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Tuberculosis (abbreviated as TB or Tuberculosis) is a common [[infectious disease]] caused by ''[[Mycobacterium tuberculosis]]''. Tuberculosis most commonly involves the [[lungs]] as the [[organism]] thrives in high [[oxygen]] environments, but it can also cause [[disease]] in the [[central nervous system]], the [[lymphatic system]], the [[circulatory system]], the [[genitourinary system]], [[bone]]s, [[joint]]s and even the [[skin]]. Over one-third of the world's [[population]] has been [[exposed]] to ''[[M. tuberculosis]]'', and new [[infections]] occur at a [[rate]] of one per second.  Not all individuals exposed to the [[bacterium]] develop [[clinically]] overt tuberculosis [[infection]]; in fact, [[asymptomatic]], [[Latent|latent TB]] infection discovered by [[screening]] is more [[common]]. Approximately, one in ten latent infections progresses to active ([[symptomatic]]) TB disease, which, if left untreated, carries [[mortality]] rates of up to 50%.  [[Symptoms]] include [[shortness of breath]], [[hemoptysis]], [[fever]], [[chills]], [[night sweats]], and [[weight loss]].  Several treatment regimens are available for the latent and active forms of TB. Classically, a prolonged course of 6-9 months of a single agent ([[rifampin]] or [[isoniazid]]) is administered to patients with latent TB, while a more [[aggressive]] course that consists of 4 major anti-tuberculous [[agents]] [[(rifampin]], [[isoniazid]], [[ethambutol]], [[pyrazinamide]]) is reserved for patients with active disease.
Tuberculosis (abbreviated as TB or Tuberculosis) is a common [[infectious disease]] caused by ''[[Mycobacterium tuberculosis]]''. Tuberculosis most commonly involves the [[lungs]] as the [[organism]] thrives in high [[oxygen]] environments, but it can also cause [[disease]] in the [[central nervous system]], the [[lymphatic system]], the [[circulatory system]], the [[genitourinary system]], [[bone]]s, [[joint]]s and even the [[skin]]. Over one-third of the world's [[population]] has been [[exposed]] to ''[[M. tuberculosis]]'', and new [[infections]] occur at a [[rate]] of one per second.  Not all individuals exposed to the [[bacterium]] develop [[clinically]] overt tuberculosis [[infection]]; in fact, [[asymptomatic]], [[Latent|latent TB]] infection discovered by [[screening]] is more [[common]]. Approximately, one in ten latent infections progresses to active ([[symptomatic]]) TB disease, which, if left untreated, carries [[mortality]] rates of up to 50%.  [[Symptoms]] include [[shortness of breath]], [[hemoptysis]], [[fever]], [[chills]], [[night sweats]], and [[weight loss]].  Several treatment regimens are available for the latent and active forms of TB. Classically, a prolonged course of 6-9 months of a single agent ([[rifampin]] or [[isoniazid]]) is administered to patients with latent TB, while a more [[aggressive]] course that consists of 4 major anti-tuberculous [[agents]] [[(rifampin]], [[isoniazid]], [[ethambutol]], [[pyrazinamide]]) is reserved for patients with active disease.


==Historical Perspective==
==Historical Perspective==  
 
*[[Tuberculosis]] has been present in humans for thousands of years.  
*[[Tuberculosis]] has been present in humans for thousands of years.  
*The earliest unambiguous detection of ''[[Mycobacterium tuberculosis]]'' was in the [[remains]] of [[bison]], dated 18,000 BC.  
*The earliest unambiguous detection of ''[[Mycobacterium tuberculosis]]'' was in the [[remains]] of [[bison]], dated 18,000 BC.  
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===Other Imaging findings===
===Other Imaging findings===
The [[abreugraphy]] is a smaller [[variant]] of the [[chest X-ray]] that allows the [[Identification of sites|identification]] of [[lung]] [[abnormalities]] that may suggest the [[diagnosis]] of TB.  With the decrease of [[incidence]] of TB, the [[abreugraphy]] is no longer recommended in most countries for low-risk populations.  However, depending on the [[screening]] resources of each country, it may be used for the [[screening]] of [[high-risk]] groups, such as [[HIV]]-positive patients and [[alcoholics]].
*The [[abreugraphy]] is a smaller [[variant]] of the [[chest X-ray]] that allows the [[Identification of sites|identification]] of [[lung]] [[abnormalities]] that may suggest the [[diagnosis]] of TB.   
*With the decrease of [[incidence]] of TB, the [[abreugraphy]] is no longer recommended in most countries for low-risk populations.   
*However, depending on the [[screening]] resources of each country, it may be used for the [[screening]] of [[high-risk]] groups, such as [[HIV]]-positive patients and [[alcoholics]].


