treatment plan

A Question of Culture

BY WILLIAM TOWNSEND, OD
APRIL 1998

Mr. P., 71 years old, presented with pain and photophobia in his left eye. His right eye had been enucleated following an accident many years earlier. His presenting vision was 20/30, and he denied any history of trauma, including contact with a tree branch or other vegetative material. His health history was normal except for hypertension that was controlled by medications. Slit lamp evaluation showed a 2.0mm area of corneal epithelial ulceration that extended into the denied any history of trauma. His health history was normal except for hypertension, which was controlled by medications. Slit lamp evaluation showed a 2.0mm area of corneal epithelial ulceration which extended into the anterior stroma. The lesion was not on the visual axis, but was located midway between the limbus and central cornea (Fig. 1). We noted grade 1+ cells and flare in the anterior chamber and grade 2+ circumlimbal injection. There was no purulent discharge. All findings indicated that this was a bacterial corneal ulcer, but before initiating treatment, we decided to obtain cultures on blood agar and chocolate agar because Mr. P. was monocular. We then began treating him with Ciloxan ophthalmic solution, one drop every hour.

Over the next two days, the lab reported no growth on the plates, but there was also no improvement in his ulcer. In an act of desperation, I went to the lab and asked to see the plates. One had a very small colony growing, which the technician felt was a contaminant. We examined a stain of the colony and saw what appeared to be gram positive rods. The lab streaked the "contaminant" onto another plate. The next morning, the second plate was covered with wisps of hairy hyphae, revealing the true nature of this Aspergillus fungal ulcer. We immediately started Mr. P. on natamycin ophthalmic solution every hour, and within 24 hours, the size and depth of the lesion dramatically reduced. Mr. P. was left with a surprisingly small scar and 20/30 vision.

To Culture or Not to Culture

The emergence of fluoroquinolones as potent antibacterial agents has contributed to the reluctance of many doctors to routinely culture. In today's current climate of managed care and keeping costs to a minimum, we must be selective. We must establish standards so that we can be scientific and consistent in our approach to these cases. Table 1 lists a few guidelines you may want to consider.

Dr. Townsend is in private practice in Canyon, Texas, and is a consultant at the Amarillo VA Medical Center.