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Module 10

Module 10. Tuberculosis: Guidelines for Oral Health Professionals. Tuberculosis: Guidelines for Oral Health Professionals. Louis G. DePaola, DDS, MS Professor Department of Diagnostic Sciences and Pathology Dental School University of Maryland Baltimore

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Module 10

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  1. Module 10 Tuberculosis: Guidelines for Oral Health Professionals

  2. Tuberculosis: Guidelines for Oral Health Professionals Louis G. DePaola, DDS, MSProfessor Department of Diagnostic Sciences and Pathology Dental School University of Maryland Baltimore Director, Dental Training Pennsylvania Mid-Atlantic AIDS ETC

  3. Mycobacterium tuberculosis

  4. Transmission and Pathogenesis

  5. Tuberculosis Transmission • Caused by Mycobacterium tuberculosis • Spread by: • Airborne route • Droplet nuclei • Affected by: • Infectiousness of patient • Environmental conditions • Duration of exposure • Most persons exposed do not become infected

  6. 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 • Latent TB infection not infectious

  7. PathogenesisLatent M.tuberculosis Infection • Inhaled droplet nuclei with M. tuberculosis : • Reach alveoli • Are taken up by alveolar macrophages • Reach regional lymph nodes • Enter bloodstream and disseminate • Chest radiograph may have transient abnormalities • Specific cell-mediated immune response controls further spread

  8. Tubercle bacilli enter alveoli and multiply; • Organisms disseminated systemically; • Trigger immunereaction 4. Special immune cells form a hard shell (Latent TB infection) 5.Hard shell breaks down and tubercle escape and multiply causing active TB infection

  9. PathogenesisActive M. tuberculosis Infection • Active disease state • Symptoms present: • Cough • Fever • Chills • Night sweats • May be infectious • Disease both treatable & preventable

  10. PathogenesisActive M.tuberculosis Infection • Latent M. tuberculosis progresses to active disease in: • A very small number of persons soon after infection (Primary progression) • About 5% of infected persons within first 2 years of infection • About 5% of infected persons at sometime in later life • Risk of progression greatest in first 2 years • Risk greater if cell-mediated immunity impaired

  11. Symptoms Suggestive of TB • Chronic cough, • Coughing blood, • Night sweats, and • Unexplained weight loss. • Positive TB skin test without symptoms does not indicate active infection in most cases.

  12. Tuberculosis • Infects an estimated one-third of the world population • Globally causes one death every 10 seconds • 50 million people worldwide infected with drug-resistant strains • One of leading causes of death in HIV/AIDS patients CDC HIV/STD/TB Prevention News Update 3/23/99

  13. Tuberculosis (TB) The number one single infectious disease killer • TB is not on the decline. • One third of the world's population is infected with TB • In 1999 TB caused 8,000 deaths/day • The most deaths from TB in history • 7- 8 million people become infected with TB/year • 5-10 % of these people will develop active TB • Between 1993 and 1996, TB increased 13 % • TB accounts for more than 1/4 of all preventable adult deaths the developing world. nfid.org/factsheets

  14. Tuberculosis (TB) The number one single infectious disease killer • Someone is newly infected with TB every second! • TB is the leading killer of women • TB outranks all causes of maternal mortality • TB creates more orphans than any other infectious disease • TB is the leading cause of death among HIV-positive individuals nfid.org/factsheets

  15. Tuberculosis Incidence • USA:18,371 total cases in 1998; - 7.5% decline compared to 1997; - Decline expected in 1999 • RUSSIA: < 100,000 cases in 1998, - Significant increase expected in 1999 • LONDON,UK: 50 new cases/week. • THE AMERICAS (PAHO): - 1997 > 250,000 cases reported; - Estimate as many as 400,000 cases; - Cause of 50,000 deaths/yr.CDC HIV/STD/TB Prevention News Update 3/23/99

  16. Epidemiology of TB in the USA

  17. Areas of Concern • TB cases continue to be reported in every state • Drug-resistant cases reported in almost every state • Estimated 10-15 million persons in U.S. infected with M. tuberculosis • Without intervention, about 10% will develop active TB disease at some point in life

  18. TB Morbidity Trends in the USA • From 1953-1984, reported cases decreased by an average of 5.6% a year • From 1985 to 1992, reported TB cases increased by 20% • Since 1993, reported TB cases have been declining again: • 18,361 cases reported in 1998 • Decreased to 17,531 cases in 1999

  19. Tuberculosis in the United States • 30% decline in cases 1992-1999 • Increase in foreign-born cases • 41% of cases in persons born outside US • Concentration in few states • 50% of cases in 4 states • California • New York • Texas • Florida

  20. Reported TB Cases United States, 1953 - 1998 100,000 70,000 * 50,000 * Cases (Log Scale) 30,000 20,000 10,000 53 60 70 80 90 98 Year * Change in case definition

  21. 28000 26000 24000 Cases 22000 20000 18000 16000 80 82 84 86 88 90 92 94 96 98 00 Reported TB CasesUnited States, 1980-2000 Year

  22. TB MorbidityUnited States, 1996-2000 Year Cases Rate* 1996 21,337 8.0 1997 19,851 7.4 1998 18,361 6.8 1999 17,531 6.4 2000 16,377 5.8 *Cases per 100,000

