of chorioretinal atrophy sparing the posterior pole of both eyes. Furthermore, the widefield fundus autofluorescence illustrated mid-peripheral round well-demarcation hypoautofluorescent areas of chorioretinal atrophy of both eyes. Conversely, the macular optical coherence tomography (OCT) was normal. Many of her drugs are known to be associated with retinopathy such as HCQ, tenofovir, efavirenz, and didanosine. Because our data corroborate peripheral retinal damage rather than posterior pole damage, this case report is compatible with didanosine-induced retinopathy rather than HCQ, efavirenz, or tenofovir retinal toxicity. Conclusions: All HIV patients who are presently or were previously on didanosine therapy should have their fundus examined utilising widefield fundus autofluorescence and photography.

Case Report: Multimodal Imaging of Toxic Retinopathies Related to Human Immunodeficiency Virus Antiretroviral Therapies: Maculopathy vs. Peripheral Retinopathy. Report of Two Cases and Review of the Literature

Purpose: We report two patients with toxic retinopathy from either ritonavir or didanosine and reviewed the literature on the topics. We provide an overview of the retinal toxicity of these two antiretroviral drugs in human immunodeficiency virus-positive patients.

Methods: First, we performed a retrospective study of the medical charts of two patients examined by us, one with ritonavir maculopathy and one with didanosine peripheral retinopathy. Secondly, we searched the world literature for similar cases through PubMed and Google Scholar, using the terms “HIV,” “AIDS,” “ritonavir,” “didanosine,” “maculopathy,” “retinopathy,” “visual loss,” and “toxicity” to retrieve the appropriate literature on the subject.

Results: Patient 1: A 49-year-old woman complained of progressive central visual loss over the past 12 months. History disclosed ongoing ritonavir therapy for the past 11 years. Ritonavir maculopathy was diagnosed, and visual loss increased relentlessly despite cessation of treatment. Patient 2: A 55-year-old man complained of slowly progressive peripheral visual field constriction for the past 5 years. History disclosed didanosine therapy for 13 years, however, stopped 4 years before the onset of visual symptoms. No alteration of therapy was offered to patient 2 as didanosine therapy was interrupted 9 years previously. Since 2011, 11 cases of ritonavir maculopathy have been reported in the literature. Relentless worsening of vision was reported in 3/7 patients despite cessation of ritonavir therapy. Didonasine peripheral retinopathy was first described in 1992, and a total of 24 patients have been reported since. Relentlessly progressive peripheral retinopathy was diagnosed despite the previous cessation of therapy in 14 patients.

Conclusion: Ritonavir causes a slowly progressive atrophic maculopathy, and didanosine toxicity results in a relentlessly progressing peripheral atrophic retinopathy. The relentless progression of both toxic retinopathies reflects permanent alterations of the retinal metabolism by these medications. Both ritonavir and didanosine toxic retinopathies are rare events, but their clinical presentation is highly specific.

MULTIMODAL IMAGING IN DIDANOSINE RETINOPATHY

PURPOSE

To present the multimodal retinal imaging findings in didanosine retinopathy in a patient who presented 6.5 years after stopping the use of didanosine and to highlight the absence of progression during a 1.5-year follow-up.

METHODS

Case report involving clinical examination, fundus photography, fundus autofluorescence, fluorescein angiography, optical coherence tomography, Goldmann kinetic perimetry, and full-field electroretinography.

RESULTS

A 52-year-old patient presented with bilateral retinopathy 6.5 years after stopping didanosine having used the medication for 8.5 years. Fundus examination showed a ring-shaped zone of atrophy of the retinal pigment epithelium involving the midperiphery. On autofluorescence imaging, there was diffuse hypoautofluorescence involving the midperipheral retina in both eyes. On fluorescein angiography, there was a granular mottled pattern of diffuse hyperfluorescence in the midperiphery in both eyes, with baring of the large choroidal vessels in some areas. On Goldmann kinetic perimetry, both eyes showed marked constriction of the isopter to the I4e stimulus, and there was a temporal scotoma to the III4e target in both eyes. Full-field electroretinography showed generalized rod and cone photoreceptor dysfunction in both eyes. During a follow-up for 1.5 years, there was no evidence of progression.

