TB or consumption|
- Tuberculosis is an infection caused by an organism called Mycobacterium tuberculosis. This is an organism capable of causing infections throughout the body, but the most common location is the lungs.
- M. tuberculosis is a bacterium found
throughout the world. It is often very difficult to treat.
Often, when the organism invades the body it triggers an
immune response, killing off most of the organisms in the
course of the initial infection. This is called a primary
infection and often does not cause significant symptoms.
However, only 10% of those infected with M. tuberculosis will
develop the disease, with the greatest chance of infection
occurring the first 2 years after exposure.
- However, a few organisms will remain dormant, only to become active years later. This is called a reactivation. Various factors that weaken the immune system, such as multiple medical problems, chemotherapy, HIV infection, or any other immuno-affective conditions may trigger or contribute to reactivation of the infection.
- Symptoms depend on which organ or part of the body is infected. Treatment also depends on the part of the body infected and the extent of the disease. Anti-tuberculosis medications are the main treatment. Treatment is a long process and requires months to years of therapy, often with multiple medications.
- Also, an increasing number of patients fail to respond to the usually effective medications. They have drug-resistant tuberculosis. If their infection fails to respond to antibiotics, it is almost always fatal.
- It rarely occurs between ages 5 and 14. It is, however, common among elderly whites and young adults and children less than 5 years of age. Among childhood cases, there is a slight predominance among girls.
- As stated, symptoms can vary depending on which part of the body is infected.
- Tuberculosis can infect almost any part of the body including, but not limited to, the lungs, heart, brain, bone, spine, stomach, kidneys, and fallopian tubes.
- The specific symptoms depend on the area of the body infected.
- Some general symptoms include weight loss, loss of appetite, low-grade fever, night sweats, and fatigue.
- Pulmonary tuberculosis occurs when the organism infects the lungs. Symptoms include a mild shortness of breath, fever, night sweats, poor appetite, poor weight gain, Failure to Thrive,
decreased activity, and a cough, which may be dry or productive of phlegm. Often, there is coughing up of blood. An examination may not reveal any significant abnormalities. Occasionally, the doctor may detect the presence of fluid collection in the lungs. Symptoms of primary pulmonary tuberculosis are slight in children, and infants may have more symptoms than older children.
- Tuberculosis Meningitis is usually a
tuberculosis infection of the brain or spinal cord. It usually occurs between 6 months and 4 years of age, and progresses rapidly in infants and young children. Symptoms may start with fever, lack of energy, irritability and restlessness. Eventually, the child will develop a stiff neck, headache, vomiting, Seizures, changes in the mental condition or behavior, or may go into a coma.
- Perinatal Disease symptoms may begin at birth but more commonly by 2-3 weeks of life. Symptoms include breathing difficulties, fever, enlargement of liver or spleen, poor feeding, lack of energy, irritability, enlargement of lymph nodes, distention of belly, failure of thrive, ear discharge, and skin lesions.
- Intestinal tuberculosis is an infection of the intestinal tract. It was not very common in the United States until AIDS. Some of the symptoms include stomach pain, Diarrhea, intestinal obstruction, granuloma formation, intestinal ulcerations with bleeding, or narrowing of the intestines.
- Tuberculosis lymphadenitis --
involves M. tuberculosis infecting the lymph nodes, causing enlargement of the nodes and forming masses in the neck. This is known as scrofula, and may sometimes drain to the skin. It is the most common form of tuberculosis infection outside of the lung, in children.
- Tuberculosis pericarditis occurs when the organism invades and infects the lining of the heart. This can cause fluid build-up around the heart, leading to more significant problems, including shortness of breath, fluid build-up in the lungs, low blood pressure, and even death.
- Tuberculosis peritonitis involves an infection and fluid build-up in the abdomen. It is uncommon in adolescents and rare in children. This is often very difficult to diagnose and is often missed. In addition to build-up of fluid in the abdomen, symptoms may include fever, weight loss, and weakness. Even with testing of the fluid, it is difficult to diagnose and may necessitate laparoscopy to make confirm diagnosis.
