TUBERCULOSISPulmonarytuberculosisDR CHIA KOK KINGDR CHIA KOK KINGHealth & Medical OfficerHealth & Medical OfficerPKD Langkawi, KedahPKD Langkawi, Kedah
What is tuberculosis?• Airborne infection caused by Mycobacteriumtuberculosis (MTB) or tubercle bacillus(TB)• Highly contagious• Spreads by contact with infected person viaair droplets who is activelycoughing/talking/sneezing/shouting/singing• >1 in 3 individuals is infected with TB.• 8.8 million incident cases of TB worldwide in2010, with 1.1 million deaths among HIVnegative persons, 0.35 million deaths fromHIV-associated TB.
• TB incidence rates have been falling since 2002• Absolute number of TB cases falling since 2006• 5 countries with highest incidence cases in 2010(India, China, South Africa, Indonesia, Pakistan)• Highest rates of TB infection in young adults (25-40yo)• TB is uncommon in children 5-15yo
Pulmonary tuberculosis• Lungs are the most common site of development• PTB is the commonest form as post-primary TB• 85% of TB patients presented with pulmonarycomplaints• Classical clinical features :Cough (>2 weeks in gen. pop / 7-10days in high risk)Night sweatsLOAHemoptysisLOWLethargyFeverHoarseness of voice
• Risk factors :– HIV infection– IVDU– Alcoholism– DM (3 fold risk increase)– ESRF– Pre-existing chronic respiratory disease– Low body weight– Smoking– Immunocompromised patients (immunosuppressivetherapy/cancer etc)– Mantoux positive– H/O TB infection/TB exposure– Travel/emigration from TB endemic places– Homeless/shelter-dwelling individuals– Age <5 years old
• Criteria leading to high index of suspicionfor active TB :– Cardinal symptoms– Contacts with TB patients– High risk groups– Live in TB endemic places– Cavitation on CXR– Positive AFB sputum smear results
PathophysiologyPathophysiology• Exposure of lungs or mucous membraneto infected aerosols• Person wit active PTB, a single cough cangenerate 3000 infective droplets, with asfew as 10 bacilli needed to initiateinfection.
• LTBI = no TB disease, cannot spread,LTBI = no TB disease, cannot spread,Mantoux positive, but not TB caseMantoux positive, but not TB case
• MTB which is resistant to standard antiTB drugsMTB which is resistant to standard antiTB drugs• More infectious than susceptible MTB?? - - No!More infectious than susceptible MTB?? - - No!• Delay in the recognition of drug resistance orDelay in the recognition of drug resistance orprolonged periods of infectiousness mayprolonged periods of infectiousness mayfacilitate increased transmission and furtherfacilitate increased transmission and furtherdevelopment of drug resistance.development of drug resistance.
• Multidrug-resistant TB (MDR TB) is caused byorganisms resistant to the most effective anti-TBdrugs : isoniazid and rifampin.• Extensively drug-resistant TB (XDR TB) is arare type of drug-resistant TB to isoniazid andrifampin, plus any fluoroquinolone and at leastone of three injectable second-line drugs (i.e.,amikacin, kanamycin, or capreomycin). Patientsare left with treatment options that are moretoxic, more expensive, and much less effective.
Method of diagnosis for PTBMethod of diagnosis for PTB• Sputum AFB– 3 specimens, preferably with one early morning sample– Usually positive in cavitary disease– 3 smears = sensitivity of 1 culture− Advantages- Rapid, high specificity- Accurate diagnoses- By paramedical personnel- Using simple and available equipment− Disadvantage− Low sensitivity
81%93%100%0%50%100%First Second ThirdCumulativePositivityThree sputum smearsThree sputum smearsare optimalare optimal
Proportion of patients with pulmonaryProportion of patients with pulmonaryTB who have positive AFB smearsTB who have positive AFB smears010203040506070 HIVNegativeEarly HIVLate HIVAFB positivity inTB patients
• Sputum MTB culture– Egg-based media : DELAYS (8 weeks)– BACTEC : for early diagnosis or smear negative (2weeks)– For identification and sensitivity of microorganism– Indications :– Sputum positive PTB– Suspected TB with sputum AFB –ve– Treatment failure– TAI– Sputum positive despite treatment
• CXRLesions in apical and posterior segments of upperlobes/ apical segment of lower lobesCavitation = active disease unless patient’s treated No chest X-ray pattern is absolutely typical of TB 10-15% of culture-positive TB patients not diagnosedby X-ray 40% of patients diagnosed as having TB on the basisof x-ray alone do not have active TBX-ray is unreliable for diagnosing andX-ray is unreliable for diagnosing andmonitoring treatment of tuberculosismonitoring treatment of tuberculosis⇒Toman K. Tuberculosis case finding and chemotherapy. WHO, 1979
020406080100Diagnosed by X-ray aloneActual casesX-ray-based evaluation causesX-ray-based evaluation causesover-diagnosis of TBover-diagnosis of TBNTI, Ind J Tuberc, 1974Over-diagnosis
• Mantoux testMantoux test– Useful in paediatric/extropulmonary casesUseful in paediatric/extropulmonary cases– 2T.U. in 0.1ml prepared solution, intradermally2T.U. in 0.1ml prepared solution, intradermally– Read after 72 hours – INDURATIONRead after 72 hours – INDURATION– Positive? Only TB infection, not active diseasePositive? Only TB infection, not active disease• ESRESR– Little role, not recommended!!Little role, not recommended!!• PCRPCR– Rapid, but may give false positive/negativeRapid, but may give false positive/negativeresults, even in patients on treatmentresults, even in patients on treatment
Classification of PTBClassification of PTBPulmonary tuberculosisSmear-positive PTB Smear-negative PTBTB in patient with 2 initial sputumAFB positiveTB in patient with sputum AFB x3negative and CXR findingsconsistent with PTBTB in patient with 1 sputum AFBpositive, and CXR findingsconsistent with TBTB in patient with sputum AFB x3negative, but positive MTB cultureTB in patient with at least 1sputum AFB positive with MTBculture positive
OUTPATIENT AND EMERGENCY DEPARTMENTSOUTPATIENT AND EMERGENCY DEPARTMENTS• Put up signage to inform patients with chronic cough:- to go to specific / identified counter or staff use surgical mask provided before proceeding to registrationcounter.• Triage – to separate high risk patients (i.e. patientswith history of cough for more than 2 weeks).• Provide N95 respirator for HCW in-charge of triaging.• When taking a patient’s medical history HCWs should routinelydocument whether the patient has symptoms and signs of TB.• During clinical assessment, HCW should educate patient withsuspected or confirmed infectious TB disease on strict respiratoryhygiene and cough etiquette.• Patient with persistent cough should be provided with surgical mask.
• Specific waiting area or room forisolation of patients with persistentcough should be identified.• Patients should be seen in aspecific consultation room equippedwith PPE (N95).• ensure the consultation room hasgood ventilation• performance monitoring andmaintenance of ventilation system bedone on regular basis.• disinfection of the room to be doneafter each clinic session.• patients may be required to wearsurgical mask when attending the clinic
ReferencesReferences• CDC : Transmission and Pathogenesis of TuberculosisCDC : Transmission and Pathogenesis of Tuberculosis• CPG for the control and management of Tuberculosis, 2CPG for the control and management of Tuberculosis, 2ndndedition, 2002 (MOH)edition, 2002 (MOH)• Guidelines On Prevention And Management ofGuidelines On Prevention And Management ofTuberculosis For HCWs In MOHTuberculosis For HCWs In MOH