Ocular toxoplasmosis in human immunodeficiency virus-infected patients

Long-Term Low-Dose Pyrimethamine Use for the Prevention of Ocular Toxoplasmosis Recurrences: A Cohort Study

PURPOSE

To describe the effect of long-term, low-dose pyrimethamine for the prevention of ocular toxoplasmosis (OT) recurrences.

METHODS

Sixty-three consecutive patients with inactive ocular toxoplasmosis and positive toxoplasma IgG serology were included. Pyrimethamine (25 mg) + folinic acid (15 mg) were administered every other day (three times weekly) for 12 months. Eighteen patients received the treatment for an additional six months as part of an extension study.

RESULTS

Thirty-eight patients (60.3%, n = 63) were female; 38 (60.3%) had a previous history of recurrence and 37 (58.7%) had active OT within the preceding 12 months. Three (4.8%) patients had unilateral recurrences at 8, 12 and 18 months after starting intermittent pyrimethamine treatment. Five patients (7.9%) were discontinued due to hematological, renal and hepatic changes. Treatment was considered successful in 42 patients (84%).

CONCLUSION

Long-term, low-dose pyrimethamine can be considered as a treatment option for the prevention of ocular toxoplasmosis recurrence in selected patients, with only a few, mild and reversible systemic adverse events.

Risk factors for recurrences and visual impairment in patients with ocular toxoplasmosis: A systematic review and meta-analysis

BACKGROUND

Ocular toxoplasmosis (OT) is caused by the parasite Toxoplasma gondii. OT is the leading cause of posterior uveitis globally; it is a recurrent disease that may result in visual impairment and blindness. This systematic review and meta-analysis aim to summarize and evaluate the risk factors for recurrences, visual impairment, and blindness described in the literature worldwide.

METHODS AND FINDINGS

We performed a systematic literature search in PubMed, Embase, VHL, Cochrane Library, Scopus, and DANS EASY Archive. All studies reporting patients with clinically and serologically confirmed OT presenting any clinical or paraclinical factor influencing recurrences, visual impairment, and blindness were included. Studies presenting secondary data, case reports, and case series were excluded. An initial selection was made by title and abstract, and then the studies were reviewed by full text where the eligible studies were selected. Then, the risk of bias was assessed through validated tools. Data were extracted using a validated extraction format. Qualitative synthesis and quantitative analysis were done. This study was registered on PROSPERO (CRD42022327836).

RESULTS

Seventy two studies met the inclusion criteria. Fifty-three were summarized in the qualitative synthesis in three sections: clinical and environmental factors, parasite and host factors, and treatment-related factors. Of the 72 articles, 39 were included in the meta-analysis, of which 14 were conducted in South America, 13 in Europe, four in Asia, three multinational, two in North America and Central America, respectively, and only one in Africa. A total of 4,200 patients with OT were analyzed, mean age ranged from 7.3 to 65.1 year of age, with similar distribution by sex. The frequency of recurrences in patients with OT was 49% (95% CI 40%-58%), being more frequent in the South American population than in Europeans. Additionally, visual impairment was presented in 35% (95% CI 25%-48%) and blindness in 20% (95% CI 13%-30%) of eyes, with a similar predominance in South Americans than in Europeans. On the other hand, having lesions near the macula or adjacent to the optic nerve had an OR of 4.83 (95% CI; 2.72-8.59) for blindness, similar to having more than one recurrence that had an OR of 3.18 (95% CI; 1.59-6.38). Finally, the prophylactic therapy with Trimethoprim/Sulfamethoxazole versus the placebo showed a protective factor of 83% during the first year and 87% in the second year after treatment.

CONCLUSION

Our Systematic Review showed that clinical factors such as being older than 40 years, patients with de novo OT lesions or with less than one year after the first episode, macular area involvement, lesions greater than 1 disc diameter, congenital toxoplasmosis, and bilateral compromise had more risk of recurrences. Also, environmental and parasite factors such as precipitations, geographical region where the infection is acquired, and more virulent strains confer greater risk of recurrences. Therefore, patients with the above mentioned clinical, environmental, and parasite factors could benefit from using prophylactic therapy.

Pathophysiological Aspects of Ocular Toxoplasmosis: Host-parasite Interactions

Purpose: This review aims to present the state of the art to understand the pathophysiology of ocular toxoplasmosis (OT), providing further foundations that would help to improve the future treatment and prognosis of this potentially blinding disease.Methods: A thorough literature search was performed in PubMed database. An additional search was made in Google Scholar to complete the collected items.Results: Toxoplasma gondii ocular infection is one of the most frequent causes of posterior uveitis. Despite the ocular barriers, the parasite reaches the eye through different mechanisms. Once inside, it remains encysted livelong within the retina, and recurrences cannot be completely avoided. The complexity of host-parasite interactions, leading to the success of this parasite, encompasses host factors such as genetic predisposition, immune status, and age; and parasite factors such as strain diversity, virulence, phylogenetic origin, and geographical distribution. These factors influence the clinical presentation, course, and progression of the disease. Additional elements, such as pregnancy, eating behavior, and environmental, social, and cultural factors may also contribute to this complex balance.Conclusions: The host-parasite interaction in OT is a complex and multifactorial relationship, with the parasite always on the driving edge of the game. There are still multiple incompletely understood fields to be investigated. Future research would permit further insight into the immune-biology of the parasite and recognition of the host-parasite interplay to improve the diagnostic and management performance.

