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For further information, see CMDT Part 9-13: Pulmonary Tuberculosis

Key Features

Essentials of Diagnosis

  • Fatigue, weight loss, fever, night sweats, and productive cough

  • Risk factors for acquisition of infection: household exposure, incarceration, drug use, travel to an endemic area

  • Chest radiograph: pulmonary opacities, including nodular or cavitating lesions

  • Acid-fast bacilli on smear of sputum; rapid molecular testing positive or sputum culture positive for Mycobacterium tuberculosis

General Considerations

  • Primary infection

    • Occurs with inhalation of airborne droplets containing viable tubercle bacilli and subsequent lymphangitic and hematogenous spread before immunity develops

    • Up to one-third of new urban cases are from primary infection acquired by person-to-person transmission

  • Latent tuberculosis infection (LTBI)

    • Occurs when bacilli are contained within granulomata

    • Nontransmissible while latent, but may become active disease if the infected person's immune function becomes impaired

  • Multidrug-resistant strains of M tuberculosis are increasingly common worldwide, though rates in the US have fallen to < 1%

  • Risk factors for drug resistance include

    • Immigration from countries with a high prevalence of drug-resistant tuberculosis

    • Close and prolonged contact with individuals with drug-resistant tuberculosis

    • Unsuccessful previous antituberculosis therapy

    • Patient nonadherence to such therapy

  • Resistance may be to single or multiple drugs

    • Drug-resistant tuberculosis is resistant to one first-line antituberculous drug, either isoniazid (INH) or rifampin (RIF)

    • Multidrug-resistant tuberculosis (MDR-TB) is resistant to INH and RIF, and possibly additional agents

    • Extensively drug-resistant tuberculosis (XDR-TB) is resistant to INH, RIF, fluoroquinolones and either aminoglycosides or capreomycin or both

  • Nonadherence is a major cause of treatment failure, disease transmission, and development of drug resistance


  • Infects one-quarter of the world's population, nearly 2 billion people

  • In 2020, there were 10 million new cases of tuberculosis worldwide with 1.5 million people dying of the disease—a provisional increase in mortality for the first time since 2005, with a global increase in case-fatality rate to 15%

  • In the United States, an estimated 13 million people are infected with M tuberculosis

  • In 2020, there were 7174 reported active cases—a decrease, though the disruption to detection and reporting during the COVID-19 pandemic may have contributed to the apparent "decreased" incidence

  • While most incident cases occur in low- and middle-income countries, tuberculosis is present in all regions of the world

  • Occurs disproportionately among malnourished, homeless, and marginally housed individuals

  • Risk factors for reactivation

    • Gastrectomy

    • Silicosis

    • Diabetes mellitus

    • HIV

    • Immunosuppressive medications

  • Risk factors for drug resistance

    • Immigration from regions with drug-resistant tuberculosis

    • Close contact with patients infected with drug-resistant tuberculosis

    • Unsuccessful prior antituberculosis therapy

    • Patient noncompliance with such treatment

Clinical Findings

Symptoms and Signs

  • Cough is the most common symptom

  • Blood-streaked sputum is common, frank hemoptysis is rare

  • Slowly progressive constitutional symptoms include malaise, anorexia, weight loss, fever, and night sweats

  • Patients appear chronically ill

  • Chest examination is nonspecific; post-tussive apical rales are classic

  • Atypical ...

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