CONCLUSION

Patients who have used didanosine should be evaluated for the presence of retinopathy, which involves the midperipheral retina.

Human immunodeficiency virus and intraocular inflammation in the era of highly active anti retroviral therapy - An update

Intraocular inflammation in patients with human immunodeficiency virus (HIV) infection is commonly due to infectious uveitis. Ocular lesions due to opportunistic infections (OI) are the most common and have been described extensively in the pre highly active antiretroviral therapy (HAART) era. Many eye lesions were classified as acquired immunodeficiency syndrome (AIDS) defining illnesses. HAART-associated improvement in immunity of the individual has changed the pattern of incidence of these hitherto reported known lesions leading to a marked reduction in the occurrence of ocular OI. Newer ocular lesions and newer ocular manifestations of known agents have been noted. Immune recovery uveitis (IRU), the new menace, which occurs as part of immune recovery inflammatory syndrome (IRIS) in the eye, can present with significant ocular inflammation and can pose a diagnostic and therapeutic challenge. Balancing the treatment of inflammation with the risk of reactivation of OI is a task by itself. Ocular involvement in the HAART era can be due to the adverse effects of some systemic drugs used in the management of HIV/AIDS. Drug-associated retinal toxicity and other ocular side effects are being increasingly reported. In this review, we discuss the ocular manifestations in HIV patients and its varied presentations following the introduction of HAART, drug-associated lesions, and the current treatment guidelines.

The Changing Global Epidemic of HIV and Ocular Disease

Purpose: Overview of the evolving epidemiology of human immunodeficiency virus (HIV)-related ocular disease over time. Method: Narrative review. Results: HIV enhances susceptibility to opportunistic eye infections, has direct pathogenic effects, and places patients at risk of immune recovery inflammatory syndromes in previously infected eyes after starting highly-active antiretroviral therapy (HAART). Widespread availability of HAART has resulted in a decrease of infectious ocular conditions such as cytomegalovirus retinitis, toxoplasmic retinitis, squamous cell carcinoma of the conjunctiva, and microvascular retinopathy. However, large coexisting burdens of tuberculosis, herpesvirus infection and syphilis (among others) continue to contribute to the burden of ocular disease, especially in low-resource settings. Growing risks of cataract, retinopathy and retinal nerve fiber thinning can affect patients with chronic HIV on HAART; thought due to chronic inflammation and immune activation. Conclusion: The changing epidemic of ocular disease in HIV-infected patients warrants close monitoring and identification of interventions that can help reduce the imminent burden of disease.

Wide field retinal imaging and the detection of drug associated retinal toxicity

Background

To describe the peripheral retinal findings associated with systemic medication toxicity and to outline the importance of ultra-widefield imaging in the detection, analysis and monitoring of these abnormalities.

Main text

This review highlights the retinal manifestations associated with the more common drug toxicities, with emphasis on the peripheral features and the indications for wide field imaging. The presenting findings, underlying pathophysiology, and retinal alterations in hydroxychloroquine, thioridazine, didanosine, tamoxifen, MEK-inhibitor, and immune checkpoint inhibitor associated drug toxicity will be described and the importance of wide field imaging in the evaluation of these abnormalities will be emphasized.

Conclusions

Wide field retinal imaging can improve the detection of peripheral retinal abnormalities associated with drug toxicity and may be an important tool in the diagnosis and management of these disorders.

Depletion of Mitochondrial DNA in Differentiated Retinal Pigment Epithelial Cells

We investigated the effects of treating differentiated retinal pigment epithelial (RPE) cells with didanosine (ddI), which is associated with retinopathy in individuals with HIV/AIDS. We hypothesized that such treatment would cause depletion of mitochondrial DNA and provide insight into the consequences of degradation of RPE mitochondrial function in aging and disease. Treatment of differentiated ARPE-19 or human primary RPE cells with 200 µM ddI for 6–24 days was not cytotoxic but caused up to 60% depletion of mitochondrial DNA, and a similar reduction in mitochondrial membrane potential and NDUFA9 protein abundance. Mitochondrial DNA-depleted RPE cells demonstrated enhanced aerobic glycolysis by extracellular flux analysis, increased AMP kinase activation, reduced mTOR activity, and increased resistance to cell death in response to treatment with the oxidant, sodium iodate. We conclude that ddI-mediated mitochondrial DNA depletion promotes a glycolytic shift in differentiated RPE cells and enhances resistance to oxidative damage. Our use of ddI treatment to induce progressive depletion of mitochondrial DNA in differentiated human RPE cells should be widely applicable for other studies aimed at understanding RPE mitochondrial dysfunction in aging and disease.

