Bacterial keratitis
Bacterial keratitis is also often referred to as a corneal ulcer, although these terms are not directly interchangeable because a cornea may harbor a bacterial infection (i.e bacterial keratitis) without having a loss of tissue (an ulcer), and a cornea may have an ulcer without a bacterial infection.
Background
- Rapidly progressing, with corneal destruction as fast as within 24 hrs
- Corneal perforation is most sight threatening complication
- Strep, staph, pseudomonas, enterobacteriaceae
- Risk factors
- Contact lens use
- Corneal surgery, trauma
- Chronic dry eye
- Recent corneal disease (viral, fungal keratitis)
- Immune deficiency, topical steroids
Clinical Features
Bacterial keratitis due to Pseudomonas spp.
- Blurred vision
- Severe pain and photophobia
- Perilimbic injection
- Normal pupil size
- Eyelid edema
- Mucopurulent exudate
- Posterior synechiae (iris adheres to cornea)
Differential Diagnosis
- Iritis
- Conjunctivitis
- Glaucoma
- UV keratitis
- Herpes zoster
- Contact lens complication
- Fungal keratitis
- Bacterial keratitis
- Interstitial keratitis
- Herpes keratitis
- Endophthalmitis
Evaluation
- Topical anesthesia with proparacaine, as opposed to tetracaine which has bacteriostatic effects, limiting culture results
- Culture and gram stain of corneal ulcer edges, eyelids, conjunctiva, contact lenses
- Ultrasound to assess for signs of endophthalmitis and other pathologies
Management
- Broad spectrum topical antibiotics; 1 drop q1 hr
- Tobramycin 14mg/ml
- Alternate with fortified cefazolin 50mg/ml
- Smaller corneal ulcers may be treated with moxifloxacin or gatifloxacin ophthalmic
Disposition
- Ophtho consult for possible perforation risk
- Eye patch in the interim
See Also
References
- Murillo-Lopez F et al. Bacterial Keratitis. Aug 24, 2014. http://emedicine.medscape.com/article/1194028-overview.
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