There are multiple region-oriented studies carried in other parts of the world to determine prevailing pattern of uveitis.3–9 For Malaysia, this would be the first such study that has been conducted nationwide to offer us some insight into the cause and challenges when diagnosing patients with uveitis in Malaysia.
All hospitals recruited into this study, just like in real life, had a dedicated ophthalmology department equipped with the necessary facilities to carry out uveitis consultations independently. If they had doubts, they would liase with the Medical Retina and Uveitis team in Hospital Shah Alam, Hospital Selayang or Hospital Kuala Lumpur when an expert consultation was required. They would either carry out a teleconsultation if the patients were remote or incapacitated, or transportation would be arranged to one of these bigger hospitals for a face-to-face consultation. Alternately, visiting consultations are also carried out in certain centres where the number of uveitis patients are high. Therefore, the diagnosis of these patients are usually comprehensive with the support from the Medical Retina and Uveitis fraternity.
The gender and ethnic population in our study is reflective of the country’s population. According to the United Nation’s Department of Economic and Social Affairs, in 2020 the population of Malaysia stands at 32.37 million. The Malaysian-Malays are the highest with 69%, followed by Malaysian-Chinese with 22.5%, Malaysian-Indians with 6.8%, and the smaller indigenous groups constituting around 1.7%. Men constitute around 50.7% of the population and this is reflective in our study as well.
It is not surprising that most of our patients are from the more densely populated, more urbanized states, as infrastructure and ease of transportation play a crucial role in seeking healthcare in Malaysia. It is also of note that 4.4% of our patients were not Malaysians. It is likely that with urbanization and migration into the developing Malaysia, more non-Malaysians are seeking care in our hospitals.
We also note that roughly one third of our patients have an infectious etiology. These numbers correlate with many other uveitis epidemiological studies19. When compared with the meta-analysis study carried by Tsirouki et el, certain infectious etiologies correspond with causes in fellow Asian countries. In our study, viral entities contributed to 9.3% of all etiologies. This would include herpetides such as Viral PCR (CMV,VZV,HSV) positive anterior uveitis, Acute Retinal Necrosis (ARN), and Cytomegalovirus (CMV) Retinitis. This is similar with a Singaporean study that shows incidence of herpetic uveitis to be 9.2%8,20.
TB- related uveitis are the second highest in our study (8.8%). This would correlate with TB being an endemic communicable disease in Malaysia. In 2018, a total of 25173 patients were diagnosed with TB with an estimated incidence rate of 92 cases per 100,000 population.21 In Tsirouki’s paper, the countries high with TB uveitis are India (10.1%), Iraq (11.4%) and Saudi Arabia (10.8%).
The other common infectious cause would be cat-related uveitis such as toxoplasma uveitis which accounts for 7.8% of cases and bartonella uveitis (neuroretinitis) which accounts for 2.5%. This would contribute to almost 10% of infectious causes among the patients in the study. As there are lack of data on ocular toxoplasmosis, ocular bartonellosis or systemic bartonellosis in Malaysia, in this study we assume cat-related diseases are reasonably common as cats are the predominant domestic pet in Malaysia22
This reinforces the fact that infectious causes remain a common cause of uveitis among Malaysians thereby rendering management of the patients more complex. Posterior uveitis in particular have a higher probability of being infectious in nature compared to the other forms of uveitis.
It should also be noted that in our study, we excluded patients diagnosed with endophthalmitis, including endogenous endophthalmitis. Although some of these patients had infective causes like Klebsiella, as they were systemic in nature and the ocular inflammation was presumed based on clinical findings and indirect culture yield such as blood culture and not direct yield such as ocular fluids, we decided to exclude them from our study.
Looking at our results, more than half of our patients’ etiology is idiopathic. Worldwide, this appears to be similar. However, the idiopathic uveitis cases in this study may include patients that have had thorough investigations but only within the capacities of the respective centres. As a result, some of the idiopathic uveitis cases may in fact be incompletely diagnosed inflammatory or infectious uveitis patients.21
Among the non-infectious causes, Vogt-Koyanagi-Harada appears to be the most prevalent cause, followed by sarcoidosis, Behcet’s Disease and spondyloarthropathy uveitis. The reason these uveitides may not be as numerous compared to other studies could again be resource related.23 Obtaining ACE serology, HLA B-5, HLA B-55, HLA B-27 may not be easy as these tests are not readily available and are not included in most government hospitals’ national health care plan. When the diagnosis is strongly suspected, these tests are outsourced to private laboratories.
It is also worthwhile to note that a large population of Malaysians seek treatment in the private healthcare sector, thereby potentially contributing to an under reporting of uveitis cases in this study.
In Malaysia, diagnosing and treating patients with uveitis remains a challenge in many ways.
The diagnostic challenges are primarily due to lack of resources and medical retina expertise in many far-out hospitals. Equipment such as OCT Tomography, Angiography and B-scan may be lacking in departments that are smaller and remote compared to the centres in the bigger towns and cities. There are also certain serologies that are hard to obtain such as the viral PCR serologies in these places. There are other serologies that are easily available but the cost remains a barrier for most patients seeking treatment such as the highly pertinent but costly test, TB QuantiFERON Gold. Due to these many issues, sometimes arriving at the final diagnosis may be difficult.