TB Disease and Latent TB Infection

1. TB Disease and Latent TB Infection Karen Galanowsky RN, MPH Nurse Consultant, TB Program New Jersey Department of Health & Senior Services

2. Transmission of M. tuberculosis • Spread by droplet nuclei • Expelled when person with infectious TB coughs, • sneezes, speaks, or sings • Close contacts at highest risk of becoming • infected • Transmission occurs from person with infectious TB disease (not latent TB infection)

4. Latent TB Infection (LTBI) • LTBI is the presence of M. tuberculosis organisms (tubercle bacilli) without symptoms or radiographic evidence of TB disease • With LTBI, the person is healthy and cannot spread TB to anyone

5. Testing for M. tuberculosis Infection • Mantoux tuberculin skin test (TST) • Skin test that produces delayed-type hypersensitivity reaction in persons with M. tuberculosis infection • Use a cut point of 5mm or 10 mm depending upon the reason for testing • QuantiFERON® -TB Gold Test • Blood test that measures and compares amount of interferon-gamma (IFN-) released by blood cells in response to TB antigens

6. Persons at Risk for DevelopingTB Disease • Those who have been recently infected • Those with clinical conditions that increase their risk of progressing from LTBI to TB disease • HIV • Uncontrolled diabetes • Cancer of the head or neck • TNF-alpha blockers Persons at high risk for developing TB disease fall into 2 categories

7. Targeted Tuberculin Testing • Detects persons with LTBI who would benefit from treatment • De-emphasizes testing of groups that are not at high risk for TB • Can help reduce the waste of resources and prevent inappropriate treatment

8. When TB Disease Develops Symptoms • Prolonged cough • Night sweats • Loss of appetite • Weight loss • Fatigue • Fever • Chills • Coughing up blood • Chest pain

9. Evaluation for TB • Medical history • Physical examination • Mantoux tuberculin skin test or Quantiferon-TB Gold • Chest radiograph • Bacteriology testing for smear and culture identification

10. Common Sites of TB Disease • Lungs • Pleura • Central nervous system • Lymphatic system • Genitourinary systems • Bones and joints • Disseminated (miliary TB)

11. Principles of Treatment for TB Disease • Treatment for TB disease is usually 6 – 9 months • The four first-line drugs should be used initially until drug susceptibility studies are determined. • Dosages should be calculated based on weight (mg/kg) • All TB medications should be ingested together the approximately at the same time daily • TB medications may be given intermittently (twice or thrice weekly by directly observed therapy after the initial phase of treatment.

12. MDR and XDR-TB • MDR-TB - Mycobacterium TB that is resistant to at leastIsoniazid and Rifampin • XDR TB is defined as resistance to the four first-line drugs, an injectable, and one of the quinolones • Individuals with XDR TB are more likely to die during treatment or have treatment failure • XDR TB has emerged worldwide as a threat to public health and TB control raising concerns for a future epidemic of virtually untreatable TB • Second-line anti-TB medications are used in the treatment of MDR and XDR-TB. These are costly, difficult to administer, and cause serious side effects

13. Factors that Affect TB Transmission • Infectiousness of person with TB • Environment in which exposure occurred • Duration of exposure • Proximity to the infectious person