to the differential diagnosis of infectious uveitis [93-95, 101-102]. Identification of the triggering pathogen was established by serology and PCR in 60% of HIV-infected individuals presenting with undefined posterior uveitis in a study from Italy, whereas PCR provided a final diagnosis in 39% of cases where the initial diagnosis of causative pathogen was uncertain in a study from South Africa [93, 102]. Furthermore, treatment was altered on basis of PCR results in 20% of patients with posterior uveitis of suspected infectious origin in a study from USA [95]. In our study, AH samples were only obtained from participants with severe visual impairment as this procedure is not part of standard clinical practice in South Africa (chapter 5) [70]. In case of herpetic uveitis patients, AH was obtained from 20 (53%) patients and specific diagnosis based on analysis of aque- ous humour was established in the majority (65%) of patients (chapter 5) [70]. Clinical or laboratory evidence of HSV-1, HSV-2 or EBV as cause of uveitis was not observed (chapter 5) [70].
Anterior chamber paracentesis is a safe procedure that can be performed in a consul- tation room at the slit-lamp [103-104]. Three studies reported on safety of this proce- dure to diagnose uveitis [103-105]. There were only a few, non-serious, complications reported: traumatic hyphaemia (5 cases per 1,000 procedures) and injection of air into the anterior chamber (4 cases per 1,000 procedures) as the most important. Hyphaemia refers to bleeding in the anterior chamber that may cause blurred vision, but this will usually resolve spontaneously or is easily treatable with topical drops (e.g. topical ste- roids). Similarly, injection of air into the anterior chamber may cause blurred vision but is usually self-limiting [103-105].
Uveitis is a serious condition resulting in severe visual impairment and even blind- ness if not treated promptly and adequately. In South Africa, referral from lower levels of healthcare to a regional ophthalmology unit for further management and initiation of (empirical) treatment is indicated. However, even at these units, treatment outcomes may be poor due to the low predictive value of the patient’s history and clinical charac- teristics for aetiology of uveitis. Anterior chamber paracentesis, aspiration and analysis of AH will provide a valuable diagnostic procedure that optimizes treatment and sub- sequent prognosis at a very limited risk. This procedure can be performed in most clinical settings, because a well-trained ophthalmic nurse could safely perform anterior chamber paracentesis in situations when qualified ophthalmologists are not available. Paracentesis is easier to perform than cataract surgery for which ophthalmic nurses are trained in some African countries (e.g. Malawi) in the absence of ophthalmologists [106]. In addition to skills development, strengthening laboratory infrastructure is warranted. Validation of existing diagnostic assays and provision of other resources required to analyse aqueous humour for the most common uveitogenic pathogens should be con- sidered across South Africa. Furthermore, logistic systems, e.g. cold sample transport chain, would require optimisation to ensure short turnaround time and maximum clini-
Chapter 8
130
cal impact of this diagnostic test. Providing such diagnostic service will be cost-effective due to reduction of unnecessary use of expensive antimicrobial drugs and aversion of blindness and associated socioeconomic costs [107].
Collectively, increased awareness about the unmet need for valuable diagnostic plat- forms for uveitis is needed. Moreover, discussion among healthcare providers about the introduction thereof in routine work-up of uveitis patients in South Africa is highly war- ranted. Ultimately, these efforts should result in the development of clinical guidelines and a training program that includes combined clinical and laboratory evaluation for infectious aetiology, including AH sampling to detect the triggering pathogen, chest X-ray and sputum evaluation for M. tuberculosis and serological evaluation for syphilis.
OculAr cOnDItIOnS ASSOcIAtED WItH HIV InfEctIOn AnD Art
Currently there is no cure for HIV, but the mass introduction of ART has resulted in pro- longed survival even to a normal life expectancy in high-resource countries [108-109]. In Western countries, the introduction of ART resulted in a substantial reduction in in- fectious ocular conditions associated with severe immunodeficiency, but data from the African continent are largely unavailable [18-19, 21]. In South Africa, especially in rural settings, ART coverage is still low and individuals still present to healthcare facilities for the first time with moderate to severe immunodeficiency. New strategies to achieve HIV epidemic control, such as the Joint United Nations Programme on HIV/AIDS (UNAIDS) 90-90-90 campaign, aim to diagnose 90% of all HIV-infected individuals, provide ART for 90% of those diagnosed with HIV infection and achieve undetectable HIV viral loads for 90% of those on treatment by the year 2020 [110]. These efforts will most likely result in decreasing numbers of HIV-infected individuals with severe immunodeficiency and possibly in a decrease in the incidence of infectious ocular conditions as observed in Western countries [18-19]. However, available data from Western countries also suggest that metabolic and vascular changes associated with extended use of ART may affect the eye, manifesting for example as retinopathy [18]. Also, accelerated ageing and frailty among HIV-infected individuals on ART may also affect ocular structures such as the lens [21]. Finally, persistent immune activation in individuals on ART could predispose to ocular conditions like age-related macular degeneration [111]. ART is lifelong, but long-term effects of ART and chronic HIV infection on the prevalence of ocular disease are largely unknown, especially from sub-Saharan African settings with high HIV preva- lence. Such impact, may greatly affect HIV-infected individuals’ quality of life [3]. As the number of HIV-infected individuals on ART will increase, it is crucial to obtain insight in the distribution of ocular disease and manifestations among HIV-infected individuals with and without ART in rural South Africa to identify preventive measures.
131