Patient history key for treating corneal infiltrates
Determining the nature of an infiltrate through an examination or a culture can direct the course of treatment.
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Welcome to another edition of CEDARS/ASPENS Debates. CEDARS/ASPENS is a joint society of cornea, cataract and refractive surgery specialists, here to discuss some of the latest hot topics in ophthalmology.
Infectious keratitis is one of the most commonly seen diagnoses in the ophthalmologist’s office. These infections may be difficult to identify and treat. With a logical systematic strategy, the infection may be properly diagnosed and then successfully treated. This month,Alanna Nattis, DO, FAAO, and Himani Goyal, MD, describe their approaches to managing this condition. We hope you enjoy this discussion.
Kenneth A. Beckman, MD, FACS
OSN CEDARS/ASPENS Debates Editor
History is crucial
Like any problem you encounter in ophthalmology, history is definitely key when you are approaching a patient with a corneal infiltrate.
A patient’s history will direct you to the cause of the infiltrate. If a patient walks into your office with a history of corneal abrasions, an injury from the branch of a tree or from some type of vegetative material, or an infiltrate after an ocular procedure, you can narrow down the infiltrate’s cause and your course of treatment.
Size and shape
The size of the infiltrate is important. If a patient comes into your office with a 1-day history of an infiltrate and it is small in size, we usually know it will do well and heal within a 5- to 7-day time period. However, if the infiltrate is due to an abnormal organism or if the patient came into contact with a plant-like material, the course of treatment may be more extensive.
If the infiltrate is irregular in shape and looks slightly deep, even if it is on the smaller side, I have no hesitation in culturing these patients. You can garner invaluable information with cultures, and I am sometimes surprised with what comes back from the results.
I am extra suspicious with contact lens wearers when they have an infiltrate. I almost always culture them, even if their infiltrate is small. These patients are at risk for resistant and recurrent infections, so precise diagnosis and treatment are key.
For treatment, I start with broad-spectrum antibiotics. If it is a small infiltrate, I may use gatifloxacin as well as ointment at night, such as an erythromycin ointment. If it is a slightly larger or deeper infiltrate, I will not hesitate to use fortified antibiotics and will usually start with vancomycin, in combination with gatifloxacin or ofloxacin on a tapering schedule, as well as ointment at night if needed. I will usually dose the drops every hour for 1 day, then eight times daily for 3 days, and then four times daily for a week. The schedule will differ from patient to patient depending on treatment response and culture results.
Follow-up depends on the size and the depth of the infiltrate. If it is small and not deep, I may have the patient back in 3 to 4 days. If it is deep or if there is a hypopyon, no matter how small, I am seeing them daily until the hypopyon resolves and there is resolution in some of the size of the infiltrate.
Other causes
This is a good approach for patients referred to me with new corneal infiltrates that are bacterial in nature. However, the tricky patients are those who have a history of corneal grafts with infiltrates but no pain. These patients may be dealing with a possible neurotrophic situation, and some may have a latent history of herpes infection of the cornea.
I will typically start these patients on prophylactic Valtrex (valacyclovir, GlaxoSmithKline) as well as an antibiotic to try and heal whatever epithelial defect or infiltrate may be there. Culture is very important here as well.
In patients who have neurotrophic lesions, I will use antibiotics and lubrication to heal the corneal surface. If this is not enough, we might move on to a bandage contact lens, a Prokera (Bio-Tissue) or an amniotic membrane to heal the ocular surface.
In select patients who have a non-resolving neurotrophic lesion, I have used Oxervate (cenegermin-bkbj, Dompé), but that is uncommon.
If the patient is not doing better, I will re-culture them. If the re-culture comes back and we get the same or indeterminate results, we may need to perform a corneal biopsy or an aqueous tap to determine if there is something we are missing or if the scrapings of the cornea are too superficial and not reaching the organism that is causing the infection.
- For more information:
- Alanna Nattis, DO, FAAO, can be reached at SightMD, 500 W. Main St., Suite 201, Babylon, NY 11702; email: asn516lu@gmail.com.
Pay close attention to symptoms
It is important to begin with a patient’s history when trying to figure out what type of corneal infiltrate is brewing.
Is the patient having pain or just discomfort? Do they wear contact lenses? How long has this been going on? All of their symptoms clue us in.
Note the clinical findings
When looking under a slit lamp, it is important to note if there is an epithelial break and whether or not it is associated with an infiltrate. If there is no infiltrate, look carefully at the contour of the slit beam to determine whether there is stromal involvement. The differential for epithelial defects includes corneal abrasions, recurrent erosions and others. When the defect is deeper, consider corneal melt from autoimmune disease, topical steroid or NSAID use, and neurotrophic ulcers. Abrasions would present with pain and photophobia, but only mild change in vision — a key distinction between abrasions and ulcers. Sterile melts, on the other hand, may be incidental findings with no pain and visual symptoms depending on the size and location of the lesion. Treatment consists of stopping any inciting agents and treating the underlying cause.
