Tuberculosis (patient information)

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Tuberculosis
Overview
What are the symptoms?
What are the causes?
Who is at highest risk?
When to seek urgent medical care?
Diagnosis
Treatment options
Where to find medical care for Tuberculosis?
What to expect (Outlook/Prognosis)?
Possible complications
Prevention
Tuberculosis On the Web
Ongoing Trials at Clinical Trials.gov
Images of Tuberculosis
Videos on Tuberculosis
FDA on Tuberculosis
CDC on Tuberculosis
Tuberculosis in the news
Blogs on Tuberculosis
Directions to Hospitals Treating Tuberculosis
Risk calculators and risk factors for Tuberculosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ethan Leeman; João André Alves Silva, M.D. [2]

Overview

Tuberculosis (TB) is a bacterial infection that kills 1.8 million people worldwide. Approximately 10.4 million people in the world are infected with TB. Active tuberculosis kills 60% of the time if not treated, but treatment cures 90% of patients. In year 2015, the total no of cases reported with Tb in USA were approximately 9,421. Most people who are infected with TB have latent TB. This means that the bacteria is controlled by the body's immune system. People with latent TB do not have symptoms and cannot transmit TB to other people. According to WHO, about 3 million lives are saved globally in the year 2015 by treating Tb.

What are the Symptoms of Tuberculosis?

Latent TB is held in the alveoli of the lungs. As active TB develops, the bacteria spread out from the alveoli to the lungs and then to other organ systems. As a result, depending on which organ system is affected, the symptoms may be different. The primary stage of TB usually doesn't cause symptoms. When symptoms of pulmonary TB occur, they may include:

• Cough
• Night sweats
• Coughing up blood
• Excessive sweating, especially at night
• Fatigue
• Fever
• Unintentional weight loss
• Shortness of breath
• Chest pain
• Wheezing

Symptoms of TB disease in other parts of the body will depend on the affected area.

What Causes Tuberculosis?

Pulmonary tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis. The bacteria usually damages the lungs but TB bacteria can damage any part of the body such as the kidney, spine, and brain. If not treated properly, TB disease can be fatal.

Multidrug-Resistant Tuberculosis

Multi-drug-resistant tuberculosis is caused by the bacterium Mycobacterium tuberculosis resistant to anti-TB drugs. This resistance can occur when drugs are misused or mismanaged:

• When patients do not complete their full course of treatment
• When health-care providers prescribe the wrong treatment, the wrong dose, or length of time for taking the drugs
• When the supply of drugs is not always available
• When the drugs are of poor quality

Who is at Highest Risk?

Tuberculosis is spread from person to person through the air (cough, sneeze) and physical contact.

The following people are at higher risk for active TB:

• Elderly
• Infants
• People with weakened immune systems (AIDS, chemotherapy, diabetes, or certain medications)

Your risk of contracting TB increases if you:

• Are in frequent contact with people who have TB
• Have poor nutrition
• Live in crowded place or with poor hygiene

The following factors may increase the rate of TB infection in a population:

• Increase in HIV infections
• Increase in number of homeless people
• The appearance of drug-resistant strains of TB

Multidrug-Resistant Tuberculosis

Drug resistance is more common in people who:

• Do not take their TB medicine regularly
• Do not take all of their TB medicine as told by their doctor or nurse
• Develop TB disease again, after having taken TB medicine in the past
• Come from areas of the world where drug-resistant TB is common
• Have spent time with someone known to have drug-resistant TB disease

When to Seek Urgent Medical Care?

Call your health care provider if:

• You have been exposed to TB or travelled to areas having endemic disease
• You develop symptoms of TB
• Your symptoms continue despite treatment
• New symptoms develop

Diagnosis

Diagnosing active TB can be done with a combination of symptoms, patient history (any known exposure to TB), TB tests, and x-rays.

