What is Infectious Scleritis?
Scleritis is a condition where the outer layer of the eyeball, known as the sclera, becomes inflamed. This inflammation can also involve other parts of the eye like the cornea, episclera, and uvea. Symptoms of scleritis include redness in a specific or widespread areas of the eye, pain, and vision problems. Most scleritis cases are caused by autoimmune issues, but about 5% to 10% are due to infections.
The symptoms for both infective and autoimmune scleritis can look similar. That’s why it can sometimes be mistaken and treated as an autoimmune condition, which could make the condition worse. To tell the difference between an infection and an autoimmune issue, a detailed history is very important. In one study, about 94% of patients with infective scleritis had a risk factor for the infection. The most common risk factor was previous eye surgery, mainly pterygium removal (which accounted for 57% of cases). Other factors that increased the chances of getting scleritis included past accidental eye injuries, exposure to radiation, and usage of certain types of cancer drugs, like mitomycin.
Several types of bacteria have been linked to infective scleritis. The most common bacteria in developed countries is called Pseudomonas aeruginosa. Other possible causes can be bacterial or fungal organisms such as Nocardia, Streptococcus, Haemophilus, Candida, and Aspergillus. If left untreated, infectious scleritis can lead to severe consequences such as loss of the eye due to the spread of infection to nearby structures or rupture of the eyeball.
What Causes Infectious Scleritis?
Scleritis, an infection in the outer layer of your eye, can occur naturally or as a result of something else. It usually happens after an injury, either accidental or from surgery, taking up a large portion (58.5 – 88%) of cases. Sometimes, it can come about following a scrape or tear (known as trauma), an infection inside the eye (endophthalmitis), or a neighboring infection (keratitis).
People who have had a systemic infection, use systemic or topical steroids (39%) or have previously been diagnosed with an autoimmune disorder of the eye’s outer layer are more likely to get this primary infection. Certain eye surgeries also make you more susceptible to scleritis. These include surgery for removing a growth (known as pterygium) affecting 57% of patients, adjusting an eye muscle (strabismus), or procedures involving the retina, the inner lining at the back of the eye.
Interestingly, a popular eye-whitening procedure in South Korea has also caused scleritis. This procedure involves removing a small bump on the eye or growth (pterygium or pinguecula), and then adding an amniotic membrane graft. A dire side effect is a condition known as a scleral melt, which greatly increases the risk of getting scleritis.
There’s also secondary scleritis, which is when a primary infection in the cornea (the transparent front part of the eye) spreads. Those who have had the same factors as primary infectious scleritis are also at risk of corneoscleritis. Beyond this, use of contact lenses, serious systemic diseases and damaged corneal tissue also increase the risk for secondary scleritis.
Risk Factors and Frequency for Infectious Scleritis
A study found that infectious scleritis, an eye condition, typically develops about 1.9 months after the initial incident. For people who had pterygium surgery, they usually developed infectious scleritis after a longer period, around 49 months post-surgery. This is far longer than the time it takes for those with glaucoma, cataracts, or retinal surgery to develop the condition (typically between 1.0 to 1.6 months).
The average age of the patients in the study was 70, suggesting that older age might increase the risk of this condition. The most common culprits behind infectious scleritis vary depending on where you are. In developed countries, Pseudomonas aeruginosa is usually the cause; whereas in developing countries, it’s often Nocardia or various fungi.
Signs and Symptoms of Infectious Scleritis
If you have scleritis, a condition that causes inflammation and redness in the white part of the eye, you could experience symptoms like a red eye, watering of the eyes, and pain. Some individuals might notice these symptoms quicker, especially if they’ve had eye surgery before. During an eye examination, doctors often find that the white part of the eye, known as the sclera, is inflamed and sometimes decaying (scleral necrosis). Other features can include hard patches (calcified plaques), inflammation in the front part of the eye, involvement of the cornea (the clear front surface of the eye), and multiple pockets of pus on the sclera (multifocal scleral abscesses).
- Red eye
- Watery eyes
- Pain
- Inflammation of the sclera
- Scleral necrosis (possible decay of the white part of the eye)
- Calcified plaques (hard patches)
- Inflammation in the front part of the eye
- Corneal involvement
- Multiple pockets of pus on the sclera
Studies show a high frequency of inflammation where the cornea and sclera meet (peripheral keratitis) in patients with infectious scleritis. Scleritis that affects only one eye (unilateral) and involves either the layers that provide blood supply to the tissues of the eye (uvea) or the cornea (keratitis) might indicate an underlying infection, particularly if no other disease symptoms are present. Advanced diagnostic techniques like ultrasound biomicroscopy (UBM) and optical coherence tomography can be used to observe early signs of the retina and choroid detaching, the ciliary body rotating, and infection-caused changes in the eye’s structure. Such scans can also show cloudy areas in the jelly-like substance within the eye (the vitreous) and concerning deposits under the retina.
Testing for Infectious Scleritis
If you’ve recently been diagnosed with scleritis, which is the inflammation of the white part of your eye, your doctor will want to conduct several tests to check for a related inflammatory condition called vasculitis. Tests may include a complete blood count (CBC), a comprehensive metabolic panel (CMP), a urinalysis, P-ANCA and C-ANCA tests (two specific tests for autoimmune diseases), an ESR (a blood test that helps detect inflammation), a C-reactive protein blood test, and a chest X-ray. Additionally, your doctor will check for infections like Lyme disease or syphilis.
People who present high-risk symptoms may have to undergo other evaluations to rule out a type of scleritis caused by an infection. If infectious scleritis is suspected, the doctor may collect samples from your eye using a swab, spatula, or biopsy, and then have these cultured, or grown in a lab, using various types of media to identify the pathogen. The media used includes blood agar, chocolate agar, thioglycolate, Sabouraud dextrose agar, non-nutrient agar with E.Coli, and brain-heart infusion broth. If these tests do not identify the cause of the infection, additional methods such as immunohistochemistry (a test to see specific proteins in cells) and titers (measures of concentration) may be used to explore further.
