Micro & Immunology · single question
A patient presents with an acute draining fistula near tooth 8. There is no facial swelling or significant intraoral swelling. What type of cells are most predominant in the infection as presented?
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Correct answer: D. Neutrophils
An acute draining fistula (sinus tract) indicates an active acute bacterial infection. The ACUTE phase of infection is characterized by predominance of NEUTROPHILS (polymorphonuclear leukocytes = PMNs). Neutrophils are the first responders to bacterial infection, arriving within hours via chemotaxis, performing phagocytosis and releasing antimicrobial factors. Monocytes/macrophages predominate in CHRONIC inflammation. Lymphocytes predominate in chronic inflammation and adaptive immunity. Eosinophils respond to parasites and allergies.
- A. INCORRECT. Monocytes (which become macrophages in tissue) predominate in CHRONIC inflammation, not acute bacterial infection.
- B. INCORRECT. Lymphocytes (T and B cells) are associated with chronic inflammation, adaptive immunity, and specific immune responses — not the dominant cells in acute bacterial infection.
- C. INCORRECT. Eosinophils are associated with allergic reactions, parasitic infections, and certain chronic conditions — not acute bacterial dental infections.
- D. CORRECT. Neutrophils (PMNs) are the hallmark cells of ACUTE inflammation and bacterial infection. They are recruited within hours and are the predominant white blood cells in an acute draining abscess/fistula.
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