Infection Control · patient case question
A patient with ACTIVE pulmonary tuberculosis requires urgent care. What respiratory protection is required?
Patient case: Infection control and a poor panoramic film
Patient: Practice-based scenarios
Chief Complaint: Not applicable.
Background: A surgical extraction is scheduled and the patient's adult daughter asks to remain in the operatory to support her. A separate patient on the list has ACTIVE pulmonary tuberculosis and needs urgent care. Environmental surfaces are being reviewed after an inspection.
Findings: A panoramic radiograph taken earlier in the day shows a broad dark radiolucent band running across the apices of all the maxillary teeth, obscuring the region of interest. The patient was positioned correctly in the horizontal and vertical planes and the spine is straight.
Show answer and explanation
Correct answer: B. A fit-tested N95 respirator, filtering at least 95% of airborne particles
- A. Layering a surgical mask over a cloth mask improves fit marginally but achieves neither respirator-level filtration nor a tested seal, and it is not acceptable for a known airborne pathogen.
- B. CORRECT. Mycobacterium tuberculosis is transmitted by DROPLET NUCLEI that remain suspended in air for prolonged periods, so AIRBORNE precautions are required — an N95 or higher respirator, FIT-TESTED to the individual wearer, in a negative-pressure room. The N95 designation means it filters at least 95% of airborne particles at the most penetrating particle size, around 0.3 µm. The more important scheduling point: ELECTIVE dental care for a patient with active infectious TB is DEFERRED until the patient is no longer infectious, and genuinely urgent care goes to a facility with airborne infection isolation capability.
- C. A surgical mask does NOT achieve 95% filtration of small-particle aerosols, does not seal to the face, and is designed principally to protect the patient from the wearer rather than the reverse. The 95% figure belongs to the respirator.
- D. A face shield protects the eyes and face from spatter and is always an ADJUNCT. It provides no respiratory protection whatsoever.
Note: Practical points: facial hair breaks the seal and invalidates fit testing, fit testing must be repeated annually and after significant weight change, and a user seal check is performed at every donning.
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