You’re on call, and you’re consulted to see a patient with a suspected corneal ulcer. Here’s a simple stepwise approach to make sure you get the patient on the road to recovery and don’t miss anything.
Ulcers are visually threatening diagnoses that come in all shapes and sizes. They’re defined as an epithelial defect with stromal loss and inflammation and can be bacterial, viral, fungal and parasitic in nature. Most ulcers are caused after a micro-abrasion, but some bacteria can perforate intact epithelium. Additionally, neurotrophic corneas can be prone to infection or sterile ulceration.
Your role is to document and diagnose the infection and then start treatment as soon as possible. This stepwise approach can guide you, whatever the cause.
History
- Duration of symptoms
- Pain. Pain out of proportion to exam findings can be seen with Acanthamoeba.
- Contact lens use. Think of pseudomonas.
- Environmental exposure. Increases likelihood of fungal infection.
Exam
- Eye vitals
- Location. If central, then scarring can lead to vision loss and may necessitate a transplant.
- Depth. Slit beam can determine percentage of stroma lost and if perforation is imminent.
- Anterior chamber reaction. Cell/hypopyon can indicate a severe infection.
- Photos/documentation. Monitor for improvement.
Management
Culture. Can narrow antibiotics in the future.
- Most ulcers should be cultured — the 3-2-1 rule can guide you when to obtain a culture:
<3 mm from corneal center
>2 mm in size
>1+ cell in anterior chamber
- After anesthetizing, scrape with a sterile blade or Kimura spatula or scrape aggressively with a calcium alginate swab. If possible, plate on each of the culture mediums below:
- Saboraud agar: fungal
- Chocolate agar: aerobes
- Blood agar: aerobes and anaerobes
- Thioglycolate broth: aerobes and anaerobes
- Viral transport media
- Sterile saline: for transport if you are unable to plate yourself
- Glass slides: gram stain
- Culture contact lenses/case if available
Antibiotic management. Antibiotics should be broad spectrum and given frequently. The most common pathogens are Staphylococcus aureus, Streptococcus pneumoniae and Pseudomonas species. When in doubt, give stronger and broader antibiotics.
- For mild and small ulcers, a fluoroquinolone (moxifloxacin) can provide adequate gram-positive and gram-negative coverage.
- For most ulcers (central, large or with robust anterior chamber reaction), start fortified antibiotics. Ensure you have both gram-positive and gram-negative/ Pseudomonas
- Our institution typically uses vancomycin 50 mg/mL and ceftazidime 50 mg/mL every hour.
- Vancomycin 50 mg/mL: Gram-positive
- Cefazolin 50 mg/mL: Gram-positive
- Ceftazidime 25-50 mg/mL: Gram-negative, Pseudomonas, some gram-positive
- Gentamicin 15 mg/mL: Gram-negative, Pseudomonas
- Tobramycin 15 mg/mL: Gram-negative, Pseudomonas
- Drops should be given initially every one to two hours, 24 hours per day (even overnight), and spaced out five minutes between drops. After improvement, the frequency can be decreased to allow for sleep.
Cycloplegia
Atropine daily or cyclopentolate 3 times a day can provide comfort and prevent synechiae formation.
Steroids
Steroids can help with wound healing and prevent scarring, but only after improvement and once sterility is achieved. The decision to initiate therapy is typically made in consultation with a corneal specialist.
Invasive/Surgical Management
Patching or tarsorrhaphy can help wound healing, but only after sterility is achieved.
Glue can help patch small perforations. Full-thickness transplants are used for large perforations, but they do have high failure rates.
Follow-Up
See the patient daily until you see improvement. If the patient cannot reliably administer drops, admission to the ICU for nursing requirements is often warranted. If there is no improvement or the condition is worsening, consider atypical causes (Acanthamoeba or fungal infections).
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Bryan A. Goldman, MD, is a is a PGY4 resident at Virginia Commonwealth University. He joined the Academy in 2021.