Differential Diagnosis for the 76-year-old Male Patient
The patient presents with a four-day history of right eye pain, redness, and significant discomfort, with a history of herpes simplex infection of the right eye. Given the clinical presentation and the lack of improvement with ciprofloxacin eye drops, the differential diagnosis can be categorized as follows:
- Single Most Likely Diagnosis
- Bacterial conjunctivitis: This is the most likely diagnosis given the patient's symptoms of eye pain, redness, and discharge, which have worsened despite the use of ciprofloxacin eye drops. The fact that the symptoms have not improved with antibiotic drops suggests a possible resistance or a more severe infection.
- Other Likely Diagnoses
- Herpes simplex keratitis: Given the patient's history of herpes simplex infection, this is a likely diagnosis. Herpes simplex keratitis can cause eye pain, redness, and discharge, and can be recurrent.
- Corneal ulcer: The patient's symptoms and the presence of a mild corneal abrasion on the Woods lamp exam suggest the possibility of a corneal ulcer, which can be caused by bacterial or fungal infections.
- Do Not Miss Diagnoses
- Endophthalmitis: This is a rare but potentially devastating infection of the inner eye that can cause severe vision loss. It is often associated with recent surgery or trauma, but can also occur spontaneously.
- Acute angle-closure glaucoma: This is a medical emergency that can cause severe eye pain, redness, and vision loss. It is often associated with a history of glaucoma or anatomical abnormalities of the eye.
- Rare Diagnoses
- Fungal keratitis: This is a rare infection of the cornea that can cause eye pain, redness, and discharge. It is often associated with trauma or contact lens use.
- Acanthamoeba keratitis: This is a rare infection of the cornea that can cause eye pain, redness, and discharge. It is often associated with contact lens use or exposure to contaminated water.
Given the clinical suspicion of bacterial conjunctivitis, the patient should be prescribed a broad-spectrum antibiotic eye drop, such as moifloxacin or gatifloxacin, to cover for potential resistant organisms. Additionally, the patient should be advised to follow up with their ophthalmologist, Dr. Kearney, as soon as possible to further evaluate and manage the condition.