Active ocular toxoplasmosis in Turkish patients: a report on 109 cases

Clinical characteristics, visual acuity outcomes, and factors associated with loss of vision among patients with active ocular toxoplasmosis: A retrospective study in a Thai tertiary center

BACKGROUND

Ocular toxoplasmosis (OT) is the most common cause of infectious uveitis worldwide, including Thailand. This study describes the clinical presentation, visual acuity (VA) outcomes, and factors associated with VA loss in patients with active OT following antiparasitic treatment.

METHODOLOGY/PRINCIPAL FINDINGS

A retrospective chart review of patients with active OT treated with antiparasitic drugs between 2010 and 2020 was performed. Outcome measures included clinical characteristics, interval VA, and predictive factors associated with loss of VA ≤ 20/50 at 6 months post-treatment. Ninety-two patients (95 eyes) were enrolled. The median follow-up time was 10.9 months (IQR 4.9-31.8 months). The median age at presentation was 35.9 years, 51% were male, and 92.4% had unilateral OT. Eleven patients (12%) were immunocompromised (HIV infection, eight patients; receiving immunosuppressive agents, three patients). Patients mainly presented with primary retinitis without previous scar (62%), posterior pole lesion (56%), and lesion size of ≤ 2-disc area (75%). Immunocompromised patients showed a significantly larger size of retinitis than immunocompetent patients. Oral trimethoprim/sulfamethoxazole monotherapy was the primary short-term antiparasitic drug prescribed (85%). At the final visit, 21% of all affected eyes suffered VA ≤ 20/200. The cumulative incidence of recurrent OT at three years was 33.9% (95% CI, 19.7%-54.2%). Immunocompromised patients [adjusted odds ratio (aOR) 4.9, p = 0.041], macular lesion (aOR 5.4, p = 0.032), and initial VA ≤ 20/200 (aOR 9.1, p = 0.014) were predictive of having VA ≤ 20/50 at 6 months post-treatment.

CONCLUSIONS

Ocular toxoplasmosis mainly presents as unilateral primary retinitis within the posterior pole. Severe VA loss was observed in one-fifth of eyes following treatment with lesion resolution. Immunocompromised patients, eyes with macular lesions, and poor initial VA were associated with poor VA outcomes.

The role of age in ocular toxoplasmosis: clinical signs of immunosenescence and inflammaging

Purpose

This study aimed to investigate the association between age, immune response, and clinical presentation of ocular toxoplasmosis (OT).

Design

This was a monocentric, retrospective, observational cohort study.

Methods

A review of the medical records of patients with active OT at the Uveitis Center, Charité Universitätsmedizin, was conducted. Baseline parameters included age at presentation, visual acuity, intraocular pressure (IOP), size and location of active lesions, inflammatory activity, antibody index (AI), and complications of intraocular inflammation. The data were presented as the mean ± standard deviation (SD). The level of significance was set at a p-value of <0.05.

Results

Between 1998 and 2019, 290 patients with active OT were diagnosed at our tertiary reference center. The mean age of the participants was 37.7 ± 17.1 years, 53.8% of them were female individuals, and 195 patients (70.9%) showed recurrent disease. Older age was associated with lower baseline visual acuity (p = 0.043), poor visual outcome (p = 0.019), increased inflammatory activity (p < 0.005), and larger retinal lesions (p < 0.005). Older patients presented a lower AI (<35 years: 45.1 ± 82.7, median: 12.1; ≥35 years: 18.6 ± 50.5, median: 5.8; p = 0.046), confirmed by a decrease in AI with increasing age (R2 = 0.045; p = 0.024). Finally, AI was correlated with lesion size (multiple linear regression analysis: p = 0.043). Macular involvement (24.3% of patients) was positively correlated with complications (macular/peripapillary edema and retinal detachment, p < 0.005) and poor visual outcome (p < 0.005) and was negatively correlated with inflammatory activity (p < 0.005).

Conclusion

We found a strong and clinically relevant impact of age on the clinical presentation and course of OT. While an unspecific inflammatory response increased with age, the specific, local humoral immune response declined. These findings are well in line with the concept of immunosenescence and inflammaging in uveitis.

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.

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.

A review of toxoplasmosis in humans and animals in Turkey

Infections by the protozoan parasite Toxoplasma gondii are widely prevalent in humans and animals in Turkey but little is known of the burden of their clinical toxoplasmosis. Many early papers on toxoplasmosis in Turkey were published in Turkish and often not available widely. Here, we review prevalence, clinical spectrum, epidemiology and diagnosis of T. gondii in humans and animals in Turkey. This knowledge should be useful to biologists, public health workers, veterinarians and physicians. Although one-third of the human population in Turkey is seropositive, the rate of congenital toxoplasmosis is unknown and no information is available in children 12 years old or younger. One large outbreak of acute toxoplasmosis has been reported in 14–18-year old school children in Turkey. An alarming rate (36%) of T. gondii tissue cysts were reported in tissues of sheep and water buffalo meats destined for human consumption; these reports require verification. Genetically, T. gondii strains from domestic cats and wild birds in Turkey were generally classical type II and III, like those prevalent in Europe. A separate genotype, Type 1 Africa, was isolated from two congenitally infected children and a domestic cat in Turkey.

