Which statement is true about infiltrates and infection?

Which statement is true about infiltrates and infection?

• A. All infections have an infiltrate
• B. Every infection has an infiltrate, but not every infiltrate is infectious
• C. Infiltrates never stain with NaFl
• D. Infiltrates are caused by bacterial infection only

Answer: (B)

Infiltrates are focal collections of inflammatory cells within the corneal stroma, reflecting an inflammatory process in the eye. When infection is present, the immune response in the cornea typically produces an infiltrate, so infections often have this finding. However, inflammation can be sterile as well—there are noninfectious conditions that cause stromal infiltrates, such as immune or hypersensitivity reactions—so not every infiltrate means there’s an infection. That’s why the statement that captures this nuance is that every infection tends to show an infiltrate, but not every infiltrate is due to infection. Fluorescein staining highlights disruptions in the corneal epithelium. The stromal infiltrate itself usually does not stain with fluorescein, because the dye pools where the epithelial surface is breached. If an epithelial defect overlies the infiltrate, you may see staining around or over the area, but the infiltrate itself isn’t defined by fluorescein uptake. This is why infiltrates aren’t described as inherently staining with fluorescein, and why that choice isn’t correct. Infiltrates can arise from bacteria, fungi, viruses, parasites, or sterile inflammation, so they are not exclusive to bacterial infection.

Infiltrates are focal collections of inflammatory cells within the corneal stroma, reflecting an inflammatory process in the eye. When infection is present, the immune response in the cornea typically produces an infiltrate, so infections often have this finding. However, inflammation can be sterile as well—there are noninfectious conditions that cause stromal infiltrates, such as immune or hypersensitivity reactions—so not every infiltrate means there’s an infection. That’s why the statement that captures this nuance is that every infection tends to show an infiltrate, but not every infiltrate is due to infection.

Fluorescein staining highlights disruptions in the corneal epithelium. The stromal infiltrate itself usually does not stain with fluorescein, because the dye pools where the epithelial surface is breached. If an epithelial defect overlies the infiltrate, you may see staining around or over the area, but the infiltrate itself isn’t defined by fluorescein uptake. This is why infiltrates aren’t described as inherently staining with fluorescein, and why that choice isn’t correct. Infiltrates can arise from bacteria, fungi, viruses, parasites, or sterile inflammation, so they are not exclusive to bacterial infection.