RITONAVIR-ASSOCIATED TOXICITY MIMICKING RETINITIS PIGMENTOSA IN AN HIV-INFECTED PATIENT ON HIGHLY ACTIVE ANTIRETROVIRAL THERAPY

PURPOSE

To report ritonavir-associated retinal pigment epithelium toxicity in a patient infected with the HIV on highly active antiretroviral therapy including ritonavir.

METHODS

Retrospective single case report. The authors describe a case of gradual onset of blurry vision in both eyes in an HIV-positive male. Visual acuity, clinical examination findings, and functional testing (electroretinogram and Goldmann perimetry) were reviewed. Diagnostic imaging, including fundus photography, spectral domain optical coherence tomography, fluorescein angiography, and fundus autofluorescence were assessed.

RESULTS

59-year-old HIV-infected male, treated with ritonavir for eight years, presented with a history of decreased night vision and peripheral field loss. Ophthalmologic examination confirmed the diagnosis of retinal toxicity. Goldmann perimetry showed areas of central and para-central scotomas. Electroretinograms demonstrated mild to moderate photoreceptor dysfunction. Fundus examination revealed a diffuse pattern of retinal pigment epithelium mottling in both eyes. Spectral domain optical coherence tomography confirmed the presence of choroidal thinning, whereas fundus autofluorescence showed mottled hypoautofluorescence.

CONCLUSION

Although ritonavir-associated retinal toxicity is clinically uncommon, the clinical features of our findings support this diagnosis. Consideration of highly active antiretroviral therapy-associated retinal toxicity should be given to the differential diagnosis in HIV-positive patients with retinopathy of unclear etiology. This report also highlights the need for constant monitoring of patients using the ritonavir for early detection of possible retinal toxicity.

Ophthalmologic Disease in HIV Infection: Recent Changes in Pathophysiology and Treatment

PURPOSE OF REVIEW

Ophthalmologic conditions were among the earliest described findings in patients with the acquired immunodeficiency syndrome (AIDS). The purpose of this review is to highlight recent changes in the pathophysiology and management of ophthalmologic conditions in patients infected with the human immunodeficiency virus (HIV).

RECENT FINDINGS

The introduction of highly active antiretroviral therapy (HAART) in 1996 changed ophthalmologic findings from predominantly acute infectious diseases to chronic, slowly progressive, debilitating conditions. HIV-associated neuroretinal disorder infrequently leads to blindness, but it causes visual disability in a large percentage of patients. Cytomegalovirus retinitis is now seen less commonly in the USA, but it remains an important cause of blindness in HIV-infected patients from developing countries. Immune recovery uveitis has emerged as a major cause of visual disability in the USA. As HIV has become a chronic disease, visual disability due to chronic noninfectious diseases have become increasingly important.

DIDANOSINE RETINAL TOXICITY

PURPOSE

To report nine new cases of retinal degeneration secondary to didanosine toxicity and to summarize the previously reported cases in the literature.

METHODS

This was a multicenter, retrospective, observational case study from seven institutions. Medical records of patients who demonstrated well-demarcated severe midperipheral chorioretinal degeneration and who were previously treated with didanosine therapy were collected and the following information was reviewed: age, gender, medical history, detailed medication history including current and previous antiretroviral use, ocular and retinal examination findings, and multimodal imaging findings with optical coherence tomography, fundus photography, wide-field fundus autofluorescence, and wide-field fluorescein angiography. When available, findings with electrophysiology testing and automated perimetry were also collected and reviewed. A literature review was also performed to collect all reported cases of chorioretinal degeneration secondary to didanosine toxicity.

RESULTS

Nine patients were identified who had findings consistent with peripheral retinal toxicity secondary to didanosine use. Eight of the 9 patients were men, and the median age was 54 years at the time of presentation (mean: 55 years, range, 42-71 years). Snellen distance acuity ranged from 20/20 to 20/32. At least three of the cases in the series demonstrated progression of the peripheral retinal pigment epithelium and photoreceptor atrophy despite didanosine cessation. A review of the literature revealed 10 additional cases of didanosine toxicity. Seven of the 10 cases were in men (70%), and the average age was 26 years with a wide range (2-54 years). Chorioretinal findings were very similar to this cohort.

