Presentation on theme: "Introduction to Tuberculosis"— Presentation transcript:
1 Introduction to Tuberculosis This isn’t meant to be an exhaustive presentation regarding tuberculosis, but an overview, so that the topic to tuberculosis risk assessment and tuberculin skin testing has a context as it relates to TB disease.We want to welcome you, and hope the next 4 hours will be helpful to you and the facilities where you work.VDH TB Control and Prevention Program2011
2 VDH TB Prevention and Control Policies and Procedures Based on USPHS/CDC, ATS, IDSA and Pediatric “Red Book” guidelinesAdapted to address uniquely Virginia issuesThese are some of the various guidelines that the Virginia Department of Health TB Program depends on for program standards and guidance.We don’t have separate guidance. We don’t have separate guidance from that provided by the CDC, except in particular clinical situations.Show the “Guidelines for Preventing Transmission of Mycobacterium tuberculosis in Health-Care Settings, 2005.”Every health care setting should be familiar with this document, including the facility risk assessment on page 128.
4 M. Tuberculosis - the causative agent for tuberculosis We have already seen this slide, but take a look at the two pictures to the right. One is a positive AFB stain or smear, with the TB mycobacteria staining red; the dye that is “acid fast”. The other is a TB culture growing on traditional media.Dr. Koch received a microscope for Christmas from his wife, and the rest is history.Robert Koch ~ 1886
5 Mycobacterium tuberculosis BacteriaA weakly gram positive rodAppears “rough and buff” in standard cultureAn organism that holds a red stain even in the presence of acid, i.e. “acid fast”Slow growing
6 The Mycobacteria Human pathogens M. tuberculosis complex includes: M. tb, M. bovis, M. africanum,M. microti, M. canettiM. lepraeNTM – non-tuberculous mycobacteriaNTM, previously MOTTS (mycobacteria other than TB).We will talk about the various lab work regarding TB later, but all mycobacteria, as well as fungi and some other bacteria can be AFB stain positive.
8 Transmission of TB Spread person to person through the air A key principle in TB transmission; you must share air with a TB case to develop TB infection.Cough is the major mechanism in transmission, though the droplet nuclei that are spread can also be expelled by shouting or singing.Young children rarely transmit disease, even with cough.
9 TB: Airborne Transmission TB bacteria airbornePerson withactivepulmonary TBPerson breathingTB bacteriaThis is just another way to show that for TB infection to occur, a person must share air with the TB case.Those with TB infection alone are not contagious.
10 TB Invades and Infects the Body Hematogenic spreadof bacteriaEffective immuneresponseInfection limitedDescribe two pathways, leading to infection or active disease.Immune responseinsufficientOr Immune response failsActive Disease
11 Pathogenesis of TBInfection begins when the inhaled droplets reach the alveoli of lungsTubercle bacilli multiplyA number of tubercle bacilli enter the bloodstream and spread throughout the body (lungs, kidneys, brain, bone)Within 2-10 weeks, the immune system produces an immune response which encapsulates the bacteria, and is detectable with a TST or IGRA blood testIn other words, [read the slide]. IGRA stands for interferon gamma release assay. We will talk about IGRAs in a bit.TB disease can occur after infection, wherever the TB bacteria are in the body.
