Crystalline Retinopathy Following Intravitreal Clindamycin

This case report describes a 74-year-old woman who developed a crystalline retinopathy following intravitreal injection of clindamycin. The patient presented with ocular toxoplasmosis in the left eye but was allergic to sulfa medications, so she was treated with intravitreal clindamycin. Subsequently, fine refractile yellow-white crystals were observed on examination of the left macula. Optical coherence tomography localized the crystals to the posterior hyaloid. Intravitreal clindamycin should be considered in the differential diagnosis of crystalline retinopathy. [Ophthalmic Surg Lasers Imaging Retina 2024;55:168-170.].

Comparison of immunological and molecular methods for laboratory diagnosis of ocular toxoplasmosis in blood, serum and tears in Brazil

Ocular toxoplasmosis (OT) is caused by protozoan T. gondii. Ophthalmological examination is considered the gold standard for OT diagnosis, and laboratory tests are used for diagnostic confirmation. However, these tests can present different results, which change depending on their basis, on sample type and on patients' clinical alteration. Thus, the aim of the present study is to assess immunodiagnostic and molecular techniques applied in blood, serum and tear fluid to diagnose T. gondii infection in patients seen at an Ophthalmology Clinic. In total, 160 patients were included in the study, 40 of them had OT with active lesions (G1); 40 had OT with healed lesions (G2), 40 had non-toxoplasmic uveitis (G3) and 40 had no ocular alterations (G4). Serum samples were subjected to Immunoenzymatic Assay (ELISA) and to Indirect Immunofluorescence Reaction (IFAT) to search for anti-T. gondii IgM and IgG. Tear fluid samples were analyzed through ELISA for IgA research. All blood and tear fluid samples were subjected to conventional polymerase chain reaction (cPCR) and in a Nested PCR model for T. gondii DNA amplification with targets B1, GRA7 and REP 529. IgG and IgM anti-T. gondii was detected in serum samples from 106 and 15 patients, respectively, when combining ELISA and IFAT results. Anti-T.gondii IgA antibodies were detected in 9.2% of the tear material. Nested PCR with GRA7 target showed higher positivity in blood samples (24.4%); Nested PCR with B1 target showed a higher frequency of positivity in tears (15%). Biological samples of patients with active lesions showed the highest positivity frequencies in all immunodiagnostic assays, as well as in most PCR models. The present results highlighted the need of associating techniques with different fundamentals to confirm OT diagnosis. Furthermore, further tear fluid analyses should be performed to validate this biological material as lesser invasive alternative for the more accurate OT diagnosis.

Animal Models for Toxoplasma gondii Infection

Toxoplasma gondii is an obligate intracellular protozoan parasite that commonly infects mammals and birds throughout the world. This protocol describes murine models of acute T. gondii infection, toxoplasmic encephalitis and toxoplasma retinochoroiditis. T. gondii infection in severe combined immunodeficient (SCID) mice, deficient in T and B cells, has allowed for the study of T cell-independent mechanisms of defense against intracellular organisms, as described here. The uracil auxotroph strain cps1-1 and temperature-sensitive mutant strains of T. gondii induce protection against challenge with virulent strains of the parasite. They have allowed studies of immunization and adoptive-transfer experiments. A protocol is provided for infection with these mutant strains. The EGS strain of T. gondii has the unique feature of spontaneously forming tissue cysts in cell culture. Dual fluorescent reporter stains of this strain have allowed the study of tachyzoite to bradyzoite transitions in vitro and in vivo. A protocol for in vitro and in vivo growth of this strain and tissue cyst isolation is provided. Genetic manipulation of T. gondii and mice has led to the development of parasites that express fluorescent proteins as well as mice with fluorescently labeled leukocytes. This together with the use of T. gondii that express model antigens and transgenic mice that express the appropriate T cell receptor have facilitated the in vivo study of parasite host-interaction. In addition, parasites that express bioluminescent markers have made it possible to study the dynamics of infection in real time using bioluminescence imaging. Support protocols present methodology for evaluation of progression of infection and immune response to the parasite that includes these newer methodologies. In addition, support protocols address the maintenance of T. gondii tissue cysts and tachyzoites, as well as preparation of T. gondii lysate antigens. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Induction of acute T. gondii infection in mice Basic Protocol 2: Model of toxoplasmic encephalitis and toxoplasma retinochoroiditis in chronically infected mice Basic Protocol 3: Assessment of T. gondii invasion into neural tissue Basic Protocol 4: T. gondii infection in scid/scid (SCID) mice Basic Protocol 5: Infection with the uracil auxotroph strain CPS1-1 or the temperature-sensitive TS-4 strain of T. gondii Basic Protocol 6: In vivo and in vitro maintenance of the EGS strain of T. gondii Support Protocol 1: Assessment of progression of infection and immune response to T. gondii Support Protocol 2: Maintenance of a bank of T. gondii cysts of the ME49 strain Support Protocol 3: Maintenance of T. gondii tachyzoites using human foreskin fibroblasts Support Protocol 4: Maintenance of T. gondii tachyzoites in mice Support Protocol 5: Preparation of T. gondii lysate antigens Support Protocol 6: Isolation of T. gondii tissue cysts from brain.

