Tuberculosis
An old foe is making a comeback. Definite signs of a new and potentially very dangerous
epidemic of tuberculosis (TB) have already appeared.
TB is a chronic, recurrent infection most common in the lungs,
but any organ or tissue may be affected.
Once an infection is established, signs and symptoms may
develop within months or it may be delayed for years or even decades.
With the onset of the AIDS epidemic, the incidence of TB has
increased alarmingly among persons infected with HIV, particularly
black and Hispanic IV drug users.
Blacks are less resistant to the initial invasion by the
organism than whites; partly accounting for the greater prevalence of
infection among blacks. People
with competent immune systems are often able to resist a TB infection
while those with weak immune systems may experience progression of the
disease.
Tuberculosis is believed to cause more deaths each year than any other
infectious disease. It is
estimated that 1.7 billion people worldwide are infected with TB and
there are an estimated 10-15 million people in the United States with
this disease. TB has
become a major public health concern again as new strains have
developed in the last ten years that are multidrug-resistant.
As the organism becomes resistant to certain drugs, TB can no
longer be treated with those drugs, increasing the possibility that
the infection cannot be controlled.
Only people with active TB are contagious and the disease is generally
spread by microscopic droplets dispersed in the air when someone with
active TB coughs or sneezes. These
microscopic droplets containing TB organisms may be inhaled by other
people, settling into the lungs where they may multiply and establish
infection.
Pulmonary TB is often so nearly asymptomatic that a patient may deny
all symptoms except “not feeling well”. A cough is the most common symptom but it is often ascribed
to smoking or recent upper respiratory infection.
The cough is usually minimally productive of yellow or green
mucus and as the disease progresses, this becomes more productive.
The clinical course of TB varies greatly, depending upon
multiple factors. Usually,
diagnosis is made by a tuberculin tine skin test and chest x-ray.
Successful treatment of TB usually requires a combination of several
drugs for at least six months. Once
an individual has been treated for at least two weeks with appropriate
drugs, they are usually not infectious. Multidrug-resistant TB may require medical treatment for as
long as two years.
Most people infected with TB never develop full-blown active TB
disease. On average,
infected people have about a 10% chance of developing active TB
sometime during their lives and this chance is increased in
individuals whose immune systems are weakened by other diseases or HIV
infections, thereby allowing the TB organisms to overcome the body’s
defenses. If you have been in close contact with someone
diagnosed with active TB or if you have other disease symptoms and
have developed respiratory symptoms and productive cough, see your
family physician. |
