tuberculosis(redirected from Smear-negative tuberculosis)
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Causes and symptoms
- Bones. TB is particularly likely to attack the spine and the ends of the long bones. Children are especially prone to spinal tuberculosis. If not treated, the spinal segments (vertebrae) may collapse and cause paralysis in one or both legs.
- Kidneys. Along with the bones, the kidneys are probably the commonest site of extrapulmonary TB. There may, however, be few symptoms even though part of a kidney is destroyed. TB may spread to the bladder. In men, it may spread to the prostate gland and nearby structures.
- Female reproductive organs. The ovaries in women may be infected; TB can spread from them to the peritoneum, which is the membrane lining the abdominal cavity.
- Abdominal cavity. Tuberculous peritonitis may cause pain ranging from the vague discomfort of stomach cramps to intense pain that may mimic the symptoms of appendicitis.
- Joints. Tubercular infection of joints causes a form of arthritis that most often affects the hips and knees. The wrist, hand, and elbow joints also may become painful and inflamed.
- Meninges. The meninges are tissues that cover the brain and the spinal cord. Infection of the meninges by the TB bacillus causes tuberculous meningitis, a condition that is most common in young children but is especially dangerous in the elderly. Patients develop headaches, become drowsy, and eventually comatose. Permanent brain damage is the rule unless prompt treatment is given. Some patients with tuberculous meningitis develop a tumor-like brain mass called a tuberculoma that can cause stroke-like symptoms.
- Skin, intestines, adrenal glands, and blood vessels. All these parts of the body can be infected by M. tuberculosis. Infection of the wall of the body's main artery (the aorta), can cause it to rupture with catastrophic results. Tuberculous pericarditis occurs when the membrane surrounding the heart (the pericardium) is infected and fills up with fluid that interferes with the heart's ability to pump blood.
- Miliary tuberculosis. Miliary TB is a life-threatening condition that occurs when large numbers of tubercle bacilli spread throughout the body. Huge numbers of tiny tubercular lesions develop that cause marked weakness and weight loss, severe anemia, and gradual wasting of the body.
Diseases similar to tuberculosis
- Lowering the number of bacilli as quickly as possible. This measure minimizes the risk of transmitting the disease. When sputum cultures become negative, this has been achieved. Conversely, if the sputum remains positive afterfive to six months, treatment has failed.
- Preventing the development of drug resistance. For this reason, at least two different drugs and sometimes three are always given at first. If drug resistance is suspected, at least two different drugs should be tried.
- Long-term treatment to prevent relapse.
Prophylactic use of isoniazid
- close contacts of TB patients, including health care workers
- newly infected patients whose skin test has turned positive in the past two years
- anyone who is HIV-positive with a positive PPD skin test; Isoniazid may be given even if the PPD results are negative if there is a risk of exposure to active tuberculosis
- intravenous drug users, even if they are negative for HIV
- persons with positive PPD results and evidence of old disease on the chest x-ray who have never been treated for TB
- patients who have an illness or are taking a drug that can suppress the immune system
- persons with positive PPD results who have had intestinal surgery; have diabetes or chronic kidney failure; have any type of cancer; or are more than 10% below their ideal body weight
- people from countries with high rates of TB who have positive PPD results
- people from low-income groups with positive skin test results
- persons with a positive PPD reaction who belong to high-risk ethnic groups (African Americans, Hispanics, Native Americans, Asians, and Pacific Islanders)
The most common mode of transmission of tuberculosis in the United States is inhalation of infected droplet nuclei. In some other parts of the world bovine tuberculosis, which is carried by unpasteurized milk and other dairy products from tuberculous cattle, is more prevalent. A rare mode of transmission is by infected urine, especially for young children using the same toilet facilities. Tuberculosis is also seen as an opportunistic infection in human immunodeficiency virus (HIV) infection.
The tubercle bacillus is capable of surviving for months in dried sputum that is not exposed to sunlight. Within the body it can lie dormant for decades and then become reactivated years after an initial infection. This secondary tuberculosis infection (endogenous reinfection) can occur at any time the patient's resistance is lowered. For this reason, periodic evaluation for evidence of the disease is extremely important for anyone who has had a primary tuberculosis infection. The tubercle bacillus is destroyed by boiling for 5 minutes, by autoclaving, by contact with coal tar preparations, e.g., phenol, and by ultraviolet radiation.