If an infiltrate is present, pay close attention to the shape of the lesion. Circular patterns are more likely bacterial, whereas dendritic patterns are more likely viral.
For any infiltrate with an epithelial break, take a culture. If the patient is a contact lens wearer, ask them to bring in their contact lens case for culture as well. The case will likely grow several different types of bacteria, but if there is a predominant bacterium, it will guide our treatment, especially for infiltrates in their early stages for which it is difficult to acquire an adequate sample for culture.
Start with antibiotics
Once the culture is completed, for presumed bacterial ulcers, start the patient on antibiotics. For small ulcers that are 1 mm or less in size, my treatment of choice is moxifloxacin every 15 minutes for the first hour, then hourly thereafter until the ulcer is healed. For larger ulcers, a combination of fortified antibiotics is more appropriate. Vancomycin and tobramycin offer good coverage for the most common bugs, including MRSA and Pseudomonas.
Follow up the gram stain and see the patient back within 24 hours to confirm that you are on the right track with your initial choice of antibiotics. Follow through until cultures and sensitivities are final, and alter the treatment accordingly. Once the epithelial defect is healed, the addition of topical steroids can be considered if there is a significant sterile infiltrate or scar.
It is important to also take the opportunity to educate our patients on proper contact lens hygiene. Prevention of these sight-threatening infections is the ultimate goal. Sleeping in contact lenses increases the risk for infection fourfold.
Viral issues
Viral keratitis will present with discomfort and tearing but not necessarily pain, as corneal sensation is generally decreased. Usually, the symptoms have persisted for a few days with no worsening or improvement. The presence of vesicular lesions confined to either the V1 or V2 dermatome would point toward herpes zoster virus, whereas involvement of both the upper and lower lids or bilateral lesions would be consistent with herpes simplex virus. Debridement of the dendritic area can be both therapeutic and diagnostic — send for viral PCR.
My treatment of choice for epithelial viral keratitis is ganciclovir ophthalmic gel. It is well tolerated but can be difficult to obtain. The other options are topical trifluridine or oral antivirals.
Fungal issues
There are several scenarios in which you must consider fungal keratitis. If the patient has a non-healing epithelial defect and a history of long-term topical steroid use, consider the possibility of a fungal infiltrate.
Patients can also present with chronic infections in which the epithelium is intact and a fluffy infiltrate is present in the deeper layers of the cornea, including the endothelium. Satellite lesions are also a characteristic of fungal infections. Risk factors include use of homemade contact lens solution and a history of endothelial keratoplasty.
If suspicious based on history, cultures should be kept for at least 2 weeks to monitor for fungal growth. When the epithelium is intact, it is difficult to obtain a culture, but for more anterior infiltrates, creating an epithelial defect may be more effective and also allow better penetration of topical therapy.
When the treatment course for bacterial keratitis is not effective, the addition of topical antifungal therapy, such as amphotericin B, should be considered. Treatment is typically long term, sometimes lasting for months.
Neurotrophic ulcers
Neurotrophic ulcers will usually present with a more chronic history or have an abnormal ocular surface. They result from decreased corneal sensation leading to decreased tear production, which in turn leads to a chronically dry and malnourished ocular surface. These ulcers can be associated with and exacerbated by anatomical abnormalities of the eyelid.
If lubrication is the issue, upper and lower punctal plugs with copious preservative-free tears and ointments are indicated. Wet amniotic membrane, such as Prokera (Bio-Tissue), or a freeze-dried amniotic membrane disc with an extended wear contact lens, a moisture chamber or tarsorrhaphy can be helpful for ocular surface protection and healing.
Oxervate (cenegermin-bkbj, Dompé) is an exciting and relatively new treatment for neurotrophic ulcers, consisting of a 6-week topical therapy course intended to reinnervate the cornea.
Surgical intervention
There are times when corneal ulcers are unresponsive to treatment, necessitating a biopsy for culture. They can also advance to the point of perforation, necessitating a therapeutic penetrating keratoplasty.
Avoiding water
Whenever there is a break in the corneal epithelium, I ask my patients to avoid getting water in their eyes. Water is not sterile and can introduce ubiquitous bugs, such as Acanthamoeba and Candida, that may cause a superinfection in addition to whatever else is going on.
- For more information:
- Himani Goyal, MD, can be reached at NYU Langone Eye Center – Bay Ridge Location, 7901 Fourth Ave., Brooklyn, NY 11209; email: himani.goyal.md@gmail.com.
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