Use of chlorazol black E mounts of corneal scrapes for diagnosis of filamentous fungal keratitis

Pathogenesis, Immunology and Management of Dermatophytosis

Dermatophytic infections of the skin and appendages are a common occurrence. The pathogenesis involves complex interplay of agent (dermatophytes), host (inherent host defense and host immune response) and the environment. Infection management has become an important public health issue, due to increased incidence of recurrent, recalcitrant or extensive infections. Recent years have seen a significant rise in incidence of chronic infections which have been difficult to treat. In this review, we review the literature on management of dermatophytoses and bridge the gap in therapeutic recommendations.

The role of in vivo confocal microscopy in the diagnosis of hidden corneal foreign bodies

OBJECTIVE

To investigate in vivo confocal microscopy (IVCM) to diagnose hidden corneal foreign bodies.

METHODS

Male Kunming mice (n = 25; 12 weeks old) were anaesthetized prior to the insertion of five different materials (spiny wood, rusty iron, sharp stone, sharp glass fragment and human hair fragment) into the cornea by different traumatic processes. A separate mouse was used for each corneal foreign body. The corneas of the mice were scanned 24 h later by a laser scanning IVCM to establish the characteristics (shape, reflectivity and depth in the cornea) of each foreign body. These findings were used to help screen and identify corneal foreign bodies in patients. Corneal smears and scraping cultures were performed in cases of probable corneal infection.

RESULTS

Animal models for the five different foreign particles were established successfully, with each showing distinctive characteristics. These animal results were used to diagnose 41 patients with suspected corneal foreign bodies who were negative by slit lamp examination, but positive by IVCM (observational case series). The most prevalent type of hidden foreign body was plant material (51.2%), followed by metal (29.3%). Ten patients with corneal foreign bodies developed fungal keratitis, found using IVCM.

CONCLUSIONS

Laser IVCM is an effective and reliable tool for the diagnosis of hidden corneal foreign bodies.

PCR for the molecular diagnosis of mycotic keratitis

Mycotic keratitis, an infection of the cornea caused by fungi, is a medical emergency, with patients presenting with considerable pain and distress. For effective management of the condition, a specific diagnosis must be made rapidly to permit early initiation of antifungal therapy. Currently, direct microscopic examination and culture of corneal material constitute the 'gold standard' for diagnosis. However, rapid, sensitive yet specific tests are needed to detect a small number of, or nonviable, fungi. PCR has many potential advantages when used as a diagnostic aid for mycotic keratitis; the present review covers these advantages, and possible limitations. An expert assessment is also made of studies that have used PCR for the diagnosis of mycotic keratitis. The review concludes with a Five-year view of the potential impact of PCR in management of mycotic keratitis.

Pythium insidiosum keratitis in contact lens wear: a case report

PURPOSE

The purpose of this study was to report a case of contact lens-related Pythium insidiosum corneal ulcer.

METHODS

The authors conducted an interventional case report. We report the clinical presentations, histopathologic findings, and treatments of a patient with P. insidiosum keratitis associated with contact lens wear.

RESULTS

A 22-year-old Thai woman presented to our clinic with a nonresponsive, progressive corneal ulcer of the left eye. Slit lamp examination showed a large central ulcer measuring 5.4 x 5.2 mm with underlying dense stromal infiltrates surrounded by subepithelial and superficial stromal opacity in a reticular pattern along with radial perineural-like infiltrates. Histopathologic examination revealed broad, branched, thin-walled nonparallel hyaline hyphae with rare septates consistent with P. insidiosum. The corneal culture confirmed the diagnosis. The infection recurred after multiple therapeutic penetrating keratoplasties. Enucleation was eventually performed to eradicate the infection. No definite report of contact lens-related P. insidiosum keratitis existed in the literature.

CONCLUSION

Pythium keratitis may present with central ulcer and radial keratoneuritis similar to acanthamoeba keratitis. Contact lens wear can be a risk factor for this infection. Increasing awareness, early diagnosis, and intervention may improve the prognosis.