[Ocular toxoplasmosis: demonstration of free Toxoplasma in the aqueous humor].
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Adolescent↗
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Results for “TOXOPLASMOSIS, OCULAR”
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Short-term effects of the clindamycin-steroid regimen in the treatment of ocular toxoplasmosis.
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Adolescent↗
Massive congenital ocular toxoplasmosis.
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Humans↗
White-centered retinal hemorrhages in ocular toxoplasmosis.
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Adult↗
[Value of clindamycin in the treatment of ocular toxoplasmosis].
PURPOSE: Chorioretinal toxoplasmosis can threaten visual function when located in the posterior pole. The aim of this study was to compare the advantages and disadvantage of combination of malocid-sulfadiazine and clindamycin subconjunctivally. METHODS: Two groups of patients affected by unilateral chorioretinal toxoplasmosis were studied. The diagnosis was performed in 77% of cases on acqueous humor analysis. The first group of twenty-six patients was treated with a combination of malocid-sulfadiazine while the second group (seventeen patients) was treated with clindamycin subconjunctivally. Local and general corticosteroids were associated in all cases. Mean follow-up was 19 months in the first group and 16.5 months in the second. RESULTS: Visual acuity was increased in 88.5% of cases in the first group and in 94% of cases in the second group. Cicatrization obtained in both groups was comparably delayed 1.68 months for the first and 1.26 months for the second. Recurrences were rarely observed in the two groups: respectively 8% and 6% of cases. No local and general complication was noted. CONCLUSION: These findings suggest the advantages of subconjunctival clindamycin treatment due to the absence of general hematological toxicity.
Adolescent↗
Results of treatment of ocular toxoplasmosis with injectable corticosteroids.
Sixty-seven patients with toxoplasmic retinochoroiditis who were treated with periocular injections of depot forms of corticosteroids were studied in an attempt to determine (1) whether patients who did poorly on this regimen could be differentiated predictively from those who responded in a more favorable fashion, and (2) whether a treatment regimen that would allow the safe use of periocular depot corticosteroids in patients with toxoplasmic retinochoroiditis could be delineated. The study did not reveal any reliable way of predicting which patients would be good risks for the use of periocular injections of depot corticosteroids. It does suggest that the concurrent use of antitoxoplasma agents might protect patients in such a way that periocular depot corticosteroids would not worsen their disease. For the reasons outlined, the use of periocular injections of depot corticosteroids in toxoplasmic uveitis must be approached with great caution in the future.
Adult↗
Acquired and congenital ocular toxoplasmosis experimentally induced in Calomys callosus (Rodentia, Cricetidae).
An experimental model for acquired and congenital ocular toxoplasmosis as well as a model to induce experimental autoimmune uveitis (EAU) was investigated in Calomys callosus. Toxoplasma gondii, ME-49 strain, was used to infect males and pregnant- and not pregnant-females while S-antigen, a major glycoprotein of the retinal photoreceptor cell, was used to induce EAU. The ocular lesions elicited by T. gondii were characterized by the presence of cysts, free tachyzoites and inflammatory cells in the retina or related tissues. In the congenital form, 40% of the fetus presented ocular lesions, i.e., presence of cysts in the retina, vitreous, and extra-retinal tissues. In the acquired form, 75% of the females and 50% of the males presented unilateral ocular cysts both at 21 and 47 days post-infection. It was also demonstrated that S-antigen was not uveitogenic in the C. callosus model. No lesion was observed in the animals exclusively immunized with this retinal component, even when jacalin was used as additional adjuvant for polyclonal response to the retinal antigen. It can be concluded that C. callosus may constitute in a promising model for study both acquired and congenital ocular toxoplasmosis, particularly when it is important to make sure that a non autoimmune process is involved in the genesis of the ocular infection.
Animals↗
[Ocular toxoplasmosis].
PURPOSE: To update the current concepts in ocular toxoplasmosis. METHODS: Interpretation of recent publications, meeting information and personal experience. RESULTS: Most important aspects related to transmision of the parasite and clinical presentation of the ocular disease are discussed. Special issues on diagnosis and therapy are also mentioned. CONCLUSION: A correct knowledge of the epidemiology may allow a decrease in the ocular disease and a better diagnosis will be possible by recognizing the clinical presentations. Therapies have not changed significantly over the last years.
Humans↗
Anti-toxoplasma serotitres in uveitis and ocular toxoplasmosis.
This study was based on anti-toxoplasma serotitres obtained from 80 normal healthy adults and 103 consecutive patients with anterior, posterior and panuveitis over a 42 month period. Twelve out of 80 (15%) normal healthy sera were found to have low titres (1:64 to 1:256), while 3 (3.8%) had high titres (1:1024 or higher). The distribution of serotitres in patients with clinical toxoplasmosis was significantly different from the population sample (p less than 0.001, chi-squared test). Similarly, the distribution of serotitres in patients with posterior uveitis (of which 28 out of 54 were clinically ocular toxoplasmosis) having serotitres of 1:1024 or greater, was found to be significantly different from the normal population (p less than 0.001, Chi-squared test), but not statistically different from those with clinical ocular toxoplasmosis. Hence, anti-toxoplasma serotitre is useful as a diagnostic screening tool only in patients with posterior uveitis. It is also useful in confirming cases of suspected clinically positive ocular toxoplasmosis in our local population.