CONCLUSION

Herein, we report the largest series of nine cases of peripheral chorioretinal degeneration secondary to didanosine toxicity in adults. When combined with the cases in the literature, 19 cases of didanosine toxicity, 4 of which occurred in children, were collected and analyzed. Three of the new cases presented showed clear progression of degeneration despite didanosine cessation. Newer nucleoside reverse transcriptase inhibitors may potentiate mitochondrial DNA damage and lead to continued chorioretinal degeneration.

Bull's eye maculopathy in an HIV-positive patient receiving ritonavir

Retinal toxicity involving the macula as a complication of the antiretroviral protease inhibitor ritonavir has been described in a few cases. We report retinal pigment epitheliopathy involving the macula with a bull's eye pattern in a 36-year-old man with well-controlled HIV receiving ritonavir with gradually progressive bilateral vision loss.

A woman with didanosine retinopathy and non-cirrhotic portal hypertension

We present a case of structural and functional changes compatible with didanosine retinopathy in a patient who also developed non-cirrhotic portal hypertension.

Ritonavir and bull's eye maculopathy: case report

Objective: To report on a case of retinal pigment epithelium (RPE) toxicity apparently associated with ritonavir.

Methods: We describe a case of gradual-onset blurry vision in both eyes in a 30-year-old HIV-positive male on Highly-Active Antiretroviral Therapy (HAART) including ritonavir

Results: The patient presented with a visual acuity of 3/10 in each eye, and fundoscopy revealed paracentral pigment mottling. Computerized perimetry showed a ring-scotoma in both eyes. Fluorescein angiography revealed an anular RPE defect in both eyes, congruent with hyperautofluorescent changes on autofluorescence imaging. Full-field ERG was normal.

Conclusions: Since ritonavir has previously been linked with toxicity to the RPE, we consider this report as further evidence of this association.

Ocular toxicity from systemically administered xenobiotics

INTRODUCTION

The eye is considered as the most privileged organ because of the blood-ocular barrier that acts as a barrier to systemically administered xenobiotics. However, there has been a significant increase in the number of reports on systemic drug-induced ocular complications. If such complications are left untreated, then it may cause permanent damage to vision. Hence, knowledge of most recent updates on ever-increasing reports of such toxicities has become imperative to develop better therapy while minimizing toxicities.

AREAS COVERED

The article is mainly divided into anterior and posterior segment manifestations caused by systemically administered drugs. The anterior segment is further elaborated on corneal complications where as the posterior segment is focused on optic nerve, retinal and vitreous complications. Furthermore, this article includes recent updates on acute and chronic ocular predicaments, in addition to discussing various associated symptoms caused by drugs.

EXPERT OPINION

Direct correlation of ocular toxicities due to systemic drug therapy is evident from current literature. Therefore, it is necessary to have detailed documentation of these complications to improve understanding and predict toxicities. We made an attempt to ensure that the reader is aware of the characteristic ocular complications, the potential for irreversible drug toxicity and indications for cessation.

Retinal and cochlear toxicity of drugs: new insights into mechanisms and detection

PURPOSE OF REVIEW

Various medications can modify the physiology of retinal and cochlear neurons and lead to major, sometime permanent, sensory loss. A better knowledge of pathogenic mechanisms and the establishment of relevant monitoring protocols are necessary to prevent permanent sensory impairment. In this article, we review main systemic medications associated with direct neuronal toxicity on the retina and cochlea, their putative pathogenic mechanisms, when identified, as well as current recommendations, when available, for monitoring protocols.

RECENT FINDINGS

Pathogenic mechanisms and cellular target of retinotoxic drugs are often not well characterized but a better knowledge of the course of visual defect has recently helped in defining more relevant monitoring protocols especially for antimalarials and vigabatrin. Mechanisms of ototoxicity have recently been better defined, from inner ear entry with the use of fluorescent tracers to evidence for the role of oxidative stress and program cell death pathways.