===Other Diagnostic Studies===
===Other Diagnostic Studies===
Because of difficulties with the [[Tuberculin skin test]], many [[laboratory]] methods of [[diagnosis]] are [[emerging]].
*Because of difficulties with the [[Tuberculin skin test]], many [[laboratory]] methods of [[diagnosis]] are [[emerging]].


==Treatment==
==Treatment==
===Medical Therapy===
===Medical Therapy===
If there is a high [[probability]] of [[infection]], presumptively [[treat]] the patient even if the stain is [[negative]], while waiting for the [[culture]] [[results]].  The patient should be brought back in a few weeks.  Patients usually feel better a few weeks post-treatment. Patients must be [[monitored]] for [[Adverse effect (medicine)|adverse effects]] and treatment [[failure]]. In the U.S., all TB is tested for [[drug resistance]].
*If there is a high [[probability]] of [[infection]], presumptively [[treat]] the patient even if the stain is [[negative]], while waiting for the [[culture]] [[results]].   
*The patient should be brought back in a few weeks.   
*Patients usually feel better a few weeks post-treatment.  
*Patients must be [[monitored]] for [[Adverse effect (medicine)|adverse effects]] and treatment [[failure]].  
*In the U.S., all TB is tested for [[drug resistance]].


====Special conditions====
====Special conditions====
[[Medical]] [[therapy]] for tuberculosis in special conditions include [[HIV]] co-infection and extra pulmonary [[manifestations]]. Different approaches are taken for [[patients]] taking [[AIDS antiretroviral drugs|ART]] and those who do not take [[AIDS antiretroviral drugs|ART]]. Although [[World Health Organization|WHO]] recommends the same drug regimen for pulmonary and extrapulmonary [[manifestations]], various stages of [[skeletal]] tuberculosis are managed differently. For patients with [[renal]] or [[liver]] diseases, the first line of drugs are substituted with second-line drugs to prevent [[Complication (medicine)|complications]].
*[[Medical]] [[therapy]] for tuberculosis in special conditions include [[HIV]] co-infection and extra pulmonary [[manifestations]].  
*Different approaches are taken for [[patients]] taking [[AIDS antiretroviral drugs|ART]] and those who do not take [[AIDS antiretroviral drugs|ART]].  
*Although [[World Health Organization|WHO]] recommends the same drug regimen for pulmonary and extrapulmonary [[manifestations]], various stages of [[skeletal]] tuberculosis are managed differently.  
*For patients with [[renal]] or [[liver]] diseases, the first line of drugs are substituted with second-line drugs to prevent [[Complication (medicine)|complications]].


====Drug-resistant====
====Drug-resistant====
[[Drug resistance|Drug-resistant]] tuberculosis is caused by M. tuberculosis [[organisms]] that are [[resistant]] to at least one first-line anti-TB drug.  [[Multi-drug-resistant tuberculosis|Multidrug-resistant TB]] (MDR TB) is resistant to more than one [[anti-TB drug]] and at least [[isoniazid]] ([[INH]]) and [[rifampin]] ([[RIF]]).  Treatment should be started with an [[empirical]] treatment of at least 4 drugs based on expert advice as soon as [[Multi-drug-resistant tuberculosis|drug-resistant TB]] disease is suspected.
*[[Drug resistance|Drug-resistant]] tuberculosis is caused by M. tuberculosis [[organisms]] that are [[resistant]] to at least one first-line anti-TB drug.   
*[[Multi-drug-resistant tuberculosis|Multidrug-resistant TB]] (MDR TB) is resistant to more than one [[anti-TB drug]] and at least [[isoniazid]] ([[INH]]) and [[rifampin]] ([[RIF]]).   
*Treatment should be started with an [[empirical]] treatment of at least 4 drugs based on expert advice as soon as [[Multi-drug-resistant tuberculosis|drug-resistant TB]] disease is suspected.


