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64 Cards in this Set
- Front
- Back
What causes tuberculosis?
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Mycobacterium tuberculosis
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Tuberculosis is most commonly found in:
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the lungs
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Usually, tuberculosis is screened first using a:
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skin test
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Multi-drug resistant tuberculosis:
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resists more than one drug
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It is impossible for the result of a Mantoux skin test on an HIV-infected patient to be negative if he or she is infected with tuberculosis.
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a) True
b) False answer: false |
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The bacteria that cause tuberculosis are transmitted in:
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droplet nuclei
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Where there is a substantial number of positive tuberculosis skin tests among health care staff, health care personnel should be screened for tuberculosis:
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Every six months
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What is the easiest source control method to use that reduces air contamination?
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Cover patient's mouth with tissues when coughing
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When a door or window of an isolation room with negative air pressure is opened, what happens?
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Air rushes into the room
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Filtering air through a HEPA filter is 100% effective in removing all tuberculosis particles and is the only means necessary to disinfect air.
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False
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TB is declining, True or False?
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True
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History of Tuberculosis
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Worldwide TB kills more people than any other infectious disease 2nd leading killer worldwide
See 1920's-TB leading cause of death in US 1940-1950-Rapid decline r/t drug treatment (INH) 1985-Reemergence steady increase (AIDS) 1993-Global emergency, steady increase in US 1997-Decrease in cases (more screening) 2005-All time low in US @14,097 (CDC) |
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TB CAME BACK! WHY?
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HIV (immunosuppressed)
Immigration Multidrug Resistant Strain (MDR-TB) Homelessness and crowded living Decline in Public Health Screening and Education Programs Increased Global Travel |
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Dual Infection TB/HIV
14 million worldwide |
World Health Organization 3/6/04
Reduce the spread of TB in high HIV areas Focus Africa=70% of 14m. coinfected live Increase routine screening of TB in Africa (treat Prophylactic and active) Provide more collaboration TB/HIV |
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Department of Public Health
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Serious Public Health Problem today
Reportable Communicable Disease (only 78 as of January 2003 Preventable Curable Goal of CDC Eradicate from US by 2010 |
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Tuberculosis definition
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An infectious disease caused by:
In the US - Mycobacterium Tuberculosis 3 types of Mycobacterial Species M. Bovis, M. Africanum, and M. Microti **Gram-positive, acid fast bacillus** |
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Risk Factors
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Close, prolonged contact with active disease
HIV infected IV drug abusers Immunocompromised patients (cancer) High risk environments, prison, shelters, etc. New immigrants (Africa, Asia, Latin American) Low socioeconomic groups |
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Transmission
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M. tuberculosis (bacilli) is inhaled through droplet
Implant in lower sites of the lungs such as the bronchioles or alveoli Multiply in favorable environments of the lungs: primarily upper lobes Spread through the lymphatic system to regional lymph nodes |
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Transmission
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Miliary (spread to all body organs) not usually infectious
Pulmonary transmitted through airborne droplet nuclei-cough, speak, laugh, sneeze Lungs are always primary site=then spread to other organs via lymphs, bloodstream |
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Points to remember
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Most people exposed resist infection
Clinical evidence occurs in 5-10% of those infected |
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Pathophysiology
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10% of those exposed become infected
90% of those exposed will develop latent TB capable of reactivation Estimated that of new infections reported, 60% are reactivation rather than new exposure Cycle=pneumonia, ulceration, cavitation, and scarring |
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Pathophysiology
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M. Tuberculosis causes focal inflammation reactions called epitheliod cell granuloma
The organism multiplies slowly and can be killed by ultraviolet light, heat, sunshine It resists drying, can remain viable for weeks in particles of dried sputum (viable not transmitted) It is NOT highly contagious, close prolonged frequent contact required. |
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Latent TB
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LTBI is the presence of M. tuberculosis organisms without symptoms or radiographic evidence of TB
As TB disease rates in US decrease, finding and treating LTBI has become a priority. |
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Prevention
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BCG (Bacille Calmetto-Guerin) vaccine widely used in developing countries
Results in a positive PPD but mean =<10 mm, therefore American Thoracic Society = treat >10 mm Does not prevent TB but decreases seriousness |
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Clinical Manifestations
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Early: Asymptomatic
Active TB: fatigue anorexia/weight loss night sweats low-grade fever pulmonary: cough, chest pain, hemoptysis and dyspnea |
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Diagnostic Studies
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History and Physical
TST - Tuberculin Skin Test (most common) CXR-not definitive alone Bacteriologic Studies sputum for ACID FAST BACILLUS (smear) Culture for tubercle bacilli=essential |
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Collaborative Therapy