Latent tuberculosis can be detected about 6-8 weeks after exposure. There are two tests that can be used to help detect TB infection:

• TB skin test

• The skin test is used most often
• A small needle is used to put some testing material, called tuberculin, under the skin
• In 2-3 days, the patient should return to the health care worker, who will check if there is a reaction to the test

• TB blood test

• In some cases, a TB blood test is used to test for TB infection
• This blood test measures how a person’s immune system reacts to the germs that cause TB

The drug resistance will be shown by a drug susceptibility test. To tell if someone has TB disease, other tests may be needed:

• Chest x-ray - X-ray of the lungs often show can show cavities or lesions that are typical of TB
• Sample of sputum (phlegm that is coughed up from deep in the lungs)

It is important to tell your health care provider if you have ever had a “positive” reaction to a TB skin test or TB blood test, or if you have been treated with TB drugs in the past.

Treatment Options

Typical treatment involves one or a few antibiotics for months. TB is notorious for having a lengthy treatment procedure. After two weeks of treatment, people are typically no longer contagious. Some of the medications given for TB have some negative side effects, especially in combination with other drugs. For these reasons, some patients find it very difficult to take their medicine for the necessary duration. However, doing so may make the bacteria resistant to the antibiotics and make treatment even more difficult in the future. Treatment for multi-drug-resistant tuberculosis or extensively drug-resistant TB have different treatments with far worse prognosis.

Multidrug-Resistant Tuberculosis

• TB is a treatable and curable disease. Treatment for multidrug-resistant tuberculosis must be confirmed by drug-susceptibility testing. However, since this testing can take weeks, treatment should be started with an empirical regimen based on expert advice as soon as drug-resistant TB disease is suspected.

• When the testing results are known, the treatment regimen should be adjusted according to the results, in order to avoid suboptimal treatment. Patients should be monitored closely throughout treatment.

• A common treatment regimen includes at least 5 drugs, to which the bacteria was shown to be susceptible.

• Treatment regimens are commonly divided into 2 phases: the initial phase and the continuation phase.

• A fluoroquinolone is indicated in the treatment of patients with MDR-TB.

• Directly observed therapy should always be used in the treatment of drug-resistant TB to ensure adherence.

Special Considerations

HIV-Infected Persons

• Treatment of drug-resistant TB in persons with HIV infection is the same as for patients without HIV.
• Management of HIV-related TB requires expertise in the management of both HIV and TB.
• Providers must monitor the interactions among many of the antiretroviral drugs.
• Rifampin should not be used with most antiretroviral drugs. Rifabutin, which has fewer problematic drug interactions, may be used in place of Rifampin.
• These recommendations are likely to be modified, as new antiretroviral agents and pharmacokinetic data become available.

Children

• Treatment for children who have TB disease after exposure to a drug-resistant case should be guided by the source-case susceptibility results.
• When a source is unknown and circumstances suggest an increased risk of drug resistance, children should be treated with a standard four-drug initial-phase regimen until their susceptibility pattern is known.
• Ethambutol can be used safely (15-20 mg/kg per day), in the likelihood of Isoniazide resistance.
• Streptomycin, kanamycin, or amikacin also can be selected as the fourth drug.
• Long-term use of fluoroquinolones in children has not been approved. However, most experts agree that these drugs should be considered for children with MDR-TB.
• Consultation with a specialist in pediatric TB treatment is recommended.

Pregnant Women

• Case management for pregnant women who have drug-resistant TB requires consultation with an expert because most second-line drugs can have harmful effects on the fetus.
• Pyrazinamide should not be used as part of the treatment regimen for pregnant women.
• Counseling concerning risks to the fetus should be provided.

Close Contacts of Drug-Resistant TB Patients

• Contacts of isoniazid-resistant TB.
• Persons who have been exposed to Isoniazid-resistant, Rifampin-susceptible TB and are known or suspected to have latent TB infection, a 4-month regimen of daily Rifampin is recommended.
• When Rifampin cannot be used, rifabutin may be substituted.

Contacts of MDR-TB

• For persons with known or suspected latent tuberculosis infection resistant to both Isoniazid and Rifampin, alternative regimens should be considered.
• Alternative regimens should include two drugs to which the TB strain is susceptible.
• A potential regimen should include a daily fluoroquinolone.
• Contacts who are not immunosuppressed may be treated for 6 months or observed without treatment.
• All persons with suspected MDR latent TB should be monitored for 2 years regardless of the treatment regimen.