Management of Intraocular Infections in HIV

Purpose: Overview of treatment options for the most common intraocular opportunistic infections in patients with acquired immunodeficiency syndrome (AIDS), including ocular syphilis, ocular tuberculosis, toxoplasmic chorioretinitis, and viral retinitis. Method: Narrative Review. Results: Despite the huge advances in the development of combined antiretroviral therapy (cART) for the management of patients with human immunodeficiency virus (HIV) infection, opportunistic infections still represent a significant diagnostic dilemma and cause of ocular morbidity in patients with HIV. Conclusion: Although the treatment of intraocular infections in patients with AIDS may be challenging, prompt assessment of the clinical features and appropriate aggressive management of the underlying etiology are critical to avoid life and vision threatening.

Disease of the Year 2019: Ocular Toxoplasmosis in HIV-infected Patients

Ocular toxoplasmosis (OT) may be an initial manifestation of acquired immunodeficiency syndrome (AIDS) in human immunodeficiency virus (HIV)-infected patients. OT has different clinical manifestations and can mimic other intraocular infections. Clinical findings may show single or multifocal retinochoroidal lesions or panuveitis. Atypical presentations are associated with extensive uni- or bilateral areas of retinal necrosis. OT lesions not associated with preexisting retinochoroidal scars are usually due to acquired rather than congenital infection. When CD4+ T cell counts are <100 c/uL, vitritis is frequently mild. Isolated anterior uveitis has been reported in single cases. Positive immunoglobulin M (IgM) antibodies are rare but their presence can support the diagnosis. As atypical presentations of OT are common, anterior chamber puncture for multiplex polymerase chain reaction amplification of infectious DNA should be considered, as early diagnosis and treatment can prevent massive tissue destruction and preserve vision. This review provides an overview of OT in HIV-infected patients.

Challenges in Treating Intraocular Inflammation in HIV Patients

Purpose: To describe the challenges faced by uveitis specialists when managing human immunodeficiency virus (HIV) -infected patients diagnosed with ocular opportunistic infections. Methods: Narrative Review Results: Management of opportunistic ocular infections in HIV-infected subjects still represents a diagnostic and therapeutic challenge. Atypical and aggressive clinical features can often mislead the correct diagnosis, leading to a delay in therapy and thus, a poor clinical outcome. The reliability of standard serological tests may be affected by the immune system response, further contributing to the diagnostic challenge. Life-long monitoring and long-term antimicrobial maintenance are necessary to avoid recurrences and disease dissemination. Conclusions: A multidisciplinary approach is needed to achieve the best standard of care for HIV patients with ocular opportunistic infections.

Endogenous endophthalmitis and other ocular manifestations of injection drug use

PURPOSE OF REVIEW

The United States has experienced a dramatic rise in opioid and injection drug use over the past 2 decades. A public health emergency was declared in 2017 and subsequently, there have been several new reports on the rise of endogenous endophthalmitis specifically associated with injection drug use. The purpose of this review is to provide a current perspective of the ocular harms posed by injection drug use.

RECENT FINDINGS

The opioid epidemic has prompted several new studies from New England, one of the US regions most heavily affected, that examine the trends and characteristics of injection drug use-associated endogenous endophthalmitis. Patients may delay seeking care and may be infected with a variety of rare and atypical microbes, and as a result clinical appearance may vary widely. Injection drug use also leads to embolic phenomena such as talc retinopathy and septic emboli from endocarditis. HIV is highly associated with injection drug use and although HAART has drastically reduced the morbidity and mortality of HIV-associated infections, a variety of ocular disease may accompany an immunocompromised patient.

SUMMARY

Healthcare providers must remain vigilant in the recognition of injection drug use patients with vision loss and ocular inflammation to ensure prompt medical and/or surgical treatment.