====Children====
====Children====
[[Tuberculosis]] in children aged 15 years or younger is a [[public health problem]] of special [[significance]] because it is a marker for recent [[transmission]] of TB. Infants and young [[children]] are more likely to develop life-threatening forms of tuberculosis, such as [[miliary TB]] or [[TB meningitis]]. [[Screening]] in children is very important, as the [[clinical manifestations]] are usually poor or [[non-specific]].  History of close contact with tuberculosis patients has an important role in the [[diagnosis]] of TB in children.  The [[treatment]] is similar to adults, with adjusted [[dosing]] according to the child's weight.
*[[Tuberculosis]] in children aged 15 years or younger is a [[public health problem]] of special [[significance]] because it is a marker for recent [[transmission]] of TB. *Infants and young [[children]] are more likely to develop life-threatening forms of tuberculosis, such as [[miliary TB]] or [[TB meningitis]].  
*[[Screening]] in children is very important, as the [[clinical manifestations]] are usually poor or [[non-specific]].   
*History of close contact with tuberculosis patients has an important role in the [[diagnosis]] of TB in children.   
*The [[treatment]] is similar to adults, with adjusted [[dosing]] according to the child's weight.


===Surgery===
===Surgery===
[[Surgery]] may be necessary, especially to [[Drain (surgery)|drain]]  [[abscess]]es , [[empyema]], [[venticular shun]]<nowiki/>t in [[tubercular meningitis]], [[surgical resection]] of [[tissues]] affected in [[abdominal tuberculosis]], stabilize the [[spine]] in case of [[Pott's disease]], [[lobectomy]], [[pneumonectomy]], [[pericardiocentesis]] or surgical repair of [[pericardium]].
*[[Surgery]] may be necessary, especially to [[Drain (surgery)|drain]]  [[abscess]]es , [[empyema]], [[venticular shun]]<nowiki/>t in [[tubercular meningitis]], [[surgical resection]] of [[tissues]] affected in [[abdominal tuberculosis]], stabilize the [[spine]] in case of [[Pott's disease]], [[lobectomy]], [[pneumonectomy]], [[pericardiocentesis]] or surgical repair of [[pericardium]].


===Primary Prevention===
===Primary Prevention===
[[Primary prevention]] in tuberculosis is targeted to avoid disease [[Transmission (medicine)|transmission]] and infection of [[healthy]] individuals. The [[BCG]] [[vaccine]] is used in children [[Susceptible individual|susceptible]] to TB infections, such as children living in [[Endemic (epidemiology)|endemic]] areas or having [[close contact]] with a confirmed [[case]] of TB.  Several [[Preventive medicine|preventive]] [[measures]] are used to avoid the [[transmission]] of the [[mycobacteria]], such as [[respiratory]] [[Isolation (health care)|isolation]], use of respiratory [[masks]] among [[health-care professionals]], and advising [[respiratory hygiene]] and [[cough]] etiquette.
*[[Primary prevention]] in tuberculosis is targeted to avoid disease [[Transmission (medicine)|transmission]] and infection of [[healthy]] individuals. The [[BCG]] [[vaccine]] is used in children [[Susceptible individual|susceptible]] to TB infections, such as children living in [[Endemic (epidemiology)|endemic]] areas or having [[close contact]] with a confirmed [[case]] of TB.   
*Several [[Preventive medicine|preventive]] [[measures]] are used to avoid the [[transmission]] of the [[mycobacteria]], such as [[respiratory]] [[Isolation (health care)|isolation]], use of respiratory [[masks]] among [[health-care professionals]], and advising [[respiratory hygiene]] and [[cough]] etiquette.


===Secondary Prevention===
===Secondary Prevention===
[[Secondary prevention]] for tuberculosis includes [[methods]] for [[screening]] and early [[diagnosis]], such as [[tuberculin skin test]] (TST) and [[IGRAs]]; and to guarantee the correct [[treatment]] [[regimen]] at the right time to prevent [[disease]] [[progression]].
*[[Secondary prevention]] for tuberculosis includes [[methods]] for [[screening]] and early [[diagnosis]], such as [[tuberculin skin test]] (TST) and [[IGRAs]]; and to guarantee the correct [[treatment]] [[regimen]] at the right time to prevent [[disease]] [[progression]].


===Cost effectiveness of therapy===
===Cost effectiveness of therapy===
Treatment of [[tuberculosis]] must be [[analyzed]] for relative [[Cost-effectiveness|cost]] [[effectiveness]] of [[inpatient]] and [[outpatient]] models of [[care]] as it will [[benefit]] regions where [[tuberculosis]] is highly [[prevalent]]. Unless there is severe [[Complication (medicine)|complications]] it is highly recommended to treat the TB patient in [[ambulatory care]] rather than [[inpatient]] services.
*Treatment of [[tuberculosis]] must be [[analyzed]] for relative [[Cost-effectiveness|cost]] [[effectiveness]] of [[inpatient]] and [[outpatient]] models of [[care]] as it will [[benefit]] regions where [[tuberculosis]] is highly [[prevalent]].  
*Unless there is severe [[Complication (medicine)|complications]] it is highly recommended to treat the TB patient in [[ambulatory care]] rather than [[inpatient]] services.


