Keratitis, bacterial diagnosis

The rate of progression of signs and symptoms varies depending on the infecting organism. A differential diagnosis for keratitis must include viral, fungal, and nematodal infections in addition to bacterial causes.19... 

Bacterial keratitis is one of the most frequent ophthalmic infections. In a meta-analysis of publications from 1950 to 2000, the use of a topical glucocorticoid before the diagnosis of bacterial keratitis significantly predisposed to ulcerative keratitis in eyes with preexisting corneal disease (OR = 2.63 95% Cl = 1.41, 4.91). Previous glucocorticoid use significantly increased the risk of antibiotic failure or other infectious complications (OR = 3.75 95% Cl = 2.52, 5.58). The use of glucocorticoids with an antibiotic for the treatment of bacterial keratitis did not increase the risk of complications, but neither did it improve the outcome of treatment. 

Acanthamoeba keratitis is known to be difficult to diagnosis and to treat. Most patients are initially treated fiar viral, fungal, of bacterial keratitis before the diagnosis of Acanthamoeba. Most Acanthamoeba infections are associated with contact lens wear (85% to 92%), but a smaller number are secondary to trauma. The incidence of Acanthamoeba keratitis may be greater than 1 per 30,000 contact lens wearers per year as indicated by cohort studies and questionnaires. The frequency oi Acanthamoeba keratitis in contact lens wearer may be 1 per 10,000/year or higher. 

If a definitive diagnosis between CIE and bacterial keratitis cannot be made, corneal cultures should be obtained before starting antibiotic or steroid therapy. If multiple risk fectors are present, treat the condition as a bacterial keratitis and reevaluate within 24 hours to assess any changes in corneal health. 

---