Clinical and Serological Characteristics of Ocular Toxoplasmosis in the Democratic Republic of Congo

PURPOSE

To describe demographic data, clinical features, and serological profiles in a cohort of Congolese patients with ocular toxoplasmosis (OT).

METHOD

Cross-sectional study, carried out between March 2020 and July 2021 in two ophthalmic clinics in Kinshasa.

RESULTS

The study comprised 95 participants with OT. Fifty-three patients were male (55.8%). The mean age at presentation was 35.6 ± 14.1 years (range 8-69 years); 71 had active OT (74.7%), among them, 33 had primary OT (46.5%), and 38 had recurrences (53.5%). At presentation, 51 patients (53.7%) had visual impairment (VA < 6/18). Retinochoroidal lesions were located in the central retina in 60 patients (63.1%). Patients with primary OT tend to have higher IgG levels than those with recurrent OT (P = .01).

CONCLUSION

We report the largest cohort of patients with OT in sub-Saharan Africa. In our setting, most patients had recurrent OT with multiple, extensive, and central retinochoroidal lesions.

Association of Proton Pump Inhibitor/Histamine-2 Blocker Use and Ocular Toxoplasmosis: Findings from a Large US National Database

OBJECTIVE

To test the hypothesis that the use of proton pump inhibitors (PPIs) is associated with an increased risk of being diagnosed with toxoplasmic retinochoroiditis.

DESIGN

Retrospective, matched case-control study using data from 2000 to 2020.

PARTICIPANTS

Patients with ocular toxoplasmosis and controls were matched 5:1 for age, sex, and race, with the eligibility date ± 3 months from the index date of exposed match. Patients aged < 18 years with congenital toxoplasmosis, having < 2 years in the insurance plan before the index date, and without ≥ 1 visit to an eyecare provider before the index date were excluded from the study.

METHODS

Patients with ocular toxoplasmosis were identified using the International Classification of Diseases, Ninth Revision and International Classification of Diseases, Tenth Revision codes, and PPI use or diseases highly associated with PPIs were identified using national drug codes from an administrative medical claims database.

MAIN OUTCOME MEASURES

The primary outcome was defined as having a prescription for a PPI or histamine-2 (H2) blocker. Multivariable logistic regression analyses were performed, controlling for demographic and systemic health variables.

RESULTS

A total of 4069 cases and 19 177 controls met the eligibility criteria. Of the 4069 patients with ocular toxoplasmosis, 989 (24.3%) were on PPI/H2 blockers compared with 3763 of 19 177 (19.2%) controls. The adjusted logistic regression model demonstrated 1.28 greater odds of PPI/H2 blocker use in cases of ocular toxoplasmosis than matched controls (95% confidence interval, 1.17-1.40; P < 0.001).

CONCLUSIONS

Proton pump inhibitor/H2 blocker exposure was associated with an increased risk of being diagnosed with ocular toxoplasmosis, corroborating findings from a prior case series.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

LFA-1/ ICAM-1 promotes NK cell cytotoxicity associated with the pathogenesis of ocular toxoplasmosis in murine model

Ocular toxoplasmosis (OT) is one of the most common causes of posterior uveitis. However, the pathogenic mechanisms of OT have not been well elucidated. Here, we used C57BL/6 (B6) mice to establish OT by peroral infection with 20 cysts of the TgCtWh6 strain, and severe ocular damage was observed by histopathological analysis in the eyes of infected mice. RNA-sequencing results showed that infection with T. gondii increased the expression of the NK-mediated cytotoxicity gene pathway at Day 30 after ocular T. gondii infection. Both NK-cell and CD49a+ NK-cell subsets are increased in ocular tissues, and the expression levels of LFA-1 in NK cells and ICAM-1 in the OT murine model were upregulated upon infection. Furthermore, inhibition of the interaction between LFA-1 and ICAM-1 with lifitegrast, a novel small molecule integrin antagonist, inhibited the protein expression of LFA-1 and ICAM-1 in murine OT and NK cells, improved the pathology of murine OT and influenced the secretion of cytokines in the OT murine model. In conclusion, the interaction between LFA-1 and ICAM-1 plays a role in the early regulation of the CD49a+ NK-cell proportion in an OT murine model. LFA-1/ ICAM-1 may be a key molecule in the pathogenesis of OT, and may provide new insights for potential immunotherapy.

