Clinical and Pathologic Findings in Patients with Suspected Infectious Keratitis: A Single Institution Experience

Abstract

 

Purpose

 

To compare culture and histopathologic results collected during the same procedure in patients with suspected infectious keratitis.

 

Methods

 

Computer-based search of Mayo Clinic’s pathology database identified all corneal specimens submitted to both pathology and microbiology laboratories for patients with suspected infectious keratitis from January 1, 1994 to July 1, 2012. The medical record of each patient was retrospectively reviewed to determine the clinical indication, biopsy and culture results, and clinical outcome.

 

Results

 

We identified 109 eyes (108 patients) from which 131 simultaneous corneal biopsy and culture specimens were retrieved. Mean age was 53 ± 25 years (± SD; range, 2 - 97 years), and 57 patients were female (53%). The most common indication was ulcerative keratitis (90 specimens). Microorganisms were identified in 67 specimens; by culture alone (28/67, 21%), by histopathology alone (17/67, 25%), or by both techniques (22/67, 33%). Microorganisms identified by culture alone were most commonly bacteria (22), whereas microorganisms identified by histopathology alone were typically Acanthamoeba (8) or fungi (6). There were 10 instances of polymicrobial infection, usually detected by culture (7 specimens); three of these cases resulted in evisceration. In 64 specimens (57 patients), no microorganisms were identified by either culture or histopathology. Histopathology of these cases showed acute inflammation consistent with acute keratitis in 77% (49/64), ulceration in 58% specimens (37/64), and stromal fibrosis consistent with scarring in 13% (8/64). In this group, repeat biopsies revealed bacteria in only 2 of 6 patients.

 

Conclusions

 

Histopathology and laboratory culture provide complementary information to ophthalmologists in cases of suspected infectious keratitis. Bacteria were frequently identified by culture even when not visible in histopathologic sections, while some cases of fungi and Acanthamoeba were only seen in the histopathologic examination.

 

 

^a 3 specimens had polymicrobial infections. In 2 cases, cultures were positive for bacteria whereas histology was positive for fungi. In one case, culture was positive for bacteria whereas histology revealed Acanthamoeba. ^b Mycobacteria identified in two specimens, one according to culture results and the second according to histologic findings.

 

Keywords: 479 cornea: clinical science • 573 keratitis • 638 pathology: human