HIV-associated opportunistic CNS infections: pathophysiology, diagnosis and treatment

Nearly 30 years after the advent of antiretroviral therapy (ART), CNS opportunistic infections remain a major cause of morbidity and mortality in HIV-positive individuals. Unknown HIV-positive disease status, antiretroviral drug resistance, poor drug compliance, and recreational drug abuse are factors that continue to influence the morbidity and mortality of infections. The clinical and radiographic pattern of CNS opportunistic infections is unique in the setting of HIV infection: opportunistic infections in HIV-positive patients often have characteristic clinical and radiological presentations that can differ from the presentation of opportunistic infections in immunocompetent patients and are often sufficient to establish the diagnosis. ART in the setting of these opportunistic infections can lead to a paradoxical worsening caused by an immune reconstitution inflammatory syndrome (IRIS). In this Review, we discuss several of the most common CNS opportunistic infections: cerebral toxoplasmosis, progressive multifocal leukoencephalopathy (PML), tuberculous meningitis, cryptococcal meningitis and cytomegalovirus infection, with an emphasis on clinical pearls, pathological findings, MRI findings and treatment. Moreover, we discuss the risk factors, pathophysiology and management of IRIS. We also summarize the challenges that remain in management of CNS opportunistic infections, which includes the lack of phase II and III clinical trials, absence of antimicrobials for infections such as PML, and controversy regarding the use of corticosteroids for treatment of IRIS.

Ocular toxoplasmosis: background and evidence for an antibiotic prophylaxis

PURPOSE OF REVIEW

The purpose of this review was to provide an overview of current data on antibiotic prophylaxis in ocular toxoplasmosis.

RECENT FINDINGS

Studies showing the prophylactic effect of long-term antibiotics are discussed. Prophylaxis seems to be justified in patients with a high risk of recurrence because of antibiotic's potential side-effects. Therefore, predisposing factors leading to a higher risk of recurrence and the time period during which an antibiotic prophylaxis is most appropriate are reviewed. Finally, a patient-individualized treatment recommendation is summarized.

SUMMARY

In the current literature, two prospective, randomized case-control studies exist, which show the protective effect of an antibiotic prophylaxis. Hematologic, gastrointestinal and dermatologic complications are potential side-effects. Especially during the first year after suffering a recurrence, an antibiotic prophylaxis seems to be justified. The risk of a recurrence is inter alia influenced by the duration of the disease, the immune status of the host and the patient's age. Therefore, an antibiotic prophylaxis should be considered for patients who have recently been infected with ocular toxoplasmosis, for middle-aged and elderly patients and patients with a compromised immune system. This should be discussed with each patient individually, especially if the lesion is close to the macula.

Time patterns of recurrences and factors predisposing for a higher risk of recurrence of ocular toxoplasmosis

PURPOSE

To ascertain time patterns of recurrences and factors predisposing for a higher risk of recurrence of ocular toxoplasmosis.

METHODS

Retrospective observational case series with follow-up examination. Database of 4,381 patients with uveitis was used. Data of 84 patients with ocular toxoplasmosis (sample group) could be included.

RESULTS

Two hundred and eighty active lesions in the first affected eye were detected. The mean number of recurrences per year was 0.29 (standard deviation, 0.24). Median recurrence-free survival time was 2.52 years (95% confidence interval, 2.03-3.02 years). Risk of recurrence was highest in the first year after the most recent episode (26%) implying a decrease with increasing recurrence-free interval. The risk of recurrence decreased with the duration of disease (P < 0.001). Treatment of the first active lesion influenced the risk of recurrence (P = 0.048). Furthermore, the risk of recurrence was influenced by patient age at the time of the first active lesion (P = 0.021) and the most recent episode (P = 0.002).

CONCLUSION

A secondary antibiotic prophylaxis could be discussed 1) during the first year after an active lesion has occurred, especially in case of the first active lesion of ocular toxoplasmosis, and 2) in older patients, especially if primarily infected with Toxoplasma gondii at an older age.

Risk of Recurrence of Preexisting Ocular Toxoplasmosis during Pregnancy

PURPOSE

Comparison between the risk of recurrence during pregnancy with nonpregnant periods in patients with ocular toxoplasmosis (OT).

METHODS

Records of 40 women were retrospectively reviewed. The women were subdivided into either a pregnant group or a control group formed by nonpregnant women during follow-up. Comparable cases from the literature were added. Mean number of recurrences per year was compared.

RESULTS

Eleven women with pregnancies could be included. Six cases from the literature were added (total n = 17). Mean number of recurrences per year during versus not during pregnancy was 0.16 (SD 0.39) versus 0.32 (SD 0.30; p = 0.088), respectively. In the control group (n = 29) the mean number of recurrences per year (0.31; SD 0.27) was significantly higher when compared to cases during pregnant periods (p = 0.002).

CONCLUSION

Adding to published series, the presented data do not provide evidence for a relevant impact of pregnancy on recurrence behavior in OT.

Clinical features and treatment of ocular toxoplasmosis

Ocular toxoplasmosis is a disease caused by the infection with Toxoplasma gondii through congenital or acquired routes. Once the parasite reaches the retina, it proliferates within host cells followed by rupture of the host cells and invasion into neighboring cells to make primary lesions. Sometimes the restricted parasite by the host immunity in the first scar is activated to infect another lesion nearby the scar. Blurred vision is the main complaint of ocular toxoplasmic patients and can be diagnosed by detection of antibodies or parasite DNA. Ocular toxoplasmosis needs therapy with several combinations of drugs to eliminate the parasite and accompanying inflammation; if not treated it sometimes leads to loss of vision. We describe here clinical features and currently available chemotherapy of ocular toxoplasmosis.

