Pulmonology Book

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TuberculosisAka: Mycobacterium tuberculosis, Tb

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  1. See Also
    1. Tuberculosis Screening in Children
  2. Epidemiology
    1. Worldwide
      1. Latent Tb Prevalence: 2 Billion people
        1. One third of world population has latent Tb
        2. Over half of cases in China, India, Southeast asia
      2. Active Tb will develop in 10% of latent cases
        1. Most frequent cause of death for young adults
        2. In 1998, 8 million active cases, 2 million deaths
    2. United States
      1. Incidence rose 74% between 1953 to 1985
      2. Incidence in U.S. born patients declined since 1992
      3. Foreign born persons Incidence increasing (4-5x U.S)
        1. Latent TB infection in 30-50% of Minnesota refugees
        2. Drug-resistant TB is twice as likely in refugees
  3. History
    1. George Orwell died of Tuberculosis in 1950
      1. Shortly after Nineteen Eighty four was published
  4. Transmission
    1. Mycobacterium tuberculosis carried in airborne droplets
    2. Active Pulmonary or Laryngeal Tuberculosis transmitted
      1. Sneeze, cough, speak, or sing
  5. Risk Factors
    1. See Tuberculosis Risk Factors
  6. Course
    1. Tuberculin Skin Test conversion within 2-10 weeks
    2. Latent Tuberculosis initially
      1. Tuberculin Skin Test positive without signs, symptoms
      2. Tubercle bacilli remain dormant and viable for years
    3. Lifetime risk of developing active TB: 10%
    4. Highest risk is greatest within 2 years of exposure: 5%
  7. Symptoms
    1. Non-specific presentation (most common)
      1. Fatigue
      2. Weight loss
      3. Cachexia
      4. Night Sweats
    2. Pulmonary tuberculosis symptoms
      1. Productive cough
      2. Hemoptysis
      3. Pleuritic Chest Pain
      4. Dyspnea
  8. Signs
    1. Sites of Involvement
      1. Primary infection: lung involvement
    2. Disseminated Disease
      1. See Extrapulmonary Tuberculosis
  9. Diagnosis
    1. Tuberculin Skin Test (Purified Protein Derivative, PPD)
    2. In suspected pulmonary tuberculosis
      1. Induced Sputum samples on 3 consecutive days or
      2. Gastric aspirate may be used in young children or
      3. Bronchoscopy with bronchoalveolar lavage and biopsy
    3. Detection of organisms
      1. Acid fast stain (Sputum, body fluid, biopsy)
        1. Sensitive to >5000 bacilli per ml
      2. Fluorescent stains and DNA probes for rapid diagnosis
      3. Mycobacterial cultures
        1. Sensitive to 10 bacilli per ml
  10. Radiology: Chest XRay
    1. Pleural Effusion
    2. Hilar Adenopathy
    3. Upper lobe cavitary lesion or infiltrate
      1. Apical and posterior segments often affected
      2. Superior segment of lower lobes may also be affected
    4. Ghon Complex
      1. Healed primary peripheral lesion
      2. Calcified hilar node
    5. HIV positive Chest XRay correlates with CD4 Count
      1. CD4 Cell Count <200
        1. Mediastinal adenopathy
      2. CD4 Cell Count >200
        1. Upper lobe infiltrates and cavitation
    6. Findings not suggestive of prior Tb fibrotic lesion
      1. Isolated granuloma on Chest XRay
  11. Management
    1. See Latent Tuberculosis Treatment
      1. Positive PPD without signs of active Tb
    2. See Active Tuberculosis Treatment
    3. Protocols for active tuberculosis management
      1. Susceptible Tuberculosis Treatment
      2. Possibly Resistant Tuberculosis Treatment
      3. Multiple Drug Resistant Tuberculosis Treatment
  12. Complications
    1. See Extrapulmonary Tuberculosis
  13. Prevention
    1. Bacille Calmette-Guerin Vaccine (BCG vaccine)
      1. May be indicated in high risk young children
  14. Resources
    1. See Tuberculosis Resources
  15. References
    1. Frieden (2003) Lancet 362:887
    2. Potter (2005) Am Fam Physician 72:2225

Mycobacterium tuberculosis (C0026926)

Definition (CSP)species of gram positive, aerobic bacteria that produces tuberculosis in man, other primates, dogs, and some animals which have contact with man; growth tends to be in serpentine, cordlike masses in which the bacilli show a parallel orientation.
Definition (MSH)A species of gram-positive, aerobic bacteria that produces TUBERCULOSIS in humans, other primates, CATTLE; DOGS; and some other animals which have contact with humans. Growth tends to be in serpentine, cordlike masses in which the bacilli show a parallel orientation.
ConceptsBacterium (T007)
EnglishBacillus tuberculosis, Bacterium tuberculosis, Human tubercle bacillus, Koch's bacillus, M TUBERC, M. tuberculosis, Mycobacterium tuberculosis, Mycobacterium tuberculosis hominis, Mycobacterium tuberculosis typus humanus, Mycobacterium tuberculosis var. hominis, TB bacillus
Spanishbacilo de Koch, bacilo de la tuberculosis humana, Mycobacterium tuberculosis
CreditsDerived from the NIH UMLS (Unified Medical Language System)


Tuberculosis (C0041296)

Definition (MSH)Any of the infectious diseases of man and other animals caused by species of MYCOBACTERIUM.
Definition (CSP)infectious diseases of man and animals caused by Mycobacterium species and characterized by formation of tubercles and caseous necrosis in the tissues; any organ may be affected but in man the lung is the major seat of the disease and the usual portal through which the infection reaches other organs.
Definition (NCI)A chronic, recurrent infection caused by the bacterium Mycobacterium tuberculosis. Tuberculosis (TB) may affect almost any tissue or organ of the body with the lungs being the most common site of infection. The clinical stages of TB are primary or initial infection, latent or dormant infection, and recrudescent or adult-type TB. Ninety to 95% of primary TB infections may go unrecognized. Histopathologically, tissue lesions consist of granulomas which usually undergo central caseation necrosis. Local symptoms of TB vary according to the part affected; acute symptoms include hectic fever, sweats, and emaciation; serious complications include granulomatous erosion of pulmonary bronchi associated with hemoptysis. If untreated, progressive TB may be associated with a high degree of mortality. This infection is frequently observed in immunocompromised individuals with AIDS or a history of illicit IV drug use. --2004
ConceptsDisease or Syndrome (T047)
ICD9010-018.99
EnglishInfection due to Mycobacterium tuberculosis, INFECTION TBC, INFECTION TUBERCULOSIS, Mycobacterium tuberculosis infection, TB, Tuberculoses, Tuberculosis, Tuberculous
Spanishinfección por Mycobacterium tuberculosis, infeccion por Mycobacterium tuberculosis, tubérculo, tuberculo, tuberculosis
CreditsDerived from the NIH UMLS (Unified Medical Language System)



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