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American Thoracic Society and CDC recommend TARGETED TUBERCULIN TESTING, not for everyone
Clients with clinical manifestations Belonging to high or moderate risk groups (health care workers, people who travel) |
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TB Skin Tests
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Multiple Tine Test
small button with several short needles coated with TB antigens Used in past for TB screening (lots of false negative) Mantoux Test (PPD) Called TST (Tuberculin Skin Test) TB syringe with a measured amount of TB antigen More accurate |
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Tuberculin Skin Test (TST)
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TST testing is done intradermally by injection of 0.1 mL of PPD (purified protein derivative) tuberculin
Reading in 48-72 hours Assess for induration 5-15 mm is positive |
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Administering the TST
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Inject 0.1 mL of 5 TU PPD tuberculin solution intradermally on volar surface of lower arm using a 27-gauge needle
Produce a wheal 6 to 10 mm in diameter |
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Reading the TST
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Measure reaction in 48 to 72 hours
Measure induration, NOT erythema Record reaction in millimeters, not "negative" or "positive" Ensure trained health care professional measures and interprets the TST |
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TST
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TST-Initial screening test
TST-Positive test indicates presence of TB but not whether active or dormant Once positive, stay positive, should not keep getting it Measure in mm the induration (hardness) Ignore erythema (redness) |
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TST Interpretation
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5-mm induration is interpreted as positive in:
HIV-infected persons Close contacts to an infectious TB case Persons with chest radiographs consistent with prior untreated TB |
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TST Interpretation
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5-mm induration is interpreted as positive in (cont.)
Organ transplant recipients(immunosuppressed) Other immunosuppressed patients (e.g.,those taking the equivalent of >15 mg/d of prednisone for 1 month or those taking TNF-alpha antagonists) |
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TST Interpretation
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10-mm induration is interpreted as positive in:
Recent immigrants (last 5 years) Injection drug users Healthcare workers Residents of long-term care/prisons (close contact) |
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TST Interpretation
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10-mm induration is interpreted as positive in (cont.)
Persons with clinical conditions that place them at high-risk (Immunosuppressed patients) Children <4 years; infants, children, and adolescents exposed to adults at high-risk Workers at a mycobacteriology lab |
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TST Interpretation
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15-mm induration is interpreted as positive in:
Persons with no known risk factors for TB |
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False Negative
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Not uncommon in immunosuppressed or elderly >65 years
Two step testing done to prevent this (wait 2-3 wks have another test) A strategy to determine the difference between boosted reactions and reactions in response to infection |
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Boosting
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Some people with LTBI may have a negative skin test reaction when tested years after infection because of a waning response.
An initial skin test may stimulate (boost) the ability to react to tuberculin. Positive reactions to subsequent tests may be misinterpreted as new infections rather than "boosted" reactions. |
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Two step testing
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TST positive=positive
TST negative: Repeat in 1-3 weeks. If positive (booster phenomenon has occurred.) If negative then client is considered negative. Required by many companies if no evidence of previous TB test in 1 year, for people requiring yearly TB, elderly and immunocompromised Anergy testing not recommended by CDC since 1997 (give candida, mumps if positive person is capable of mounting an immune response) |
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QuantiFERON-TB Gold Blood Test
(instead of TST) |
Whole blood used, incubated for 16-24 hrs
The QFT measures the patient's immune reactivity to Mycobacterium tuberculosis This test was approved by the U.S. Food and Drug Administration (FDA) in 2001. Will be used more in the future |
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What are the advantages?
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Only requires a single patient visit.
Assesses responses to multiple antigens simultaneously. Does not cause the booster phenomenon, which can happen with repeat tuberculin skin tests (TST) Is less subject to reader bias and error when compared to the TST. |
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What are the disadvantages?
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Blood samples must be processed within 12 hours after collection
Currently, there is limited laboratory and clinical experience with the QFT. The ability of the QFT in predicting a patient's risk of progression to TB disease has not been evaluated. As with the TST, additional tests are needed to exclude TB disease and confirm diagnosis of LTBI. |
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Sputum Specimen
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Culture & Sensitivity (gold standard for diagnosis)
2-8 weeks for results Necessary for definitive diagnosis and to determine drug resistance Sputum Smear Acid fast bacilli (Start treatment) Nucleic Acid Amplification (NAA) Rapid test (hrs) - does not replace smear, C&S but adds to clinical picture |
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Health Care Workers - Protection when obtaining cultures
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High Efficiency Particulate Air (HEPA) Filter Mask only mask you can wear taking care of TB patient
Room with reverse air flow and ultraviolet light |
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Medical Diagonosis
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Presumptive:
Positive TST Positive sputum smear for AFB Positive CXR Positive biopsy for granulomateous disease Definitive: Positive culture of M. Tubercuolosis (tubercle bacilli (May take >2 weeks) |
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Management of Latent TB: (Bulk of patients) IF TB IS ENCAPSULATED REGULAR SURGICAL MASK ONLY
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RECALL: LTBI is the presence of M. tuberculosis organisms (tubercle bacilli) without symptoms or radiographic evidence of TB disease.
