Bilateral bacterial or fungal keratitis, while not unusual, occurs typically in certain predisposed individuals. These include contact lens wearers1 those undergoing refractive corneal surgery2 and those suffering from malnutrition3 or immunodeficiency conditions such as the acquired immunodeficiency syndrome (AIDS).4 Bilateral Pseudomonas keratitis has been described mainly in contact lens wearers1 and has not been reported to develop in the absence of one of the predisposing factors mentioned above. We report a case where bilateral Pseudomonas keratitis developed in a healthy young man without any apparent risk factors.
A 30-year-old farmer presented with complaints of pain, redness and decreased vision in both eyes. There was no history of trauma, contact lens wear, systemic illness, corticosteroid use or the use of any traditional eye medicine. The only medication that had been used was 0.5% chloramphenicol eye drops purchased at a local pharmacy and used once or twice prior to consultation. The patient was unable to say for certain which eye had been affected first. The patient was of a low socioeconomic status and uneducated. He lived in unhygienic surroundings without access to clean water, but was otherwise healthy and had no history of addictions.
Examination revealed a vision of perception of light in both eyes. The right eye had a paracentral ulcer about 5 x 5 mm in the inferior part of the cornea with a small central perforation, shallow anterior chamber, copious discharge and descemet's folds [Figs. 1a and 2]. The left eye showed a near total ulcer with marked thinning and melting of the cornea [Figs. 1a and 3]. There was no evidence of chronic dacryocystitis, dry eye, lagophthalmos, lid scarring or notching, blepharitis or allergic eye or skin disease.
Corneal scrapings from the left eye and a conjunctival swab from the right eye were immediately taken for microscopy and culture. Based on the presence of gram-negative bacilli on the Gram's stain, the patient was started on topical 0.3% tobramycin eye drops and 0.3% ciprofloxacin eye drops half-hourly.
In view of the unusual presentation, the patient was investigated for evidence of immunosuppression and any systemic focus of infection. Human immunodeficiency virus serology and blood cultures were negative. Blood counts, liver function tests, renal function tests and blood sugar levels were all within normal limits. A comprehensive evaluation by a physician and a chest X-ray also failed to reveal any evidence of systemic disease. Serum vitamin A levels were not measured but the patient did not show any evidence of vitamin A deficiency and no other evidence of malabsorption could be elicited. More extensive evaluation was deemed unnecessary by the consulting physician, as the patient appeared to be in good health otherwise.
Microbiological culture of material from both eyes revealed significant growth of Pseudomonas aeruginosa sensitive to amikacin, ciprofloxacin, ofloxacin and tobramycin. In view of the perforated ulcer in the right eye, the patient underwent a therapeutic penetrating keratoplasty in the right eye (8 mm recipient bed with 8.5 mm donor graft) while medical management was continued for the left eye. The excised corneal button failed to show microbial growth on culture. Following keratoplasty, infection in the right eye appeared to be eradicated and the left eye also showed good response to medications with decrease in infiltration and discharge. However, in view of the large ulcer with marked thinning in the left eye, the patient was advised therapeutic keratoplasty for the left eye as well but he refused. At discharge, the therapeutic graft in the right eye remained clear while the corneal ulcer in the left eye had begun to heal [Fig. 1b]. The patient preferred to have further follow-up with his local ophthalmologist according to whom the ulcer in the left eye healed completely while the graft in the right eye remained clear after six weeks.
Bilateral Pseudomonas keratitis typically occurs in contact lens wearers due to contamination of the lens, sterilizing fluids or storage containers. Although Pseudomonas is ubiquitous in the environment, some form of trauma is necessary to facilitate infection as the organism cannot penetrate an intact corneal epithelium. Bilateral Pseudomonas keratitis has been reported in patients on ventilators5 who developed corneal abrasions and also in patients with AIDS.4
Our patient had none of the usual predisposing factors for bilateral infectious keratitis. Although vitamin A deficiency was not ruled out by measuring serum levels, there was no clinical evidence of hypovitaminosis A. There was no other associated illness that could lead to an immunocompromized state. We presume that the patient had developed minor corneal abrasions that passed unnoticed till Pseudomonas infection set in. The infection could have been transferred to the other eye by the patient's own fingers. Poor hygienic conditions at his residence, lack of clean water and high susceptibility to minor eye trauma while farming were the possible factors leading to simultaneous bilateral development of Pseudomonas keratitis.
This case illustrates that bilateral Pseudomonas keratitis can develop in the absence of any obvious predisposing factor. Prompt and vigorous treatment is required to save such eyes.
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4. Hemady RK. Microbial keratitis in patients infected with the human immunodeficiency virus Ophthalmology. 1995;102:1026–30
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