Tuberculosis Symptoms and Transmission
- Chronic cough
- Fever
- Cough with bloody mucus
- Weight loss
- Night sweats
- Spread through the air when infected individuals cough, spit, speak, or sneeze
- Latent TB does not spread the disease
- Active infection more common in people with HIV/AIDS and smokers
- Transmission occurs through infectious aerosol droplets
- A single sneeze can release up to 40,000 droplets

Diagnosis and Types of Tuberculosis
- Active TB diagnosed through chest X-rays, microscopic examination, and culture of body fluids
- Latent TB diagnosed through tuberculin skin test (TST) or blood tests
- Chest X-ray shows infection in the lungs and formation of cavities
- Microscopic examination identifies MTB under a microscope
- Acid-fast staining techniques used to identify MTB
- Pulmonary TB affects the lungs in about 90% of cases
- Extrapulmonary TB occurs outside the lungs in 15-20% of cases
- Extrapulmonary TB more common in people with weakened immune systems and young children
- Notable sites of extrapulmonary infection include pleura, central nervous system, lymphatic system, genitourinary system, and bones/joints
- Disseminated TB is a widespread form of TB, also known as miliary TB

Causes and Risk Factors for Tuberculosis
- Mycobacterium tuberculosis (MTB) is the main cause of TB
- MTB is a small, aerobic, nonmotile bacillus with high lipid content
- MTB divides every 16 to 20 hours, slower than other bacteria
- MTB can withstand weak disinfectants and survive in a dry state
- Other TB-causing mycobacteria include M. bovis, M. africanum, M. canettii, and M. microti
- Concurrent HIV infection is the most important risk factor globally
- In sub-Saharan Africa, high HIV infection rates contribute to the risk
- Use of certain medications, such as corticosteroids and infliximab, increases the risk
- Other risk factors include alcoholism, diabetes mellitus, silicosis, tobacco smoking, indoor air pollution, malnutrition, young age, recent TB infection, recreational drug use, severe kidney disease, low body weight, organ transplant, head and neck cancer, and genetic susceptibility

Pathogenesis, Diagnosis, and Complications of Tuberculosis
- About 90% of those infected have latent TB infections
- In those with HIV, the risk of developing active TB is increased
- Effective treatment is crucial, as the death rate for active TB cases can be up to 66%
- TB infection begins when mycobacteria invade and replicate within alveolar macrophages
- The bacteria can reproduce inside macrophages and eventually kill them
- Diagnosing active TB based on signs and symptoms is difficult
- Consider TB in those with signs of lung disease or constitutional symptoms lasting longer than two weeks
- Chest X-ray and multiple sputum cultures are typically part of the initial evaluation
- Interferon-gamma release assays and tuberculin skin tests have limitations in certain populations
- Definitive diagnosis is made by identifying M. tuberculosis in a clinical sample
- Tuberculosis can affect various parts of the body, but rarely affects the heart, skeletal muscles, pancreas, or thyroid
- Granulomas, formed by immune cells, are characteristic of tuberculosis
- Bacteria inside granulomas can become dormant, resulting in latent infection
- Severe forms of TB, such as miliary tuberculosis, have high fatality rates
- Active disease can result in tissue destruction, necrosis, scarring, and cavities filled with caseous necrotic material

Prevention, Vaccines, Public Health, Treatment, Medication Resistance, Prognosis, and Epidemiology
- Tuberculosis prevention relies on vaccination of infants and appropriate treatment of active cases
- The World Health Organization has achieved some success with improved treatment regimens
- Some countries have legislation to detain or examine suspected tuberculosis cases
- Public health campaigns in the 1800s helped to interrupt or slow the spread of tuberculosis
- The emergence of HIV created a new population of immunocompromised individuals susceptible to tuberculosis
- The only available vaccine is bacillus Calmette-Guérin (BCG)
- BCG decreases the risk of infection and active disease in children
- BCG is widely used, but its immunity decreases after about ten years
- BCG is administered to high-risk individuals in countries where tuberculosis is uncommon
- Several vaccines are being developed
- Overcrowding, public spitting, and sanitation efforts in the 1800s helped curb tuberculosis transmission
- The World Health Organization declared TB a global health emergency in 1993
- The Stop TB Partnership developed a Global Plan to Stop Tuberculosis in 2006
- Targets set by the Global Plan were not achieved due to HIV-associated tuberculosis and drug-resistant tuberculosis
- The End TB Strategy aims to reduce deaths and incidence of tuberculosis by 2035
- Tuberculosis is treated with antibiotics, but effective treatment is difficult due to the structure of mycobacterial cell walls
- Combinations of antibiotics are used to reduce the risk of antibiotic resistance
- The use of rifabutin in HIV-positive individuals with tuberculosis is of unclear benefit
- Aspirin has shown positive effects in improving clinical signs and symptoms of pulmonary tuberculosis
- Latent TB is treated with isoniazid, rifampin, or a combination of both for three to nine months
- Primary resistance occurs when a person becomes infected with a resistant strain of TB
- Secondary resistance can develop during therapy due to inadequate treatment, lack of compliance, or use of low-quality medication
- Drug-resistant TB is a serious public health issue in many developing countries
- MDR-TB is defined as resistance to rifampicin and isoniaz