Treatment Options for Infectious Scleritis
Research points out that preventing infectious scleritis, a serious eye inflammation, is crucial. Some precautionary methods include limiting the overuse of cautery (burning tissue) during surgery to promote better healing and avoiding bare sclera techniques, which expose the eye’s surface to potential infection. Additionally, it’s advised not to cover an area where dead tissue was removed with an amniotic membrane, as it could disrupt the effectiveness of infection-fighting drugs. It has been suggested to use a combination of amniotic membrane and fascia lata grafts (a type of tissue transplant) when treating an area after dead tissue removal.
When it comes to treating infectious scleritis, there isn’t a well-established protocol before identifying the specific infecting bug. Initially, general antibiotics are given, both locally to the eye and systemically (affecting the whole body), if Pseudomonas – a type of bacteria, is suspected.
If a patient has had a trauma involving agricultural material, antifungals (drugs that fight against fungi) are used. There isn’t a fixed rule for how long the antimicrobial (infection-fighting) medication should be used. One source suggests using the medication for an average of 50 days for infectious scleritis, while another advises to use it for an extended period.
Since a wide range of antibiotics are usually used to treat the most common causes of infectious scleritis, it’s recommended to adjust the treatment based on the identified infecting agent. If Staphylococcus or Streptococcus are causing the infection, eye drops with fortified cefazolin and fluoroquinolones may be used. If the infection doesn’t improve with standard antibiotic therapy or MRSA (a type of antibiotic-resistant bacteria) is detected, the patient might need to be hospitalized and given vancomycin (another antibiotic) via the vein and locally in the eye.
If the cause of the disease is tuberculosis, antituberculosis medicines are used. However, infections caused by other kinds of Mycobacterium bacteria usually don’t respond to these drugs, so they are treated with amikacin eye drops and other oral medications. For fungal infections of the sclera, a combination of natamycin eye drops and oral antifungal medication are recommended. Systemic:
trimethoprim/sulfamethoxazole can effectively treat Nocardia infection.
Oral trimethoprim/sulfamethoxazole and azithromycin can resolve infectious scleritis caused by Toxoplasma gondii parasite. Patients having viral infections of the sclera, due to varicella-zoster virus or herpes simplex virus, have shown improvement with treatments like acyclovir. It’s important to note that while steroids along with antimicrobials have been successful in some cases, they might worsen others, especially those caused by Nocardia and HSV.
In terms of treatment, research shows that different methods have been implemented – 95% involving local eye application, 77% oral medication, and 11% medication injected into the eye. But only 18% of patients were adequately treated with these methods alone, as most ended up needing surgical intervention.
Early and recurrent surgical removal of dead tissue is generally recommended for patients with infectious scleritis. Additional treatments like cold therapy (Cryotherapy), corneoscleral grafts (transplantation of eye tissues), or removal of certain eye hardware may be needed, along with antimicrobial medication. These surgeries aid in compensating for the sub-optimal penetration of the antimicrobials. It has been noted that a timely diagnosis and initiation of surgical treatment can result in a 100% rate of preserving the eyeball.
What else can Infectious Scleritis be?
People who show symptoms of infectious scleritis, an eye condition, may actually have a similar condition like autoimmune scleritis. Both these conditions show similar signs and symptoms. Other possibilities include episcleritis and anterior uveitis. Certain systemic diseases like vasculitis and syphilis can also cause similar symptoms to scleritis. Tests that look at the body’s overall health can help differentiate between these conditions and scleritis.
What to expect with Infectious Scleritis
Poor eyesight results can be linked to several factors such as difficulty seeing clearly right from the start, eye infections, inflammation of the cornea (keratitis), relying solely on medication therapies, and fungal infections. If an ocular infection spreads, it often leads to worse outcomes.
In one study, about half of affected eyes lost their functionality, meaning after correction, their vision was still less than 20/200 (when you are considered legally blind under certain legal standards). It’s important to note that the length of treatment, whether it’s a bacterial or fungal infection, or the initial cause of the problem, don’t seem to impact the overall outcomes differently.
Possible Complications When Diagnosed with Infectious Scleritis
If infectious scleritis, an eye condition, isn’t managed well or goes undiscovered, the patient could experience negative effects. Steroid treatments may actually make the condition worse. In some cases, the scleritis can come back, noticeable as new small bumps or dead tissue areas on the eye. This recurrence was observed in about 9.52% of patients, particularly those with a fungal type of scleritis.
Various complications can arise, such as:
- Cataracts, which cloud the eye’s lens
- Glaucoma, a condition that damages the eye’s optic nerve
- Epithelial defects, which are damage to the outer layer of the eye
- Fibrotic pupillary membranes, or unwanted tissue in the eye
- Corneal opacities, or cloudy areas on the cornea
- Retinal detachment, a serious eye problem that happens when the retina pulls away from its normal position
- Choroidal detachment, which occurs when the eye’s choroid layer separates
- Globe perforation, when an injury penetrates the eyeball
In severe cases, some of these complications may call for enucleation – the removal of the eye.
Preventing Infectious Scleritis
To prevent scleritis, an infection in the white part of the eye, it’s crucial to maintain strict surgical methods, follow infection control rules, and keep regular eye check-ups. A large number of scleritis cases are related to the removal of pterygium (a growth on the white of the eye) and other eye surgeries. While these complications are uncommon, it’s important that patients who are due for such surgeries understand the potential results and risks. This understanding is part of being properly informed before they agree to undergo the procedure.