The primary infection usually involves the middle or lower lung area. The primary lesion consists of a small area of exudation in the lung parenchyma (Ghon focus) which quickly becomes caseous (cheeselike) and spreads to the bronchopulmonary lymph nodes, where it gains access to the blood stream. Thus the stage is set for the development of a chronic pulmonary and extrapulmonary tuberculosis at a later time. In most instances, however, a secondary reinfection from inside the body (endogenous) or outside the body (exogenous) does not occur because of the subsequent development of tuberculin hypersensitivity and cellular immunity. The presence of antigen concentrations at the initial site of infection brings about necrosis and eventually fibrosis and calcification of the tissues, which arrests the infection and renders the disease inactive. If, however, the infection is not controlled, the patient develops the symptoms of progressive primary tuberculosis.
Secondary tuberculosis develops as a result of either endogenous or exogenous reinfection by the tubercle bacillus. This is the most common form of clinical tuberculosis. In the United States development of secondary tuberculosis is almost always the result of an endogenous reinfection, which occurs when the primary lesion becomes active. This most frequently happens in debilitated persons who have lowered resistance to disease.
Resistance to tuberculosis depends on the general health and living conditions of the individual. Poor health, crowded and unsanitary housing, malnutrition, and other illnesses can lower the body's defenses. A second factor that can lead to activation of the disease is frequent exposure to the bacilli or exposure to such numbers that even a healthy person cannot escape infection.
Chronic pulmonary tuberculosis is often accompanied by pleurisy. Pleurisy with effusion often is the first symptom of tuberculosis. In certain cases, complications are possible and each has its characteristic symptoms. At a fairly late stage, the tuberculosis bacillus may cause ulcers or inflammation around the larynx (tuberculous laryngitis). Less often, tuberculous ulcers form on the tongue or tonsils. Sometimes intestinal infections develop; they are probably caused by swallowed bacteria-contaminated sputum. A most serious complication is the sudden collapse of a lung, the indication that a deep tuberculous cavity in the lung has perforated, or opened into the pleural cavity, allowing air and infected material to flow into it.
When a fairly large and previously walled-off lesion, or infected area, suddenly discharges its contents into the bronchial tree, the result is the infection of a large part of the lung, an acute and dangerous complication which causes tuberculous pneumonia.
Tuberculosis bacilli can spread to other parts of the body by way of the blood, producing miliary tuberculosis. When a large number of bacilli suddenly enter the circulatory system, they are carried to all areas of the body and may lodge in any organ. Minute tubercles form in the tissues of the organs affected; these lesions are about the size of a pinhead or millet seed (hence the name miliary). Unless promptly treated, and occasionally even then, the tiny lesions spread, join, and produce larger areas of infection.
Tuberculous pneumonia can begin in this way, as can tuberculosis of any other organ. Miliary infections involving the meninges produce a particularly serious disease; indeed, until the development of antibiotics, this condition nearly always proved fatal.
Practically all parts and organs of the body can be secondarily invaded by tubercle bacilli, a common type being involvement of the kidneys, which often spreads to the bladder and genitalia. Bone involvement, particularly of the spine (pott's disease), was once common, especially among children.
Lupus vulgaris, or tuberculosis of the skin, is characterized by brown nodules on the corium; another form of tuberculosis of the skin is tuberculosis indurativa, a chronic disease in which indurated nodules form on the skin. When the adrenal glands are affected by tuberculosis, a rare occurrence, the condition can cause addison's disease.
Masks may be necessary for those having intimate contact with a patient who is just beginning chemotherapy, and in caring for patients who cannot or will not take precautions against spreading the infection. Usually, two to four weeks after medications are begun restrictions are removed regarding activities and contacts. Handwashing is essential to prevention of cross-infection. Fomites are not considered important in the transmission of tuberculosis and so no special precautions are required for eating utensils and other inanimate articles in the patient's room. Screening of family members and other contacts should be done. Standard precautions are used for patients with extrapulmonary tuberculosis and those who have a positive skin test even without evidence of disease. Institutionalized patients with pulmonary or laryngeal disease should be kept on airborne precautions. The Centers for Disease Control and Prevention has published "Guidelines for Preventing the Transmission of Mycobacterium Tuberculosis in Health Care Facilities." The document can be read on their web site at http://www.cdc.gov.
