Tuberculosis (TB) is an infectious disease caused by a germ (bacterium) calledMycobacterium tuberculosis. This germ primarily affects the lungs and may infectanyone at any age.
In the United States, the number of TB cases steadily decreased until 1986 whenan increase was noted; TB has continued to rise since. Today, ten millionindividuals are infected in the U. S. , as evidenced by positive skin tests, withapproximately 26,000 new cases of active disease each year. The increase in TBcases is related to HIV/AIDS, homelessness, drug abuse and immigration ofpersons with active infections. How is TB Contracted?TB is a contagious or infectious disease that is spread from person-to- person.Order now
A person is usually infected by inhaling the germs which have been sprayed intothe air by someone with the active disease who coughs. However, inhaling the germ does not usually mean you will develop active disease. A person’s natural body defenses are usually able to control the infection sothat it does not cause disease. In this case, the person would be infected, butnot have active disease. Only about 10% of those infected will actually developTB in their lifetimes. Active disease can occur in an infected person when the body’s resistance is lowor if there is a large or prolonged exposure to the germs that overcome thebody’s natural defenses.
The body’s response to active TB infection producesinflammation which can eventually damage the lungs. The amount of damage may bequite extensive, yet the symptoms may be minimal. The usual symptoms of diseasedue to TB are:-Fever -Night sweats -Cough -Loss of appetite -Weight Loss -Blood in the sputum(phlegm) -Loss of energyDiagnosing TBTo diagnose TB, your clinician will gather five important pieces of information:-Symptoms -History of possible exposure and onset of symptoms -Tuberculin skintest or PPD -Chest X-ray Sputum testTuberculin Skin TestThe tuberculin skin test (or PPD) is performed with an extract of killedtuberculosis germs that is injected into the skin. If a person has been infectedwith tuberculosis, a lump will form at the site of the injection–this is apositive test. This generally means that TB germs have infected the body. Itdoes not usually mean the person has active disease.
People with positive skintests but without active disease cannot transmit the infection to others. Chest X-RayIf a person has been infected with TB, but active disease has not developed, thechest X-ray usually will be normal. Most people with a positive PPD have normalchest X-rays and continue to be healthy. For such persons, preventive drugtherapy may be recommended.
However, if the germ has attacked and caused inflammation in the lungs, anabnormal shadow is usually visible on the chest X-rays. For these persons,aggressive diagnostic studies (sputum tests) and treatment usually areappropriate. Sputum TestSamples of sputum coughed up from the lungs can be tested to see if TB germs arepresent. The sputum is examined under a microscope (a “sputum smear”) to lookfor evidence of the presence of TB organisms.
The organisms are then grown inthe laboratory to identify them as TB germs and to determine what medicationsare effective in treating them. These studies are referred to as culture andsusceptibility testing. State health department laboratories and referencelaboratories can perform such testing. Treatment of TBIndividuals with a positive tuberculin skin test may or may not receivepreventive drug therapy depending on the exposure history, the timing of theskin test conversion (when the test changes from negative to positive) and otherfactors in the individual’s medical history.
When it is known that a person hasrecently been in close contact with an individual with active tuberculosis andhas developed a positive tuberculin skin test, preventive treatment is advisabledue to a relatively high risk of developing active disease. Isoniazid (INH) maybe prescribed for six to nine months as preventive treatment and for twelvemonths in persons who are HIV positive. Since the advent of anti-tuberculosis drugs in the 1940s, the treatment of drugsusceptible tuberculosis has become highly effective if administered and takenproperly. Treatment no longer requires prolonged hospital stays.
In many cases,a patient with a new case of TB can be treated at home. Others will enter thehospital to be placed on a medication program and to be isolated until thedisease is controlled. When the person is no longer infectious, he or she canleave the hospital and continue on medication at home. Hospitalization in suchcases may be a few weeks to several months depending on the severity of thedisease and the effectiveness of the treatment program.
In most cases, a treatment program for drug-susceptible TB involves taking twoor four drugs for a period of time ranging from six to nine months. Medicationsmay include isoniazid, rifampin, pyrazinamide, ethambutol or streptomycin. It isnecessary to take multiple drugs and to take all of the doses prescribed,because all of the TB germs cannot be destroyed by one drug. It is important to realize that hospitalization for a TB patient, when necessary,represents only the beginning of treatment.
Since active TB is slow to respondcompletely to therapy, medications prescribed by a clinician must be takenfaithfully for a long period of time (at least 6 months, in some cases for ayear or more). If the TB medications are not taken regularly, seriouscomplications may develop:-the organisms may become resistant to one or more of the drugs, -there may bean increased risk of toxic reactions from the drugs and -there is a high risk ofdisease relapse or recurrence. Given the many effective medications available today, the chances are excellentthat tuberculosis in an individual can be cured. It is important, however, forthe patient to understand the disease and to cooperate fully in the therapyprogram.
Drug-Resistant TBIn a small percentage of cases, the initial treatment does not go as planned. Itmay be that the patient is not taking the medications regularly, the medicationprogram is not sufficient for a particular infection or the medications are notabsorbed properly. In these patients, there is a tendency for the germs tobecome resistant to some or all of the drugs. Sometimes a person has initialdrug-resistant disease. In other words, the TB germs they contracted were from aperson with drug-resistant TB. Drug-resistant TB is very difficult to treat and requires more and differentmedications for a longer period of treatment.
Sometimes, surgery is needed toremove areas of destroyed lung that contain many millions of germs that areinaccessible to antibiotics. A person with drug-resistant TB should be treatedby a specialist with considerable experience in managing the disease and thistreatment should be initiated in a hospital setting. TB and National JewishSince 1899, the National Jewish Center for Immunology and Respiratory Medicinein Denver has treated tuberculosis patients. The hospital was established tocare for the thousands of persons who flocked to Colorado’s high altitude anddry climate, seeking the elusive cure for their tuberculosis. In 1919, a research department was established at the hospital. When anti-TBdrugs became available in the late 1940s, National Jewish was one of the firstinstitutions to base its TB treatment program on the new chemotherapy,contributing refinements and developing combinations of drugs to overcome theproblems of drug toxicity and resistance.
Today, National Jewish is one of the world’s leading centers for the diagnosisand treatment of tuberculosis. Research continues at the Center to define newapproaches to treat difficult TB infections. Our world renowned doctors arebacked by state-of-the-art laboratories that help them select the most effectivedrug combinations and dosages. For drug-resistant TB, the New York Timesrecently wrote that National Jewish provides “the most sophisticated andaggressive treatment the world has to offer. ” National Jewish offers acomprehensive evaluation for TB and drug-resistant TB. It is important to have areferral from the doctor along with previous medical records, chest X-rays andrecent TB drug susceptibility testing before scheduling a TB evaluation at theCenter.
In most cases doctors refer a patient for our highly specialized in-patient program. To refer a patient for a TB evaluation, a doctor can call 303-398-1279. In addition, doctors and other health-care professionals can use thisnumber to obtain consultations regarding current diagnosis and treatmentinformation. Consultation is available for health-care professionals only.Category: Science