Nematode infections of the eye: toxocariasis and diffuse unilateral subacute neuroretinitis.

In many parts of the world, parasitic infections of the eye are a major cause of blindness. The parasites Toxocara canis, Onchocerca volvulus, Taenia solium, Ancylostoma caninum, and Cysticercus celulosae all have been responsible for blinding ocular infections. The nematodes T. canis and Toxocara cati are parasitic roundworms that infect dogs (toxocarosis), other canidae, and cats. Ocular toxocariasis is an uncommon worldwide infection caused by the nematode larvae of T. canis, commonly found in dogs. Human transmission is usually via geophagia, the ingestion of food contaminated with Toxocara eggs, or contact with infected puppies, often resulting in devastating ocular or systemic effects. Ocular toxocariasis is typically a monocular disease of young children, and its clinical findings include posterior and peripheral retinochoroiditis, optic papillitis, and endophthalmitis. The inflammatory response created by ocular involvement may result in epiretinal membrane formation, traction retinal detachment, and combined traction-rhegmatogenous retinal detachment. Diffuse unilateral subacute neuroretinitis is another ocular parasitic infection that usually results in severe visual loss. Evidence suggests that diffuse unilateral subacute neuroretinitis is caused by a solitary unidentified nematode of two different sizes, but to date, only a small number of nematodes have been recovered from eyes affected with the infection. Diffuse unilateral subacute neuroretinitis occasionally can affect the fellow eye.     

Ocular toxoplasmosis and toxocariasis in childhood

Toxoplasmosis and toxocariasis are parasitic infections that are transmitted by cats and dogs, respectively, to humans, and which may induce posterior uveitis already in childhood. Toxoplasmosis presents as a congenitally or postnatally contracted infection whereas toxocariasis is always an acquired disease. The typical ocular sign of toxoplasmosis is retinochoroiditis, occurring as an active lesion, in most instances, associated with an inactive pigmented scar. In contrast, toxocariasis leads to a choroidal granuloma secondarily involving the retina or an endophthalmitis-like picture. Although toxoplasmosis represents the most common cause of posterior uveitis, there are uncertainties regarding the timing and specificity of the diagnosis, namely in atypical cases and those at risk of permanent severe loss of function. Antiparasitic treatment should be tailored to the severity of the inflammation and the risk of visual function loss. Concomitant steroids may be used to control the sequelae of unspecific inflammation, but should be used with caution and must be combined with an antimicrobial regimen. Because it is a rare disorder, one may not be familiar with the clinical presentation and suggested therapy for ocular toxocariasis. With this survey we, therefore, wish to provide a current, practice-oriented overview on the infection, ocular manifestations, diagnosis and treatment of ocular toxoplasmosis and toxocariasis in childhood.     

Ocular toxocariasis. Value of local immunodiagnosis

Toxocara canis is a nematode that may be involved in human ocular toxocariasis. Specific immunotesting is of importance but may be negative as toxocara antigens may localize exclusively in vitreous humor. We report here the case of one patient with optic disc toxocariasis granuloma negative for toxocara canis immunodiagnostic on serum. Clinical diagnosis was confirmed by toxocara canis specific enzyme-linked immunosorbent assay (ELISA) on aqueous humor showing elevated titers of antibodies. Systemic steroids associated to specific treatment of toxocariasis were initiated. Follow-up displayed regression of uveitis but development of vitreous bands leading to posterior retinal detachment. Toxocara posterior granuloma is of poor visual prognosis. Moreover, diagnosis may be of late setting, as clinical features are often unrecognized and specific immunodiagnostic on serum negative. Specific immunotesting on aqueous humor is of particular importance to rule out severe clinical differential diagnosis such as retinoblastoma in children. Ultrasound biomicroscopy (UBM) seems to be specific and sensitive in patients with a presumed diagnosis of peripheral toxocariasis. Granuloma surgery appears to yield good clinical results and allows histological confirmation of the diagnosis.     