In 1993 the World Health Organization (WHO) declared TB a global emergency. Fully one third of the world's population is infected with TB. On a global scale, TB ranks first among infectious diseases as a cause of death. Two thirds of all the world's cases are in Asia, but the disease is also endemic in parts of Africa (where the highest incidence rates per capita are found) and eastern Europe. War and social upheaval have played a role in the spread of tuberculosis beyond endemic zones. Prevalence of infection is higher among refugees and immigrants. One third of all people with tuberculosis in the U.S. were born outside this country, and more than 50% of newly diagnosed cases occur in people of foreign birth. From the 1950s, when antibiotics began to be used for the treatment of TB, until the 1980s, the incidence and mortality of the disease declined steadily in the U.S. During the 1980s the incidence began to rise because of many new cases in people with AIDS and because of increasing prevalence of multidrug-resistant strains of M. tuberculosis. Since 1993 the figures have again declined, chiefly because of improvements in TB prevention and control programs in state and local health departments as a result of increased federal funding provided to states. At least one third of people with AIDS contract TB, and TB is the cause of death in one third of people who die of AIDS. Because antibiotic resistance in M. tuberculosis has been a growing problem for years, multidrug regimens, usually including isoniazid, rifampin, and pyrazinamide, are standard. Other drugs, such as ethambutol, streptomycin, kanamycin, and capreomycin, may be added or substituted. The success of treatment is limited not only by the resistance of organisms to several agents but also by the risk of severe toxic effects with all standard agents. Unlike most infections treated with antibiotics, TB requires not merely days or weeks of treatment but rather months and years. Long-term compliance with treatment regimens tends to be poor among mobile, indigent, and uneducated people. According to WHO, the principal reason for the spread of multidrug-resistant strains of M. tuberculosis is ineffectual management of TB control programs, particularly in developing countries. An inappropriate or unfinished course of chemotherapy not only leaves the patient still sick and still contagious, but favors the selection of resistant bacteria. It is estimated that 50 million of the world's cases of TB involve multiply resistant tubercle bacilli. The prevalence of infection due to drug-resistant strains is particularly high in some former Soviet states. Currently WHO urges that TB programs worldwide adopt the practice of directly observed therapy (DOT), in which a health care worker observes each patient swallowing each dose of medicine. In a study performed at several U.S. centers, DOT for TB was found to be cost effective when the cost of relapses and treatment failures was added to the cost of self-administered therapy, even though the raw cost of DOT was higher. U.S. public health authorities have established as a national goal the elimination of TB (defined as an incidence of less than 1 case per 1 million population) by 2010.
tuberculosis/tu·ber·cu·lo·sis/ (-sis) any of the infectious diseases of humans and other animals due to species of Mycobacterium and marked by formation of tubercles and caseous necrosis in tissues of any organ; in humans the lung is the major seat of infection and the usual portal through which infection reaches other organs.
Substance abuse A popular term for the epidemic of cocaine abuse
tuberculosisInfectious disease A disease first known to the ancients; there are one million new cases of Mycobacterium tuberculosis/yr worldwide, of which ±10% of those in developing nations eventually die; 'smear'-positive cases in Africa–165/105, are more often clinically inactive than those in Asia where the rate is 110/105 US incidence: 9.3 cases/105–white/Hispanic 5.7/105, black 26.7/105, Asian 49.6/105; the previous trend of ↓ TB in the US reversed itself in the mid-1980s, due to ↑ of M tuberculosis and M avium complex in AIDS; up to 10 million in the US have latent TB–many of whom are poor, aged, malnourished; homeless or IVDAs Clinical Coughing, chest pain, hemoptysis, weight loss, fatigue, malaise, fever, night sweats Diagnosis Ziehl-Neelsen or Kinyoun AFB stains, viewed by LM; auramine-rhodamine stain with fluorescent microscopy; NAP test, nucleic acid probes, PCR Treatment-1º drugs Isoniazid, ethambutol, rifampicin, streptomycin 2º drugs Ethionamide, capreomycin, kanamycin, cycloserine, pyrazinamide, para-aminosalicylic acid. See Latent tuberculosis, MOTT, Mycobacterial infection, Multidrug resistant tuberculosis, Runyon classification. Cf Pseudotuberculosis.
tuberculosis(too-ber?kyu-lo'sis, tu-) [ tubercle + -osis],
Tuberculosis usually affects the lungs, but the disease may spread to other organs, including the gastrointestinal and genitourinary tracts, bones, joints, nervous system, lymph nodes, and skin. Macrophages surround the bacilli in an attempt to engulf them but cannot, producing granulomas with a soft, cheesy (caseous) core. From this state, lesions may heal by fibrosis and calcification and the disease may exist in an arrested or inactive stage. Depending on the person’s immune status and other factors, the disease may become reactivated as pulmonary TB or disseminated infection. Reactivation or exacerbation of the disease or reinfection gives rise to the chronic progressive form.
