Tuberculosis: Types,Causes, Symptoms and Risk Factors

Updated: November 21, 2017

Tuberculosis or TB is a contagious infection that usually attacks the lungs which is caused by a type of bacteria called Mycobacterium tuberculosis(MTB).
The bacteria that cause tuberculosis are spread from one person to another through tiny droplets released into the air through coughs and sneezes.  It can also spread to other parts of the body, like the brain and spine.

Types of Tuberculosis:

Tuberculosis infection can be of two types: latent and active.

Latent TB :

The bacteria remain in the body in an inactive state. They cause no symptoms and are not contagious, but they can become active.

Active TB :

The bacteria do cause symptoms and can be transmitted to others.

Causes of Tuberculosis:

The main cause of TB is Mycobacterium tuberculosis (MTB). When a person with TB whose lungs are affected, coughs, sneezes, spits, laughs, or talks will spread it through the air. Although tuberculosis is contagious, it is not easy to catch. You are much more likely to get tuberculosis from someone you live with or work with than from a stranger.  Most people with active TB who have received appropriate treatment for at least 2 weeks are no longer contagious.

Signs and symptoms of Tuberculosis:

Signs and symptoms of active TB include:

• Chest pain, or pain with breathing or coughing
• Coughing that lasts three or more weeks
• Coughing up blood
• Fever
• Chills
• Night sweats
• Unintentional weight loss
• Fatigue
• Loss of appetite

Tuberculosis can also affect other parts of your body, including your kidneys, spine or brain. Signs and symptoms vary according to the organs involved when TB occurs outside your lungs.  For example, tuberculosis of the spine may give you back pain, and tuberculosis in your kidneys might cause blood in your urine.
Without treatment, TB can spread to other parts of the body through the bloodstream:

• TB infecting the brain can cause meningitis
• TB infecting the bones can lead to spinal pain and joint destruction
• TB infecting the heart can impair the heart's ability to pump blood which can be fatal
• TB infecting the liver and kidneys can impair their waste filtration functions and lead to blood in the urine

Risk factors:

Certain factors can increase your risk of the disease. These factors include:

Weakened immune system:

A healthy immune system often successfully fights TB bacteria. But people with compromised immune systems are most at risk of developing active tuberculosis because of low resistance of the body.
A number of diseases and medications can weaken your immune system, including:

• HIV/AIDS that suppresses the immune system, making it harder for the body to control TB bacteria.
• Diabetes
• Severe kidney disease
• Certain cancers
• Cancer treatment, such as chemotherapy
• Very young or advanced age
• Malnutrition
• Medicines to prevent rejection of transplanted organs
• Some medicines used to treat rheumatoid arthritis, Crohn's disease and psoriasis

Traveling or living in certain areas:

The risk of contracting tuberculosis is higher for people who live in or travel to countries that have high rates of tuberculosis and drug-resistant tuberculosis. These include:

• Asia
• Russia
• Africa
• Eastern Europe
• Caribbean Islands
• Latin America

Lifestyle factor:

IV drug use or alcohol abuse:

This weakens your immune system and makes you more prone to tuberculosis.

Tobacco use:

Using tobacco greatly increases the risk of getting TB and dying because of it.

Lack of medical care:

You may lack access to the medical care needed to diagnose and treat TB if you receive a low or fixed income, live in a remote area, have recently immigrated to TB prone areas, or are homeless.

Place you work or live:

Health care work:

If you are in regular contact with people who are ill increases your chances of exposure to TB bacteria. Wearing a mask and frequent hand washing greatly reduce your risk.

Living or working in a residential care facility:

People who live or work in prisons, immigration centers or nursing homes are all at a higher risk of tuberculosis. That is because in overcrowded and poor ventilation areas the risk of the disease is higher.

Living in a refugee camp or shelter:

Refugees lives usually in crowded and unsanitary conditions. Weakened by poor nutrition and ill health they are at high risk of tuberculosis infection.