12 Probability of TB Transmission Transmission dependent on three factorsInfectiousness of the person with TBHost factors of the exposed personEnvironment in which the transmission occursNot all cases of TB are equally contagious.TB infection depends on:Infectiousness: smear positivity, cavitary vs. non-cavitary diseaseHost factors: immune competencyEnvironment: ventilation, humidity, duration, proximity
13 Likelihood of Developing TB Disease Once infected with tubercle bacilli10% life time chance that TB disease will developHalf the risk within the first 2 yearsGradually decreasing risk after the first 2 years90% chance of never developing the diseaseOther personal health factors can influence riskHIV infection - single highest risk for progress to active disease, at 10% risk annuallyDiabetes – 30% risk over lifetime
14 Sites of TB DiseasePulmonary TB (TB of the lungs) – 80-85% of TB casesPotential for transmission – infectious until proven otherwiseExtra-pulmonary TB (outside the lungs)Can occur anywhere in bodyTypical sites include larynx, lymph nodes, the pleura, brain, kidneys, bones, or jointsUsually not infectious – always rule out pulmonary!Laryngeal TB is extremely contagious - hoarsenessExtra-pulmonary disease – portal of entry through the lungs at time of infectionPut this somewhere else:Before Anti TB drugs 50 % of all TB patients died...AND OF THE 45% WHO SURVIVED, 25% were chronically ill for a lifetime
15 Diagnosis of TB Disease SymptomsTST or IGRACXRBacteriology
16 Diagnosis of TB Disease: Symptoms Pulmonary symptomsCoughPain in the chest when breathing or coughingCoughing up sputum or bloodSystemic symptomsFatigue / malaiseDecreased appetiteWeight lossFeverNight sweatsOther symptoms specific to the site of the TB diseaseThe first thing that usually prompts suspicion of TB are symptoms.TB is slow in onset, and will often go unnoticed, even by the patient, for months.Symptoms should be evaluated in the context of the patient’s overall history. For example, a women, aged 50 with night sweats and no other symptoms would not be a concern.
17 Evaluation for TB Disease Medical HistorySymptoms of TBExposure to TB, Hx previous TB infection, or Hx TB diseaseRisk factors for progression to TB diseaseTB skin test or IGRAChest x-ray or CTBacteriologic Examination of sputa, including:Smears (+AFB)MTD or PCR “direct test (RNA based)Culture results “DNA probes” or traditional culture
18 Diagnosis of TB Disease Evaluate all patients with symptoms of TB forTB disease, regardless of the patient’s skin test reaction1/4 to 1/3 of all active MTB cases have negativeTST at onset of treatment
19 Diagnosis of TB Disease: Chest X-Ray Check for lung abnormalities suggestive of TB diseaseTypical findings may include cavities, infiltrates, effusions, opacitiesA chest x-ray does not confirm TB diseaseA chest x-ray does not rule out active TB in immune compromised individuals and children
20 Diagnosis of TB Disease: Bacteriologic Examinations Sputum collection – those symptomatic or with abnormal chest x-rays consistent with TB, for AFB smear and culture:A series of three samplesSpontaneous or inducedAt least 8 hrs. apart, and one in early AMAll specimens should be cultured, regardless of smear resultSmear/stain results in 1 day, culture results take up to 6-8 weeksM.tb can be cultured from any body fluid or tissueSpecimen collected depends on the site of potential disease
21 Direct Tests for TB MTD – Mycobacterium tuberculosis direct or TB PCR These rapid tests are done directly on raw respiratory samples; culture growth is not neededVery sensitive on samples with higher smear positivityA negative test does not rule out TB, especially with negative smear resultsDoes not provide enough evidence to release from isolationAnyone with a positive culture for M.Tb or a positive rapid test is counted as a case of TB.Clinical cases that don’t have confirming culture results can also be counted under certain circumstances.
22 Antituberculosis Drugs Currently in Use in the US Second-line DrugsCycloserineEthionamideLevofloxacinMoxifloxacinGatifloxacinP-Aminosalicylic acidStreptomycinAmikacin/kanamycinCapreomycinLinezolidFirst-line DrugsIsoniazid*Rifampin*Ethambutol*Pyrazinamide*RifapentineRifabutinThe purpose here is not to make you TB nurses, but recognize some of these medications, especially the 4 most common *, isoniazid, rifampim, ethambutol, and pyrazinamide.TB is usually treated for 6 to 9 months.Drug resistant cases can take years to treat.
