Lesson of the week: microbial keratitis in intensive care

Case 1

A 74 year old man underwent a coronary artery bypass graft. He subsequently had renal failure and the adult respiratory distress syndrome. He was admitted to intensive care, where he was artificially ventilated for two weeks. After a tracheostomy he contracted a respiratory tract infection with Pseudomonas aeruginosa for which no obvious source was found. Twelve days later he developed bilateral microbial keratitis secondary to corneal exposure. This rapidly deteriorated and he developed bilateral endophthalmitis and a corneal perforation in the left eye. He was treated with intravitreal and topical gentamicin, intravenous ceftazidime, and ciprofloxacin. The inflammation gradually resolved. The patient, however, was left with bilateral scarred, thinned, and vascularised corneas. Visual acuity was reduced to light perception only in each eye.

Over the following six months there was little improvement in vision. The main cause of visual loss in the right eye was thought to be the result of corneal opacity and cataract. He underwent a right combined corneal transplantation, cataract extraction, and insertion of an intraocular lens. The procedure was technically difficult because of the caseous nature of the recipient corneal tissue, which tended to disintegrate. Despite some persisting …