Where to Find Medical Care for Tuberculosis?

Directions to Hospitals Treating Tuberculosis

What to Expect (Outlook/Prognosis)?

Symptoms often improve in 2 - 3 weeks. A chest x-ray will not show this improvement until later. The outlook is excellent if pulmonary TB is diagnosed early and treatment is begun quickly.

Multidrug-Resistant Tuberculosis

The prognosis of multidrug-resistant TB is worst than that of tuberculosis susceptible to common treatment. Therefore it is mandatory to perform a drug susceptibility test and to monitor adherence to the treatment regimen, in order to avoid new drug resistances and ensure a better outcome.

Possible Complications

Pulmonary TB can cause permanent lung damage if not treated early. Medicines used to treat TB may cause side effects, including liver problems. Other side effects include:

• Changes in vision
• Orange- or brown-colored tears and urine
• Rash

A vision test may be done before treatment so your doctor can monitor any changes in your eyes' health over time.

Prevention

On an individual basis, covering coughs and sneezes does reduce transmission. On a larger scale, adequate ventilation and reduction of crowded areas can also reduce transmission. As with all infectious diseases, earlier identification of the disease is necessary to prevent spreading. A prophylactic antibiotic INH can cure latent TB before it progresses to active TB, and should be given to people who:

• Have latent TB
• Are close contact with known infected patients
• Live in countries where TB is prevalent.
• Are at risk of TB infection

A vaccine called BCG prevents the spread of TB to other parts of the body but not the infection. It is recommended just for infants in countries known to have high levels of TB. It is not recommended for overall use in the US because it has limited effectiveness for preventing TB. TB is not spread by

• Shaking someone’s hand
• Sharing food or drink
• Touching bed linens or toilet seats
• Sharing toothbrushes
• Kissing

BCG is known to interfere with TB skin tests, giving false positives, and other tests are needed to test for TB in these cases.

Travel warning and guidelines

• Travelers who anticipate possible prolonged exposure to persons with TB (for example, those who expect to come in contact routinely with clinic, hospital, prison, or homeless shelter populations) should have a tuberculin skin test (TST) or TB blood test before leaving the United States.
• If the reaction to the TST or TB blood test is negative, they should have a repeat test 8 to 10 weeks after returning to the United States.
• Additionally, annual testing may be recommended for those who anticipate repeated or prolonged exposure or an extended stay over a period of years.
• Because persons with HIV infection are more likely to have an impaired response to both the TST and TB blood test, travelers who are HIV positive should tell their physicians about their HIV infection status.
• According to WHO, the list of countries having high burden of TB includes:
• India
• Pakistan
• Bangladesh
• South Africa
• China
• Congo
• Columbia
• Cambodia
• Indonesia
• Korea
• Brazil
• Ethopia
• Myanmar
• Mozambique
• Thailand
• Angola
• Vietnam
• Kenya
• Central Africa
• Russia
• Liberia
• Zimbabwe
• Namibia
• Phillipine
• Nigeria
• Tanzania
• Sierra leone zambia
• Papua New Guinea
• Lesotho

Multidrug-Resistant Tuberculosis

To prevent multi-drug-resistant tuberculosis, the following rules should be observed:

• Take all medications exactly as prescribed by the health care provider
• No doses should be missed and treatment should not be stopped early
• Patients should tell their health care provider if they are having trouble taking the medications
• If patients plan to travel, they should talk to their health care providers and make sure they have enough medicine to last while away
• Avoid exposure to known MDR TB patients in closed or crowded places such as hospitals, prisons, or homeless shelters:

• In the case of health care workers who are more likely to have contact with TB patients, infection control or occupational health experts should be consulted
• Administrative and environmental procedures for preventing exposure to TB should be implemented. Once those procedures are implemented, additional measures could include using personal respiratory protective devices

Health care providers can help prevent MDR-TB by:

• Quickly diagnosing cases
• Following recommended treatment guidelines
• Monitoring patients’ response to treatment
• Making sure therapy is completed

Sources

• NLM
  

Center for Disease Control or Prevention
World Health Organization