2. What is tuberculosis?
• Airborne infection caused by Mycobacterium
tuberculosis (MTB) or tubercle bacillus
(TB)
• Highly contagious
• Spreads by contact with infected person via
air droplets who is actively
coughing/talking/sneezing/shouting/singing
• >1 in 3 individuals is infected with TB.
• 8.8 million incident cases of TB worldwide in
2010, with 1.1 million deaths among HIV
negative persons, 0.35 million deaths from
HIV-associated TB.
3. • 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
4. 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 pulmonary
complaints
• Classical clinical features :
Cough (>2 weeks in gen. pop / 7-10days in high risk)
Night sweats
LOA
Hemoptysis
LOW
Lethargy
Fever
Hoarseness of voice
5. • Risk factors :
– HIV infection
– IVDU
– Alcoholism
– DM (3 fold risk increase)
– ESRF
– Pre-existing chronic respiratory disease
– Low body weight
– Smoking
– Immunocompromised patients (immunosuppressive
therapy/cancer etc)
– Mantoux positive
– H/O TB infection/TB exposure
– Travel/emigration from TB endemic places
– Homeless/shelter-dwelling individuals
– Age <5 years old
6.
7. • Criteria leading to high index of suspicion
for active TB :
– Cardinal symptoms
– Contacts with TB patients
– High risk groups
– Live in TB endemic places
– Cavitation on CXR
– Positive AFB sputum smear results
8. PathophysiologyPathophysiology
• Exposure of lungs or mucous membrane
to infected aerosols
• Person wit active PTB, a single cough can
generate 3000 infective droplets, with as
few as 10 bacilli needed to initiate
infection.
9.
10. • LTBI = no TB disease, cannot spread,LTBI = no TB disease, cannot spread,
Mantoux positive, but not TB caseMantoux positive, but not TB case
13. • 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 or
prolonged periods of infectiousness mayprolonged periods of infectiousness may
facilitate increased transmission and furtherfacilitate increased transmission and further
development of drug resistance.development of drug resistance.
14. • Multidrug-resistant TB (MDR TB) is caused by
organisms resistant to the most effective anti-TB
drugs : isoniazid and rifampin.
• Extensively drug-resistant TB (XDR TB) is a
rare type of drug-resistant TB to isoniazid and
rifampin, plus any fluoroquinolone and at least
one of three injectable second-line drugs (i.e.,
amikacin, kanamycin, or capreomycin). Patients
are left with treatment options that are more
toxic, more expensive, and much less effective.
16. 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
18. Proportion of patients with pulmonaryProportion of patients with pulmonary
TB who have positive AFB smearsTB who have positive AFB smears
0
10
20
30
40
50
60
70 HIV
Negative
Early HIV
Late HIV
AFB positivity in
TB patients
19. • Sputum MTB culture
– Egg-based media : DELAYS (8 weeks)
– BACTEC : for early diagnosis or smear negative (2
weeks)
– For identification and sensitivity of microorganism
– Indications :
– Sputum positive PTB
– Suspected TB with sputum AFB –ve
– Treatment failure
– TAI
– Sputum positive despite treatment
20. • CXR
Lesions in apical and posterior segments of upper
lobes/ apical segment of lower lobes
Cavitation = active disease unless patient’s treated
No chest X-ray pattern is absolutely typical of TB
10-15% of culture-positive TB patients not diagnosed
by X-ray
40% of patients diagnosed as having TB on the basis
of x-ray alone do not have active TBX-ray is unreliable for diagnosing andX-ray is unreliable for diagnosing and
monitoring treatment of tuberculosismonitoring treatment of tuberculosis
⇒
Toman K. Tuberculosis case finding and chemotherapy. WHO, 1979
21.
22.
23. 0
20
40
60
80
100
Diagnosed by X-
ray alone
Actual cases
X-ray-based evaluation causesX-ray-based evaluation causes
over-diagnosis of TBover-diagnosis of TB
NTI, Ind J Tuberc, 1974
Over-
diagnosis
24. • 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/negative
results, even in patients on treatmentresults, even in patients on treatment
25. Classification of PTBClassification of PTB
Pulmonary tuberculosis
Smear-positive PTB Smear-negative PTB
TB in patient with 2 initial sputum
AFB positive
TB in patient with sputum AFB x3
negative and CXR findings
consistent with PTB
TB in patient with 1 sputum AFB
positive, and CXR findings
consistent with TB
TB in patient with sputum AFB x3
negative, but positive MTB culture
TB in patient with at least 1
sputum AFB positive with MTB
culture positive
26. 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 registration
counter.
• Triage – to separate high risk patients (i.e. patients
with 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 routinely
document whether the patient has symptoms and signs of TB.
• During clinical assessment, HCW should educate patient with
suspected or confirmed infectious TB disease on strict respiratory
hygiene and cough etiquette.
• Patient with persistent cough should be provided with surgical mask.
27. • Specific waiting area or room for
isolation of patients with persistent
cough should be identified.
• Patients should be seen in a
specific consultation room equipped
with PPE (N95).
• ensure the consultation room has
good ventilation
• performance monitoring and
maintenance of ventilation system be
done on regular basis.
• disinfection of the room to be done
after each clinic session.
• patients may be required to wear
surgical mask when attending the clinic
28.
29. 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, 2ndnd
edition, 2002 (MOH)edition, 2002 (MOH)
• Guidelines On Prevention And Management ofGuidelines On Prevention And Management of
Tuberculosis For HCWs In MOHTuberculosis For HCWs In MOH