The incidence of TB declined steadily from the 1950s to about 1990, when the acquired immunodeficiency syndrome (AIDS) epidemic, an increase in the homeless population, an increase in immigrants from endemic areas, and a decrease in public surveillance caused a resurgence of the disease. Populations at greatest risk for TB include patients with human immunodeficiency virus (HIV), Asian and other refugees, the urban homeless, alcoholics and other substance abusers, persons incarcerated in prisons and psychiatric facilities, nursing home residents, patients taking immunosuppressive drugs, and people with chronic respiratory disorders, diabetes mellitus, renal failure, or malnutrition. People from these risk groups should be assessed for TB if they develop pneumonia; all health care workers should be tested annually.
Currently the only vaccine available to prevent tuberculosis is the BCG vaccine. It has somewhat limited effectiveness but is used in regions of the world where TB is endemic. illustration; immunological therapy; tuberculin skin test; vaccine, BCG;
Approx. 4 to 12 weeks elapse between the time of infection and the time a demonstrable primary lesion or positive tuberculin skin test (TST) occurs.
Pulmonary TB produces chronic cough, sputum, fevers, sweats, and weight loss. TB may also cause neurological disease (meningitis), bone infections, urinary bleeding, and other symptoms if it spreads to other organs. TB is a major cause of infertility around the world.
Tests used to diagnose latent infection with tuberculosis include a positive tuberculin skin test (TST) or a blood assay. A presumptive diagnosis of active disease is made by finding acid-fast bacilli in stained smears from sputum or other body fluids. The diagnosis is confirmed by isolating M. tuberculosis in cultures or rapid nucleic acid test probes.
Regimens for TB have been developed for patients, depending on their HIV status, the prevalence of multidrug resistant disease in the community, drug allergies, and drug interactions. Uncomplicated TB in the non-HIV infected patient is typically treated with a four-drug regimen for 6 months. Regimens evolve: prescribers should consult published guidelines for current standards of care. Commonly used drugs include isoniazid (INH), rifampin (RIF), ethambutol (EMB), pyrazinamide, ciprofloxacin, and rifapentin. Medications are typically given in combinations rather than alone. A long course of therapy may be prescribed for patients co-infected with HIV/AIDS or for patients with drug-resistant bacilli. Multiply drug-resistant TB (MDR-TB) is tuberculosis resistant to either INH or RIF. Extensively drug-resistant TB (XDR-TB) is resistant to INH or RIF, any fluoroquinolone (e.g., ciprofloxacin), and at least one parenteral TB drug. Both MDR-TB and XDR-TB have very high mortality rates. See: multidrug resistant tuberculosis
CAUTION!All patients with HIV should be tested for TB, and all patients with TB should be tested for HIV, because about one fourth of all patients with one disease will be infected with the other.
All patients suspected of or confirmed to have TB should be placed in airborne isolation until they are no longer infectious. Health care professionals and visitors should wear particulate respirators when in the patient’s room. Patients should be taught to cough and sneeze into tissues, and to dispose of secretions in a lined bag taped to the side of the bed or in a covered disposal. The patient should wear a mask when outside the isolation room for any reason. Patients should be observed for complications such as hemoptysis, bone or back pain, and bloody urine. The patient and family or other support persons should be taught about the importance of regular follow-up visits, of following and completing the treatment regimen exactly as prescribed, of adverse effects to be reported, and of signs and symptoms of recurring TB. Persons who have been exposed to an infected patient should receive a TB test; chest x-rays and prophylactic INH also may be prescribed.
multidrug resistant tuberculosisAbbreviation: MDR-TB
tuberculosisInfection with the organism Mycobacterium tuberculosis , either in the lungs (pulmonary tuberculosis) or in the LYMPH NODES (tuberculous ADENITIS), the skin (SCROFULA), the bones or in other organs. Pulmonary tuberculosis is usually acquired by aerosol spread from other people, while general (systemic) tuberculosis is transmitted in milk from cows with bovine tuberculosis. Pulmonary tuberculosis causes fever, fatigue, loss of appetite and weight, night sweats and persistent cough often with blood-streaked sputum and may spread to cause tubercular MENINGITIS or generalized (miliary) tuberculosis. Systemic tuberculosis causes areas of local tissue destruction often with SINUSES that discharge pus to the exterior. Tuberculosis is treated with a range of drugs used in various combinations for periods of up to a year. Antituberculous drugs include streptomycin, isoniazid, para-aminosalicylic acid (PAS), rifampicin, ethambutol and pyrazinamide.
