Tuberculosis

What proportion of people who are exposed to TB become infected?

5-10% become ill

What percent of TB cases were co-infected with HIV in 2013?

6.8%

What is the advantage of the GeneXpert test for M. tuberculosis?

Can be done on sputum, pleural fluid, CSF, tissue biopsy; very important in identifying resistant strains (resistance to rifampicin)

Who are the groups that account for the most cases of TB in the US currently?

Currently, 64.6% of TB are cases in foreign born individuals

What is "DOTS"? What are its benefits? What are the global DOTS goals?

D-O-T: Directly Observed Therapy. Active TB patient does not properly take multi-drug regimen, missing doses, drug resistance

True or False: Internationally, generally a positive sputum smear for acid-fast bacilli confirms a diagnosis of TB disease due to M. tuberculosis in regions of high TB prevalence.

False

True or False: TB control is different from other areas in public health because it is mainly based on TB treatment and not prevention of infection.

False

True or False: The rate of TB decline in the US is higher in foreign born than US born people.

False

What are possible reasons given for the increase in TB cases in places like New York City starting in the later 1980's after the initial drop in TB up through the early 1980's?

Increase in coinfections with HIV political commitment

List the first line of TB medications.

Isoniazid, Rifampin, ethambutol, pyrazinamide, streptomycin

List factors that increase the risk of disease progression in those with latent TB infection.

Low immunity due to cancer chemotherapy, high dose steroids

Distinguish between MDR-TB, XDR-TB and TDR-TB. What is the cost of treating each type of infection?

MDR-TB: Multidrug resistant TB XDR-TB: eXtensively drug resistant TB TDR-TB (or XXDR-TB): Totally drug resistant TB

World TB day is celebrated on

March 24

What is the IGRA test? List advantages of this test over the PPD test

Modern equivalent of tuberculin skin test (TST or PPD) to detect latent TB infection (LTBI) Offers several advantages over traditional TB skin testing: Single blood draw, no need for 48-72 hour read No cross reactivity in BCG vaccinated people Less cross reactivity with non-tuberculous mycobacteria (eg, MAI, etc) More predictive than PPD of those at risk to develop active TB in next 2-3 years More sensitive in immunocompromised patients

List the 4 states that account for 50% of all US TB cases in 2014.

New York, Florida, Texas, California

List common symptoms of TB

Night sweats, fever, weight loss, cough, sometimes hemoptysis, loss of appetite

Who discovered the TB bacillus?

Robert Koch

Who made the following conclusions from his study of the detailed analysis of TB patients medically and socially? "The enemy tuberculosis has been tracked to its stronghold, which is defended by three allies - poverty, bad housing and drink". "Tuberculosis is a social disease with a medical aspect".

Sir William Henry Osler

Explain how TB is transmitted.? Droplet of TB case

TB bacteria are spread through the air from one person to another. The TB bacteria are put into the air when a person with TB disease of the lungs or throat coughs, speaks. People nearby may breathe in these bacteria and become infected.

Distinguish between TB infection and TB disease.

TB infection can be either latent or active, TB disease implies a current active condition

Give examples of high burden TB countries that have high rates of TB/HIV and MDR-TB cases

TB/HIV: Botswana, Cameroon, Chad, Ghana, Bissau, Malawi, Swaziland, Uganda. MDR/TB: Azerbejan, Belarus, Khazakhstan, Peru, Moldova, Somalia, Tajikistan, Ukraine, and Uzbekistan.

In countries like the US, how is TB confirmed?

TST or IGRA

List the goals or priorities in TB prevention.

The #1 means of preventing TB cases is to identify active cases as early as possible and start them on treatment The second priority is to identify exposed and latently infected individuals and treat them for LTBI

How is the treatment for latent TB different from treatment for TB disease?

Treatment for LTBI is considered preventative; different drugs are used (usually 1 or 2 drugs depending upon prevalence of resistance in that area) Duration of treatment for latent TB is shorter than TB disease.

True or False: Active TB should never be treated with just one drug because this increases the likelihood of developing drug resistance.

True

True or False: Contact investigation is indicated following identification of cases that are TB smear positive.

True

True or False: For people infected with HIV, the risk of developing TB disease is 5-10% per year.

True

True or False: For people with latent TB, the risk of reactivation to TB disease is 5% over a lifetime.

True

True or False: Smear positivity indicates a significantly infectious disease and is associated with a highly transmissible state.

True

True or False: TB cases have been declining in the US since 1953.

True

True or False: TB may present differently in HIV positive persons (smear-negative, absence of cough, extra-pulmonary TB) compared to HIV negative people.

True

Explain the 2 mechanisms by which drug resistant TB develops

active TB patient does not properly take multi-drug regimen, missing doses (esp. if not under D-O-T: Directly Observed Therapy) or not on sufficiently active regimen patient who has developed drug resistant TB then transmits it by aerosol to another person

List high risk groups for TB infection.

• Homelessness • Incarceration (sejen) • Time spent in congregate (jama3a) settings • Foreign born from country of high TB endemicity • Extended travel within TB endemic country(s) • Family history of tuberculosis • History of a positive TB test in the past