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Corneal ulcer

Patient will present as → a 34-year-old contact lens wearer with severe pain, redness, and photophobia. Eyes are injected with cloudy discharge unilaterally. A dense corneal infiltrate is visible with fluorescein staining. 

A corneal ulcer is an open sore on the cornea, the clear front part of the eye. It is caused by a loss of corneal tissue, which can be caused by infection, injury, or other eye disorders

  • Infection: Bacterial, viral, or fungal infections are the most common cause of corneal ulcers.
  • Injury: A corneal ulcer can also be caused by an eye injury, such as a scratch from a fingernail or a foreign object in the eye.
  • Other eye disorders: Dry eye, contact lens wear, and certain autoimmune diseases can also increase the risk of developing a corneal ulcer.

Risk factor for contact lens wearers - a corneal ulcer is perhaps the most serious risk of contact lens wear

Corneal Ulcers vs. Keratitis

The main difference between a corneal ulcer and keratitis is that a corneal ulcer is an open sore on the cornea, while keratitis is a general term for inflammation of the cornea. Not all cases of keratitis lead to corneal ulcers, but a corneal ulcer is always accompanied by keratitis!

  • Corneal ulcer is an open sore on the cornea, the clear front part of the eye. It is caused by a loss of corneal tissue, which can be caused by infectioninjury, or other eye disorders.
  • Keratitis is a more general term for inflammation of the cornea. It can be caused by infectioninjuryautoimmune diseases, dry eye, and other conditions

Fluorescein stain is diagnostic (ulcers will often appear round “ulcerated”- like an "ulcer" vs. dendritic like herpes keratitis)

  • Corneal cultures should be obtained before starting antibiotics
Contact Lens Related Small Corneal Ulcer with Sodium Fluorescein Staining 7 copy

Corneal Ulcer as visualized with and without stain

Immediate referral - if immediate referral is not possible, it is reasonable to start antibiotics without delay

  • Ophthalmic antibiotics include ciprofloxacin 0.3%, ofloxacin 0.3%, gentamicin 0.3%, erythromycin 0.5%, polymyxin B/trimethoprim (Polytrim), and tobramycin 0.3%
  • Most appropriately treated corneal ulcers should improve within two to three weeks. Treatment may continue for longer to reduce the amount of potential scarring
  • Corneal ulceration is a serious condition, and with inadequate or no treatment, loss of vision and blindness may occur