Adolescent↗
[Treatment difficulties in ocular toxoplasmosis].
PURPOSE: To determine the increased incidence of ocular infection with Toxoplasma gondii, the variety of ocular manifestations and therapeutical problems of this potential blind disease. We analyzed 22 patients hospitalized in our clinic in last 2 years at whom clinical diagnosis was confirmed by positive serological tests. Is discussed the correlation between serum level antibody(IgG and IgM) and ocular manifestations and the opportunity of beginning specific treatment depend on these two parameters. CONCLUSIONS: The incidence of ocular toxoplasmosis is increasingly, the ophthalmologist must be open on atypical manifestations of this disease. The treatment remains controversial, we believe that it must be specific and correlated with ocular lesions evolutions and serum antibody level in time.
Adrenal Cortex Hormones↗
Experimental ocular toxoplasmosis in naive and primed rabbits.
PURPOSE: Investigations of the course of ocular toxoplasmosis and the influence of a host's immunological status in an animal model would contribute to our understanding of the pathophysiology underlying this condition. In the current study, these aspects are addressed using naive and primed rabbits infected transvitreally with the non-cyst-forming BK strain of Toxoplasma gondii. MATERIALS AND METHODS: Of 45 latex agglutination test-negative rabbits, 27 were infected subcutaneously with 5,000 Toxoplasma tachyzoites, and the ensuing infection treated by systemic administration of clindamycin for 20 days. Four of these rabbits died from generalized infection. The remaining 23 primed rabbits were then inoculated periretinally with a further 5,000 Toxoplasma tachyzoites, administered via the transvitreal route; the 18 naive rabbits were treated likewise. RESULTS: All 18 naive and 21 of the 23 primed rabbits developed toxoplasmic retinochoroiditis. As regarded progression of the disease, dissemination of the condition (p = 0.0001), degree of vitreal infiltration (p = 0.0001) and incidence of retinal detachment (p < 0.05) were all more pronounced in the naive group. Despite treatment, 4 of the 18 (22%) naive rabbits died from generalized infection, as did 4 of the 27 (15%) subcutaneously infected ones (prior to periretinal infection). In the primed (secondarily infected) animal group, only moderate signs of systemic infection were manifested, and there were no fatalities. CONCLUSION: The high incidence (>90%) of retinochoroiditis achieved even in primed animals, by introducing Toxoplasma tachyzoites via the transvitreal route, may reflect the maintenance of an intact uveovascular barrier during the early stages of the disease. The pattern of infection, in being restricted primarily to the retina, mimics the situation evinced in humans. Regarding propagation of the disease, the condition manifested in naive rabbits resembles that occurring in immunodeficient patients, whereas that evoked in primed animals corresponds to recurrence of infection in immunocompetent patients.
Animals↗
[Treatment of ocular toxoplasmosis. Part 2: Therapeutic approaches].
Retinochorioditis is the most common complication of ocular toxoplasmosis and also the most dangerous one in respect of central visual acuity. New treatment concepts are increasingly replacing the therapy that had become established since the fifties and that had been based on pyrimethamine and sulphadiazine. The new concepts entail fewer complications and are better accepted by the patients. However, prospective randomised studies that are based on severe criteria could not prove for any of the employed treatment courses that it promotes healing of retinochorioditis or prevents relapses. However, if central visual acuity is endangered, drug therapy should nevertheless be initiated. In babies and in persons with immunodeficiency treatment must be in accordance with the overall pattern of symptoms.
Child↗
Clindamycin in the treatment of human ocular toxoplasmosis.
Clindamycin was used systemically and periocularly to treat six patients with ocular toxoplasmosis who had a total of eight attacks. Although it appeared to quiet the attack promptly, several side effects were noted. Transient diplopia occured after large periocular doses and papillitis resulted from retrobulbar administration. Despite its efficacy, the results do not seem to warrant high systemic doses for prolonged periods in view of its systemic toxicity. Clindamycin may be most useful as a periocular injection in moderate dosage. A controlled double-blind study is needed.
Adult↗
Ocular toxoplasmosis in patients with the acquired immunodeficiency syndrome.
In seven of eight cases of presumed ocular toxoplasmosis in patients with AIDS, the diagnosis was supported by a reduction or resolution of intraocular inflammation and healing of necrotic retinal lesions after initiation of antiparasitic drug therapy including one or more of the following medications: pyrimethamine, sulfadiazine, clindamycin, tetracycline, or spiramycin. In two cases the diagnosis was confirmed histologically. The cases differed clinically and histopathologically from those in immunocompetent patients. There was no evidence that disease originated in preexisting retinochoroidal scars. Lesions frequently were bilateral and multifocal. Vitreous inflammatory reaction was a common clinical finding, but histopathologic examination demonstrated scant retinal inflammation in areas of necrosis. Ocular toxoplasmosis in these patients with AIDS probably resulted from newly acquired infection or dissemination of organisms from nonocular sites of disease. Infections became clinically inactive with drug therapy in all treated patients, but reactivation and progression of disease occurred when therapy was stopped in two of three patients. Severe retinal necrosis led to retinal tears or detachment in three cases. Ocular lesions were the first manifestation of Toxoplasma gondii infection in four of five patients with evidence of multisystem infection.
