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Infection Control · patient case with 3 questions

Newly Diagnosed Tuberculosis

demo: 41-year-old male

chief: Presents to urgent dental care with severe pain from tooth #14.

history: Diagnosed with active pulmonary tuberculosis one week ago; started on therapy 3 days ago. Productive cough, night sweats, weight loss.

meds: Isoniazid, rifampin, pyrazinamide, ethambutol

findings: Tooth #14 with pulp necrosis and symptomatic apical periodontitis. Also requests a routine cleaning.

Question 1

How should the urgent treatment be managed?

  1. Treat in an isolation room with airborne precautions, wearing an N95 respirator
  2. Treat only after 6 months of therapy is complete
  3. Treat in an open bay wearing a standard surgical mask
  4. Refer to the emergency department for extraction under general anesthesia
Show answer and explanation

Correct answer: A. Treat in an isolation room with airborne precautions, wearing an N95 respirator

  • A. Correct. Active TB is transmitted by airborne droplet nuclei. Urgent care requires an airborne infection isolation room and an N95 respirator — a surgical mask does not filter droplet nuclei.
  • B. Deferring urgent care for 6 months is not acceptable for a patient in acute pain.
  • C. A surgical mask protects against splatter, not the 1–5 micron droplet nuclei that carry M. tuberculosis.
  • D. Referral does not remove the airborne risk; it merely relocates it, and the pain is dentally manageable.

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Question 2

The patient also wants his routine prophylaxis appointment. What is the correct decision?

  1. Proceed only if the patient wears a surgical mask during treatment
  2. Proceed with the cleaning using an ultrasonic scaler in the isolation room
  3. Defer elective treatment until the disease is no longer in the acute infectious stage
  4. Proceed with hand instrumentation only, in a standard operatory
Show answer and explanation

Correct answer: C. Defer elective treatment until the disease is no longer in the acute infectious stage

  • A. A patient cannot wear a mask during dental treatment, and the source control would be inadequate anyway.
  • B. Ultrasonics generate large volumes of aerosol and are precisely what should be avoided in an infectious TB patient.
  • C. Correct. Elective care is postponed until the patient is no longer infectious — typically documented by clinical improvement and negative sputum smears after adequate therapy.
  • D. Elective care is postponed regardless of instrumentation, because the exposure risk is not justified by an elective benefit.

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Question 3

Which characteristic of a chemical agent is used to establish that it qualifies as an intermediate-level disinfectant?

  1. Its ability to inactivate hepatitis B virus only
  2. Its ability to kill vegetative bacteria within 30 minutes
  3. Its ability to kill Mycobacterium tuberculosis
  4. Its ability to kill bacterial endospores
Show answer and explanation

Correct answer: C. Its ability to kill Mycobacterium tuberculosis

  • A. Inactivating HBV alone is insufficient; the tuberculocidal claim is the recognized marker.
  • B. Killing ordinary vegetative bacteria is the low-level disinfectant standard, met by quaternary ammonium compounds.
  • C. Correct. Tuberculocidal activity is the benchmark that defines intermediate-level disinfection, because mycobacteria are unusually resistant to chemical agents and survive on surfaces for months.
  • D. Sporicidal activity defines a sterilant or high-level disinfectant such as glutaraldehyde, not the intermediate level.

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