Nematode infections of the eye: toxocariasis,onchocerciasis, diffuse unilateral subacute neuroretinitis,and cysticercosis

Nematode infections of the eye are common in different parts of the world, but some are usually encountered only in developing nations, such as onchocerciasis and cysticercosis. Ocular toxocariasis is a well-known cause of unilateral ocular disease affecting mainly children and young adults, and is usually caused by T canis. Prevention of ocular toxocariasis is based on such measures as appropriate health care for dogs and cats, including regular anthelmintic treatments, preventing contamination of the environment with feces, and promoting responsible pet ownership [1,49-51]. Onchocerciasis is caused by infection with the filarial parasite O volvulus, and occurs in endemic areas along rivers and streams. In hyperendemic areas almost every person is infected and about half of the population is eventually blinded by onchocerciasis. Because of this, elimination of host-vector contact is very important. DUSN is caused by a motile nematode and is found in the Southeastern and Midwestern United States and in many parts of the world. In Brazil, DUSN is becoming an important cause of posterior uveitis in children and young healthy adults. The destruction of the worm during the early stages of the disease can prevent progression of the visual loss. It is important to remain aware of this entity, not only in areas where it has been described, but also in regions not yet identified as being endemic [52]. Cysticercosis is caused by the encystment of the larvae of the tapeworm T solium, and usually results from ingesting eggs from food, water, or other material contaminated with human feces. Surgical removal of the cyst is usually indicated when possible.     

眼弓蛔虫病的诊治进展

眼弓蛔虫病(OT)是因蛔虫科线虫感染眼组织而引起的一种眼寄生虫病,常由犬弓蛔虫或猫弓蛔虫引起。易感人群多与自己的卫生状况、接触猫犬的频率、食用被弓蛔虫幼卵污染的食物或水源有关。目前在全球范围内的报道多见于儿童,但是近几年也陆续有成人感染的病例被报道,可能因目前对其诊断、治疗和预防还缺乏系统的归纳和总结有关。本文通过查阅国内外相关文献,将OT的四种临床表现、先进的无创诊断技术、实验室免疫学检查进行梳理和补充,同时本文介绍了OT近几年的治疗进展,如驱虫药和激素的联合使用,玻璃体腔内注射与玻璃体手术的应用等。希望引起临床医生对本病的重视,提高OT早期诊断的准确性,保护患者视力。     

Clinical characteristics of ocular toxocariasis in Eastern China

Purpose

To explore the clinical characteristics of patients with ocular toxocariasis in eastern China.

Methods

The medical records of 35 cases of ocular toxocariasis in Fudan University Eye &; ENT Hospital between May 2009 and April 2011 were retrospectively reviewed and analyzed. UBM, RetCam or fundus imaging, and high-frequency or conventional ultrasonography were performed in these patients.

Results

The mean patient age in our series of ocular toxocariasis was 11.86?±?8.80?years. There were 28 children and seven adults, the majority residing in a rural area (88.57%). All cases were classified into three clinical subtypes: granuloma in the peripheral retina (60% of cases); granuloma in the posterior pole (28.57% of cases); and vitreous inflammation mimicking chronic endophthalmitis (5.71% of cases). We also identified an additional subtype with unique clinical features that we termed “combined type” presenting in 5.71% of our patients. This subtype exhibited granulomas in both the posterior pole and peripheral retina. RetCam fundus imaging was able to identify granulomas in the posterior and peripheral subtypes, 100% and 80.95% of cases respectively. Moreover, UBM combined with conventional ultrasonography identified granulomas in 95% of the peripheral subtype cases and in 100% of the posterior pole subtype cases.

Conclusions

This is the first ocular toxocariasis series described in Chinese patients. Compared with reports from developed countries, the ocular features in our series were more severe and complicated, presenting with poorer visual acuity and a high rate of retinal detachment (45.7%). The application of RetCam and UBM during examination in ocular toxocariasis can provide valuable information in determining the severity of disease and features important in considering surgical procedures in such patients.     

Ocular toxocariasis in adults.

Human infection by toxocara larvae has been thought to be predominantly a disease of young children, but the percentage of the population with antibodies to this nematode worm has recently been shown to increase with age. Although a definite diagnosis of ocular toxocariasis can be made only by identifying the larva histologically, the evidence in three cases presenting with recent uniocular loss of vision strongly suggests that adults may also be affected. The lesions noted on ophthalmoscopy closely resembled toxocaral granulomata in children. Toxocaral fluorescent antibody tests were positive in each case.     

