Take-home message: Consider infectious scleritis if a patient with scleritis tests negative for rheumatological disease.
By Vanessa Caceres; Reviewed by Ana Luisa Höfling-Lima, MD, MBA
São Paulo, Brazil
—Infectious scleritis occurs in only 5% to 10% of scleritis patients, but it can have poor visual outcomes, said Ana Luisa Höfling-Lima, MD, MBA.
“Since it’s uncommon, there is usually a late diagnosis,” said Dr. Höfling-Lima, head professor, Ophthalmology Department at Escola Paulista de Medicina – UNIFESP, São Paulo, Brazil. “The visual outcome can be poor because of aggressive infection and difficulty in penetration of drugs in the scleral tissue.”
It is crucial to evaluate if the tests for infectious scleritis are negative before proceeding with treatment for rheumatological disease as in most situations, high doses of steroids or immunosuppressors will be prescribed, she said.
Infectious scleritis can be caused by bacteria, virus, fungi and protozoan, and the infections can be endogenous or exogenous. Cases are often traced back to trauma, immunosuppression, conjunctiva or pterygium surgery, or geographic-specific systemic diseases that include syphillis, tuberculosis, toxoplasmosis, and leprosy.
Patients will present with redness, pain, lacrimation, intraocular inflammation, scleral necrosis anterior chamber reaction with anterior and posterior involvement, scleral abscesses, and tissue damage beyond obvious clinical findings.
Ultrasound biomicroscopy, optical coherence tomography, scleral scrapings when possible, polymerase chain reaction used with tissue specimens from the scleral biopsy, and immunofluorescence are all useful in helping to diagnose and track infectious scleritis, Dr. Höfling-Lima said.
Also, “new CT technology has become a tool for us not for diagnosis but to follow patients with necrotizing scleritis,” she said.
Dr. Höfling-Lima outlined several forms of infectious scleritis and how to treat it. For example, she said that herpes scleritis is hard to diagnose and requires both systemic steroids and systemic antivirals.
“The drug of choice is acyclovir for three to eight weeks,” she said. “If the patient has had previous treatment with immunotherapy, this can worsen their inflammation.”
Inflammation may last 5 months to more than 2 years.
Bacterial scleritis includes Pseudomonas aeruginosa
, Mycobacterium chelonae
, Mycobacterium absessus
, and Mycobacterium tuberculosis
. Bacterial scleritis has been seen after pterygium surgery. It can sometimes have a delayed occurrence after surgery or trauma and could be caused by a dormant organism, Dr. Höfling-Lima said.
“We have to pay attention to that possibility,” she said.
In her home country of Brazil, Dr. Höfling-Lima and fellow ophthalmologists have seen Pseudomonas
scleritis caused by trauma caused by sugar cane leaves. They treated these cases with topical and systemic amikacin.
Treatment for Pseudomonas
scleritis can typically include intravenous ceftazidime and aminoglycosides, which may be more effective with single-intravenous agents when used in addition to topical antibiotics.
“These may obviate the need for adjunctive surgical procedures, such as cryotherapy, surgical extirpation, or conjunctival recession,” she said.
Topical ceftazidime 5% and fortified aminoglycosides 1.4% also may be useful, safe, and effective therapy for pseudomonal keratitis, she added.
Another possibility in infectious scleritis, although it is not that common, is Nocardia
scleritis, Dr. Höfling-Lima said. Signs of this include scleritis with multiple nodules that do not respond to fluoroquinolones.
Mycotic scleritis can also occur and often progresses quickly despite treatment. This can turn quickly into cataracts, serious retinal or choroidal detachments, and endophthalmitis, Dr. Höfling-Lima said. However, prognosis is often poor because of late diagnosis, poor penetration of antifungal drugs into the avascular sclera, and the ability of organisms to remain in the avascular scleral tissue without inciting an inflammatory response.
Dr. Höfling-Lima addressed Acanthamoeba
scleritis, noting that 14% of Acanthamoeba
keratitis cases have associated scleritis that can be anterior, diffuse, or nodular necrotizing. Causes include scleral invasion by Acanthamoeba
and immune-mediated response to dead and dying ameba. Treatment in these cases can include systemic treatment with miltefosine or voriconazole as well as cryotherapy. Sometimes, enucleation is required.
If a patient presents with M. tuberculosis
scleritis, it is secondary to a primary spot, such as on the lung.
However, it can also be seen without systemic symptoms, Dr. Höfling-Lima said.
Diagnosis is made with a PPD test, a chest X-ray, and a smear of the scleral lesion. The most common treatment is systemic steroids as well as a fixed combination with rifampcin, isoniazid, and pyrazinamide.
For Mycobacterium other than tuberculosis scleritis, treatments are commonly clarithroymycin 500 mg every 12 hours and amikacin 7.5 mg/kg three times a day for 3 weeks.
Yet another infectious possibility is toxopolasmosis, Dr. Höfling-Lima said.
Ana Luisa Höfling-Lima, MD, MBA
E: [email protected]
This article was adapted from Dr. Höfling-Lima’s presentation at the 2014 meeting of the American Academy of Ophthalmology. She did not indicate any proprietary interest in the subject matter.