Adjunctive bradyzoite-directed therapy for reducing complications of congenital toxoplasmosis

Congenital toxoplasmosis is caused by in utero infection of the fetus with the intracellular parasite Toxoplasma gondii. Upon infection, the parasite forms life-long cysts in fetal brain and eyes which are resistant to the currently accepted therapy of pyrimethamine and sulfadiazine. These cysts commonly reactivate later in life causing chorioretinitis and visual impairment, and rarely cause neurological complications. I hypothesize that adjunctive, bradyzoite-directed therapies have the potential to alleviate a significant burden of disease by reducing cyst burden in neonatal brain and eyes. Atovaquone is perhaps the most promising drug for further evaluation given its low side-effect profile, established safety, and efficacy in animal models reducing cyst burden. Very limited observational data in humans suggests atovaquone may prevent Toxoplasma-associated chorioretinitis recurrence. Clinical trials are needed to evaluate it and other potential drugs as adjunctive treatment in congenital toxoplasmosis.

Disseminated toxoplasmosis with atypical symptoms which developed with exacerbation of systemic lupus erythematosus

Toxoplasma is a common parasite worldwide that mainly affects the brain, lungs and eyes. Although toxoplasmic encephalitis is a lethal disease without treatment, past case reports show most patients with systemic lupus erythematosus who developed toxoplasmic encephalitis were misdiagnosed and treated as neuropsychiatric systemic lupus erythematosus, which led to unfavorable outcomes. We herein describe a case of disseminated toxoplasmosis affecting all the above organs with atypical symptoms, which developed with exacerbation of systemic lupus erythematosus. She had initially manifested with retinochoroiditis without vitritis, mild cognitive impairment and an isolated lung mass. These are completely different from the classic symptoms of toxoplasmosis that have been reported in patients with HIV infection and/or those after hematopoietic transplantation. Our case, together with previously reported cases, suggests the manifestation of toxoplasmosis that develops in systemic lupus erythematosus patients can be different from that seen in conventional cases and varies between individual patients. Our case highlights both the difficulty in and the importance of diagnosing toxoplasmosis in patients with systemic lupus erythematosus and provides helpful information to identify this rare, devastating, yet treatable disease.

OCTA Imaging of Choroidal Neovascular Membrane Secondary to Toxoplasma Retinochoroiditis

Two patients (a 37-year-old man and a 28-year-old woman) who had choroidal neovascular membrane (CNVM) secondary to inactive toxoplasma retinochoroiditis scarring were evaluated. Multimodal imaging including fluorescein angiography, optical coherence tomography (OCT), and OCT angiography (OCTA) was used. CNVM secondary to inactive toxoplasma retinochoroiditis scarring was detected. Representative images of CNVM were demonstrated in the outer retinal layer and choriocapillary layer on OCTA. OCTA, a relatively new technique, is useful in the diagnosis of the CNVMs secondary to retinochoroiditis. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:509-511.].

The Impact of Short-Term, Intensive Antifolate Treatment (with Pyrimethamine and Sulfadoxine) and Antibiotics Followed by Long-Term, Secondary Antifolate Prophylaxis on the Rate of Toxoplasmic Retinochoroiditis Recurrence

PURPOSE

To assess the impact of intensive antifolate treatment, followed by secondary antifolate prophylaxis (A-SP) on the recurrence rate of toxoplasmic retinochoroiditis (TRC). To investigate whether there are any other factors potentially predisposing for recurrence.

MATERIAL AND METHODS

A total of 637 medical records of TRC patients, who had been treated in the years 1994-2013 were reviewed. All patients were treated with pyrimethamine /sulfadoxine one 25mg/500mg tablet daily (P/S 25/500mg) for 21 days with a double loading dose for the first two days. From Day 2 the patients also received prednisone at a starting dose of 40mg and spiramycine 3 million IU three times daily, given for 10 days followed by azithromycin 500mg once daily for another 6 days. The analysis of the recurrence rate involved 352 patients who had completed 6-month secondary prophylaxis (P/S one 25 mg/500mg tablet twice a week).