Clinical features of ocular toxocariasis in Japan

Purpose: To characterize the clinical features of ocular toxocariasis and to describe the unique aspects of the disease in Japan. Methods: Thirty-six cases diagnosed as ocular toxocariasis at the uveitis clinic of Tokyo Medical University Hospital were analyzed retrospectively. Results: Thirty-six cases comprised 34 adults (average age: 39 ± 10 years) and two nine-year-old boys. All cases were classified into two clinical types: posterior pole type (13 cases) and peripheral type (23 cases). Visual acuity was maintained over 20/20 in 50% and less than 20/200 in 14% of the cases. The peripheral type had worse outcomes than the posterior pole type in all of the endpoints examined: final visual outcome, frequency of ocular complications, and effectiveness of vitreous surgery. Antibody titers in intraocular fluids led to a diagnosis of ocular toxocariasis in eight seronegative cases of 33 cases examined for antibodies in both serum and intraocular fluid samples. Conclusions: The peripheral type had a worse prognosis than the posterior pole type. However, in general, ocular toxocariasis resulted in fair visual outcomes. The antibody titer in intraocular fluid was helpful in the diagnosis.     

Fuchs heterochromic cyclitis and ocular toxocariasis

PURPOSE: To report the association of Fuchs heterochromic cyclitis (FHC) and ocular toxocariasis in a young adult. DESIGN: Observational case report. METHODS: A 26-year-old patient was referred for the management of a unilateral intermediate uveitis associated with a lower peripheral subretinal fibrotic lesion near the pars plana. Diagnosis of FHC was clinically confirmed. Laboratory examination was performed to exclude an infectious condition. RESULTS: LISA assay detected significant levels of IgG directed against Toxocara canis. Toxoplasmic serology was negative, excluding this differential diagnosis. Other examinations, including complete blood cell count, urinalysis, serum angiotensin-converting enzyme, lysosyme, chest CT scan, and syphilis serology were noncontributive. CONCLUSIONS: Previous studies have reported on the association of FHC and other parasitic conditions, such as toxoplasmosis but also on herpetic ocular infections. Serologic analysis for toxocariasis may be proposed in patients with FHC and retinal scars in the absence of toxoplasmosis.     

A case of presumed ocular toxocariasis in a 28-year old woman

This is a case of presumed ocular toxocariasis in a 28-year old woman complaining of a sudden onset of nasal side field defect of the right eye. The patient had been suffering from uveitis for ten months. Fundoscopic examination of the right eye showed a rhegmatogenous retinal detachment. Furthermore, a retinochoroidal granulomatous lesion was observed nearby the tear site. Scleral buckling, cryotherapy, and gas injection(SF6, pure gas, 0.7 cc) were conducted. Mebendazole was prescribed for one month at 25 mg/kg per body weight daily. Even though the interventions resulted in the recovery of the field defect, anti-Toxocara IgG and IgE titer levels did not decrease when checked three months after the treatment ended. This is the first confirmed serological ocular toxocariasis case in Korea. Uveitis may be a clinical presentation prior to retinal detachment of a person with toxocariasis.     

Toxocara canis infestation. Clinical and epidemiological associations with seropositivity in kindergarten children

We studied a cohort of 333 children in kindergarten to determine the prevalence of seropositivity to Toxocara canis, and to detect and measure chronic health effects that might be attributable to past infection. We found that 23.1% of the children had serologic evidence of infection (antibody titer greater than or equal to 1:32), assayed by means of an enzyme-linked immunosorbent assay. Black children were more frequently infested than white children, as were children of parents who did not graduate from high school. In a subsample of seropositive and seronegative children, we found associations between seropositivity and both pica and puppy ownership; we did not find differences in the symptoms and signs that occur in toxocaral visceral larva migrans nor differences in measures of growth and nutrition. No child had ocular toxocariasis although 31.8% (106) of the children had antibody titers greater than or equal to 1:16. In a population in which approximately 20 to 30% of the children show serologic evidence of Toxocara infestation, care must be taken in differentiating toxocariasis-like ophthalmic lesions, due to the potential for the coincidental occurrence of retinoblastoma in a child who is seropositive for the Toxocara parasite.     

