What Is Tuberculosis? What Causes Tuberculosis?

Tuberculosis (TB) is an infectious disease that is caused by a bacterium calledMycobacterium tuberculosis. TB primarily affects the lungs, but it can also affect organs in the central nervous system, lymphatic system, and circulatory system among others. The disease was called "consumption" in the past because of the way it would consume from within anyone who became infected.

According to Medilexicon`s medical dictionary, tuberculosis is "A specific disease caused by infection withMycobacterium tuberculosis, the tubercle bacillus, which can affect almost any tissue or organ of the body, the most common site of the disease being the lungs."

When a person becomes infected with tuberculosis, the bacteria in the lungs multiply and cause pneumonia along with chest pain, coughing up blood, and a prolonged cough. In addition, lymph nodes near the heart and lungs become enlarged. As the TB tries to spread to other parts of the body, it is often interrupted by the body's immune system. The immune system forms scar tissue or fibrosis around the TB bacteria, and this helps fight the infection and prevents the disease from spreading throughout the body and to other people. If the body's immune system is unable to fight TB or if the bacteria breaks through the scar tissue, the disease returns to an active state with pneumonia and damage to kidneys, bones, and the meninges that line the spinal cord and brain. 

TB is generally classified as being either latent or active. Latent TB occurs when the bacteria are present in the body, but this state is inactive and presents no symptoms. Latent TB is also not contagious. Active TB is contagious and is the condition that can make you sick with symptoms. 

TB is a major cause of illness and death worldwide, especially in Africa and Asia. Each year the disease kills almost 2 million people. The disease is also prevalent among people with HIV/AIDS.

What causes tuberculosis?

Tuberculosis is ultimately caused by the Mycobacterium tuberculosis that is spread from person to person through airborne particles. It is not guaranteed, though, that you will become infected with TB if you inhale the infected particles. Some people have strong enough immune systems that quickly destroy the bacteria once they enter the body. Others will develop latent TB infection and will carry the bacteria but will not be contagious and will not present symptoms. Still others will become immediately sick and will also be contagious.

What are the symptoms of tuberculosis?

Most people who become infected with the bacteria that cause tuberculosis actually do not present symptoms of the disease. However, when symptoms are present, they include unexplained weight loss, tiredness, fatigue, shortness of breath, fever, night sweats, chills, and a loss of appetite. Symptoms specific to the lungs include coughing that lasts for 3 or more weeks, coughing up blood, chest pain, and pain with breathing or coughing.

How is tuberculosis diagnosed?

Tuberculosis diagnosis usually occurs after a combination of skin, blood, and imaging tests. 

A little talk about Tuberculosis

• Tuberculosis (TB) is an infection, primarily in the lungs (a pneumonia), caused by bacteria calledMycobacterium tuberculosis. It is spread usually from person to person by breathing infected air during close contact.
• TB can remain in an inactive (dormant) state for years without causing symptoms or spreading to other people.
• When the immune system of a patient with dormant TB is weakened, the TB can become active (reactivate) and cause infection in the lungs or other parts of the body.
• The risk factors for acquiring TB include close-contact situations, alcohol and IV drug abuse, and certain diseases (for example, diabetes, cancer, and HIV) and occupations (for example, health-care workers).
• The most common symptoms and signs of TB are fatigue, fever, weight loss, coughing, and night sweats.
• The diagnosis of TB involves skin tests, chest X-rays, sputum analysis (smear and culture), and PCRtests to detect the genetic material of the causative bacteria.
• Inactive tuberculosis may be treated with an antibiotic, isoniazid (INH), to prevent the TB infection from becoming active.
• Active TB is treated, usually successfully, with INH in combination with one or more of several drugs, including rifampin (Rifadin), ethambutol (Myambutol), pyrazinamide, and streptomycin.
• Drug-resistant TB is a serious, as yet unsolved, public-health problem, especially in Southeast Asia, the countries of the former Soviet Union, Africa, and in prison populations. Poor patient compliance, lack of detection of resistant strains, and unavailable therapy are key reasons for the development of drug-resistant TB.
• The occurrence of HIV has been responsible for an increased frequency of tuberculosis. Control of HIV in the future, however, should substantially decrease the frequency of TB.