SUMMARY

Experimental and clinical studies have elucidated some of the pathogenic mechanisms, courses and risk factors of retinal toxicity and ototoxicity, which have led to establishment of relevant monitoring protocols. Further studies are, however, warranted to better understand cellular pathways leading to degeneration. These would help to build more efficient preventive intervention and may also contribute to understanding of other degenerative processes such as genetic disorders.

Retinal pigment epitheliopathy, macular telangiectasis, and intraretinal crystal deposits in HIV-positive patients receiving ritonavir

PURPOSE

The purpose of this study was to describe the occurrence of a retinal pigment epitheliopathy associated with macular telangiectasis and intraretinal crystal deposits in three human immunodeficiency virus-positive patients receiving long-term ritonavir as part of highly active antiretroviral therapy.

METHODS

The patient's records were reviewed.

RESULTS

The CD4 T-cell counts at presentation were 163 cells per microliter, 464 cells per microliter, and 349 cells per microliter, and viral loads were undetectable in all patients. None of the patients had a concurrent AIDS-defining illness. Other significant medical history included hyperlipidemia in one patient and a remote history of lymphoma and tuberculosis in a second patient. Initial visual acuity ranged from 20/32 to 20/400, with a median of 20/150. Anterior segment examination and intraocular pressures were normal in all eyes. Posterior segment examination revealed bilateral macular retinal pigment epitheliopathy with intraretinal crystalline deposits. No hemorrhage or cotton wool spots were seen consistent with human immunodeficiency virus retinopathy, and there was no evidence of previous or active cystomegalovirus retinitis. Fluorescein angiography revealed parafoveal telangiectasis with late leakage in two of the three patients. Optical coherence tomography showed thickening of the macula in three eyes and inner foveal cysts in two eyes. Autofluorescence performed on one patient revealed complete loss of normal retinal pigment epithelium autofluorescence corresponding to the area of retinal pigment epitheliopathy bilaterally. The only medicine common to all 3 patients was ritonavir, and the duration of ritonavir therapy before presentation was 19 months in one patient, 30 months in the second patient, and 5 years in the third patient.

CONCLUSION

Retinal changes characterized by retinal pigment epitheliopathy, parafoveal telangiectasias, and intraretinal crystal deposits occurred in three human immunodeficiency virus-positive patients on long-term ritonavir as part of highly active antiretroviral therapy.

Nucleoside and nucleotide reverse transcriptase inhibitors in children

By the end of 2006, approximately 2.3 million children worldwide were living with HIV infection, representing about 15% of all HIV-infected individuals but only 5-7% of the total population of treated patients worldwide. Despite a general increase in the use of antiretroviral therapy (ART) in resource-limited settings, appropriate care and ART remain inaccessible for most of the world's HIV-infected children. ART of children is challenging because of a general lack of paediatric formulations (including tablets in paediatric strengths), limited options of drugs available for children (some have been approved only for use in adults), different viral and immunological responses, dependency on caregivers for administration of the therapy, and specific issues of toxicity in long-term therapy related to maturation and development. As in adults, nucleoside reverse transcriptase inhibitors (NRTIs) are a key component of any ART schedule in children, being the recommended 'backbone' treatment in US, European and WHO guidelines, and, indeed, NRTIs have been extensively studied in children. NRTIs are the class of antiretroviral drugs that have more drugs licensed for paediatric use and more paediatric formulations.Generally, the dual NRTI backbone treatment of combination with a non-NRTI (NNRTI) or protease inhibitor (PI) should comprise a cytidine analogue (lamivudine, emtricitabine) and a thymidine analogue (stavudine, zidovudine), guanosine analogue (i.e. abacavir), or nucleotide RTI (NtRTI; i.e. tenofovir). European and US guidelines recommend the use of triple NRTI therapy (abacavir/lamivudine/zidovudine) in children with anticipated poor adherence to other treatment regimens because of tablet burden. In conclusion, while use of ART in children needs to be dramatically increased, selecting and administering the best drug combination for children is still limited by a lack of paediatric formulations and knowledge of drug metabolism, safety and efficacy in children. NRTIs are already a key component of paediatric ART, but fixed-dose combinations and specific research in children are needed to optimise their use. In this article we review the available information to facilitate selection of the best NRTI for backbone treatment in combination ART for HIV-infected children.