Ultrasound biomicroscopy findings in peripheral vitreoretinal toxocariasis

PURPOSE: To describe the morphologic alterations in ultrasound biomicroscopy (UBM) present in peripheral vitreoretinal toxocariasis. METHODS: An observational prospective study of case series. Fifteen eyes of 15 patients with clinical and laboratory diagnosis of peripheral vitreoretinal toxocariasis were enrolled. The patients were submitted to UBM examination of the region corresponding to the pars plana of the affected eye. RESULTS: The most common morphologic alterations found by UBM in patients with peripheral vitreoretinal toxocariasis were as follows: vitreal membranes (13 cases), toxocara granuloma (11 cases), and pseudocysts (8 cases). Other less frequent findings were thickening of the ciliary body (6 cases), cystic formation (2 cases), peripheral retinal detachment (2 cases), rectification of the iris root (1 case), and posterior synechiae (1 case). CONCLUSIONS: UBM allows detection of well-defined morphologic alterations associated with peripheral vitreoretinal toxocariasis, being useful to reinforce the clinical diagnosis.     

Six cases of scleritis associated with systemic infection.

Isolated scleritis (without keratitis) associated with infections is uncommon, and correct diagnosis and appropriate therapy for it are often delayed. Six patients with infection-associated scleritis were seen at our institution between May 1983 and May 1990 (these patients represented 4.6% of all patients with scleritis [six of 130 patients] in that period). Three of these cases were associated with systemic infections. One was associated with syphilis, one was associated with tuberculosis, and one was associated with toxocariasis. Three cases resulted from local infections. One was associated with infection with Proteus mirabilis, one was associated with infection with herpes zoster virus, and one was associated with infection with Aspergillus. The Aspergillus infection developed after trauma and the P. mirabilis-induced infection developed after strabismus surgical procedures. Four of the six cases were initially misdiagnosed and inappropriately managed. Correct diagnosis was made seven days to four years after onset of symptoms. Review of systems, scleral biopsy, culture, and laboratory investigation were used to make the diagnosis. Differential diagnosis of scleritis must include infective agents.     

Ocular manifestation of systemic infections

Careful examination of external and internal ocular structures in patients with systemic infections may assist in early diagnosis and institution of appropriate therapy. Recent literature discussing ocular manifestations in the following systemic infectious diseases are reviewed: tuberculosis, Lyme borreliosis, cat scratch disease, toxocariasis, congenital toxoplasmosis, and invasive aspergillosis.     

Clinical Features of Ocular Toxocariasis in Adult Korean Patients

Purpose: To investigate the clinical characteristics and treatment results of adult patients with ocular toxocariasis.

Methods: A total of 54 consecutive patients who were clinically and serologically diagnosed with ocular toxocariasis were retrospectively reviewed.

Results: Among patients, 66.7 and 77.3% showed increases in eosinophil cationic protein (ECP) and total Ig E in serum, respectively. Four eyes (7.2%) initially presented as neuroretinitis with subsequent motile retinal lesion. The recurrence rates in the combination treatment group with albendazole and corticosteroids were significantly lower than those in the steroid-alone group during the mean follow-up of 27.6 months (p?=?0.001).

Conclusions: The adjunctive test of serum total IgE level may be helpful for the diagnosis of ocular toxocariasis. Ocular toxocariasis should be considered in the differential diagnosis of unilateral neuroretinitis with subsequent motile retinal lesion. Combined treatment with albendazole and corticosteroids appeared to be effective for reducing the recurrence of intraocular inflammation.     

Long-term follow-up in patients with ocular toxocariasis as measured by ELISA titers

Twenty patients with ocular toxocariasis were followed-up with serial elisa titers. Eighty-five percent showed a decrease in serum titers, 10% showed an increase, and 5% were stable. One should not be dissuaded from making the diagnosis clinically of ocular toxocariasis because of low titers, as the patient may have had higher titers previously. In the past, results were reported as positive if a titer of at least 1:32 was present and negative if below this level. Exact titers should be requested, as any positive titer (even as low as 1:2) with clinical correlation is believed to be significant.     