RESULTS

When secondary antifolate prophylaxis (A-SP) was instituted immediately after the treatment for TRC, the probability of 3-year recurrence-free survival after the first course of A-SP was 90.9%. A recurrence was most likely approximately 3.5 years after the first treatment. A univariate Cox regression model demonstrated that a risk for recurrence was 2.82 times higher (p = 0.02) in patients with retinal scars. In the multivariate analysis, the risk for recurrence was 2.41 higher (p = 0.06). In patients with haemorrhagic lesions the risk for recurrence was lower, aRR = 0.17 (approaching borderline statistical significance p = 0.08).

CONCLUSIONS

With the institution of A-SP of immediately after the intensive treatment for TRC, i.e. when a reactivation was most likely, there was no recurrence during A-SP. Following A-SP the recurrence rates were low and recurrence-free periods tended to be longer. The treatment regimen employed had a beneficial effect on the recurrence interval as it reduced and delayed the highest probability of recurrence.

Activation of toxoplasma retinochoroiditis during pregnancy and evaluation of ocular findings in newborns

The purpose of this study was to evaluate patients with activation of toxoplasma retinochoroiditis during pregnancy and ocular findings in newborns. A total of 17 pregnant patients who were clinically and serologically diagnosed with ocular toxoplasmosis were retrospectively reviewed. After birth, ocular findings for all infants were recorded. The mean age of the patients was 29.08 ± 5.71 years. In all cases, activation was present in only one eye. In 13 cases, anterior uveitis was associated with posterior uveitis. Visual acuity in all cases prior to treatment was 0.3 ± 0.21 and increased to 0.55 ± 0.29 after treatment. The mean gestational age of the patients was 19.76 ± 8.71 weeks at the time of hospital admission. No case of toxoplasmic ocular involvement was identified in the infants on postnatal examination. In the case of toxoplasma retinochoroiditis during pregnancy, appropriate treatment and follow-up is very important to protect the newborns and to prevent impaired vision in mothers.

Retinal tear: an unusual complication of ocular toxoplasmosis

Purpose

It is aimed to report on a 16-year-old patient with acquired ocular toxoplasmosis complicated by a retinal tear.

Methods

Retrospective medical chart review

Results

A 16-year-old Caucasian female presented with vision loss in her right eye. In addition to a white active lesion between the fovea and the optic nerve head, marked vitreous opacification was noted. She was diagnosed with ocular toxoplasmosis. The patient was treated with oral azithromycin, clindamycin, and trimethoprimsulfamethoxazole. One month later, retinochoroiditis resolved and vitreous cleared. Three months after onset, patient presented with floaters in the right eye and a retinal tear was located at the temporal region of the retina. Prophylactic argon laser treatment that encircled the retinal tear was performed. No other abnormalities were noted during 6 months of follow-up.

Conclusions

Retinal tear associated with ocular toxoplasmosis is rare; however, a retinal tear can occur due to vitreoretinal traction following post-inflammatory structural alteration of the vitreous. Retinal tears may be seen during the healing phase, when the inflammation turns into tightening of vitreous substance. Careful retinal examination in cases of ocular toxoplasmosis is warranted, especially in patients with severe vitreous inflammation.

Cuban Ocular Toxoplasmosis Epidemiology Study (COTES): incidence and prevalence of ocular toxoplasmosis in Central Cuba

BACKGROUND

Serological studies indicate that rates of ocular toxoplasmosis (OT) vary geographically, with higher rates in tropical regions. Little is known about population-based rates of active OT. We aimed to describe the epidemiology of OT in Central Cuba.

METHODS

This large-population, cross-sectional cohort study used a prospective database at a large regional referral centre in Central Cuba. The patient database was searched for all patients who presented with OT during the 12-month study period from 1 April 2011 to 31 March 2012. Inclusion criteria were the clinical diagnosis of OT, characterised by focal retinochoroidal inflammation and a response to therapy as expected. Gender-stratified and age-stratified study population data from the 2012 Cuban Census were used to calculate incidence rates and prevalence ratios.

RESULTS

Among 279 identified patients with OT, 158 presented with active OT. Of these, 122 new-onset and 36 prior-onset cases were confirmed. Based on the total population in the Sancti Spiritus province (466,106 persons), the overall incidence of active OT was 26.2 per 100,000 person-years (95% CI 21.7 to 31.3) with an annual prevalence ratio of 33.9 per 100,000 persons (95% CI 28.8 to 39.6). The incidence of active OT was lowest in the oldest age group and highest in patients aged 25-44 years (4.5 and 42.1 per 100,000 person-years, respectively).

CONCLUSIONS

This first report describing population-based rates of OT in the Cuban population highlights the importance of patient age as a likely risk factor for OT. Disease rates were found to be highest in females and young to middle-aged adults.

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.