Ocular toxoplasmosis II: clinical features, pathology and management

The term, ocular toxoplasmosis, refers to eye disease related to infection with the parasite, Toxoplasma gondii. Recurrent posterior uveitis is the typical form of this disease, characterized by unilateral, necrotizing retinitis with secondary choroiditis, occurring adjacent to a pigmented retinochoroidal scar and associated with retinal vasculitis and vitritis. Multiple atypical presentations are also described, and severe inflammation is observed in immunocompromised patients. Histopathological correlations demonstrate focal coagulative retinal necrosis, and early in the course of the disease, this inflammation is based in the inner retina. For typical ocular toxoplasmosis, a diagnosis is easily made on clinical examination. In atypical cases, ocular fluid testing to detect parasite DNA by polymerase chain reaction or to determine intraocular production of specific antibody may be extremely helpful for establishing aetiology. Given the high seroprevalence of toxoplasmosis in most communities, serological testing for T. gondii antibodies is generally not useful. Despite a lack of published evidence for effectiveness of current therapies, most ophthalmologists elect to treat patients with ocular toxoplasmosis that reduces or threatens to impact vision. Classic therapy consists of oral pyrimethamine and sulfadiazine, plus systemic corticosteroid. Substantial toxicity of this drug combination has spurred interest in alternative antimicrobials, as well as local forms of drug delivery. At this time, however, no therapeutic approach is curative of ocular toxoplasmosis.

Prevalence, clinical characteristics, and causes of vision loss in patients with ocular toxoplasmosis

PURPOSE

To describe the prevalence, demographics, clinical features, and contributors to vision loss at presentation in a large cohort of patients with ocular toxoplasmosis seen at a tertiary referral center in northern California.

METHODS

A retrospective review of the charts of 233 patients with ocular toxoplasmosis examined over 24 years.

RESULTS

Ocular toxoplasmosis was diagnosed in 233 (8.4%) of 2761 patients with uveitis. The mean age at presentation was 27.2 years. Patients with ocular toxoplasmosis were more likely to be young (p<0.01), male (p<0.001), and Latino (p<0.001) as compared with patients in the entire uveitis cohort. At presentation, 159 patients (68.2%) had active disease, which was unilateral in all but one. Among the 160 eyes with active disease, 145 (90.6%) presented with a focal retinochoroiditis, 57.2% of which had an adjacent retinochoroidal scar. Atypical presentations occurred in 11 patients (6.9%). Of eyes with active disease, the main contributors to vision loss at presentation were intraocular inflammation (74.8%) and macular involvement (24.3%), whereas in eyes with inactive lesions the main contributors to vision loss were macular scar formation (67.9%) and amblyopia (11.3%). Younger age was the single significant predictor of macular involvement.

CONCLUSIONS

Ocular toxoplasmosis is a common cause of uveitis. Our patients were more likely than general uveitis patients to be young, male, and Latino, often having emigrated from Mexico or Central or South America. The most common contributors to decreased vision in eyes with active lesions were inflammation and macular involvement, whereas in eyes with inactive lesions they were macular scar formation and amblyopia.

Therapy for ocular toxoplasmosis

PURPOSE

To review current evidence for the treatment of ocular toxoplasmosis (OT).

DESIGN

Narrative review and expert recommendations.

METHODS

Meta-analysis and selected original articles from the medical literature were reviewed critically. Expert recommendations were analyzed.

RESULTS

Numerous observational studies suggest a benefit of short-term antimicrobial therapy for toxoplasmic retinochoroiditis in immunocompetent patients, although its efficacy has not been proven in randomized clinical trials. A randomized clinical trial revealed that intermittent trimethoprim/sulfamethoxazole treatment could decrease the rate of recurrence in high-risk patients. Intravitreal injection of clindamycin and dexamethasone was an acceptable alternative to the classic treatment for OT in a randomized clinical trial.

CONCLUSIONS

Opinions about therapy differ and controversy remains about its type, efficacy, and length. Intravitreal therapy may be promising for OT. A recent description of the presence of parasitemia in patients with active and inactive ocular toxoplasmosis raises new questions that need to be explored.

Treating ocular toxoplasmosis: current evidence

The current treatment of ocular toxoplasmosis is controversial. The mainstay of treatment has been pyrimethamine and sulphonamides with or without systemic corticosteroids, but the actual evidence that antibiotics have a beneficial effect in recurrent toxoplasmic retinochoroiditis is unsupported by randomised placebo controlled trials. Thus far there have only been three studies looking at the efficacy of antibiotic treatment, all of which were methodologically weak and two of which were perfomed more than 30 years ago. All studies reported adverse effects from treatment. There is an urgent need for further randomised, double blind, placebo controlled studies for lesions in all parts of the retina and to test the efficacy of adjunctive corticosteroid treatment.