巩膜切口位置调整下玻璃体切除术治疗眼弓蛔虫病的效果

目的 观察巩膜切口位置调整后玻璃体切除术治疗眼弓蛔虫的临床效果。设计 回顾性病例系列。研究对象 2012年3月至2018年3月北京同仁医院眼科因眼弓蛔虫病行巩膜切口位置调整下玻璃体切除术、随诊≥5个月的患者139例（139眼）。方法 回顾性分析患者病历资料,描述其一般情况,术前行UBM检查,根据术前UBM检查结果或双目间接检眼镜检查结果进行巩膜切口位置调整。描述手术前后视力及局部解剖变化和手术并发症。术后最佳矫正视力较术前提高≥2行者定为视力改善,下降≥2行为视力下降,提高或下降≤1行定为视力稳定。主要指标 手术前后视力和局部解剖变化及手术并发症。结果 139眼眼弓蛔虫患者64眼（46.0%）联合晶状体切除术。平均随访（29±9）个月。末次随访时视力较术前改善者70.2%（85/121）,视力稳定者22.3%（27/121）,视力下降者7.5%（9/121）;69.1%（96/139）的患者术前合并牵拉性视网膜脱离,其中65眼术后视网膜脱离复位或改善;术后1周内22.3%低眼压（31/139）和1个月后13.7％高眼压（19/139）。 结论 巩膜切口位置调整下玻璃体切除术有助于改善眼弓蛔虫病患者视功能和眼局部解剖预后;术前UBM检查可明确周边玻璃体视网膜病变的位置和范围而引导巩膜切口位置调整。     

The behavior of angiotensin-converting enzyme in patients with uveitis]

ABSTRACT: Serum angiotensin-converting enzyme (ACE) is considered as a marker in many disorders, especially in sarcoidosis. The aim of this study was to assess ACE activity using Haiakari spectrophotometry in patients with non-sarcoidosis uveitis before and after treatment. MATERIAL AND METHODS: 36 patients, including 21 adults and 15 children, were investigated. ACE concentration was increased mostly in patients with recurrent toxoplasmic and toxocaral iridocyclitis and choroiditis. RESULTS: It was demonstrated that concentration of ACE was increased especially in toxocariasis uveitis. After treatment the concentration of ACE was significantly decreased in all patients.     

Echographic characteristics of ocular toxocariasis

Ocular toxocariasis most commonly presents as one of three distinct clinical syndromes: endophthalmitis, localized posterior granuloma, or peripheral granuloma. Using standardized echography, the authors studied 11 toxocariasis patients presenting with one of these syndromes. Common echographic findings were noted in ten of these patients, and included: (1) a solid, high-reflective peripheral mass, (2) a vitreous band or membranes extending between the posterior pole and the mass, and (3) a traction retinal detachment or fold from the posterior pole to the mass. These findings were present in patients presenting with leukocoria or endophthalmitis, as well as in patients in whom the peripheral nematode lesion could be visualized clinically. In combination with the history, clinical examination, and enzyme-linked immunosorbent assay (ELISA), standardized echography may be useful in establishing the diagnosis of ocular toxocariasis in cases of leukocoria in which nematode endophthalmitis is suspected.     

Prevalence, clinical features, and causes of vision loss among patients with ocular toxocariasis

BACKGROUND: To describe the prevalence, clinical features, and causes of vision loss among patients with ocular toxocariasis seen at a uveitis referral center. METHODS: A review was completed of the charts of patients with ocular toxocariasis who were examined between 1977 and 1996 at the Francis I. Proctor Foundation of the University of California at San Francisco. The prevalence of ocular toxocariasis among all uveitis patients seen at the center was determined. Demographic features, symptoms, and signs in all patients were evaluated. RESULTS: Ocular toxocariasis occurred in 22 (1.0%) of 2,185 uveitis patients. The mean patient age was 16.5 years. Inflammation was usually unilateral (90.9%). Toxocara uveitis presented as a granuloma in the peripheral retina in 50% of cases, as a granuloma in the macula in 25% of cases, and as a moderate to severe vitreous inflammation mimicking endophthalmitis in 25% cases. The primary causes of vision loss were vitritis (52.6%), cystoid macular edema (47.4%), and traction retinal detachment (36.8%). CONCLUSIONS: Ocular toxocariasis is an uncommon cause of uveitis that mainly affects younger patients. Inflammation is typically unilateral and presents as either a granuloma in the peripheral or posterior retina or a moderate to severe vitreous inflammation mimicking endophthalmitis.