Tuberculosis (TB) is a rare and sometimes fatal disease. It most often affects the lungs (pulmonary) but can also attack other parts of the body including the brain, spine and kidneys (extrapulmonary). Latent tuberculosis infection (LTBI) is asymptomatic and does not cause disease in the host or infect others. However, latent tuberculosis can become active and infectious.
TB, prevalent in animals, can infect humans. In the United States, tuberculosis is most commonly found in deer and cattle. However, because of extensive testing and stringent guidelines in the cattle industry, transmission from cattle to humans is uncommon.
The oldest cases of TB in humans were discovered in 2008 during an archeological dig from the now submersed Mediterranean city of Atlit Yam. The remains of a mother and child, thought to be 9000 years old, showed evidence of TB infection in their bones.
Causes of Tuberculosis
Tuberculosis infection, caused by the bacterium Mycobacterium tuberculosis, is transmitted from person to person by inhaling expelled droplets when an infected person sneezes or coughs. It usually requires repeated exposure to become infected. There is no evidence that tuberculosis is transmitted from kissing, hugging or shaking hands.
People living in close quarters like jails or homeless shelters are susceptible to the disease as are people experiencing HIV infection and other individuals with compromised immune systems. Having diabetes or kidney disease also increases the chances of contracting the disease. Young children exposed to adults with TB have a higher incidence of disease due to underdeveloped immune systems.
Because TB is an airborne disease that can remain suspended for several hours, good ventilation while indoors can greatly reduce the risk of becoming infected. Exposure to UV light found in natural sunlight destroys the bacteria. Covering the nose and mouth while sneezing or coughing is one of the easiest and most effective ways to avoid transmission.
Signs of Tuberculosis
An individual may host the bacterium that causes TB for weeks or even years before manifesting symptoms of an infection. Typical signs of pulmonary TB include:
- Coughing up mucus or blood
- Coughing for more than three weeks consecutively
- Chest pain while breathing or coughing
- Loss of appetite
- Fatigue
- Night sweats
- Fever and chills
Extrapulmonary TB symptoms might include blood in the urine when the kidneys are affected or back pain from a spine infection. Skeletal pain is often reported in TB bone and bone marrow infections. Additional signs and symptoms of extrapulmonary TB may include abdominal swelling and pain, headache, and personality changes when the brain is affected.
People who have been in close contact with infected individuals or who suspect they may have been exposed to TB should consult a medical care provider as soon as possible. Disease prognosis is greatly improved when treatment is initiated ​early.
Treating Tuberculosis
Treating tuberculosis, both latent and active forms, is paramount to a positive prognosis and to prevent the uncontrolled spread of the disease in communities. Treatment for both forms of the disease are similar but differ in duration. Treating latent TB is recommended for individuals with certain risk factors such as:
- A compromised immune system
- Pre-existing conditions like kidney disease, diabetes or HIV
- Children aged 4 years or younger
- Residents or workers in crowded environments like nursing homes, prisons and homeless shelters
- Recent exposure to people with active TB
The most common treatment for latent TB includes a 3-6 month course with one or more of the antibiotics. Active TB treatment consists of a similar treatment with a longer duration of 6-9 months.
As with all antibiotic treatment, it is crucial for patients to complete the course to prevent drug resistant disease. However, because long-term antibiotic treatment may cause uncomfortable side effects such as nausea and fatigue, many patients find it difficult to complete the course. Drug resistant TB is treatable but has a higher fatality rate and may cause long-term health consequences.