- Tuberculosis salpingitis -- is an infection of the uterine fallopian tubes that causes pelvic pain. Examination may reveal the presence of masses in the pelvis, and the patient may report irregular periods. It is not sexually transmitted.
- It is important to understand that many of these symptoms may also be present with numerous other medical conditions. Quite often, tuberculosis is not even suspected until other more common conditions are treated without success.
- As above, tuberculosis is caused by Mycobacterium tuberculosis, an organism found throughout the world.
- Respiratory droplets most often spread it person-to-person when people cough.
- Congenital infection is caused by aspiration or ingestion of the mother's infected amniotic fluid, just before birth or during pregnancy.
- Most cases of newborn infection are caused by airborne transmission from adults.
- Initially, the infection is acquired from another person. Once the organism enters the body, it spreads via the bloodstream and lymph system throughout the body. This is called primary tuberculosis, and often there are no symptoms. The immune system fights off the infection, destroying the majority of organisms. Some become dormant and survive within the body for years or even decades. These organisms usually do not cause any problems.
- However, in a few cases, reactivation of the disease occurs. This does not require any new infection. The organism, dormant and inactive for years, has become active again.
- The risk of reactivation increases if the immune system is weakened for any reason.
- On average, a normal person who has been infected with tuberculosis has about a 10% chance of developing a reactivation of the disease over the course of their lifetime. In people with HIV, however, they have a risk of about 7% per year.
- In the past, it was thought that almost all adult cases of tuberculosis were due to reactivation. However, newer testing methods have revealed that a sizeable number of adult cases may actually be due to newly acquired infections, especially in areas where there are a large number of people with tuberculosis.
- People from certain parts of the world, such as the Philippines, China, Southeast Asia, Haiti, and India have a much higher risk of having resistant tuberculosis. Resistant tuberculosis occurs when the organism is not sensitive to the usual anti-tuberculosis medicines.
- Diagnosis in almost all cases should be approached with suspicion. TB is notorious for progressing very slowly, and exhibiting only vague symptoms. It is often missed or misdiagnosed for a long period of time. Often, when patients are treated unsuccessfully for numerous other diseases, only then is the diagnosis of tuberculosis actually considered. The doctor needs to be informed of any risk factors that may increase the chance of tuberculosis in order to consider it sooner.
- Even when the diagnosis is considered early, confirming it can take a long time. In some cases, tests are performed and the diagnosis made within a few days. In other cases, the organism will have to be cultured, which may take 4-8 weeks. At times, tests may appear normal at first, and then come back abnormal, i.e., positive for TB.
- In making the diagnosis, two main
tests are used.
- The first is called an AFB stain or smear, in which a sample of suspect tissue is stained with special dye, then examined under microscope. This test is usually done within a day or two.
- In the second test, a culture is used in an attempt to grow the organism in the lab. M. tuberculosis is very slow growing and this test can take up to 6-8 weeks for results. In some cases, the AFB stain may not show anything, but the cultures may come back weeks later with positive results. The culture results are extremely important because they determine which drugs will work against the organism.
- There are other tests used, such as PCR, Bactec, and RFLP, but the two above are the main diagnostic tools.
- Tests for diagnosing tuberculosis depend upon where the infection is located. The guiding principal is that some of the suspect tissue or fluid has to be removed and studied. If necessary, a biopsy is performed.
- For pulmonary tuberculosis:
- The principal method of diagnosis involves finding the organism in sputum samples. Specimens are obtained immediately after waking up (best results) on 3 consecutive days. The sputum is then tested to see if the organism is present.
- When it is difficult to secure a sputum sample, a bronchoscopy may be required, using a camera to look into the lungs and obtain specimens from the lungs and breathing tubes.
- The last option is to try to culture the organism from early morning stomach fluid.
- Whenever tuberculosis is suspected, blood cultures are used to discover if the organism is in the bloodstream.
- A chest X-ray is used to discover infection of the lung.
- CT scans can also help identify lung infection.