Avaliação oftalmológica em pacientes com AIDS e neurotoxoplasmose

INTRODUÇÃO: Descrever os achados fundoscópicos em pacientes com AIDS e neurotoxoplasmose em fase ativa. MÉTODOS: Foi desenvolvido estudo prospectivo tipo série de casos incluindo 70 pacientes, de ambos os sexos, com idade variando de 20 a 63 anos, internados nas enfermarias de três hospitais públicos da Cidade do Recife, Pernambuco, com diagnósticos de AIDS e neurotoxoplasmose firmados segundo os critérios do Centers for Disease Control and Prevention (1992), no período de janeiro a outubro de 2008. Os pacientes se caracterizavam por: primeiro episódio de neurotoxoplasmose (65; 92,9%) ou recidiva (5; 7,1%); desconhecimento de ter AIDS (23; 32,9%), contagem média de linfócitos T CD4 de 139,8 ± 3,04 células/mm3 e carga viral média igual a 137.080 ± 39.380 cópias/mL. Todos foram submetidos a exame oftalmológico, consistindo de: inspeção ocular; aferição da acuidade visual; investigação da função muscular extrínseca ocular e fundoscopia, empregando oftalmoscópio indireto binocular (modelo OHN 3.5 (Eyetec®) e lente externa de 20 dioptrias (Volk®). RESULTADOS: Os achados consistiram em: exsudatos algodonosos retinianos (8,6%), constricção arteriolar difusa leve (8,6%); lesões de retinocoroidite cicatricial, características de toxoplasmose ocular (5,7%), atrofia do epitélio pigmentar retiniano (2,9%), descolamento da retina (2,9%), aumento de escavação papilar (1,4%), degeneração periférica retiniana (1,4%), macroaneurisma (1,4%), papiledema bilateral (1,4%), tração vítreo-retiniana (1,4%). CONCLUSÕES: Pacientes com AIDS e neurotoxoplasmose podem apresentar alterações fundoscópicas características da toxoplasmose ocular, na forma ativa ou cicatricial, relacionadas ao HIV ou, ainda, a outras doenças oportunistas ou sistêmicas, podendo ser de grande auxílio num tratamento integral do paciente por uma equipe multiprofissional.

[Ocular toxoplasmosis]

Toxoplasmosis is a parasitic zoonosis which occurs worldwide and is an important cause of blindness. The infection is naturally acquired by the ingestion of oocysts excreted by infected cats or by ingestion of tissue cysts in undercooked or raw meat. Primary infection during pregnancy may result in a congenital infection. Toxoplasmic retinochoroiditis is the most common cause of posterior uveitis in immunocompetent patients. Depending on the patient's age, ocular symptoms vary presenting with reduced visual acuity, strabismus, and nystagmus in young children - in adults decreased vision and floaters are most frequently reported. Active toxoplasmic retinochoroiditis typically presents as grey-white retinal necrosis with choroiditis, vasculitis and vitritis. However, atypical presentations including neuroretinitis, papillitis, Fuchs-like anterior uveitis, scleritis and acute retinal necrosis have been described. The diagnosis is based on clinical findings and can be supported by the detection of antibodies and Toxoplasma gondii DNA. Toxoplasmosis therapy includes antimicrobial drugs and corticosteroids. There are several regimens with different drug combinations including, among others, pyrimethamine, sulfadiazine, clindamycin, and trimethoprim-sulfamethoxazol. The prognosis for ocular toxoplasmosis is favorable in immunocompetent individuals, as long as the central macula is not directly involved. The present article reviews the epidemiology, pathogenesis, clinical presentation and management of toxoplasmic retinochoroiditis.

Toxoplasmosis

Toxoplasmosis is the most common cause of posterior uveitis in immunocompetent subjects. The infection can be congenital or acquired. Ocular symptoms are variable according to the age of the subject. For instance, young children present with reduced visual acuity, strabismus, nystagmus, and leucocoria, while teenagers and adults complain of decreased vision, floaters, photophobia, pain, and hyperemia. Toxoplasmic retinochoroiditis typically affects the posterior pole, and the lesions can be solitary, multiple or satellite to a pigmented retinal scar. Active lesions present as grey-white focus of retinal necrosis with adjacent choroiditis, vasculitis, hemorrhage and vitreitis. Cicatrization occurs from the periphery towards the center, with variable pigmentary hyperplasia. Anterior uveitis is a common finding, with mutton-fat keratic precipitates, fibrine, cells and flare, iris nodules and posterior synechiae. Atypical presentations include punctate outer retinitis, neuroretinitis, papillitis, pseudo-multiple retinochoroiditis, intraocular inflammation without retinochoroiditis, unilateral pigmentary retinopathy, Fuchs'-like anterior uveitis, scleritis and multifocal or diffuse necrotizing retinitis. The laboratory diagnosis of toxoplasmosis is based on detection of antibodies and T. gondii DNA using polymerase chain reaction (PCR). Toxoplasmosis therapy includes specific medication and corticosteroids. There are several regimens, with different drug combinations. Medications include pirimetamine, sulfadiazine, clindamycin, trimethoprime-sulphamethoxazol, spiramycin, azithromycin, atovaquone, tetracycline and minocycline. The prognosis of ocular toxoplasmosis is usually good in immunocompetent individuals, as long as the central macula is not directly involved.

