Uveitis Causes And Risk Factors

Introduction

Uveitis is an inflammation of the middle layer of the eye, which is called the uvea or, in other words, the uveal tract. It is an indication that the immune system is fighting an eye infection; however, sometimes, it happens when the immune system attacks healthy tissue in the eyes. Uveitis goes away quickly, but it comes back. It is considered a chronic condition that lasts for a long time, and it can affect one or both eyes. In most cases, uveitis gets better with treatment and taking steroid medicine. Sometimes, it may lead to eye problems like glaucoma and cataracts. When it is neglected, it may cause vision loss. Therefore, you are in the safe zone if you seek medical treatment once you notice the symptoms. It is important to understand the causes and risk factors of uveitis to prevent it from happening. This article will provide you with information about uveitis types, causes, and risk factors.

Causes of uveitis

There are several causes of uveitis, although doctors do not always know what causes it. Uveitis may result from infections, autoimmune disorders, injuries or eye trauma, toxin exposure, and certain medications.

Infections

Viral infections

Viral uveitis can appear in multiple forms. There is anterior uveitis, intermediate uveitis, acute retinal necrosis (ARN), progressive outer retinal necrosis (PORN) and neuroretinitis. Poxviruses and adenoviruses, particularly those that are responsible for epidemic keratoconjunctivitis and pharyngoconjunctival fever, are additional DNA viruses that can cause uveitis. The influenza virus, mumps virus, measles virus, rubella virus, Rift Valley fever virus, and Newcastle virus are the RNA viruses that were isolated.

Bacterial infections

Uveitis can be caused by bacterial infections like 

• Lyme disease
• Tuberculosis
• Syphilis
• Cat scratch disease
• Chlamydia trachomatis
• Gonorrhea
• Brucellosis

In syphilis cases, although posterior uveitis and panuveitis are the most common manifestations, syphilis can affect almost any ocular structure. Bacterial uveitis is uncommon, whereas viral and infectious uveitis is more common.

Fungal infections

Hematogenous seeding of highly vascularised structures like the choroid or retina frequently leads to fungal intraocular infection, which typically manifests as creamy-white chorioretinal infiltrates and vitreous.

Autoimmune disorders

Rheumatoid arthritis

After receiving a diagnosis of an autoimmune disease, such as rheumatoid arthritis, some people develop uveitis; in different cases, eye issues may be an early side effect that assists you with getting determined to get diagnosed with inflammatory arthritis.

Lupus

Systemic lupus erythematosus (SLE) is a rare cause of uveitis. Routine antinuclear antibody testing has a low positive predictive value for SLE.

Ankylosing spondylitis (AS) 

Higher rates of uveitis in AS may be linked to the presence of hip joint lesions and peripheral arthritis. The possibility of uveitis in AS should not be overlooked if patients with these risk factors present with unusual ocular symptoms simultaneously. Additionally, additional ocular examination would be beneficial for a definitive diagnosis.¹

Injuries or trauma to the eye

A trauma to the eye, like being hit or scratched, can lead to traumatic iritis which is a type of iritis or inflammation of the coloured part of the eye. It is a type of uveitis. Traumatic iritis is also referred to as anterior uveitis. Sometimes, a combination of inflammation of the iris and the ciliary body is called iridocyclitis.

Exposure to toxins

Uveitis can also be brought on by being around harmful chemicals and toxins like acids used in manufacturing and pesticides.

Medications

Even though it is uncommon, drug-induced uveitis (DIU) is a significant cause of uveitis that one should be aware of. Uveitis can be brought on by the use of various medications. In all patients with otherwise undiagnosed uveitis, whether a new event of inflammation or a recurrence, a thorough drug history is therefore essential. Uveitis can occur immediately or over several months following the administration of the inducing medication. Due to the possibility of vaccine-induced uveitis, vaccination against several viral diseases is still required and a major focus of public health policy worldwide. It should not be stopped or reduced.

Risk factors for uveitis

Age and gender

The rate and prevalence vary significantly around the world. It appears that females and those between the ages of 20 and 50 who are working are most affected.²

Genetics and family history

A gene known as HLA-B27 has been linked to an increased risk of developing anterior uveitis, or uveitis at the front of the eye, even though uveitis is not passed down through families. About half of all people with anterior uveitis have the HLA-B27 gene. This gene has been found in people with certain autoimmune conditions, including ankylosing spondylitis and ulcerative colitis.

Other health conditions

HIV/AIDS

In infectious uveitis, intraocular inflammation is frequently the cause of HIV infection in patients. The majority of opportunistic infections (OI)-related ocular lesions have been extensively described before the introduction of highly active antiretroviral therapy (HAART).³

Diabetes

Acute uveitis is more likely in people with diabetes with poor glycaemic control; patients with an HbA1c of more than 11.3% (100 mmol/mol) are almost five times more likely to experience the condition. Proliferative retinopathy was also associated with an increased risk of acute uveitis.⁴

Multiple sclerosis

Multiple sclerosis (MS) is a disease that can affect the brain and spinal cord. This can lead to a wide range of symptoms, including problems with balance, movement of the arms or legs, and vision. For several decades, it has been known that uveitis and MS are related. In MS patients, the frequency of uveitis ranges from 0.4 to 26.9%, and the prevalence of MS in those with uveitis is between 1 and 14%.⁵

Smoking

All anatomical subtypes of uveitis and infectious uveitis are significantly associated with a history of smoking. There is a strong relationship between smoking and the inflammatory cystoid macular oedema (CME) which is a painless disorder that affects the central retina or macula and causes swelling in the eye as a result of the cyst-like areas of fluid.⁶

Eye surgeries

Cataract surgery can result in postoperative uveitis.  The functional outcome may be compromised, and the eyeball may be lost as a result of this complication.

Summary

Uveitis is an inflammation of the middle layer of the eye known as the uvea. Infections, autoimmune disorders, eye injuries or trauma, exposure to toxins, and certain medications can all contribute to the condition. There are viral, bacterial, and fungal infections that can cause uveitis. Immune system issues that can cause uveitis include rheumatoid joint inflammation, lupus, and ankylosing spondylitis. The risk factors incorporate age and orientation, hereditary qualities and family ancestry, and other ailments like HIV/AIDS, diabetes, and multiple sclerosis. To prevent uveitis, you should seek medical attention when symptoms appear.