Four recommended treatment regimes INH qd X 9 months. 1999=Rifampin qd X 2 mos. & pyrazinamide for HIV INH qd X 12 months. HIV Rifampin qd X 4 months |
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Who should be treated for LTBI
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HIV
IV Drug Users Immunosuppressed CXR evidence of previous disease Clients with high risk medical conditions Based on: Risk And size of induration |
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LTBI vs. Pulmonary TB Disease
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Latent TB Infection:
TST or QFT positive Negative chest radiograph No symptoms or physical findings suggestive of TB disease PULMONARY TB DISEASE TST or QFT usually positive Chest radiograph may be abnormal Symptoms may include one or more of the following: fever, cough, night sweats, weight loss, fatique, hemoptysis, decreased appetite Respiratory specimens may be smear or culture positive |
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Active TB
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Always use combination therapy
First Line Drug Therapy - RIPE Rifampin* (longer acting rifampetine) Isoniazide* (INH) Pyrazimide Ethambutol |
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INH=Isoniazide
**Primary agent for Rx (in combo) and prophylaxis (alone=Latent TB) |
IM and PO
Highly selective for mycobacteria May develop resistence Principle SE=liver toxicity (over 35) Depletes vitamin B6=peripheral neuropathy |
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Prolonged Treatment
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Considerations:
poor compliance Drug toxicity emergence of drug resistance See handout |
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Clinical Monitoring
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Instruct patient to report signs or symptoms of adverse drug reactions:
rash anorexia, nausea, vomiting, or abdominal pain in Right Upper Quadrant Fatigue or Weakness Dark Urine Persistent numbness in hands or feet |
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Clinical Monitoring
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Monthly visits should include a brief physical exam and a review of:
rational for treatment adherence with drug therapy symptoms of adverse drug reactions plans to continue treatment |
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Management of Patient who Missed Doses
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Extend or re-start treatment if interruptions were frequent or prolonged enough to preclude complettion
When treatment has been interrupted for more than 2 months, patient should be examined to rule out TB disease Recommend and arrange for DOT (directly observed therapy) as needed |
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DOTS (Directly Observed Therapy)
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Standard of care for TB
Ensures compliance Allows for observation of SE Decrease risk of transmission Decrease risk of drug resistance |
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Management & Evaluation
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A short hospital stay is possible for teaching and evaluation
1994, the CDC requires isolation for unknown pulmonary problem or TB Negative pressure room; air is filtered to outside & changed 6-12 X q hour HIV testing is recommended (pt. consent) Weekly, monthly & 1 year sputum culture follow-up |
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Management & Evaluation
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Inpatient Care
AFB (acid fast bacillus) Isolation until (-) sputum X 3 days, on meds X 2 weeks and shows clinical response HEPA air filtration masks by all health care workers Negative Air Flow Room Ultraviolet radiation-bactericidal lights Teaching - cover mouth & nose when coughing, handwashing, compliance, medications (very important) |
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Complications
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Permanent Lung Disease and Damage
Possible Lung Resection |
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Nursing Diagnosis and Planning
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Ineffective Breathing Pattern
High Risk for Noncompliance Activity Intolerance Ineffective Airway Clearance Pain Sleep Pattern Disturbance Ineffective Individual or Family Coping |
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Assessment
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Diagnostic Phase:
H&P PMH Medications Travel Living conditions Pulmonary assessment Treatment Phase: Knowledge deficits Willingness and ability to comply with treatment modality Emotional response to diagnosis |
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Implementation & Evaluation
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Infection Control Measures
Education Compliance -- Directly Observed Therapy (DOT) Home Care see handout |
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Research
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R207910-a new class of antimicrobial drugs called diarylquinolines
Faster, better, safer...clinical trials Still need combination of drugs Medications: Combinations Less frequent dosing With HIV therapies |
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Meeting the Challenge of TB Prevention
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For every patient
Assess TB risk factors for all patients If risk is present, perform TST or QFT If TST or QFT is positive, rule out active TB disease If active TB disease is ruled out, initiate treatment for LTBI If treatment is initiated, ensure completion |