Ocular association of HIV infection in the era of highly active antiretroviral therapy and the global perspective

Ocular involvement is a common complication of HIV infection. Since the late 1990s, widespread use of highly active antiretroviral therapy (HAART) has altered the spectrum, and reduced the incidence of ocular involvement in developed countries. The incidence of the most common ocular opportunistic infection, cytomegalovirus retinitis, has decreased tremendously. However, immune recovery uveitis secondary to HAART has emerged as a frequent visually threatening condition. Early diagnosis and treatment with periocular steroids is helpful in minimizing visual loss. Clinicians should also be aware that certain antimicrobial agents used to treat opportunistic infections in HIV-positive patients are associated with potentially serious ocular side effects. In developing countries, where most of the world's 40 million HIV-positive patients live, the spectrum and incidence of ocular involvement differ from those in developed countries. The lack of HAART availability is among the many causes of these differences, which may include nutritional factors, basic medical care availability and the levels of exposure to different infectious agents. These factors add to the already challenging task of treating ocular complications and preventing blindness in HIV-positive patients in developing countries.

Delayed diagnosis of HIV infection in ophthalmic practice

The introduction of potent antiretroviral drug combinations has transformed human immunodeficiency virus/acquired immunodeficiency disease syndrome (HIV/AIDS) from an intractable and rapidly fatal disease to a chronic manageable illness with prolonged life survival for many patients. This paper discusses the ophthalmic and medical histories of two young female patients who presented with 'atypical' optic neuropathy and toxoplasma gondii retinochoroiditis and were later found to be HIV infected. We discuss the need for increased vigilance in the ophthalmic community for suspecting HIV infection to allow optimal management of the ophthalmic and systemic manifestations of the disease spectrum associated with HIV/AIDS.

HIV/AIDS and the eye

The type of ocular involvement in the patient with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) depends on the level of immune function and systemic diseases present. Although the prognosis for patients with HIV/AIDS has changed dramatically with the introduction of antiretroviral therapy, infections involving the retina, such as toxoplasmosis, herpes simplex and herpes zoster (HZV), still occur although opportunistic infections such as cytomegalovirus (CMV) retinitis are much less common except in patients who present late in the course of the disease (Jabs and Bartlett, 1997; Jabs et al, 2002).

Atypical presentations of ocular toxoplasmosis

The diagnosis of ocular toxoplasmosis is based most often on the presence of characteristic clinical findings, which include focal retinochoroiditis, an adjacent or nearby retinochoroidal scar, and moderate to severe vitreous inflammation. However, a variety of less common, "atypical" presentations may be unfamiliar to clinicians, delaying both diagnosis and treatment. Patients who are immunocompromised or elderly may, for example, present with large, multiple and/or bilateral lesions. Other unusual manifestations include punctate outer retinal toxoplasmosis, retinal vasculitis, retinal vascular occlusions, rhegmatogenous and serous retinal detachments, a unilateral pigmentary retinopathy mimicking retinitis pigmentosa, neuroretinitis and other forms of optic neuropathy, and scleritis. Although in the past most cases of ocular toxoplasmosis were considered to result from reactivation of a congenital infection, it is now believed that postnatally acquired infection accounts for many cases of this disease. With appropriate use of antiparasitic therapy, the visual prognosis for patients with both typical and atypical forms of ocular toxoplasmosis may be good.

An update on current practices in the management of ocular toxoplasmosis

PURPOSE

To update information that was published by the AMERICAN JOURNAL OF OPHTHALMOLOGY in 1991 about treatment practices for ocular toxoplasmosis by uveitis specialists.

DESIGN

Physician survey.

METHODS

A written questionnaire was distributed to all physician-members (n = 147) of the American Uveitis Society. The questionnaire was modeled after a similar device used to survey uveitis specialists in 1991. Information contained on 96 returned questionnaires was tabulated.

