Tuberculosis
Wyoming Department of Health
Communicable Diseases
307-777-8939
What is Tuberculosis?
•An infection caused by Mycobacterium tuberculosis
•Spread person to person through droplets released from an infected
person by sneezing, coughing, singing or laughing
•Can be classified as:
•Active TB Disease
•Latent TB Infection (LTBI)
Transmission
•Occurs when an individual inhales infected droplets
•Depends on
•Infectiousness of TB infected individual
•Environment in which the exposure took place
•Closed, tight environments pose a greater risk of
transmission
•Length of exposure
•The longer the exposure, the greater the risk
•Virulence of TB bacteria
Who is at risk?
•HIV Infected Individuals
•Individuals born in TB endemic countries
•Individuals who have been in contact with someone with TB
•Alcohol and illicit drug users
•Individuals with conditions that may compromise the immune system
•Individuals who were previously treated incorrectly for TB infection
TB Worldwide
•1/3 of the World’s population is infected with TB
•Approximately 9 million people became infected with TB in 2010
•1.4 million people die from TB each year
•TB is the leading cause of death among individuals with AIDS
TB in the United States
•The rate of TB in the US in 2010 was 3.6 cases per 100,000
population
•The rate has been steadily decreasing since 1992
•A total of 11,182 cases were reported in 2010
•Hawaii reported the highest case rate of 8.8 cases per 100,000
population
•Maine reported the lowest case rate of 0.6 cases per 100,000
population
Center for Disease Control and Prevention (2011, October 7). Reported Tuberculosis in the United States, 2010.
TB in Wyoming
•Wyoming is a low incidence state
•Reported case rate of 1.3 per 100,000 population in 2010
•This number increased by 0.9 cases per 100,000 population from 2009
•Wyoming had the 42nd highest case rate in 2010
•Active TB Disease is a REPORTABLE disease in Wyoming
Active TB Disease
•Infectious stage of TB
•Manifests six or more weeks after exposure
•Occurs when the body cannot control the TB bacteria in the body
•Symptoms may include:
•Prolonged Cough
•Unexplained Weight Loss
•Fever
•Night Sweats
•Chest Pain
•Blood in Sputum
•Patients diagnosed with active TB disease should:
•Be isolated and provided with a mask to wear for doctor
appointments, etc
•Immediately start a treatment regimen
•If HIV status is unknown, an HIV test should be done in order to
correctly prescribe the best treatment regimen
Diagnosis of Active TB
•Physical Exam/Symptom evaluation
•Chest X-ray
•Cannot confirm TB Disease
•Used to detect lung abnormalities or rule out disease
•Bacteriologic Cultures (AFB smears)
•Used to confirm/rule out TB disease
•Sputum sample, bronchoscopy, gastric washing
•Sputum Sample
•Most cost-effective
•Patient coughs sputum into a sterile container at least 3 different
times in 8-24 hour intervals, at least one being an early morning
specimen
Active TB Treatment
•Treatment must last 6 months or more (depends on patient’s response
to the treatment regimen)
•2 phases of treatment
•Initial Phase
•First 8 weeks of treatment
•4 drugs used
•Isoniazid (INH)
•Rifampin (RIF)
•Pyrazinamide (PZA)
•Ethambutol (EMB)
•Kills most bacteria
•Continuation Phase
•Starts after the first 8 weeks of treatment until treatment is
complete
•At least 2 drugs used
•Kills remaining bacteria
Active TB Treatment
•Adherence to proper treatment is essential in treating active TB and
avoiding drug resistance
•Drugs should be taken as prescribed
•This time should be convenient for the patient
•Can be monitored by Direct Observed Therapy (DOT)
•A medical provider watches the patient take the
medication in person, by webcam or other means
•Drug resistance can occur if
•An improper treatment regimen is prescribed
•The patient does not take all of their medication as prescribed
Active TB Treatment Evaluation
•The patient should be evaluated regularly to ensure the patient is
properly responding to treatment by
•Symptom evaluation
•Chest x-ray
•Sputum smears or other bacteriologic specimens
•Patients should be reevaluated and treatment regimen should be
assessed if:
•Symptoms do not improve after 2 months of therapy
•Symptoms worsen
•Positive cultures remain after 2 months of treatment
•Culture results become positive after having a negative culture
Active TB Treatment Evaluation
•Liver function tests
•INH can impact the liver causing hepatitis, liver function tests
should be routinely performed on individuals that:
•Are HIV positive
•Have conditions that may cause hepatitis
•Are taking other medications which may cause hepatitis
•Are pregnant
•Use alcohol regularly
•Have symptoms of hepatitis
Extrapulmonary TB
•More common in young children and HIV infected individuals
•Symptoms often coincide with the location of infection
•Infection can spread to:
•Brain
•Kidneys
•Bones/Joints
•Pleura
•Lymph nodes
•Larynx
•Miliary (Disseminated) TB (very rare)
•All parts of the body can be infected
•Travels through blood stream
Tuberculous lymphadenitis
http://www.aafp.org/afp/2005/1101/p1761.html
Extrapulmonary TB
Tests for Extrapulmonary TB are bacteriologic tests of samples taken
from affected areas such as:
•Urine sample for kidney
•Spinal fluids for TB meningitis
•Etc.