23 Latent Infection vs. Active Disease Latent TB Infection or LTBIActive TB DiseaseTubercle bacilli in the bodyTuberculin skin test reaction or IGRA usually positiveNo symptomsSymptoms such as cough, fever, weight lossChest x-ray usually normalChest x-ray usually abnormalSputum smears and cultures, if done, are negativeSputum smears and cultures may be positiveNot infectiousOften infectious before treatmentNot a case of TB, but risk for future diseaseA current case of TBThis chart summarizes the difference between TB infection and TB disease. [read through]After evaluation for TB disease, if the skin test has been positive, there is always the question of what to do for what has been determined to be TB infection.If sputa samples are awaiting culture, NO medication should be started for latent TB infection.However, if TB disease has been ruled out, consideration should be given to treatment for latent TB infection.Treatment of latent TB infection reduces the amount of future TB disease from approximately 1 in 10, to 1 in 100.
25 Targeted Tuberculin Testing and Treatment of Latent Tuberculosis Infection As tuberculosis (TB) disease rates in the United States (U.S.) decrease, finding and treating persons at high risk for latent TB infection (LTBI) has become a priority.
26 Before Initiating Treatment Rule out TB disease (i.e., wait for culture result if specimen obtained)Determine prior history of treatment for LTBI or TB diseaseAssess risks and benefits of treatmentDetermine current and previous drug therapy
27 Isoniazid Regimens9-month regimen of isoniazid (INH) is the preferred regimen (270 doses)6-month regimen is less effective but may be used if unable to complete 9 monthsMay be given daily or intermittently (twice weekly)Use directly observed therapy (DOT) for intermittent regimen
28 Rifampin Regimens (1)Rifampin (RIF) given daily for 4 months is an acceptable alternative when treatment with INH is not feasible.In situations where RIF cannot be used (e.g., HIV-infected persons receiving protease inhibitors), rifabutin may be substituted.
29 Rifampin Regimens RIF daily for 4 months (120 doses within 6 months) RIF and PZA for 2 months should generally not be offered due to risk of severe adverse eventsMMWR August 8, 2003; 52 (31):
30 Completion of TherapyCompletion of therapy is based on the total number of doses administered, not on duration alone.
31 Tuberculosis Control and Prevention – it takes a Team!
32 Elements of a Tuberculosis Control Program X-rayTargeted testing/LTBI treatmentInpatient careClinicalServicesPharmacyMedical evaluationand follow-upNon-TB medicalservicesSocialservicesInterpreter/translatorservicesLaboratoryHIV testing andcounselingPatienteducationData collectionCoordination ofmedical careEpidemiologyand SurveillanceDOTHomeevaluationCaseManagementContactinvestigationOutbreakInvestigationData analysisHousingProgramevaluation &planningIsolation,detentionFollow-up/treatmentof contactsA team effortReview components of slideMention that DOT is the program standard for treatment of TB disease, meaning a health care worker observes patient taking medication.QA, QI for casemanagementConsultation ondifficult casesData for nationalsurveillance reportTrainingFederal TBControl ProgramState TB Control ProgramGuidelinesInformation for publicState statutes,regulations,policies, guidelinesFundingNational surveillanceTrainingTechnical assistanceFundingVDH/DDP/TBApr 2006
33 What is Reportable According to VA Regulation? By medical provider or designeeConfirmed or suspected TB diseasePositive TST in children under age 4 yearsBy directors of medical laboratoriesPositive AFB smears or cultures
34 The Public Health Nurse – TB Case Management EducationAssure treatment according to national standardsContact investigationAssure treatment adherence and adequate therapyDOT as international program standardIdentify adverse drug reactionsMonitor clinical improvementRecognize patient behaviorsDevelop strategies to problem-solve
35 Teamwork!!Tuberculosis is suspected, diagnosed, and treated as a team.Treatment of LTBI prevents future TB diseaseIt takes all of us to get the job done!Know your local TB health department staff and ask questions!Only with knowledgeable and trained personnel can tuberculosis be quickly identified and completely managed.