Question 1
A 35-year-old woman presents to the clinic complaining of severe pain in her right eye and a noticeable decrease in vision over the past two days. She reports a sensation of something being in her eye and increased sensitivity to light. On examination, her visual acuity is 20/200 in the right eye and 20/20 in the left eye. Fluorescein staining of the right eye reveals a branching dendritic ulcer. Which of the following is the most likely diagnosis?
A
Herpes Simplex Keratitis
B
Bacterial Corneal Ulcer
Hint:
While bacterial infections can cause corneal ulcers, they typically do not present with the dendritic pattern seen in fluorescein staining, which is characteristic of Herpes Simplex Keratitis.
C
Acanthamoeba Keratitis
Hint:
This is usually associated with contact lens wear and presents with a ring-shaped stromal infiltrate, not a dendritic ulcer.
D
Fungal Keratitis
Hint:
Fungal corneal ulcers often have a feathery edge or satellite lesions, which are different from the dendritic pattern seen in Herpes Simplex Keratitis.
E
Neurotrophic Keratopathy
Hint:
This condition results from impaired corneal innervation and typically presents with a persistent epithelial defect but without the dendritic pattern seen in Herpes Simplex Keratitis.
Question 1 Explanation: 
Herpes Simplex Keratitis is characterized by the presence of a dendritic ulcer, which is typically revealed under fluorescein staining. This condition is caused by the herpes simplex virus and often presents with symptoms such as eye pain, blurred vision, photophobia, and a foreign body sensation. The branching pattern of the dendritic ulcer is a classic finding for Herpes Simplex Keratitis.
Question 2
A 34-year-old woman, who is a habitual contact lens wearer, presents with a painful red eye and visual impairment. She reports that she often sleeps with her contact lenses in. Slit-lamp examination reveals a white infiltrate in the cornea with an overlying epithelial defect and stromal involvement. Which of the following is the most likely pathogen responsible for her corneal ulcer?
A
Staphylococcus aureus
Hint:
While it can cause corneal ulcers, it is less likely in the context of contact lens use.
B
Pseudomonas aeruginosa
C
Herpes simplex virus
Hint:
Typically presents with a dendritic ulcer, not the presentation described.
D
Candida albicans
Hint:
More common in immunocompromised patients or those with chronic ocular surface disease.
E
Acanthamoeba
Hint:
Although it is associated with contact lens use, it is less common than Pseudomonas.
Question 2 Explanation: 
Pseudomonas aeruginosa is a common cause of corneal ulcers, particularly in contact lens wearers. The risk is increased in individuals who wear their lenses overnight. Pseudomonas is known for its aggressive nature and can lead to rapid corneal destruction.
Question 3
A 45-year-old male presents with severe pain in his left eye, photophobia, and blurred vision. He works as a welder and denies any history of contact lens use. Slit-lamp examination reveals a round ulcer with feathery edges on the cornea. Which of the following is the most appropriate diagnostic test to determine the etiology of his corneal ulcer?
A
Corneal scraping for Gram stain and culture
B
Intraocular pressure measurement
Hint:
Important in glaucoma but not primarily for corneal ulcer diagnosis.
C
Fluorescein angiography
Hint:
Used in retinal disorders, not typically for corneal ulcers.
D
Schirmer's test
Hint:
Assesses tear production, relevant in dry eye syndrome.
E
Visual acuity test
Hint:
While important, it does not determine the etiology of a corneal ulcer.
Question 3 Explanation: 
Corneal scraping for Gram stain and culture is essential in the diagnosis of corneal ulcers. It helps identify the causative organism, which is crucial for targeted antimicrobial therapy. This is particularly important in cases with atypical presentations or in occupational settings like welding, where various types of foreign bodies or contaminants might be involved.
Question 4
A 29-year-old female presents with a corneal ulcer and is found to have a bacterial infection. She has no known drug allergies. Which of the following is the most appropriate initial treatment for her condition?
A
Topical antiviral therapy
Hint:
Indicated for viral, not bacterial, corneal ulcers.
B
Topical corticosteroids
Hint:
Used cautiously in corneal ulcers as they can exacerbate infections.
C
Topical broad-spectrum antibiotics
D
Oral broad-spectrum antibiotics
Hint:
Typically, topical antibiotics are sufficient unless there is evidence of systemic infection or deep ocular involvement.
E
IV broad-spectrum antibiotics
Hint:
Typically, topical antibiotics are sufficient unless there is evidence of systemic infection or deep ocular involvement.
Question 4 Explanation: 
Topical broad-spectrum antibiotics are the first-line treatment for bacterial corneal ulcers. They cover a wide range of potential bacterial pathogens and are crucial in preventing further corneal damage and potential vision loss.
Question 5
A 29-year-old female presents with a corneal ulcer and is found to have a bacterial infection. She has no known drug allergies. Which of the following is the most appropriate initial treatment for her condition?
A
Topical antiviral therapy
Hint:
Indicated for viral, not bacterial, corneal ulcers.
B
Topical corticosteroids
Hint:
Used cautiously in corneal ulcers as they can exacerbate infections.
C
Topical broad-spectrum antibiotics
D
Oral broad-spectrum antibiotics
Hint:
Typically, topical antibiotics are sufficient unless there is evidence of systemic infection or deep ocular involvement.
E
IV broad-spectrum antibiotics
Hint:
Typically, topical antibiotics are sufficient unless there is evidence of systemic infection or deep ocular involvement.
Question 5 Explanation: 
Topical broad-spectrum antibiotics are the first-line treatment for bacterial corneal ulcers. They cover a wide range of potential bacterial pathogens and are crucial in preventing further corneal damage and potential vision loss.
There are 5 questions to complete.
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References: Merck Manual · UpToDate

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