RESULTS

Among 79 respondents who evaluate and manage patients with ocular toxoplasmosis, 15% treat all cases regardless of clinical findings (in contrast to 6% in 1991). The major indications for treatment among other respondents were severe inflammatory responses and proximity of retinal lesions to the fovea and optic disk. The majority of clinical factors considered in five categories (vision, lesion location, lesion size, lesion characteristics, and vitreous inflammatory reaction) were identified to be relative or absolute indications for treatment by a greater proportion of respondents in the current survey than in the 1991 survey. A total of nine drugs (or commercially available combinations) were used in 24 different regimens as treatments of choice for typical cases of recurrent toxoplasmic retinochoroiditis, with the combination of pyrimethamine, sulfadiazine, and prednisone being the most commonly used regimen (29% of respondents).

CONCLUSIONS

Uveitis specialists appear to be more likely to treat patients with ocular toxoplasmosis in 2001 than in 1991. Although the majority of survey respondents adhere to a traditional approach to the management of toxoplasmic retinochoroiditis (a discrete course of systemic drug treatment during active disease using multiple antiparasitic drugs with or without corticosteroids), there is still no consensus regarding the choice of antiparasitic agents for treatment regimens. Survey results provide useful information for treating physicians and for clinical investigators interested in therapy.

The effect of long-term intermittent trimethoprim/sulfamethoxazole treatment on recurrences of toxoplasmic retinochoroiditis

PURPOSE

To determine the effect of long-term intermittent trimethoprim/sulfamethoxazole treatment on recurrences of toxoplasmic retinochoroiditis.

DESIGN

Prospective randomized open-labeled interventional clinical trial.

METHODS

A total of 124 patients with a history of recurrent toxoplasmic retinochoroiditis were randomized to treatment with one tablet of trimethoprim (160 mg)/sulfamethoxazole (800 mg) (Bactrim F; Roche Pharmaceuticals, Rio de Janeiro, Brazil) every 3 days (61 patients) or to observation without treatment (63 patients) and were followed monthly for up to 20 consecutive months for clinical signs of disease recurrence. A recurrence was defined as a new focus of necrotizing retinochoroiditis with active inflammation either adjacent to or remote from preexisting retinochoroidal scars.

RESULTS

Recurrences developed in four (6.6%) treated patients and in 15 (23.8%) controls (P =.01). Treatment was discontinued prematurely in four patients because of mild drug reactions.

CONCLUSION

Long-term intermittent treatment with trimethoprim/sulfamethoxazole can reduce the rate of recurrent toxoplasmic retinochoroiditis.

Ocular toxoplasmosis after the fifth decade

PURPOSE

To describe the clinical features in patients presenting with ocular toxoplasmosis after the fifth decade and to analyze laboratory findings in comparison to uveitis history and clinical data.

DESIGN

Prospective consecutive observational case series.

METHODS

A prospective clinical analysis of 27 consecutive patients older than 50 years of age with primary or recurrent ocular toxoplasmosis was performed during a period of 8 years. These cases account for 12% of all ocular toxoplasmosis cases irrespective of age indexed in our institution during the same period. Paired serum and aqueous humor samples were tested for anti-Toxoplasma gondii IgG, IgM, and IgA antibodies. The presence of T. gondii DNA in aqueous humor was determined by polymerase chain reaction followed by DNA hydridization method.

RESULTS

Although similar in age, two groups were distinguished clinically: 12 patients (44%) presented with usual forms of retinochoroiditis (mean +/- SD, 1.6 +/- 0.5 disk areas [DA] in size); 15 patients (56%) presented with atypical lesions, greater than 3 DA in size (mean +/- SD, 5.0 +/- 2.0 DA). The second group showed a higher rate of complications (P =.028) and a poorer visual outcome (P =.015). Twenty-four patients (89%) had intraocular IgG production, 17 (63%) had intraocular IgA production, 3 (11%) had intraocular IgM production, and 12 (44%) had a positive T. gondii DNA detection.

CONCLUSIONS

After the fifth decade, ocular toxoplasmosis remains an important cause of posterior uveitis. The combination of antibody detection by immunocapture tests with T. gondii DNA detection, both in aqueous humor, allowed the diagnosis of toxoplasmic infection in the atypical cases with large ocular lesions.

Utility of tissue culture for detection of Toxoplasma gondii in vitreous humor of patients diagnosed with toxoplasmic retinochoroiditis

Laboratory recovery and confirmation of the etiologic agent in necrotizing retinochoroiditis are problematic. Tissue culture and intraocular antibody titers were compared as adjuncts to clinical diagnosis for toxoplasmic retinochoroiditis: the correlations were 91 and 67%, respectively. Isolation of Toxoplasma gondii may establish a definitive diagnosis in patients with toxoplasmic retinochoroiditis.

Azithromycin for ocular toxoplasmosis

AIMS

To investigate the efficacy of azithromycin in patients with ocular toxoplasmosis.

METHODS

11 immunocompetent patients with ocular toxoplasmosis were treated with azithromycin (500 mg the first day, followed by 250 mg/day for 5 weeks). Ocular and systemic examinations were performed during active retinitis episodes and all patients were followed for at least 1 year.