Evaluating of Wistar rat and BALB/c mouse as animal models for congenital, cerebral and ocular toxoplasmosis

This study was conducted to evaluate the potential of cyst production by Toxoplasma (T.) gondii, RH strain, in Wistar rat and BALB/c mouse and the purpose of this study was to introduce an animal model suitable for congenital, cerebral, and ocular toxoplasmosis. The mice and rats, considered as cerebral and ocular toxoplasmosis models, were intraperitoneally infected by different number of the parasite and their eyes and brain were evaluated for the presence of T. gondii cyst using the microscopic examination and the bioassay method. Moreover, the pregnant mice and rats, considered as congenital toxoplasmosis models, were intraperitoneally infected by different number of the parasite and their infants were examined by the method mentioned above. The best result for the cerebral toxoplasmosis model was observed in the rats infected with the 107 parasites, so that all infants (100%) were infected with the parasite when examined using the bioassay method. Furthermore, the best result was observed for the congenital cerebral toxoplasmosis model with 100% infection rate in the infants born to mothers infected with the 107 parasites. Overall, just few the ocular samples were positive using bioassay method. The best result in the current study was for the congenital cerebral toxoplasmosis model where the pregnant rats were infected with the 107 parasites and all infants were infected (100%). Therefore, these infants can be used as a congenital cerebral toxoplasmosis model when they are in the fetal stage, and can be used as a cerebral toxoplasmosis model one month after birth.

[A case of primary toxoplasmosis in an immunocompetent patient]

CASE REPORT

A case of an immunocompetent patient presenting primary systemic toxoplasma infection involving the eye (condition seen in less than 3% of primary infections). The patient showed reactivation of this primary focus two years later.

DISCUSSION

Diagnosis of toxoplasm retinitis is based on a typical lesion consisting in an area of active retinitis adjacent to an inactive corioretinal scar. Differential diagnosis must consider other causes of retinal coroiditis in primary infection cases: sarcoidosis, tuberculosis, syphilis as well as viral and fungal infections. Ocular toxoplasmosis was confirmed by serum tests.

Ocular toxoplasmosis in HIV infection

Toxoplasmosis accounts for 1-3% of ocular infections in patients with AIDS1. There are a variety of clinical manifestations that can be confused with other ocular disease. It may be the first manifestations of intracranial and disseminated Toxoplasma gondii infection. Prompt recognition and early treatment with antiparasitic drug therapy will prevent widespread tissue destruction, preserve vision and reduce dissemination. This current review will provide a broad-based overview of toxoplasmosis and ocular infection.

Human immunodeficiency virus and opportunistic ocular infections

Opportunistic ocular infections are a common and important complication of the acquired immunodeficiency syndrome. Cytomegalovirus retinitis is by far the most frequent infection, but other viral, bacterial, and parasitic infections of the posterior segment of the eye may be seen. Infections of the anterior segment are less common but may cause visual loss if not treated. Prompt recognition of these diseases is essential because ocular involvement may be an early sign of systemic dissemination.

Toxoplasmic retinochoroiditis and hydrocephalus

A child presenting with hydrocephalus with extensive inactive retinochoroiditis and his mother with a healed toxoplasmic scar is being discussed. Maternal ocular examination in each case of hydrocephalus is recommended, as uveitis work up of the child is often unrewarding.

[Toxoplasma infection and endogenous uveitis]

The indirect fluorescent antibody technique was used to study the relationship between endogenous uveitis and toxoplasma infection. The seropositive rates of toxoplasma antibody in healthy people, farmers and patients with endogenous uveitis were 10.7%, 15.2% and 30.8% respectively. Compared with the healthy people, the infection rate in uveitic patients was significantly higher (P less than 0.01). The odds ratio of toxoplasma infection in endogenous uveitic patients was 3.72. The results suggest that toxoplasma infection is an infectious cause of endogenous uveitis.

