Microbiology Lecture: Tuberculosis Overview
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Questions and Answers

What is one factor that increases the spread of tuberculous disease?

  • Consuming contaminated food
  • Living in crowded conditions (correct)
  • Exercising regularly
  • Drinking herbal teas

    • What percentage of infected people develop active TB disease?

  • 20%
  • 10% (correct)
  • 15%
  • 5%

    • Which host factor increases the risk of developing TB after infection?

  • Being under 5 years old (correct)
  • Engaging in outdoor activities
  • Eating a balanced diet
  • Regular exercise routine

    • Which nationality is more likely to develop TB?

    <p>People from Africa, Asia, and Latin America</p> Signup and view all the answers

    In most parts of the world, who is more likely to be infected with TB?

    <p>Men</p> Signup and view all the answers

    Which race in the United States is at a higher risk of TB compared to whites?

    <p>Hispanics, American Indians, and blacks</p> Signup and view all the answers

    Why are older adults at greater risk of TB?

    <p>Weakening immune systems due to aging or illness</p> Signup and view all the answers

    What is the primary method used to confirm the diagnosis of tuberculosis?

    <p>Culture of clinical specimens</p> Signup and view all the answers

    What is the recommended treatment regimen for latent tuberculosis infection (LTBI)?

    <p>Isoniazid and rifampicin</p> Signup and view all the answers

    What is the purpose of using chemotherapy for tuberculosis treatment?

    <p>All of the above</p> Signup and view all the answers

    What is the recommended interpretation of a positive tuberculin skin test (TST) result in a person who has been vaccinated with BCG?

    <p>A positive TST result of more than 10 mm is likely due to tuberculosis infection, not the BCG vaccination.</p> Signup and view all the answers

    What is the purpose of using targeted testing to find persons at high risk for tuberculosis?

    <p>All of the above</p> Signup and view all the answers

    What is the typical time frame for obtaining results from a tuberculosis culture using liquid media systems?

    <p>4-14 days</p> Signup and view all the answers

    What is the purpose of administering the tuberculin skin test (TST) by injecting 0.1 ml of PPD (5 tuberculin units) into the forearm?

    <p>All of the above</p> Signup and view all the answers

    What is the recommended interpretation of a tuberculin skin test (TST) result of 10 mm or more in a person who has not been vaccinated with BCG?

    <p>Both a and b</p> Signup and view all the answers

    What is the purpose of monitoring tuberculosis culture results monthly until conversion (2 consecutive negative cultures)?

    <p>All of the above</p> Signup and view all the answers

    What is the main reservoir of Mycobacterium tuberculosis?

    <p>Humans</p> Signup and view all the answers

    Which of the following best describes the Mycobacterium tuberculosis organism?

    <p>Aerobic, non-spore forming, non-motile rod</p> Signup and view all the answers

    Which of the following is NOT a reason for the decline in the number of TB cases in developed countries?

    <p>Increased TB transmission</p> Signup and view all the answers

    What is the approximate annual global death toll from tuberculosis?

    <p>3 million</p> Signup and view all the answers

    What is the definition of tuberculous infection according to the text?

    <p>A state where the body is infected with the tuberculosis bacteria but shows no symptoms</p> Signup and view all the answers

    Which of the following is NOT a key objective of the tuberculosis lecture?

    <p>Preventing the spread of tuberculosis</p> Signup and view all the answers

    What is the approximate percentage of global TB cases and deaths that occur in developing countries?

    <p>90% of cases and 95% of deaths</p> Signup and view all the answers

    How is Mycobacterium tuberculosis resistant to disinfectants?

    <p>It has a thick, waxy cell wall</p> Signup and view all the answers

    What is the significance of the decline in TB cases in developed countries mentioned in the text?

    <p>It demonstrates the effectiveness of TB control measures in developed countries</p> Signup and view all the answers

    What is the primary difference between latent and active tuberculosis (TB)?

    <p>In latent TB, the immune system confines the bacilli in tubercles, while in active TB, the bacilli overwhelm the immune system and spread through the bloodstream.</p> Signup and view all the answers

    Which of the following groups is at higher risk of developing active tuberculosis (TB)?

    <p>All of the above</p> Signup and view all the answers

    Which of the following statements about the relationship between HIV/AIDS and tuberculosis (TB) is true?

    <p>All of the above</p> Signup and view all the answers

    Which of the following is NOT a typical symptom of pulmonary tuberculosis (TB)?

    <p>Abdominal cramps</p> Signup and view all the answers

    Which of the following diagnostic tests is considered the definitive method for diagnosing tuberculosis (TB)?

    <p>Sputum culture for acid-fast bacilli</p> Signup and view all the answers

    Which of the following statements about the presentation of tuberculosis (TB) in HIV-positive individuals is FALSE?

    <p>HIV-positive individuals with TB are more likely to have cavitation on chest X-ray.</p> Signup and view all the answers

    Which of the following groups is at higher risk of tuberculosis (TB) infection?

    <p>All of the above</p> Signup and view all the answers

    Which of the following media is recommended for culturing Mycobacterium tuberculosis from sputum samples?

    <p>Lowenstein-Jensen media</p> Signup and view all the answers

    In individuals with suspected tuberculosis (TB), which of the following diagnostic tests should be performed if the chest X-ray is abnormal?

    <p>Both sputum smear and culture</p> Signup and view all the answers

    What is the recommended treatment approach for a patient positive for both TB and HIV?

