Serology in ocular toxoplasmosis.

The diagnostic value of toxoplasma serology in ocular disease was evaluated in the following groups of patients: (I) uveitis cases of various causes (n = 291); (II) consecutive posterior and panuveitis patients (n = 60); (III) patients with definite congenital and ocular toxoplasmosis (n = 8); (IV) cases of clinical ocular toxoplasmosis (n = 25); and control patients with uveitis of non-toxoplasma origin (n = 12). No relation was observed between the level of the dye test titres and the diagnosis of ocular toxoplasmosis (groups I and II). During the active stages of the disease no typical change of the titres occurred in several longitudinally studied patients with toxoplasmosis. In group III one case was discovered to be negative by the dye test despite active ocular disease; however, IgG antibodies against toxoplasma were detected by the ELISA technique. In group IV, which was investigated by the ELISA technique, 100% of the toxoplasmosis patients were positive for IgG versus 58% of the control patients. Circulating immune complexes containing IgG and toxoplasma antigen were detected in seven of 25 toxoplasmosis patients (28%) and in two of 12 control patients (16%). Our study shows that the definite diagnosis of ocular toxoplasmosis or its exclusion by serological means only is not yet feasible. The possible superiority of the ELISA test to the dye test warrants further investigation.     

Diagnostic and therapeutic dilemmas in ocular toxoplasmosis

Ocular toxoplasmosis, a leading cause of visual handicaps in young people, represents a late manifestation of congenital infection in the majority of cases. Ocular involvement in acquired toxoplasmosis has been repeatedly reported and shows that toxoplasmic retinitis may develop in the wake of acquired infection. The diagnosis of ocular toxoplasmosis is mainly clinical since serologic tests are positive for a considerable percentage of the general population and are not indicative for ocular involvement. The demonstration of local synthesis of toxoplasma antibodies in the eye by intraocular fluid analysis is a valuable diagnostic tool. The application of the polymerase chain reaction, in which the parasite's DNA is detected, may be expected to change the diagnostic repertoire drastically in the future. The need for appropriate therapy for patients with ocular toxoplasmosis is a matter of continued debate: the majority of the medications used for treatment have potentially serious side effects and the efficacy of treatments has not been clarified in previous studies. Recently, a prospective multicenter study to evaluate the efficacy of current therapeutic strategies for ocular toxoplasmosis was performed in The Netherlands and included 106 patients with active ocular toxoplasmosis. The principal conclusion of this study is that only drug therapy with pyrimethamine had any perceptible influence on any aspect of ocular toxoplasmosis, but this effect may not be worth the risk of side effects except in fovea threatening lesions.     

The Usefulness of Aqueous Fluid Analysis for Epstein–Barr Virus in Patients with Uveitis

ABSTRACT

Purpose: To determine characteristics of patients with laboratory findings indicative of intraocular Epstein–Barr-virus (EBV) infection and to establish the usefulness of the laboratory analysis in patients with uveitis.

Methods: Retrospective study of patients who underwent diagnostic aqueous fluid analysis. Diverse demographic data of patients were registered.

Results: EBV-PCR tested positive in 3/201 (1%) and EBV-GWC in 22/245 (9%). The prevalence of immunosuppression was similar in EBV positive (by PCR/GWC) and EBV negative patients (7/25; 28% vs. 50/272;18%, P = 0.29). Out of all 22 EBV-GWC positive patients, GWC was between 3 and 10 in 91%. In total, 14 patients had laboratory results indicating only EBV infection. Patients without an alternative explanation for uveitis (6/14; 43%) had a chronic recurrent course and good visual prognosis.

Conclusion: Low EBV-GWC values combined with multiple positive GWC and/or PCR for other infectious agents. Intraocular assessment for EBV in the initial examination of uveitis patients has limited value.     

Elevated serum angiotensin-converting enzyme activity in onchocerciasis

Our objective was to measure serum angiotensin-converting enzyme (ACE) activity in patients with onchocerciasis. Serum ACE activity is commonly used in the diagnosis and follow-up of patients with sarcoidosis. However, serum ACE activity can also be elevated in a number of other granulomatous disorders. In onchocerciasis, a parasitic disease affecting millions of people in Africa and Central and South America, granulomatous tissue around adult worms has been identified, yet raised serum ACE activity has not been reported so far. We measured serum ACE activity in serum samples from 42 onchocerciasis patients and 39 endemic controls previously enrolled in two studies concerning the side effects after ivermectin treatment in Sierra Leone, West Africa. The mean ACE activity in the patient group was 53.8 units/liter (S.D. 19.8) compared with 35.2 units/liter (S.D. 14.0) in the control group (p < 0.0001). Nine of 42 patients had elevated ACE activity (mean of the endemic controls ± 2 S.D.) compared with 1 of 39 controls (p = 0.01). Sensitivity and specificity of elevated ACE in serum from onchocerciasis patients from Sierra Leone was 21 and 97%, respectively. ACE activity was not related to the microfilarial skin load or development of side effects after ivermectin treatment. Serum ACE activity can be elevated in onchocerciasis. Clinicians should be aware of this phenomenon when determining serum ACE activity in persons from endemic areas. Offprint requests to: Marjolein J. H. Ronday     

Rhegmatogenous retinal detachment and uveitis

PURPOSE: To evaluate the frequency, high-risk factors, and visual prognosis of rhegmatogenous retinal detachment (RRD) in patients with uveitis. DESIGN: Retrospective case-control study. PARTICIPANTS: We included 1387 consecutive patients with uveitis who consulted our uveitis clinic from January 1990 through December 1997 of whom 43 patients (46 eyes) with RRD were identified. The retinal detachment (RD) controls were 212 consecutive patients with RRD (221 eyes, first occurrence of RD, not associated with uveitis) who were admitted for surgery in the period from April 1999 to April 2000. The uveitis control group consisted of 150 age-matched patients (210 eyes) selected from the entire uveitis series. INTERVENTION: Retrospective analysis of clinical data. MAIN OUTCOME MEASURES: The presence of RRD and eventual risk factors for RRD, such as myopia, retinal lattice degeneration, prior intraocular surgery, anatomic location of uveitis, its specific diagnosis, and clinical manifestations. Furthermore, the surgical and nonsurgical outcomes of RRD, as well as the results of various treatment regimens, were analyzed. RESULTS: RRD was identified in 3.1% of the patients with uveitis. RRD was most frequently associated with panuveitis (6.6%). RRD was associated more frequently with infectious (7.6%) than noninfectious uveitis (2.1%). At the onset of RRD, uveitis was active in most (46%) affected eyes. Proliferative vitreoretinopathy was present in 30% of the uveitic RRD eyes at presentation in contrast to 12% of the RRD control eyes. In uveitic RRD, the retina was reattached in 59% of eyes with a single operation; the final anatomic reattachment rate was 88%. Finally, a visual acuity of less than 20/200 was present in 71% of the uveitic RRD eyes, 10% of which had no light perception. CONCLUSIONS: We discovered a high prevalence of RRD in patients with active panuveitis and infectious uveitis and document that uveitis in itself is a risk factor for the development of RRD. The visual prognosis of RRD in uveitis was poor because of the uveitis itself and the frequent development of proliferative vitreoretinopathy.