24th March is World TB Day

Health Care, Medicine Comments Off

Even singing can spread TB

  1. Person-to-person transmission of TB occurs via inhalation of droplet nuclei (airborne particles 1 to 5 microns in diameter).
  2. Coughing and singing facilitate formation of droplet nuclei.
  3. Persons with active untreated respiratory tract disease (pulmonary or laryngeal) are contagious, particularly when cavitary disease is present or when the sputum is AFB smear-positive.
  4. Patients with sputum smear-negative, culture-positive lung TB can transmit infection.
  5. Extra pulmonary TB is not contagious unless the person also has lung TB.
  6. Many procedures can result in the dispersal of droplet nuclei like endo-tracheal intubation, bronchoscopy, sputum induction, aerosol treatments, irrigation of a TB abscess, and autopsy.
  7. Suspect TB if there is persistent (>3 weeks) cough and constitutional symptoms (fever, drenching night sweats, unintentional weight loss).
  8. In HIV, the clinical and X-ray presentations of TB are often atypical. Such patients have an increased frequency of extrapulmonary TB and can have pulmonary disease despite a normal chest x-ray.
  9. Results of acid-fast smears should be available within 24 hours.
  10. Suspected or confirmed cases of TB should be reported promptly to the local public health department in order to expedite contact investigation and to help plan outpatient follow-up.
  11. Suspicion of active pulmonary TB should prompt placement in an AII room. Such patients should be educated about the purpose of such isolation and instructed to cover their nose and mouth when coughing or sneezing, even when in the room. Whenever possible, procedures should be performed in the AII room to minimize exposure to the rest of the hospital. If the patient must leave the room, a surgical mask must be worn. All other persons entering the room must use respiratory protection, usually an N95 mask.
  12. Anti-TB treatment administered during hospitalization should be directly observed therapy (DOT).
  13. TB isolation rooms: Negative pressure is employed to prevent the escape of droplet nuclei. To accomplish this goal, doors must be kept closed and negative pressure should be verified daily. There must be 6-12 six air exchanges per hour. If recirculation to general ventilation is unavoidable, HEPA filters must be installed in the exhaust ducts.
  14. Respiratory protection masks must filter particles 1 micron in diameter with at least 95% efficiency (N95) given flow rates up to 50 L per minute, must fit to a person’s face with less than 10% seal leakage.  Health care workers should use these masks.
  15. N 95 mask is designed to filter air before it is inhaled; thus, patients with known or suspected TB should not wear these masks. For the surgical masks are sufficient.
  16. A patient may be transferred from an AII room once TB is ruled out or on treatment 3 consecutive sputum samples, obtained on different days, are smear-negative for AFB.
  17. For patients with initially positive AFB smears, at least 2 weeks of TB treatment should be administered before isolation is discontinued.
  18. For patients with MDR-TB, maintaining isolation throughout hospitalization is prudent.
  19. Ideally a TB OPD clinic should be an AII room. If unavailable, an enclosed area should be used and a surgical mask (not an N95 mask) should be placed on the patient.  The patient should be instructed to cover the mouth and nose with tissues when sneezing or coughing. If an area other than an AII room is used, it should not be used again for one hour once the patient has left.
  20. An individual with AFB smear-positive involving the respiratory tract is generally considered to have been contagious starting three months before the first smear-positive sputum or onset of pertinent symptoms, whichever is earlier.
  21. For persons with AFB smear-negative disease, the contagious period is considered to have begun one month before the onset of symptoms.
  22. HCWs and patients with potential exposure should be screened (by symptoms and, unless positive at baseline, TST or IGRA) as soon as possible after the exposure. If initial screening is negative testing should be repeated 8 to 10 weeks following the end of the exposure.