- In order to diagnose tuberculosis in
other parts of the body, tests are done of the suspect areas,
including CT scan, ultrasound, MRI scan, echocardiogram,
endoscopy, etc. These tests are only suggestive. Final diagnosis can only be made by obtaining a specimen for establishing the presence of the tuberculosis organism, i.e., from sample of fluid or biopsy of the suspected site of infection.
- In cases of suspected tuberculous Meningitis, a spinal tap may be done.
- Another test, called a PPD, is usually administered to anyone suspected of having TB. See the section below labeled "Prevention" for more details. In most patients with tuberculosis, it will give a positive reaction. However, sometimes, the test can be negative even in someone with the disease. Similarly, a positive test does not absolutely confirm TB. The test is helpful as part of the work-up, but it does not make the diagnosis.
- Risk factors for developing tuberculosis include:
- Being around someone with active tuberculosis
- Having a chronic illness such as diabetes
- Having a weakened immune system, either from HIV, chemotherapy, prolonged steroid use, etc.
- Working in the health care field
- Overcrowding: Living in a long-term
care, or close-quarters, such as a nursery schools, child-care centers, elementary and high schools, churches, school buses, or sports teams.
- Poor nutrition
- Inadequate health care
- Low socioeconomic status
- Older people and children less than 2 years of age are at much higher risk to contract TB, if exposed.
- Treatment for tuberculosis should be started on all individuals in whom the doctor suspects the disease. If there is any risk that the patient may not take the medications, or may expose others, then initial treatment needs to be done in the hospital. Most of the time, other household members have already been exposed, and isolation from them is not needed. However, if there is a possibility of new exposures, then isolation is in order. In the hospital, patients are placed in a special room (called a negative pressure room), to prevent spread of the disease to staff and others. All hospital staff and family members in contact with the patient will have to wear protective masks.
- Treatment -- there are many options and treatment needs to be tailored to the individual and his lifestyle, as well as to the location and type of the infection
- There are two main conditions of treatment. In the first case, the patient is treated at home, coming in for periodic check-ups. In the second, called DOT (directly observed therapy), the patient comes into the health department or other agency 2-3 times a week for medication, to ensure that he is actually taking his medicines.
- The four main drugs used to treat tuberculosis are isoniazid (INH), rifampin (RIF), pyrazinamide (PZA), and either ethambutol or streptomycin. Streptomycin is used when initial INH resistance is suspected or when a child has a life-threatening form of TB. Ethambutol is not recommended for general use in young children for whom vision examinations cannot be performed. At least two anti-TB drugs must be used. Usually a 6-month duration of INH and RIF, supplemented during the first 2 months of treatment with PZA, is standard therapy; these four drugs are given in combination to treat for INH-resistant TB.
- Treatment is with four medications until the tests identify which anti-tuberculosis medicines will be most effective. Medications are adjusted accordingly. Usually, all four are continued for about 4-6 weeks. If the organism proves to be sensitive to isoniazid and rifampin, they are continued, and ethambutol or streptomycin is stopped. Pyrazinamide is continued for 8 weeks then stopped. Therapy is continued for at least 6 months, or for at least 3 months after the cultures are negative -- whichever is longer.
- There are various combinations of treatment and the best option will have to be tailored to the patient's needs by the doctor and the health care department.
- HIV-seropositive children need to continue treatment with INH, RIF, and PZA for 2 months, followed by INH and RIF, for total treatment duration of 9-12 months, or 6 months after the cultures are negative.
- If cultures are not available to guide the doctor, options will need to be discussed with a specialist because the type, length, and method of treatment all vary.
- Directly observed therapy (DOT) is more expensive to administer, but it ensures that the patient takes his medicines, especially in those with drug-resistant tuberculosis, and in those who refuse to take their medication or have difficulty following directions.
- Treatment for tuberculosis outside the lungs is usually the same as pulmonary tuberculosis, but it is usually continued for at least 9 months.
- Steroids can be used for people with tuberculosis Meningitis and tuberculosis pericarditis to help reduce inflammation.