tuberculosisa contagious human disease (the consumption of Victorian times) affecting particularly the lungs, that is caused by the bacterium Mycobacterium tuberculosis. Response to infection is varied amongst individuals, some showing no signs while a few will die of the effects, these variations in host resistance being under genetic control. Tuberculosis is endemic in many parts of the world but, since the introduction of drugs and immunization with vaccines such as BCG, the world death rate has declined dramatically. A typical European mortality rate in 1900 was 190 per 100 000. This dropped to around 10 per 100 000 but is increasing worldwide due to the spread of AIDS.
tuberculosis; TB chronic, debilitating disease caused by infection with Mycobacterium tuberculosis ; characterized by night sweats, fever, weight loss and local effects (e.g. chronic cough [pulmonary TB]; local pain, swelling, bone/joint distortion [TB osteomyelitis/septic arthritis]); of increasing incidence/prevalence due to TB bacillus resistance to antimicrobial drugs (especially in the immunocompromised [including those with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS)]), homeless, debilitated); bacille Calmette-Guérin (BCG) vaccination offers immunity to TB
acute miliary TB generalized dissemination of TB bacillus via blood; characterized by multiple tubercles in organs/tissues
cutaneous TB; lupus vulgaris; tuberculosis verrucosa cutis localized TB skin lesions caused by direct inoculation of bacillus into skin (occasionally by haematogenous spread); cutaneous TB often affects foot skin; symptoms (e.g. patches of dry, atrophic skin, pigmentation changes, nodules and verrucous plaques) develop slowly
open TB; pulmonary TB; TB ulcer characterized by TB bacilli in body secretions; subject is actively contagious
TB of the skin cutaneous TB
fungal uveitis Uveitis caused by a fungus such as Candida albicans, Cryptococcus neoformans and Histoplasma capsulatum. It is often accompanied by other disorders (e.g. choroiditis, retinitis). It may have spread from other bodily tissues (e.g. skin, mouth, gastrointestinal tract) in patients who are intravenous drug addicts, patients with indwelling venous catheters or patients who are immunosuppressed.
intermediate uveitis A chronic inflammation of the ciliary body (cyclitis) or its pars plana zone (pars planitis) or of the peripheral retina and vitreous (peripheral uveitis). The cause is unknown in most cases but others are associated with systemic conditions such as multiple sclerosis, sarcoidosis or HIV infection. It affects mainly young adults and is bilateral in about 80% of cases. Symptoms are floaters and, sometimes, blurred vision, and there may be anterior chamber cells and flare. Ophthalmoscopic examination may show vitreous condensation and gelatinous exudates ('cotton balls' or 'snowballs'). Snowbanking, i.e. a whitish plaque or exudates involving the pars plana, often the inferior part of it, appears mainly in pars planitis. Intermediate uveitis may be associated with retinal vasculitis (i.e. inflammation of a retinal blood vessel). In a few cases the condition is self-limiting within a few months. However, in most cases the condition lasts several years may lead to complications such as cystoid macular oedema, posterior subcapsular cataract, retinal detachment or cyclitic membrane formation. Treatment includes corticosteroids and in resistant cases immunosuppressive agents.
posterior uveitis A uveitis involving the posterior segment of the eye. Symptoms include floaters and visual loss if the choroiditis involves the macular area. Ophthalmoscopically there is an accumulation of debris in the vitreous and choroidal lesions appear as yellow-white areas of infiltrates surrounded by normal fundus. Retinitis is also present in most cases, as well as retinal vasculitis. Posterior uveitis may be associated with AIDS, Behçet's disease, Lyme disease, histoplasmosis, sarcoidosis, toxoplasmosis, syphilis, tuberculosis, Vogt-Koyanagi-Harada syndrome, sympathetic ophthalmia, etc.
viral uveitis Uveitis caused by a virus. Common viruses are: herpes simplex, which is usually associated with keratitis and may cause anterior uveitis; herpes zoster which may also be associated with keratitis; human T-cell lymphotrophic virus; measles; cytomegalovirus; rubella; human immunodeficiency virus (HIV). See herpes simplex blepharoconjunctivitis; herpes zoster ophthalmicus.
M. tuberculosis and characterized by the formation of tubercles in the tissues.
Patient discussion about tuberculosis
Q. Can a low back pain start from picking up something from the oven? My mother has a low back pain. It started five days ago while she picked up a cake from the oven. the pain is always there, it bugs her while she sleeps and it excruciate while she is doing her regular physical activity. What can it be? should we go to our GP? Is there anything we can do to ease the pain except Tylenol? Just for the record my mom is 69 years old, and she has tuberculosis and a heart disease.