[Acute acquired toxoplasmosis presenting as polymyositis and chorioretinitis in a Japanese male]

A 55-year-old Japanese male who developed acute polymyositis and chorioretinitis due to toxoplasmosis is described. The patients was well until one month prior to the present admission, when he had an onset of painful swelling of lymphnodes in the posterior cervical region, proximal muscle weakness, myalgia and a partial defect in the visual field of the right eye. He admitted that he had had a chance to eat half-cooked mutton while he had visited Saudi Arabia 40 days before. He was unable to go up and down the stairs at the peak of the illness. Serum CPK was 2050 u/l (N = 5-50) on January 11, 1989. These symptoms improved spontaneously except for the visual field defect. He was admitted to our hospital on January 31, 1989. On admission, neurological examination was unremarkable except for retinal exudate in the right eye which appeared consistent with the clinical diagnosis of toxoplasma chorioretinitis. Serum CPK was 103 u/l, and EMG showed myogenic changes. The IgM-immunofluorescent (IFA) anti-Toxoplasma gondii antibody titer was elevated to 640, and IgG-immunofluorescent antibody to 20480 after IgM-IFA. These clinical and serological findings indicate acute and recent Toxoplasma gondii infection. It appeared likely that Toxoplasma gondii directly caused acute myositis and chorioretinitis. Clinical manifestations of toxoplasma myositis may mimic those of idiopathic polymyositis, however, the clinical course of the former is usually self-limited probably because of generation of antibodies which will inhibit the growth of the organism.(ABSTRACT TRUNCATED AT 250 WORDS)

Toxoplasmic scleritis

Although toxoplasmosis is the most common infectious cause of posterior intraocular inflammation, it is rarely described in association with scleritis. The authors present five cases of toxoplasmosis with scleritis. Two of the five cases were diagnosed clinically and serologically as having toxoplasmosis. Their retinochoroiditis and scleritis responded well to medical therapy. Retinochroiditis and scleritis that was refractory to treatment developed in the other three patients, two of whom had been receiving immunosuppressive therapy for systemic diseases. Their therapeutic regimens did not include treatment for toxoplasmosis. All three eyes became blind and were enucleated. Results of pathologic examination of all three enucleated eyes showed Toxoplasma gondii in the retina. There was severe inflammation of the retina, choroid, and sclera. Toxoplasmosis should be considered in the clinical differential diagnosis of scleritis associated with retinochoroiditis, particularly in immunosuppressed patients.

Changing patterns of uveitis

We conducted a retrospective analysis of 600 patients with uveitis seen at the Estelle Doheny Eye Center to determine the frequency of occurrence of the various forms of uveitis and to see if the causes of uveitis have changed as compared with previous studies. In 402 cases (67.0%) we established a specific diagnosis based on history, physical findings, and laboratory studies: 167 cases (27.8%) involved primarily the anterior segment, 230 (38.4%) the posterior segment, and 111 (18.4%) occurred as panuveitis. Intermediate uveitis (pars planitis) was the single most frequently diagnosed uveitic entity and accounted for 92 cases (15.4%). We compared our findings with those of previously published studies and found that, as new diseases occur and improved diagnostic techniques become available, the differential diagnosis of uveitis continues to change.

Opportunistic infections of the retina and posterior segment

Opportunistic infections of the retina are becoming a more frequent diagnostic and therapeutic challenge as immunosuppressed patients become more common. Viral, fungal, protozoan, and bacterial agents may be encountered. Diagnostic and therapeutic considerations, illustrated by case histories, are presented in this article. Viral infections are characterized by progressive exudation and hemorrhagic necrosis in a segmental distribution corresponding to the retinal vasculature. Protozoan, fungal, and bacterial infections may demonstrate more focal lesions with greater vitreous involvement. Diagnosis is established by clinical examination of body fluids. Antimicrobial drugs alone or combined with vitrectomy are effective therapy for fungal, bacterial, and protozoan infections. Antiviral drugs have yielded more disappointing results in the management of viral retinitis.

Toxoplasmic chorioretinitis affecting the macula

To study macular changes in toxoplasmic chorioretinitis 41 patients with ocular toxoplasmosis were reviewed. Of the 41 patients, seven had central, large, deep, pigment ringed scars of congenital toxoplasmosis with poor central vision; squint was seen in two and nystagmus in two; 32, including 11 cases with a macular lesion, had recurrent active toxoplasmic chorioretinitis with a focal, yellowish-white, elevated lesion with indistinct borders mostly at the margin of an old scar and associated with vitreous opacities in all, secondary anterior uveitis in 28, macular oedema in 22, papilloedema in 14, and retinal perivasculitis in 16 cases; two had rare acquired toxoplasmic chorioretinitis affecting the macula. The results show that active toxoplasmic chorioretinitis often causes a widespread intraocular inflammation with vitritis, macular oedema, papilloedema, retinal perivasculitis and secondary anterior uveitis, and suggest a combined treatment of active lesions with antimicrobial agents and corticosteroids.

Toxoplasmosis

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