- Streptomycin should not be used by pregnant women. Pyrazinamide use during pregnancy is not advised either.
- All treatment starts with multiple medications because of the risk of resistance if only 1 or 2 medications are used. Treatment should start with all four, and then altered according to results.
- Patients should take all of their medicines until the doctor tells then to stop. If the doctor's orders are not followed, there is a high risk of not adequately treating the infection. The organism may become resistant, making repeat infection difficult to treat.
- Tuberculosis lymphadenitis is treated with surgery to remove all infected lymph nodes, after which the patient is placed on anti-TB medications.
- Tuberculosis Meningitis -- using the four anti-TB medications described above, treatment has to be started even before all of the test results are back. Occasionally, steroids may also be used in the case of nerve deficits.
- Tuberculosis pericarditis -- requires drainage of the fluid and anti-TB medications. In some cases, the sac surrounding the heart may have to be removed.
- Tuberculosis peritonitis -- is treated with the usual combination of anti-TB medications.
- Tuberculosis salpingitis -- this is treated with the usual anti-TB medications. If there is a large mass, or if the TB does not respond to medication, surgery may be necessary.
- The risk of contracting drug-resistant TB increases in regions known to have a high incidence of drug-resistant TB. Other high risk factors for drug resistant TB include close contact with someone with drug-resistant TB, previous unsuccessful treatment for TB, and previous failure to take all medicines and complete treatment. The risk of drug-resistant TB is especially high in the United State in large urban centers, such as New York, Dallas, and Los Angeles. In those with drug-resistant TB, the infection is almost always fatal, unless an alternative drug regimen is found and followed. This requires the input of trained specialists to help structure treatment options.
- There are many potential complications of varying severity that may occur with tuberculosis, depending on the location and kind of infection.
- In lung infections, there can be fluid build-up around the lungs, resulting in shortness of breath and/or fluid collection within the lung. In such cases, removal of part of the lung may be necessary.
- In cases of intestinal tuberculosis infections, patients may develop obstruction, perforation, malabsorption, or bleeding from the intestine.
- In those with brain infections, patients may develop chronic brain syndrome, Seizures, neurological deficits, stroke, or hydrocephalus.
- People with heart infections can develop constrictive pericarditis.
- Seek medical attention as soon as possible.
- It is important to inform the doctor or health care workers immediately if you think that your child has tuberculosis. Precautions can be taken to prevent spread of the infection.
- Until the diagnosis is made, it is best to try to limit your child's contact with others to prevent spreading.
- Prevention is the key to controlling this disease.
- The first line of prevention is to try to keep the infection from spreading by isolating anyone with an active virus until the infection is brought under control. In modern hospitals, negative pressure rooms prevent the infection from spreading within the hospital.
- Also, facemasks may be used to trap the organism and prevent its spread. All those in contact with the patient should wear them. They may also be worn by the patient, allowing him mobility so long as the mask is secure.
- Anyone even suspected of having the infection should be isolated immediately, or given a mask to wear to prevent the infection from spreading. Discontinue such precautions only when it safe to do so-when it has been proven that the patient no longer has the infection, or was falsely diagnosed and never had it.
- People with active tuberculosis are very infectious, and may easily spread the disease to others around them by coughing or sneezing. As stated above, they must be kept in isolation until they no longer pose a risk -- when at least 3 separate AFB tests prove normal and they evidence no other indications of the presence of the organism.
- The PPD skin test -- is a screening test commonly done in the United States, and is often used as part of a strategy to prevent the disease.
- The PPD skin test is done by injecting a small amount of protein (derived from tuberculosis bacteria) under the skin of the forearm -- swelling and redness indicate a positive result.
- The test result is determined 48 hours after injection.
- It reveals only previous exposure to tuberculosis. It does not determine whether the test subject has an active infection, or merely past exposure to the organism. The PPD test result has to be interpreted based on a number of factors. Alone it is not conclusive.
- In a patient with HIV who has had close contact with someone infected with active TB, and in patients with X-ray evidence of prior healed tuberculosis, a PPD test is considered to be positive if the swelling is more than 5 millimeters in width.