===Future or investigational therapy===
===Future or investigational therapy===
Since new [[drug-resistant tuberculosis]] has been emerging, the role of future [[therapies]] is [[vital]] in curbing [[outbreaks]]. The new [[:Category:Drugs|drugs]] should be more effective than the current [[regimen]] and a few drugs in [[clinical]] trials have been showing good [[results]].
*Since new [[drug-resistant tuberculosis]] has been emerging, the role of future [[therapies]] is [[vital]] in curbing [[outbreaks]].  
*The new [[:Category:Drugs|drugs]] should be more effective than the current [[regimen]] and a few drugs in [[clinical]] trials have been showing good [[results]].


==References==
==References==

Latest revision as of 21:55, 26 June 2021

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Overview

Tuberculosis (abbreviated as TB or Tuberculosis) is a common infectious disease caused by Mycobacterium tuberculosis. Tuberculosis most commonly involves the lungs as the organism thrives in high oxygen environments, but it can also cause disease in the central nervous system, the lymphatic system, the circulatory system, the genitourinary system, bones, joints and even the skin. Over one-third of the world's population has been exposed to M. tuberculosis, and new infections occur at a rate of one per second. Not all individuals exposed to the bacterium develop clinically overt tuberculosis infection; in fact, asymptomatic, latent TB infection discovered by screening is more common. Approximately, one in ten latent infections progresses to active (symptomatic) TB disease, which, if left untreated, carries mortality rates of up to 50%. Symptoms include shortness of breath, hemoptysis, fever, chills, night sweats, and weight loss. Several treatment regimens are available for the latent and active forms of TB. Classically, a prolonged course of 6-9 months of a single agent (rifampin or isoniazid) is administered to patients with latent TB, while a more aggressive course that consists of 4 major anti-tuberculous agents (rifampin, isoniazid, ethambutol, pyrazinamide) is reserved for patients with active disease.

Historical Perspective

Classification

TB Classification System

  • As per CDC (Centers of Disease Control and Prevention), the clinical classification system for TB used in the United States is based on the pathogenesis of the disease.
  • This classification system provides clinicians the opportunity to keep an eye on the development of TB in their patients.
  • Health care providers should follow with state and local laws and regulations requiring the reporting of TB disease.
  • All persons with Class 3 or Class 5 TB should be reported directly to the local or state health department.
  • A patient should not have a Class 5 classification for more than 3 months.
Class Type Description
0 *No TB exposure
*Not infected
*No history of TB exposure and no evidence of M. tuberculosis infection or disease
*Negative reaction to TST or IGRA
1 *TB exposure
*No evidence of infection
*History of exposure to M. tuberculosis
*Negative reaction to TST (Tuberculin skin tests) or IGRA (an interferon gamma release assay blood test) (given at least 8 to 10 weeks after exposure)
2 *TB infection
*No TB disease
*Positive reaction to TST or IGRA
*Negative bacteriological studies (smear and cultures)
*No bacteriological or radiographic evidence of active TB disease
3 *TB clinically active *Positive culture for M. tuberculosis OR
*Positive reaction to TST or IGRA, plus clinical, bacteriological, or radiographic evidence of current active TB
4 *Previous TB disease (not clinically active) *May have past medical history of TB disease
*Abnormal but stable radiographic findings
*Positive reaction to the TST or IGRA
*Negative bacteriologic studies (smear and cultures)
*No clinical or radiographic evidence of current active TB disease
5 *TB suspected *Signs and symptoms of active TB disease, but medical evaluation not complete

Pathophysiology

Causes

Epidemiology and Demographics

Risk Factors

Screening

Natural history, complications and prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory findings

Electrocardiogram

Chest X-Ray

CT

MRI

Echocardiography or Ultrasound

Other Imaging findings

Other Diagnostic Studies

Treatment

Medical Therapy

Special conditions

  • Medical therapy for tuberculosis in special conditions include HIV co-infection and extra pulmonary manifestations.
  • Different approaches are taken for patients taking ART and those who do not take ART.
  • Although WHO recommends the same drug regimen for pulmonary and extrapulmonary manifestations, various stages of skeletal tuberculosis are managed differently.
  • For patients with renal or liver diseases, the first line of drugs are substituted with second-line drugs to prevent complications.

Drug-resistant

Children

Surgery

Primary Prevention

Secondary Prevention

Cost effectiveness of therapy

Future or investigational therapy

References

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