  23. Reported TB Cases by State United States, 1997 and 1998 Change in Cases % 1997 State 1998 Change 2,265 New York 2,000 -265 -11.7 4,056 California 1,992 3,852 -204 -5.0 Texas 1,820 -172 -8.6 974 Illinois 850 -124 -12.7 1,400 Florida 1,302 -98 -7.0 9,164 All Others 8,537 -627 -6.8 19,851 Total 18,361 -1,490 -7.5

  24. TB Case Rates by State United States, 1998 D.C. P.R. <3.5 (Year 2000 target) 3.6 - 6.8 >6.8 (National average)

  25. TB Case Rates, 2000 D.C. < 3.5 (year 2000 target) 3.6 - 5.8 > 5.8 (national average) Rate: cases per 100,000

  26. TB Case Rates by Age Group and Sex, USA, 2000 Cases per 100,000

  27. Number of TB Cases in USA, 1992-2000 US-born vs. Foreign-born Persons No. of Cases

  28. Percentage of TB CasesAmong Foreign-born Persons 1992 2000 >50% 25%-49% <25%

  29. Global Tuberculosis: 2000 • 7.8 million incident cases • 1.8-2.4 million deaths • Co-epidemic with HIV in Africa, Asia • MDRTB in former USSR, South America and other pockets • Concentration of cases in few countries • 22 countries with 80% of cases www.hopkins-tb.org

  30. s e s a C B T f o e g a t n e c r e P Trends in TB Cases in Foreign-born Persons, United States*, 1986-1998 45 16,000 Percentage of Cases Number of Cases 40 14,000 35 N 12,000 u 30 m 10,000 b e 25 r o 8,000 f 20 C a 6,000 s 15 e s 4,000 10 2,000 5 0 0 86 87 88 89 90 91 92 93 94 95 96 97 98 Year * Comprises the 50 states, the District of Columbia, and New York City

  31. South Korea 3% India Haiti 7% 4% Republic of China 5% Country of Origin of Foreign-born Persons with TB, United States,1998 Other* 36% Mexico 23% Philippines 13% Vietnam 10% *Includes 149 countries

  32. Drug Use and TB • Persons who inject drugs are at high risk for: - HIV disease - Developing active TB if infected • Crack cocaine has been associated with the transmission of HIV and TB

  33. HIV Related Increase

  34. Tuberculosis • Multiple Drug Resistant TB • Related to HIV AIDS and non-compliance • Some strains resistant to up to 8 drugs • Virulent TB (NEJM 1998;338:633-9) • 21 cases in non-TB endemic areas between 1994 and 1996 • Apparently spread by casual contact • Growth characteristics exceeded other clinical isolates www.hopkins-tb.org

  35. Drug-Resistant TB • Drug-resistant TB transmitted same way as drug-susceptible TB • Drug resistance is divided into two types: • Primary resistance develops in persons initially infected with resistant organisms • Secondary resistance (acquired resistance) develops during TB therapy www.hopkins-tb.org

  36. Factors Contributing to the Increase in TB Morbidity: 1985-1992 • Deterioration of the TB public health infrastructure • Decreased funding for surveillance and treatment programs • Poverty and crowding in urban centers • HIV/AIDS epidemic • Immigration from countries where TB is common • Transmission of TB in congregate settings www.hopkins-tb.org

  37. Factors Contributing to the Decrease in TB Morbidity Since 1993 • Increased efforts to strengthen TB control • programs that • Promptly identify persons with TB • Initiate appropriate treatment • Ensure completion of therapy www.hopkins-tb.org

  38. MDR TB Cases, 1993 - 1998 None > 1 case

  39. Diagnosis of TB

  40. Diagnosis of Active TB • History and epidemiologic clues • Think TB!!! • Chest X-ray • Tuberculin skin test • AFB smear • AFB culture • Nucleic acid amplification • Fast but sensitivity poor in smear neg. • Empiric treatment trial

  41. AFB Smear AFB (shown in red) are tubercle bacilli

  42. Cultures • Use to confirm diagnosis of TB • Culture all specimens, even if smear negative • Results in 4 to 14 days when liquid medium systems used Colonies of M. tuberculosis growing on media

  43. Testing for TB Disease and Infection

  44. All Testing Activities Should Be Accompanied By a Plan for Follow-up Care.

  45. Administering the Tuberculin Skin Test • Inject intra-dermally: • 0.1 ml of 5 TU PPD tuberculin • Produce wheal: • 6 mm to 10 mm in diameter • Do not recap, bend, or break needles, or remove needles from syringes • Follow universal precautions for infection control

  46. Reading the Tuberculin Skin Test • Read reaction: • 48-72 hours after injection • Measure only induration! • Record reaction in millimeters

  47. Factors that May Affect the Skin Test Reaction Type of Reaction Possible Cause False-positive Non-tuberculous mycobacteria BCG vaccination Anergy False-negative Recent TB infection Very young age (< 6 months old) Live-virus vaccination Overwhelming TB disease

  48. Anergy • Do not rule out diagnosis based on negative skin test result • Consider anergy in persons with no reaction if • HIV infected • Overwhelming TB disease • Severe or febrile illness • Viral infections • Live-virus vaccinations • Immunosuppressive therapy. • Anergy skin testing no longer routinelyrecommended

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