- Subjects from countries with a high rate of TB, HIV-positive IV-drug users, those in correctional facilities or nursing homes, people from medically- underserved areas, and people with certain medical conditions are considered to have a positive PPD if the swelling is more than 10 millimeters in diameter.
- The rest of those tested are considered to have a positive PPD if the swelling is more than 15 millimeters in diameter.
- In some cases, test subjects may initially have a negative skin test but on repeat testing, their skin test may turn positive. This may be a "booster phenomenon," in which the first test triggered an immune response, rather than a true conversion to a positive test.
- The PPD test is not 100% accurate. Some who do not have the infection will have a positive test result. These false positives occur occasionally in those with an infection closely related to tuberculosis.
- Also, there are those who have a negative test but do have the infection. These false negatives occur more often in the malnourished, older people, those with AIDS, those on steroids, those with severe tuberculosis, those with certain types of cancers, people with kidney failure, people who are very ill from other causes, or those in whom the test was not administered properly.
- People who have been given the BCG vaccine may have a positive skin test for a year after the vaccination. After a year, their skin test response should be interpreted the same as anyone else.
- Also, some people do not react to the PPD skin test at all. They are said to be anergic, and they do not have any response to skin tests. Their test results are of no value. To determine anergic test subjects, give other injections to see if they have any response.
- Most patients given preventive therapy for tuberculosis usually receive six (6) months of isoniazid.
- All subjects with a positive PPD should be given preventive therapy if they fall into one of the following categories:
- All people with HIV. Also, if the person is HIV positive and has a high risk of tuberculosis, then they need to be given preventive therapy even if their skin test is negative.
- All people who are close contacts of someone with tuberculosis and have a positive skin test. Children must be treated with preventive therapy even if their skin test is initially negative. Children should be re-tested 3 months later, and if they test positive, they will need to continue therapy for a total of nine (9) months.
- Anyone who has recently developed a positive skin test (within the past 2 years). That is, they previously had a negative skin test and then became positive.
- People with medical conditions that increase their chances of developing tuberculosis should be treated with preventive medications. This includes patients with diabetes, people on chronic steroid therapy, those with blood cancers, intravenous drug users, people with kidney failure, and people who are undernourished.
- In the following cases, only those who are under 35 years old and have a positive PPD need preventive therapy:
- People born in countries with a high rate of tuberculosis, such as African, Asian, and South American countries.
- People from the U.S. who are medically underserved or have very low incomes.
- People who live in or work in long-term care facilities, such as mental institutions and nursing homes.
- All other people who do not have risk factors for tuberculosis but have a positive skin test with more than 15 millimeters of swelling should be given preventive therapy if they are under 35 years of age.
- In most cases, preventive therapy is with isoniazid for 6 months.
- Children need preventive therapy with INS (usually for 9 months) if they are in one of the following categories:
- Positive skin test, normal chest x-ray findings, normal physical examination
- Children less than 6 years of age with a negative tuberculin skin test who had recent contact with infected people.
- All children who do not have risk factors for
tuberculosis but have a positive skin test with more than
15 millimeters of swelling should be given preventive
- Also, people on isoniazid need to have liver tests done prior to starting therapy. They will need to be monitored with questioning to see if they develop symptoms of hepatitis. If they do, blood tests will be needed, and the medicine stopped if they have elevated liver tests. If they are under 35 and have no symptoms, routine testing is not needed. If over 35, routine blood tests to check the liver may be warranted.
- BCG vaccine (BCG stands for bacille Calmette-Guerin):
- In some countries, this vaccine is routinely used.
- In the United States, it is not common. It is used mainly in people who have a positive PPD but cannot take isoniazid prophylaxis.
- Also, it can be given to PPD negative children who are exposed to people with inadequately treated tuberculosis but cannot receive the usual preventive treatments.
- This vaccine can also be used in areas where there is a high rate of new infections, despite appropriate measures to prevent new infections.
- BCG has been shown to reduce the risk of developing tuberculosis.