    <p>Initiate anti-TB medications first, then anti-HIV medications</p> Signup and view all the answers

    What is the typical duration of treatment for tuberculosis (TB)?

    <p>6 months, but may extend to 12 months in certain cases</p> Signup and view all the answers

    Based on the clinical scenario, what is the most likely diagnosis for the 23-year-old man?

    <p>Tuberculosis (TB)</p> Signup and view all the answers

    What is the initial recommended treatment regimen for the 23-year-old man with tuberculosis?

    <p>Isoniazid (INH), Rifampin (RIF), Pyrazinamide (PZA), Ethambutol (EMB) daily for 8 weeks</p> Signup and view all the answers

    Which statement is true regarding the treatment regimen for different types and sites of tuberculosis infection?

    <p>The treatment regimen is the same for all types of TB, but the duration varies depending on the site of infection</p> Signup and view all the answers

    In the clinical scenario, which of the following findings is not consistent with a diagnosis of tuberculosis?

    <p>History of hemoptysis (coughing up blood)</p> Signup and view all the answers

    Which of the following statements regarding the treatment duration for meningeal or spinal tuberculosis is correct?

    <p>The treatment duration is extended to 12 months, longer than for other types of TB</p> Signup and view all the answers

    Based on the information provided, which of the following statements is correct regarding the 70-year-old man being evaluated for placement in an extended care facility?

    <p>Tuberculosis screening should be done, but the text does not provide enough information to determine if it is necessary for this patient</p> Signup and view all the answers

    Which of the following statements is not true regarding the treatment of tuberculosis?

    <p>The treatment regimen is the same for all types of tuberculosis</p> Signup and view all the answers

    Study Notes

    Overview of Tuberculosis (TB)

    • TB is a bacterial infection caused by Mycobacterium tuberculosis (also known as tubercle bacillus)
    • Damages a person's lungs or other parts of the body
    • Fatal if not treated properly

    Epidemiology

    • TB is a worldwide disease
    • Infects 1.7 billion people with 3 million deaths per year
    • 90% of cases and 95% of deaths occur in developing countries
    • Number of cases in developed countries has declined due to case finding, treatment, and improved nutrition

    Microbiology

    • Mycobacterium tuberculosis is an aerobic, non-spore forming, non-motile rod (2-5 mm long)
    • Facultative intracellular organism
    • Resistant to disinfectant
    • Once stained, it resists de-colorization with acid and alcohol

    Human Reservoir

    • Human is the main reservoir of Mycobacterium tuberculosis

    Transmission and Pathogenesis

    • Crowding of living and migration of people from endemic areas increase the spread of the disease
    • 10% of infected people develop active disease, and 50% of active disease cases are contagious
    • Factors that increase the risk of developing disease after TB infection include:
      • Infecting dose
      • Host factors (age, gastrectomy, diabetes, debilitating illness, poor nutrition, alcoholism)
      • Nationality (people from regions with high rates of TB)
      • Sex (men are more likely to be infected and die from TB)
      • Race (Hispanics, American Indians, and blacks are at higher risk of TB)
      • Age (older adults are at greater risk of TB due to weakened immune systems)
      • Substance abuse (weakens immune system)
      • Malnutrition (poor diet or low-calorie intake)

    Diagnosis

    • Culture remains the gold standard for confirming diagnosis of TB
    • Culture all specimens, even if smear or NAA negative
    • Results in 4-14 days when liquid medium systems are used
    • Culture monthly until conversion (2 consecutive negative cultures)
    • PPD intradermal test: 5 units in 0.1 ml, 10 mm: 90% infected, more than 15 mm: 100% infected
    • BCG and positive PPD: unless very recent, positive PPD of more than 10 mm should not be due to BCG

    Treatment

    • Treatment for latent TB infection (LTBI) is essential to controlling and eliminating TB disease
    • Reduces risk of LTBI to TB disease progression
    • Use targeted testing to find persons at high risk for TB who would benefit from LTBI treatment
    • Chemotherapy: cure with Isonised Rifampicin, Pyrazinamide, Ethambutol/Streptomycin
    • Treatment regimens available for 6-12 months

    TB and AIDS

    • Person with active TB is more frequent to have HIV than the general population
    • AIDS in Haitians: almost all children are positive for PPD, active TB in 60%
    • New York: 50% of active TB patients are HIV+
    • Africans: 60% of active TB patients are HIV+
    • TB can appear at any stage of HIV infection
    • Early: Typical pattern of upper lobe infiltrate +/- cavitation
    • Late: Diffuse infiltrate - no cavitation -LN
    • Sputum is less frequent to be + for AFB with HIV than without

    Most Susceptible

    • People at higher risk of TB infection:
      • Close contacts with people with infectious TB
      • People born in areas where TB is common
      • People with poor access to health care
      • People who live or work in residential facilities
      • Health care professionals
      • The elderly
      • People who visit TB-prevalent countries
    • People at higher risk of active TB disease:
      • People with weak immune systems (especially those with HIV or AIDS)
      • People with diabetes or silicosis
      • People infected within the last 2 years
      • People with chest x-rays that show previous TB disease

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    Description

    Learn about Tuberculosis (TB) including its overview, epidemiology, transmission, pathogenesis, testing methods, diagnosis, treatment for latent TB infection, treatment for TB disease, and infection control measures. Taught by Dr. Nisreen Jawad at Warith Al-Anbiyaa University College of Medicine.

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