Pathology · patient case question
The fistula of a chronic abscess produces an exudate mainly composed of which cells?
Patient case: Trauma to #8 and #9 with a discoloured tooth and sinus tract
Scenario: A patient had trauma and FRACTURED #8 and #9. Tooth #9 has a PULP EXPOSURE, an ABSCESS WITH A SINUS TRACT, and a DARK COLOUR.
Show answer and explanation
Correct answer: A. Neutrophils
- A. Correct. The material draining through a sinus tract is PUS, and pus is composed predominantly of NEUTROPHILS (polymorphonuclear leukocytes) — living and degenerating — together with tissue debris and bacteria. Even in a 'chronic' abscess, the actively draining exudate is neutrophil-rich because the suppurative process is ongoing.
- B. Eosinophils are elevated in parasitic infection and allergic/type I hypersensitivity reactions.
- C. Lymphocytes dominate CHRONIC granulomatous inflammation in the surrounding tissue (as in a periapical granuloma), but they are not the main cell in the purulent exudate itself.
- D. Plasma cells are the antibody-producing effectors of chronic inflammation, prominent in periapical granulomas and chronic periodontitis — again in the tissue, not the pus.
Note: Useful distinction: the periapical GRANULOMA (the surrounding tissue) is a chronic inflammatory lesion rich in lymphocytes, plasma cells and macrophages, while the PUS draining out of it is acute and neutrophil-rich.