Tolerabilities of antiretrovirals in paediatric HIV infection

Data on the efficacy and tolerability of antiretrovirals in children are limited as, in contrast to adult studies, large paediatric cohort studies are lacking. Thus, data pertaining to adults are often extrapolated to children despite the acknowledgement that children are not little adults. This review summarises information gathered from existing reports and focuses on the tolerabilities of antiretrovirals in children infected with HIV-1. The efficacy of antiretrovirals is not included in the scope of the discussion. Taste of antiretrovirals should be an important factor when considering the tolerability of antiretrovirals in children. However, antiretroviral options are often limited in young children as only some of the antiretrovirals are available as paediatric formulations. All antiretrovirals have been associated with toxicities in children, but in general, they are relatively well tolerated. The gastrointestinal system including hepatic system is most prone to being affected by these drugs. Skin rashes and hypersensitivity reactions are also associated with antiretroviral use, particularly with the non-nucleoside reverse transcriptase inhibitors. Mitochondrial toxicities that lead to impairment of liver function, pancreatic function and lactic acidosis are associated with most of the nucleoside analogues. Haematological toxicity is often a dose limiting adverse effect especially of the nucleoside analogues, in particular zidovudine. The protease inhibitors are associated with gastrointestinal intolerance (diarrhoea) and metabolic derangements that can lead to hypercholesterolaemia and hypertriglyceridaemia, which in turn and can lead to changes in body habitus. The renal system is also affected by several drugs, the most important of which is indinavir, which has been associated with renal stones and damage to the renal tubules. Fortunately, with lower incidence of major toxicity and with the range of drugs now available for paediatric use, toxicities are usually not a barrier to effect antiretroviral therapy in children.

Safety of intravitreous fomivirsen for treatment of cytomegalovirus retinitis in patients with AIDS

PURPOSE

To report data regarding the safety of intravitreous fomivirsen for treatment of cytomegalovirus (CMV) retinitis in patients with acquired immunodeficiency syndrome (AIDS).

DESIGN

Critical review of safety data from three randomized controlled clinical trials with supplemental information from an expanded drug access program.

METHODS

Adverse ocular events reported by clinician investigators were listed using terms modified from the COSTART dictionary. Data for two doses (165-microg/injection [35 eyes, 30 patients] and 330-microg/injection [153 eyes, 120 patients]) and two 330-microg/injection dose schedules of different intensity were pooled to calculate incidence rates for each event. Rates were calculated as "events/patient-year" (based on total cumulative reported events and duration of treatment) for events that could recur during treatment. Rates were calculated as "patients with events/person-year" for the following events: retinal detachment, cataract, visual field disturbance, and retinal pigment epitheliopathy. To assess the ability to manage events, we reviewed treatments given for two events (anterior chamber inflammation, increased intraocular pressure) in one trial. We also report an analysis comparing the proportion of eyes that developed one or more key events to the cumulative number of injections.

RESULTS

Incidence rates were dose and schedule dependent (165 microg/injection, 4.06 events/patient-year; 330 microg/injection, 6.58 events/patient-year [less intense regimen] and 8.35 events/patient-year [more intense regimen]). The most frequently reported events were anterior chamber inflammation and increased intraocular pressure. We found no evidence that the proportion of patients with events increased as the number of injections increased.

CONCLUSIONS

Intravitreous fomivirsen is well tolerated with an acceptable safety profile. Adverse ocular events associated with doses and schedules used clinically can be managed successfully with medical therapy.

Retinal microvasculopathy in human immunodeficiency type 1 (HIV)-infected children

PURPOSE

To report two cases of retinal peripheral lesions in vertically HIV-infected children.

METHODS

Complete ophthalmological examinations were performed in both cases over a period of four years.

RESULTS

We found retinal peripheral lesions in four eyes of two patients who were referred to us for routine examination. Both cases showed focal, segmental and white patches around the vessel wall in the far periphery and at the equator. These findings hardly changed after 3.5 and 2.5 years of follow-up, respectively. We suppose the cause of these lesions is an immune-mediated reaction.

CONCLUSIONS

Even although there is a low incidence of retinal alterations in pediatric patients infected by HIV, we believe that complete and systematic ophthalmic examinations should be performed in these children.