Differential diagnosis of behçet uveitis

The diagnosis of Behçet disease is clinical and based on the presence of characteristic ocular and systemic inflammatory manifestations. Patients may present with anterior, posterior, or panuveitis in one or both eyes. The differential diagnosis includes a variety of infectious and noninfectious causes of acute nongranulomatous anterior uveitis, intermediate uveitis, occlusive retinal vasculitis, focal or multifocal retinitis, and necrotizing retinitis. A course characterized by sudden onset with improvement followed by recurrence of inflammatory signs is most typical for Behçet uveitis.

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.

Clinical pattern of ocular toxoplasmosis treated in a referral centre in Serbia

PURPOSE

To analyze the clinical pattern of ocular toxoplasmosis (OT) in a referral centre in Serbia.

PATIENTS AND METHODS

The medical records of consecutive patients admitted for OT to the single referral centre for uveitis in Serbia between 2006 and 2010 were retrospectively analyzed. OT was diagnosed on the basis of typical fundus lesions and positive serology for Toxoplasma.

RESULTS

In a total of 457 uveitis patients, OT was the third leading cause, with 59 patients (12.9%). Most OT cases (73%) were monocular. An active primary retinal lesion was observed in 36% and recurrent OT in 64% patients. Localization of lesions was central/paracentral (44%), juxtapapillar (27%), peripheral (19%), and multifocal (10%). Other ocular manifestations of inflammation included vitritis (44%), anterior uveitis (19%), and retinal vasculitis (10%). Complications included choroidal neovascularization in two and exudative retinal detachment with cataract, glaucoma, and cystoid macular oedema in one patient each. The detection of Toxoplasma-specific IgM antibodies in a single patient indicates a low rate of OT concomitant with acute infection. After treatment, the mean best-corrected visual acuity (BCVA) increased significantly. However, 14 (24%) patients ended up legally blind in the affected eye, of which 2 (3%) with bilateral blindness, all with a very poor BCVA (0.047 ± 0.055) at presentation. Visual impairment and treatment outcome were both associated with central localization of lesions (P<0.0001 and P=0.006, respectively).

CONCLUSION

OT is a significant cause of posterior uveitis in Serbia. Patients should be aware of the recurring nature of OT and react immediately if symptoms occur.

Acute papillitis in young female with toxoplasmosis

Papillitis and complicating acute toxoplasma retinochoroiditis, are unusual and atypical features of toxoplasmosis. This report presents a female with unusual acute papillitis. This patient had an active toxoplasmic chorioretinitis lesion that appeared to involve the optic nerve head and a major blood vessel as well as central nervous systems (CNS). Papillitis may be secondary to juxtapapillary retinitis (Jensen choroiditis). Very rarely, the optic nerve head may be the primary site of involvement. This case report illustrates a rare presentation of acute papillitis in a young immunocompetent female.

Clinical features of ocular toxoplasmosis in Korean patients

We report here the records of 10 consecutive Korean patients (10 eyes) with ocular toxoplasmosis which showed the typical clinical manifestations with seropositivity for Toxoplasma gondii specific IgG antibodies by micro-ELISA between 2006 and 2010. Nine patients were males and 1 was female; their age was 50.5 ± 13.8 years. The most common accompanying signs were vitritis (100%), anterior uveitis (70%), and scattered white deposit (80%). Pre-existing retinochoroidal scar was found in 1 (10%) patient. All patients received antiparasitic chemotherapy and systemic corticosteroid treatment, which resolved the presenting attack and recovered the visual acuity better than initial one in 9 patients and worse in 1. Optic atrophy, cataract, and retinal neovascularization were observed during the follow-up period and recurrence was detected in 3 eyes (30%) 6 to 20 months after the initial attack. In Korea, although rarely detected and reported, ocular toxoplasmosis needs more attention in clinical field of retinal diseases.

Does atovaquone prolong the disease-free interval of toxoplasmic retinochoroiditis?

BACKGROUND

To evaluate the efficacy of suppressing a recurrence of Toxoplasma retinochoroiditis after treatment with atovaquone.

METHODS

Retrospective, nonrandomized, clinical trial. Forty-one immunocompetent patients were treated for Toxoplasma retinochoroiditis with atovaquone between 1999 and 2006. The diagnosis was based on clinical signs alone. Atovaquone was given 750 mg two to three times daily together with oral steroids. Lesion location, time interval until recurrence, visual function, and adverse events were recorded.

RESULTS

Forty-two eyes of 41 patients were treated with atovaquone for Toxoplasma retinochoroiditis. Side-effects were usually mild and only one patient stopped therapy with atovaquone because of nausea. Reactivation of retinochoroiditis occurred in 18 patients (44%) during a time interval of 3-70 months.

CONCLUSIONS

The therapy of Toxoplasma retinochoroiditis with atovaquone is well tolerated. Our data suggests that therapy with atovaquone has the potential to prolong the time to recurrence of Toxoplasma retinochoroiditis. A prospective randomized comparative long-term clinical trial would be necessary to confirm our data.