Presumed Pneumocystis carinii Choroiditis

Antimicrobial guide to posterior segment infections

PURPOSE

This review article is meant to serve as a reference guide and to assist the treating physician in making an appropriate selection and duration of an antimicrobial agent.

METHODS

Literature review.

RESULTS

Infections of the posterior segment require prompt medical or surgical therapy to reduce the risk of permanent vision loss. While numerous options exist to treat these infections, doses and alternative therapies, especially with contraindications for first-line therapy, are often elusive. Antimicrobial agents to treat posterior segment infections can be administered via various routes, including topical, intravitreal, intravenous, and oral.

CONCLUSIONS

Although there are many excellent review articles on the management of endophthalmitis, we take the opportunity in this review to comprehensively summarize the appropriate antimicrobial regimen of both common and rare infectious etiologies of the posterior segment, using evidence from clinical trials and large case series.

HIV-associated retinopathy in the HAART era

BACKGROUND

The effectiveness of highly active antiretroviral therapy (HAART) in restoring immune function in patients with acquired immunodeficiency syndrome (AIDS) has led to changes in the incidence, natural history, management, and sequelae of human immunodeficiency virus (HIV)-associated retinopathies, especially cytomegalovirus (CMV) retinitis.

METHODS

The medical literature pertaining to HIV-associated retinopathies was reviewed with special attention to the differences in incidence, management strategies, and complications of these conditions in the eras both before and after the widespread use of HAART.

RESULTS

In the pre-HAART era, CMV retinitis was the most common HIV-associated retinopathy, occurring in 20%-40% of patients. Median time to progression was 47 to 104 days, mean survival after diagnosis was 6 to 10 months, and indefinite intravenous maintenance therapy was mandatory. Retinal detachment occurred in 24%-50% of patients annually. Herpetic retinopathy and toxoplasmosis retinochoroiditis occurred in 1%-3% of patients and Pneumocystis carinii choroiditis, syphilitic retinitis, tuberculous choroiditis, cryptococcal choroiditis, and intraocular lymphoma occurred infrequently. In the HAART era the incidence of CMV retinitis has declined 80% and survival after diagnosis has increased to over 1 year. Immune recovery in patients on HAART has allowed safe discontinuation of maintenance therapy in patients with regressed CMV retinitis and other HIV-associated retinopathies. Immune recovery uveitis (IRU) is a HAART dependent inflammatory response that may occur in up to 63% of patients with regressed CMV retinitis and elevated CD4 counts and is associated with vision loss from epiretinal membrane, cataract, and cystoid macular edema.

CONCLUSIONS

The incidence, visual morbidity, and mortality of CMV retinitis and other HIV-associated retinopathies have decreased in the era of HAART and lifelong maintenance therapy may safely be discontinued in patients with restored immune function. Patients with regressed CMV retinitis, however, may still lose vision from epiretinal membrane, cystoid macular edema, and cataract secondary to IRU.

Posterior segment manifestations of HIV/AIDS

The ocular posterior segment manifestations of AIDS may be divided into four categories: retinal vasculopathy, unusual malignancies, neuro-ophthalmologic abnormalities, and opportunistic infections. Microvasculopathy is the most common manifestation. Opportunistic infections, particularly cytomegalovirus retinitis and progressive outer retinal necrosis, are the most likely to result in visual loss due to infection or subsequent retinal detachment. Diagnosis and treatment are guided by the particular conditions and immune status of the patient.

Current perspectives on ophthalmic mycoses

Fungi may infect the cornea, orbit and other ocular structures. Species of Fusarium, Aspergillus, Candida, dematiaceous fungi, and Scedosporium predominate. Diagnosis is aided by recognition of typical clinical features and by direct microscopic detection of fungi in scrapes, biopsy specimens, and other samples. Culture confirms the diagnosis. Histopathological, immunohistochemical, or DNA-based tests may also be needed. Pathogenesis involves agent (invasiveness, toxigenicity) and host factors. Specific antifungal therapy is instituted as soon as the diagnosis is made. Amphotericin B by various routes is the mainstay of treatment for life-threatening and severe ophthalmic mycoses. Topical natamycin is usually the first choice for filamentous fungal keratitis, and topical amphotericin B is the first choice for yeast keratitis. Increasingly, the triazoles itraconazole and fluconazole are being evaluated as therapeutic options in ophthalmic mycoses. Medical therapy alone does not usually suffice for invasive fungal orbital infections, scleritis, and keratitis due to Fusarium spp., Lasiodiplodia theobromae, and Pythium insidiosum. Surgical debridement is essential in orbital infections, while various surgical procedures may be required for other infections not responding to medical therapy. Corticosteroids are contraindicated in most ophthalmic mycoses; therefore, other methods are being sought to control inflammatory tissue damage. Fungal infections following ophthalmic surgical procedures, in patients with AIDS, and due to use of various ocular biomaterials are unique subsets of ophthalmic mycoses. Future research needs to focus on the development of rapid, species-specific diagnostic aids, broad-spectrum fungicidal compounds that are active by various routes, and therapeutic modalities which curtail the harmful effects of fungus- and host tissue-derived factors.

Endophthalmitis

Endophthalmitis is an inflammatory reaction of intraocular fluids or tissues. Infectious endophthalmitis is one of the most serious complications of ophthalmic surgery. Occasionally, infectious endophthalmitis is the presenting feature of an underlying systemic infection. Successful management of infectious endophthalmitis depends on timely diagnosis and institution of appropriate therapy. Recognition of the different clinical settings in which endophthalmitis occurs and awareness of the highly variable presentation it may have facilitate timely diagnosis. Biopsy of intraocular fluid/tissue is the only method that permits reliable diagnosis and treatment. The different presenting clinical settings, a rational approach to diagnosis (i.e., when, what, and how to biopsy), and the treatment of infectious endophthalmitis are reviewed.

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.

Pneumocystis carinii infection of the conjunctiva in a patient with acquired immune deficiency syndrome

BACKGROUND

Ocular disease, especially the development of choroidal lesions, is a known extrapulmonary manifestation of Pneumocystis carinii infection in the acquired immune deficiency syndrome (AIDS). To our knowledge, conjunctival involvement due to P. carinii has not been described previously.

METHODS

The authors describe a 33-year-old homosexual male with AIDS in whom a large placoid, white lesion developed involving the tarsal conjunctiva of the right upper lid. Conjunctival malignancy was suspected and biopsies and swabs were taken. At this time, the patient had been receiving monthly aerosolized pentamidine prophylaxis for 18 months, and there was neither a history of pneumonia nor any clinical signs of disseminated infection due to P. carinii.

RESULTS

Histopathologic examination results of the conjunctival biopsy specimen showed a necrotic, frothy tissue surrounded by activated fibroblasts. Within this material, Gomori methenamine silver stains showed numerous round and cup-like cysts of P. carinii, confirming the diagnosis that had already been obtained by an indirect fluorescent-antibody stain of a conjunctival smear specimen.

CONCLUSIONS

The presence of white placoid conjunctival lesions in a patient with AIDS may indicate an infection due to P. carinii. Conjunctival disease due to P. carinii widens the spectrum of AIDS-associated ophthalmic pneumocystosis.