Lecture Notes: Tuberculosis

Introduction to Tuberculosis (TB)

• Referred to historically as consumption, the king's evil, scrofula, Pott's disease.
• Disease has been around for approximately three million years.
• Inspired cultural works by poets, artists, novelists, composers.

Symptoms of TB

• Similar to the flu: chills, vomiting, weakness, night sweats, persistent cough, sore throat, fever.
• Warning sign: cough lasting three weeks or longer.

Causative Agent

• Mycobacterium tuberculosis:
  • Weakly gram-positive aerobic rods.
  • Resistant to detergents, antibacterial antibiotics, disinfectants.
  • Establish a lifelong infection in host.

Pathogenesis

• Enters respiratory airways, taken up by immune cells.
• Evades immune system, replicates and spreads.
• Can spread to lymph nodes, bloodstream, tissues (bone marrow, spleen, kidneys, CNS).

TB Transmission

• Spread through air via talking, singing, coughing.
• Bacteria can float for hours in air.
• Not spread by sharing food, shaking hands, kissing, sharing toothbrushes.

Types of TB Conditions

• Latent TB:
  • Bacteria live in body, not causing sickness.
  • No symptoms, can't spread TB.
• TB Disease:
  • Bacteria become active, multiply.
  • Symptoms present, can spread TB.

Importance of Antibiotic Adherence

• Essential to complete full course of antibiotics.
• Premature cessation leads to drug-resistant TB.

Drug-Resistant TB

• Multidrug-Resistant TB (MDR-TB):
  • Resistant to isoniazid (INH) and rifampicin (RMP).
  • Caused by misuse/mismanagement of TB drugs.
• Extensively Drug-Resistant TB (XDR-TB):
  • Resistant to at least four main anti-TB drugs.

Diagnosis of TB

• Tests:
  • TB skin test (TST) or TB blood test.
  • Positive results indicate infection, not type (latent or active).
  • Chest X-ray or sputum sample for further diagnosis.

Prevention and Vaccine

• Vaccine available prevents severe TB in children.
• Not recommended for general adult use.

Conclusion

• Highlights the importance of proper antibiotic use to prevent drug-resistant TB.