•Extrapulmonary TB can be treated with 9 months of INH or RIF
•Duration of treatment can be shortened to 6 months if a
combination of four drugs are used daily for the first two months
•For more information visit http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6048a3.htm?s_cid=mm6048a3_w
Latent TB Infection (LTBI)
•Occurs when an individual inhales infected droplets but the bodies
immune system keeps the bacteria under control in the body
•Can progress to active TB disease if the immune system cannot
continue to control the infection
•Asymptomatic
•Should be treated to prevent progression to active disease
•Is not infectious at this stage
Targeted Screening for TB
The CDC recommends that the following should be screened for TB:
•Close contacts to individuals with active TB disease
•HIV Infected individuals
•Injection drugs users and users of other high risk substances
•Individuals with medical conditions that are at greater risk for TB
•Individuals/Employees in high risk congregate settings
•Healthcare workers who serve high-risk clients
•Individuals born in countries with high prevalence/incidence
•Infants and children exposed to high risk adults
•WDH recommends that all healthcare facilities conduct the CDC
evaluation to determine the frequency for employee screening.
Diagnosis
•TARGETED Screening/Risk Assessment
•A risk assessment should be completed to determine if someone
is at risk for TB
•This assessment and other resources can be found at
http://www.health.wyo.gov/phsd/tb/comptherapy.html
•TST/IGRA
•If risks are present, a TST test should be placed
•BCG status should be ignored after 1 year of vaccination
•IGRA is another option but there is limited availability and should
be approved by WDH TB Program staff before testing
•Chest x-ray
•A chest x-ray should be done to rule out active infection if the TST
or IGRA is positive
Tuberculin Skin Test (TST)
•Administration
•0.1 mL of PPD tuberculin solution
•Inject intradermally on the forearm
•Produce a 6 to 10 mm wheal
•Reading
•Read the test 48-72 hours later
•Measure the induration, NOT the erythema
•Measure transversely across forearm
•Record induration in mm, no induration = 0mm
•Positivity depends on risk factors!
http://www.health.state.mn.us/divs/idepc/diseases/tb/tst.html
LTBI Treatment
•Treatment of LTBI is essential in preventing progression into active
disease
•Treatment regimen is recommended for 9 months but can be done
in 6 under specific circumstances
•6 month regimen is not recommended for those living with HIV,
previous TB disease, or children
•INH is the recommended medication
•RIF can be given to people who cannot take INH
•RIF should not be used in conjunction with certain antiretroviral medications
•For more information visit http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6048a3.htm?s_cid=mm6048a3_w
Progression of Disease
•Progression of LTBI to Active TB Disease is 7%-10% over the lifetime
unless other conditions exist
•Individuals with LTBI are more likely to progress to active infection
within 2 years of becoming infected
•Progression of LTBI to Active TB is more likely if:
•LTBI is untreated
•LTBI is treated improperly
•The immune system is compromised (HIV, certain cancers,
immune suppressants, etc.)
•HIV infected individuals with LTBI have a 7%-10% chance of
progression to active infection EVERY YEAR.
http://www.answersingenesis.org/articles/am/v2/n3/antibiotic-resistance-of-bacteria
Prevention
•The spread of TB can be prevented by:
•Quickly identifying individuals with TB by targeted testing of those at
risk
•Isolating individuals with active disease
•Correctly utilizing PPE when dealing with an Active TB patient
•Promptly starting appropriate treatment for those diagnosed with TB
•Verifying that patients are compliant with and complete treatment
(DOT)
http://www.health.state.mn.us/divs/idepc/diseases/tb/tst.html
References
Center for Disease Control and Prevention. (2011, May 25). Tuberculosis- Testing and Diagnosis. Retrieved from
www.cdc.gov/TB/topic/testing/default.htm
Center for Disease Control and Prevention. (2011, October 11). Tuberculosis- Data and Statistics. Retrieved from
www.cdc.gov/TB/statistics/default.htm
Center for Disease Control and Prevention. (2011, November 2). Tuberculosis- Treatment. Retrieved from
www.cdc.gov/TB/topic/treatment/default.htm
Center for Disease Control and Prevention. (2010, July 1). Tuberculosis- Basic TB Facts. Retrieved from
www.cdc.gov/TB/topic/basics/default.htm
Center for Disease Control and Prevention. (2010, July 1). Tuberculosis- Infection control and prevention. Retrieved
from www.cdc.gov/TB/topic/infectioncontrol/default.htm