RESULTS

The intraocular inflammation disappeared within 4 weeks in seven patients, including two cases with progressive retinitis despite previous treatment with pyrimethamine, sulphadiazine, and folinic acid. Recurrence of retinitis occurred in three patients (27%) within the first year of follow up. No systemic side effects of azithromycin were encountered.

CONCLUSION

These results indicate that although azithromycin cannot prevent recurrent disease it may be an effective alternative for patients with ocular toxoplasmosis who cannot tolerate standard therapies.

Ocular opportunistic infection incidences among patients who are HIV positive compared to patients who are HIV negative

OBJECTIVE

The purpose of the study was to examine the incidence of ocular opportunistic infections among patients who are human immunodeficiency virus (HIV) positive compared to patients who are HIV negative.

DESIGN

The study design was a retrospective cohort study.

PARTICIPANTS

All patients were recruited from 1984 until 1995 at the San Francisco General Hospital.

INTERVENTION

Incidences for numerous diagnoses were compared among the exposure group (HIV positive) and nonexposed control group (HIV negative).

MAIN OUTCOME MEASURES

The diagnoses studied were cytomegalovirus (CMV) retinitis, herpes zoster ophthalmicus, Pneumocystis carinii choroidopathy, herpes simplex keratitis, Toxoplasma retinitis, fungal retinitis, ocular syphilis, and ocular lymphoma.

RESULTS

Among the HIV-positive pool, there were 1800 patient visits with a total of 5200 person-years of follow-up. Among the HIV-negative control pool, there were 48,200 patient visits with a total of 30,100 person-years of follow-up. Incidence rates were calculated using the product-limit method, and risk ratios were calculated using the Cox proportional hazards model. Incidence rate differences were calculated using the incidence density method. Among the outcomes studied, only CMV retinitis, herpes zoster ophthalmicus, and, to a lesser extent, Toxoplasma retinitis showed both an elevated risk ratio and rate difference among patients who were HIV positive compared to patients who were HIV negative. Of the other outcomes studied, either the risk ratio, rate difference, or both were similar among patients who were HIV positive compared to patients who were HIV negative.

CONCLUSIONS

Not all ocular infections seen in patients who are HIV positive should be considered opportunistic, because many occur with similar incidence among patients who are HIV negative. The biologic reasons for this will require further study.

Prevalence of IgG and IgM anti-Toxoplasma antibodies in patients with HIV and acquired immunodeficiency syndrome (AIDS)

With the emergence of the human immunodeficiency virus (HIV), in patients with acquired immunodeficiency syndrome (AIDS), Toxoplasma gondii has arisen as an important opportunist pathogenic agent, especially in the central nervous system, being the most common cause of intracerebral lesions. The incidence of Toxoplasma gondii in HIV-infected patients depends principally on the existence of latent Toxoplasma parasitosis in the population affected. Through the enzyme-linked immunosorbent assay (ELISA), IgG and IgM anti-Toxoplasma antibodies were found in 92 patients of which 46 (50.0%) were IgG seropositive, and only one case (1.0%) had IgM antibodies. Of the 92 patients: 53 were HIV seropositives and 39 had AIDS. The detection and monitoring of anti-Toxoplasma antibodies in HIV patients is essential, since in this group there is a high percentage risk of developing cerebral toxoplasmosis, which is the second cause of death in this type of patients.

Atypical, severe toxoplasmic retinochoroiditis in elderly patients

BACKGROUND

The diagnosis of toxoplasmic retinochoroiditis is based primarily on characteristic ocular findings, with supportive serologic evidence. Clinical recognition of atypical presentations is critical for timely antiparasitic drug therapy.

METHODS

Case histories were reviewed for seven presumed immunocompetent elderly patients with atypically severe (multifocal or diffuse or both) toxoplasmic retinochoroiditis. Three cases initially were misdiagnosed as acute retinal necrosis syndrome. The correct diagnosis was confirmed in each case by response to antiparasitic drug therapy, polymerase chain reaction studies of intraocular specimens, or histopathologic analysis.

RESULTS

The patients ranged in age from 69 to 82 years (median, 74 years). Only three patients had intercurrent medical conditions that may be associated with subtle immune dysfunction (diabetes mellitus and hepatitis C). The extensive necrotizing retinochoroiditis in each patient was nonhemorrhagic and not associated with occlusive retinal arteritis. Despite prompt response to antiparasitic drug therapy, prolonged treatment usually was required, and four patients had retinitis reactivation after discontinuing treatment. Significant visual loss accompanied the infection in most eyes.

CONCLUSION

Toxoplasmosis should be considered as a cause of multifocal or diffuse necrotizing retinitis or both in elderly patients. Older patients may be more susceptible to severe ocular Toxoplasma infections because of age-related decline in cell-mediated immunity and chronic underlying diseases.

Toxoplasma gondii and ocular toxoplasmosis: pathogenesis

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