Chronic multifocal retinal infiltrates in patients infected with human immunodeficiency virus

PURPOSE

To describe the clinical features of a disorder characterized by chronic multifocal retinal infiltrates and uveitis in individuals with human immunodeficiency virus (HIV) disease.

METHODS

We reviewed the medical records of HIV-infected patients with multifocal retinal infiltrates of unknown cause seen by investigators at four institutions. The following data were collected: demographic characteristics, presenting signs and symptoms, laboratory test results, and course of disease.

RESULTS

We identified 26 HIV-infected patients (50 involved eyes) with this syndrome. Median CD4+ T-lymphocyte count at presentation was 272 per microl (range, 7 to 2,118 per microl). The most common presenting symptom was floaters. Median visual acuity of involved eyes at presentation was 20/20 (range, 20/15 to 20/100) and remained stable (median, 20/20; range, 20/15 to 20/70) after a median follow-up period of 9 months (range, 0 to 110 months). Typical retinal lesions were gray-white or yellow, irregular in shape, and less than 200 microm in greatest dimension. All were located in the midperiphery or anterior retina and enlarged slowly or remained static in size. Mild to moderate anterior chamber or vitreous humor inflammatory cells were present in 47 of 50 eyes (26 of 26 patients). Retinal lesions possibly responded to zidovudine but not to acyclovir or ganciclovir. Anterior chamber and vitreous humor inflammatory reactions responded to topical or periocular injections of corticosteroid.

CONCLUSIONS

Uveitis with chronic multifocal retinal infiltrates is a distinct clinical entity of unknown cause that occurs in HIV-infected patients. Retinal lesions may respond to antiretroviral therapy. Visual prognosis is good.

Electroretinographic and psychophysical findings during early and late stages of human immunodeficiency virus infection and cytomegalovirus retinitis

PURPOSE

The authors examined electrophysiologic and psychophysical measures of retinal function in patients infected with human immunodeficiency virus (HIV) at different stages of infection, including patients with cytomegalovirus retinitis (CMVR).

METHODS

All patients had complete ophthalmologic examinations. Rod-mediated psychophysical thresholds were measured using a modified two-color dark-adapted perimetry technique. Rod-dominated full field flash electroretinograms (ERGs) were obtained as a function of flash intensity, followed by cone-dominated ERGs. The 26 patients infected with HIV (26 eyes) were categorized into three groups. Six patients were infected with HIV but had not progressed to acquired immunodeficiency syndrome (AIDS), and 14 had AIDS. Six patients had CMVR with less than 10% of the retina involved. The data were compared with results from age-similar control subjects.

RESULTS

Psychophysical thresholds as a function of retinal eccentricity were elevated for each of the three stages of HIV infection. The group of patients with CMVR had the greatest amount of threshold elevation and threshold elevation increased with retinal eccentricity. In addition, all three patient groups had abnormal electroretinographic findings. Patients with CMVR were affected more severely on all measures than were the other HIV-infected groups.

CONCLUSIONS

Results reveal that a diffuse functional retinal pathology exists in eyes with the funduscopic appearance of localized peripheral CMVR. Additionally, patients infected with HIV, including those without cotton wool spots, may have abnormal retinal function.

Ophthalmic complications of HIV infection

HIV retinopathy, a noninfectious microangiopathy, is the most common ocular manifestation of HIV infection. Opportunistic infections, neoplasms, neuro-ophthalmic lesions, and drug-induced lesions may also cause ocular problems. Opportunistic ocular infections, particularly CMV retinitis, are a major cause of morbidity in patients with AIDS. Because of the underlying chronic and progressive immune dysfunction, the ocular symptoms, signs, clinical course, and treatment are often atypical and severe, requiring protracted medical therapy.

Treatment of HIV infection. Tolerability of commonly used antiretroviral agents

There are a number of agents available that are active against HIV. Eight drugs are already licensed in the US: the nucleoside analogue reverse transcriptase inhibitors--zidovudine, didanosine, zalcitabine, stavudine and lamivudine--and the HIV protease inhibitors--saquinavir, indinavir and ritonavir. Antiretroviral drugs have been given as monotherapy, often as sequential monotherapy, and in alternating or simultaneous combinations. Since combination therapy has recently been shown to be superior to monotherapy, antiretrovirals will increasingly be given in combination. All available antiretroviral drugs show considerable toxicity complicating their use. In this article we describe the adverse effects of the above mentioned nucleoside analogues used in monotherapy and of several combinations of antiretroviral drugs. No unexpected toxicities were found in several different combinations tested to date and, for most combinations, no synergistic toxic effects have been reported.

