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TB and Drug Resistant TB Case Studies

TB and Drug Resistant TB Case Studies. Philip W. Smith, MD Chief, Infectious Diseases University of Nebraska Medical Canter. 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.

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TB and Drug Resistant TB Case Studies

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  1. TB andDrug Resistant TBCase Studies Philip W. Smith, MD Chief, Infectious Diseases University of Nebraska Medical Canter

  2. 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

  3. TB Resurgence Increased number of immigrants from countries with many cases of TB HIV / AIDS Epidemic Poor compliance with treatment regimens Increased poverty, injection drug use, and homeless

  4. Number of TB Cases inU.S.-born vs. Foreign-born Persons United States, 1993–2005* No. of Cases *Updated as of March 29, 2006.

  5. Tuberculosis Mycobacterium tuberculosis • Humans main reservoir • Inhalation of droplet nuclei • Most infected without disease • 5-15% develop disease • Greatest risk first two years

  6. Findings of Pulmonary TB • Cough • Fever • Weight loss • Hemoptysis • Night sweats • Chest pain • X ray shows: • Infiltrate • Cavity • Upper lobe location

  7. Transmission of M. tuberculosis • Spread by airborne route; droplet nuclei • Transmission affected by • Infectiousness of patient • Environmental conditions • Duration of exposure • Most exposed persons do not become infected

  8. Administering the TST • Inject 0.1 mL PPD intradermally • Should produce wheal of 6–10 mm • Do not recap, bend, break, remove needles from syringes • Follow standard IC precautions

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

  10. Interpreting TST Result (2) Different cut points used depending on • Patient’s risk for having LTBI • Size of induration

  11. CXR

  12. AFB smear AFB (shown in red) are tubercle bacilli

  13. 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

  14. TB therapy-general principles • TB is treated much longer than most other bacterial infections, usually 6-9 months. • Multiple drugs are needed because of resistance development issues. • Compliance is a big issue in TB therapy. • DOT (directly observed therapy) has helped TB treatment effectiveness • Most TB drugs are given orally.

  15. Treatment of TB for HIV-Negative Persons • Include four drugs in initial regimen • Isoniazid (INH) • Rifampin (RIF) • Pyrazinamide (PZA) • Ethambutol (EMB) or streptomycin (SM) • Adjust regimen when drug susceptibility results are known

  16. TB and HIV • An estimated 2 billion out of the world population of 6 billion have TB. • Each year there are 9 million new cases of TB in the world, and 2 million TB deaths. • An estimated 33 million people in the world are HIV positive. • Annual risk of TB disease with HIV is 10% per year • TB patients with HIV have a higher mortality

  17. Drug Resistant TB • There are an estimated 500,000 multi-drug resistant (MDR) cases of TB in the world per year. • 2-10 % of MDR cases are extensively drug resistant (XDR) TB. • Of the recent HIV positive MDR TB patients, 80% (of 200) died within 4-19 weeks

  18. Multidrug-Resistant Tuberculosis (MDRTB) • Seen especially in China, Russia, India, Estonia • Resistant to INH and Rifampin, the two core TB drugs • Cure rate 60% • Similar to per-chemotherapy era

  19. MDRTB: Recent Outbreaks • Large numbers of Patients • Nosocomial transmission • HIV co-infection – 80% • High mortality

  20. US MDR TB outbreaks • Inpatient or outpatient visits on an HIV ward were a major risk factor for MDR TB in Miami • 8.7% of 472 patients in an HIV dental clinic in NYC developed culture positive MDR TB • A number of nurses and doctors acquired MDR TB in the line of duty

  21. XDR TB • Definition: TB resistant to INH, rifampin, quinolones and an injectable second line agent • Causes higher death rate than susceptible TB • A worldwide problem – especially in Africa • Amplified by HIV

  22. XDR TB cases • 49 cases in the US up to 2006 • Increasing in incidence • Large outbreak in Africa in 2006 (52 of 53 died at a median of 16 days)

  23. Treatment of MDR and XDR TB • Treat with 4-7 drugs to which the organism is sensitive for 18-24 months • Second line drugs are more toxic and less effective than INH and rifampin • Mortality is higher for MDR and XDR TB.

  24. House panel review of traveling TB patient incident • The patient flew against medical advice to Paris on May 12, 2007 (with probable MDR TB) • On May 21, tests reported XDR TB. • On May 22, the CDC contacted the patient in Rome and told him not to travel • The patient and his wife changed their itinerary to elude public health authorities, and took several flights in Europe, and then flew from Prague to Montreal. • He re-entered the US, and a US Customs official let him through even though there was an order to not let him into the country. • Hundreds of airline passengers were tracked down.

  25. House panel review of traveling TB patient incident: conclusions • The government should have used more aggressive measures to restrict the patient • The Customs and Border patrol's letting the patient into the US was an "egregious failure" • It took several hours for DHS to get the patient on the "no fly" list because he was not a terrorist • The CDC should have informed the WHO about the patient immediately, not 2 days later

  26. Public Health and Welfare: Regulations to control communicable diseases • The government may quarantine (exposed persons) or isolate (infected patients) to "prevent the introduction, transmission or spread of communicable diseases". This includes "apprehension and detention" of individuals. • The Public Health Service Act authorizes DHHS to enact this provision (through the CDC) • Quarantinable diseases include diphtheria, TB, plague, smallpox, yellow fever, VHF, SARS, avian influenza. • State authority for isolation and quarantine is variable.

  27. TB and air travel "Health officials are trying to track down 44 people who sat near a woman with MDR TB aboard an airliner from India to the US". January 2008, Reuters Health

  28. TB and Air Travel (WHO, 2006) • Commercial jets built after the late 1980s recirculate cabin air, HEPA filter it, and blend it with outside air. • When the engine is running, the air is drawn from the compressor stages of the engines, enters the cabin from overhead, and exits near the floor. • While cruising, aircraft provide 20 air exchanges per hour. • In case of ground delays for more than 30 minutes the ventilation system should be operating. • TB transmission has only been documented on flights of 8 hours or more. • Most transmission occurs to persons in the same row, or 2 rows ahead or behind, the patient. SARS, and influenza, raise the question of wider spread. • TB patients should not travel until they are on therapy for 2 weeks. • MDR TB and XDR TB patients should not travel (until declared non-infectious).

  29. TB and Air Travel (WHO, 2006) • Countries may require medical examination of arriving or departing passengers (or deny them entry). • Officers in command of aircraft are required to report any cases of illness indicative of a public health hazard on board. • Officers in command of aircraft may legally deny boarding to a person if they have a valid concern that they pose a health threat. • Physicians who are aware that an infectious TB patient is flying should inform public health. • Airlines have a system in place to reach passengers, and should cooperate with health authorities to reach them. However, the responsibility for contacting exposed passengers rests with public health authorities.

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