Acquired Immunodeficiency Syndrome↗
[Laser therapy of ocular toxoplasmosis].
The authors present the results of treatment by laser coagulation of inflammatory retino-choroidal foci in 32 persons with ocular toxoplasmosis. The diagnosis of Toxoplasma etiology was set on a basis of positive immunological reaction for Toxoplasma gondii antigen and after exclusion of other etiological factors. Among 42 eyes stabilization of the process after 1 intervention was observed in 34, i.e. in 89 p.c. (period of observation--up to 4 years). In the following 8 eyes arised the necessity to perform additional coagulations because of formation of fresh foci which appeared in 5 eyes after 6 months, in 2 eyes after 1 year and in 1 eye after 2 years since onset. The authors consider the application of laser coagulation in ocular toxoplasmosis as a favourable method together--or independently--with pharmacological treatment.
Adolescent↗
A feline model of ocular toxoplasmosis.
UNLABELLED: PURPOSE. This study was performed to characterize the clinical, serologic, histopathologic, and immunohistochemical features of an experimental model of ocular toxoplasmosis in cats. METHODS: Seven specific pathogen-free cats were inoculated in the right carotid artery with 5 x 10(3) tachyzoites of the ME49 strain of Toxoplasma gondii. Control cats received heat-killed tachyzoites. RESULTS: Progressive, bilateral, multifocal retinal, and choroidal inflammatory foci developed in the principal cats, beginning 5 to 8 days postinoculation (PI). Lesion development peaked 3 weeks PI, and the lesions varied in size from pinpoint to 5 mm, had a predilection for the central tapetal fundus, and were more numerous ipsilateral to the side of inoculation. Resolution of the lesions 21 to 70 days PI was characterized by foci of tapetal destruction and retinal degeneration. Fluorescein angiography showed disruption of the blood-retinal barrier at the level of the retinal pigmented epithelium, and occasional retinal vasculitis and perivasculitis. Mild anterior uveitis developed in four cats 10 to 13 days PI. Aside from a slight febrile response 2 to 3 days PI, no physical abnormalities were observed. T. gondii antigens were detected intermittently in the serum of four of seven cats as early as 8 days PI. T. gondii-specific immunoglobulin M titers were present on day 7 PI and continued to increase until 28 days PI. Immunoglobulin G production was documented on day 13 PI, and titers continued to increase throughout the study. Evidence of anterior uveal antibody production (mean Goldmann-Witmer coefficient [C value], 80.7; range, 13.4 to 236.6) was present in 11 of 14 eyes on day 70 PI. On histopathologic evaluation 70 days PI, multifocal granulomatous chorioretinitis, with retinal degeneration, retinal vasculitis, and lymphocytic-plasmacytic anterior uveitis, was documented. Tissue cysts in the retina and choroid were found with mouse inoculation of tissue suspensions, immunohistochemical studies, and histopathologic examination. CONCLUSIONS: This nonfatal, noninvasive method of inducing ocular toxoplasmosis may prove to be a useful model for investigation of toxoplasmi retinochoroiditis, particularly with the recent characterization of a naturally occurring, immunosuppressive feline lentivirus with properties similar to human immunodeficiency virus.
Animals↗
Quadruple therapy for ocular toxoplasmosis.
Between Dec. 1, 1973, and May 30, 1989, 36 patients (37 eyes) with ocular toxoplasmosis seen at a uveitis clinic received quadruple therapy (pyrimethamine, trisulfapyrimidines, clindamycin and prednisone). The criteria for quadruple therapy were active lesions involving or threatening the macula or the optic disc, or a visual acuity of 20/70 or worse due to vitreous opacification caused by active inflammation. All but four of the cases showed improved vision. A total of 54% of the cases responded favourably within 2 weeks after the start of treatment, and 81% responded within 3 weeks. Patients took pyrimethamine for 1 to 2 weeks and received trisulfapyrimidines and clindamycin for 3 weeks, with a tapering course of orally given prednisone. The only complication was skin rash secondary to trisulfapyrimidine therapy, in four cases. None of the patients manifested diarrhea, pseudomembranous colitis or bone marrow suppression. The length of follow-up ranged from 1 month to 15.5 years. There were seven recurrences in five patients, five of which responded to a second course of quadruple therapy.
Adolescent↗
Presumed congenital ocular toxoplasmosis in two successive siblings.
We present the cases of 2 consecutive siblings with bilateral macular lesions, for which there is strong clinical and laboratory evidence supporting the diagnosis of congenital ocular toxoplasmosis. These cases raise the possibility of maternal parasitemia during Toxoplasma gondii reinfection, leading to transmission to the fetus and congenital ocular toxoplasmosis despite prior immunity and lack of an immune disturbance in the mother.
Adolescent↗