Corneal lipidosis in patients with the acquired immunodeficiency syndrome

PURPOSE

Certain drugs bind to anionic phospholipids of lysosomal membranes and produce progressive intracellular accumulation of lamellar inclusions. We studied two patients treated for opportunistic infections associated with the acquired immunodeficiency syndrome (AIDS), who developed bilateral ocular surface changes suggestive of drug-induced corneal lipidosis.

METHODS

Two patients with AIDS had translucent vacuoles within the corneal epithelium and mild conjunctival hyperemia. Because the differential diagnosis included microsporidial keratoconjunctivitis, biopsies of the ocular surface were performed for histopathologic analysis.

RESULTS

Transmission electron microscopy of corneal epithelial debridement and conjunctival biopsy specimens showed intracellular, electron-dense lipoidal bodies and multilaminated lysosomal inclusions suggestive of a drug-induced lipidosis. Both patients also had tubuloreticular inclusions in conjunctival capillary endothelial cells. The ocular surface changes resolved within one to three months after dosage reduction or discontinuation of systemic ganciclovir and acyclovir.

CONCLUSIONS

Drug-induced phospholipidosis is a cause of punctate corneal epitheliopathy during AIDS, but the responsible agent remains to be identified.

Randomized study of two doses of didanosine in children infected with human immunodeficiency virus

2'3'-Dideoxyinosine (didanosine) is a nucleoside analog active in vitro against human immunodeficiency virus. Few data are available regarding its use for the treatment of children. In a single-center, randomized, open-label trial, we compared two dosages of didanosine (120 vs 270 mg/m2 per day) for at least 6 months in 34 children infected with human immunodeficiency virus who had become resistant to or were intolerant of zidovudine. Serum levels of didanosine 1 hour after administration were significantly different in the two groups and remained stable with time. There was a significant reduction in human immunodeficiency virus-p24 antigenemia and quantitative cellular viremia with time but no difference between the two groups. The intensity of the biologic response, however, was significantly higher in the patients who had more than 50 CD4+ cells 10(6)/L at inclusion. No pancreatic or neurologic toxic effects were observed. In five children, liver function abnormalities developed that are unusual in this setting, and the death of one child from unexplained hepatocellular failure suggests that didanosine may be hepatotoxic. Three of these five children had preexisting liver disease. Although no definite conclusion can be made as to the optimal dose, there were no major differences between the two administration schedules in terms of biologic effects and tolerability.

Treatment of HIV infection: the antiretroviral nucleoside analogues. Nucleoside analogues: adverse effects

The three approved nucleoside analogues are fairly well tolerated, and only a few patients have to discontinue therapy permanently. However, because clinical experience is limited, especially with ddI and ddC, delayed toxicities are likely to emerge over time. In addition, physicians should be vigilant for overlapping toxicities from combination therapy with these and other medications.

Systemic antiviral drugs used in ophthalmology

Over the past two decades, the recognition of viral enzymes and proteins that can serve as molecular targets of drugs has revolutionized the treatment of viral infections. Beginning with acyclovir, a number of systemically administered agents which are both relatively safe and effective for the treatment of herpetic infections and human immunodeficiency virus (HIV) infections have become widely available. Because of increased numbers of herpes virus infections, as well as the rising epidemic of HIV infections, the ophthalmologist is, more likely than ever before to be involved in the treatment of severe and frequent ocular infections caused by herpes viruses. In addition, the acute retinal necrosis (ARN) syndrome has been demonstrated to be caused by herpes viruses and a once rare retinal infection caused by cytomegalovirus is common in patients with the acquired immunodeficiency syndrome (AIDS). In this article, four systemic antiviral drugs (Vidarabine, Acyclovir, Ganciclovir, and Foscarnet) that have demonstrated usefulness in the treatment of ophthalmic disease are reviewed in detail with regard to their mechanisms, applications, effectiveness, and side effects.