Each year, World Tuberculosis Day is recognized on March 24. It was on this date in 1882 that Dr. Robert Koch announced that he had discovered the bacillus that causes TB. In the 19th century, TB killed one out of every seven people in the U.S. and Europe. The discovery was an extremely important step in controlling and treating the disease.
What is TB? TB is a disease that is spread from person to person by a person who has the active disease. TB usually affects the lungs, but it can affect any body part, such as kidneys, brain and bones. When a person with TB of the lung or larynx coughs, sneezes or talks, the TB bacteria is released into the air. When people inhale the air containing the TB bacteria, they may become infected. People infected with the bacteria may not feel sick and may not have symptoms, but they may develop TB disease at some time in the future, especially if they have another illness that lowers their body’s immune system such as diabetes, HIV, cancer or prolonged use of steroids.
The general symptoms of TB disease are extreme fatigue, fever and night sweats. TB of the lung may include coughing, chest pain, and/or coughing up blood. TB of other body parts produce other symptoms related to the affected areas.
There is a difference between TB infection known as Latent TB Infection (LTBI) versus TB disease. LTBI means the TB bacteria is present in the body, but there is no illness or awareness of the infection and TB cannot be spread to others. However, people with LTBI could develop TB, especially if their immune system is compromised by other illnesses such as diabetes, cancer HIV and other medical conditions.
You are at highest risk for developing TB disease in the first two years after exposure. People with LTBI often are prescribed treatment to prevent developing the disease. People with TB disease are most likely to spread it to people they spend time with on a regular basis, such as family members and co-workers.
If you think you have been exposed to someone who has TB you should talk with your primary care provider or your local health department. Only people with TB disease can spread the bacteria, not individuals who are infected.
What is a TB skin test or a PPD? It is a test used to determine if you have been infected with the bacteria.
The skin test is done by injecting a small amount of fluid under the skin in the area of the forearm. A trained medical professional reads the test 48 to 72 hours later. The presence and size of the reaction is assessed.
A positive TB skin test means an individual is infected with the TB bacilli, but may not necessarily have TB disease. Other tests such as a chest x-ray must be done for additional evaluation. The individual may be asked to collect sputum for evaluation if the chest X-ray is not completely normal or the individual has a cough. These tests are necessary to confirm if the patient has TB disease or TB infection (LTBI). Sputum evaluation by the laboratory is the most accurate means of determining disease.
TB disease is treatable. Treatment for TB disease requires taking multiple medications for 6 months. Individuals who are infected with TB (latent TB infection), but who do not have the disease are treated to prevent development of the disease later in life. The decision is based on skin test readings, chest X-ray results, medical history and age. The treatment is typically taking INH, one tablet every day for nine months.
Who should be considered for testing with a PPD?
— Close contacts of persons known or suspected to have TB, such as people who share the same household or other enclosed environment.
— HIV-positive people.
— Persons with fibrotic changes on chest X-ray consistent with old TB.
— Recent arrivals of less than five years from foreign countries that have a high rate of TB.
— Residents and employees of high-risk congregated settings, such as correctional facilities, nursing homes, homeless shelters, hospitals and other health facilities.
— Children less than 4 years of age or children and adolescents who are exposed to adults in high risk categories.
— People who should be tested are persons who have one or more of the following conditions: diabetes, silicosis, prolonged corticosteroid therapy, other immunosuppressive therapy, cancer of the head and neck, end stage renal disease, intestinal bypass or gastrectomy, chronic malabsorption syndromes, low body weight 10 percent or more below the ideal body weight, HIV positive and substance abuse.
For more information, or if you need to have a screening for TB, call the Clark County Health Department at 744-4482 or visit the website at www.clarkhealthdept.org.