Download International Standards for Tuberculosis Care, 2009

Module 5 – March 2010
Case Finding and
Diagnosis
Project Partners
Funded by the Health Resources and Services Administration (HRSA)
Module Overview
 Case Finding
 Steps in Diagnosing TB
• Medical History
• Bacteriologic Examination
• Drug Susceptibility
Testing
• Radiographic Exam
• Sputum smear-negative
patient
International Standards 1, 2, 3, 4, 5, and 18
Learning Objectives
At the end of this presentation, participants
will be able to:
 List the steps involved in diagnosing
tuberculosis
 Describe the role of sputum smear
microscopy in the diagnosis of
tuberculosis
 Recognize the role of culture and drug
sensitivity testing in the diagnosis and
management of tuberculosis
Case Finding
 Rapid, accurate diagnosis is essential for
individual and public health
 Despite technical advances, clinical
acumen with a high index of suspicion
remains vital to the diagnosis of
tuberculosis
 THINK TB
Where can you conduct
case finding activities?
Opportunities for Case Finding
 TB Chest Clinics
 Drug Rehab Centres
 Hospitals (Public)
 HIV Care facilities
 Public Health Clinics
 Private medical clinics
 Voluntary Counselling  Occupational Health
and Testing (VCT)
facilities
clinics
 Long term care
 Prevention of Mother
facilities and shelters
to Child Transmission
(PMTCT) clinics
 Correctional facilities
(prisons, jails)
Steps in Diagnosing TB
 Medical History
 Bacteriologic
examination
 TB Culture and Drug
Susceptibility Testing
 Radiographic exam
 Other examinations
based on
site(s)/location(s)
involved
Medical History
 Known exposure to a person with
infectious pulmonary TB
 Symptoms of TB disease and onset
 Previous treatment for latent TB infection
or active TB disease
 Risk factors for developing TB disease
 Other medical conditions that might affect
treatment approach
What are the signs and
symptoms of tuberculosis?
Standard 1: Prolonged Cough
All persons with
otherwise
unexplained
productive cough
lasting two-three
weeks or more
should be evaluated
for tuberculosis
International Standards for Tuberculosis Care, 2009
Prolonged Cough
Think TB: Prolonged Cough (2 - 3 weeks)
 Cough may not be specific for TB, however,
long duration raises the likelihood of TB
diagnosis
 This is common criterion for suspecting TB in
most national and international guidelines
 The likelihood of AFB smear-positive sputum
increases with increasing duration of cough
 Will not catch all TB cases; use best
clinical judgment
“Classic” TB Clinical Presentation
 Subtle onset and chronic course
 Chest symptoms
• Cough (usually productive)
• Hemoptysis
• Chest pain (usually pleuritic)
 Nonspecific constitutional symptoms
 Extrapulmonary symptoms (if involved)
Typical Systemic Symptoms




Fever in 65-80% of cases
Night sweats
Fatigue/malaise
Anorexia/weight loss
 10-20% of TB cases have no
symptoms at the time of diagnosis
Clinical Presentation
Physical Examination (PE):
 May be normal in mild–moderate disease
 Lungs: rales, rhonchi; absent breath
sounds and dullness to percussion if
pleural fluid is present
 Extrapulmonary (site specific):
adenopathy, skin lesions, bone
tenderness, neck stiffness, etc.
 The PE is most useful when assessing
for non-pulmonary sites of TB
Bacteriologic Examination
Standard 2: Sputum Microscopy
All patients
suspected of having
pulmonary TB who
can produce sputum
should have at least
two sputum
specimens obtained
for microscopic examination in a
quality-assured laboratory.
When possible, at least one early morning
specimen should be obtained.
International Standards for Tuberculosis Care, 2009
Sputum Microscopy
 To confirm a diagnosis of TB, every effort
must be made to identify the causative
agent
 The AFB smear in high-prevalence
areas is:
• Highly specific for TB
• Most rapid method for determining TB
diagnosis
• Identifies those at greatest risk of dying from
TB
• Identifies those most likely to transmit disease
Performance of Sputum Microscopy
Specimen
Number
Incremental Yield
(of all smear positive)
Incremental
Sensitivity
(of all culture positive)
1
85.8%
53.8%
2
11.9%
11.1%
3
2.4%
3.1%
Total
100%
68.0%
Average yield of single early morning specimen: 86.4%
Average yield of single spot specimen: 73.9%
Mase SR, Int J tuberc Lung Dis 2007;11(5): 485-95
Culture & Drug Susceptibility Testing
Obtaining culture and
drug susceptibility
testing (DST) offers
significant advantages
in the diagnosis and
management of TB:
 Increases case detection
 Earlier diagnosis
 Identification of drug
resistance
Culture: Advantages
 Higher sensitivity than smear microscopy
(culture can make diagnosis despite fewer
bacilli in specimen)
 If TB disease is suspected and sputum
smears are negative, culture may provide
diagnosis
 Allows for identification of mycobacterial
species
 Allows for drug susceptibility testing
Culture: Disadvantages




Cost
Technical complexity
May take weeks to get results
Requires ongoing quality assurance
 Therefore, culture testing is more likely to
be found in major referral centers. Avoid
delaying appropriate TB treatment in
suspicious cases while awaiting results.
Case 1
A 32 year old man presents to the clinic with
complaint of cough x 1 month. He is not
severely ill and can be evaluated in an
ambulatory setting.
Questions:
 What other history do you ask him about?
 What other signs will you look for during
your examination to aide in diagnosis?
Case 1 (2)
Patient gives further history of feeling poorly
for several months now; reports weight loss
(about 3-4kg) and cough has gotten
progressively worse. Patient denies
smoking. His brother was treated for
tuberculosis last year. Patient was not
evaluated for TB at that time.
Question:
 What laboratory tests would do you order?
Case 1 (3)
Among the results you receive, one of two
sputum smears is positive for acid fast
bacilli (AFB) on direct microscopy.
Question:
 What would you do next?
Case 1 Summary
If smear result is from a Lab with EQA:
 Obtain chest X-ray, order TB culture and
initiate TB treatment
Standard 3: Extrapulmonary Specimens
For all patients
suspected of having
extrapulmonary TB,
appropriate specimens
from the suspected
sites of involvement
should be obtained for
microscopy, culture,
and histopathological
examination.
International Standards for Tuberculosis Care, 2009
Clinical Presentation: Extrapulmonary
 Incidence/site may vary  TB can involve any organ
 More common in HIV/TB (co-infection)
Both, 9%
Lymphatic, 42%
Pleural, 18%
Extrapulmonary, 21%
Other, 12%
Pulmonary, 70%
Bone/joint, 11%
TB Cases by Form of Disease,
United States, CDC, 2005
Peritoneal, 6%
Genitourinary, 5%
Meningeal, 6%
Extrapulmonary Tuberculosis
Radiographic
Examination
Standard 4: Evaluation of Abnormal CXR
All persons with
chest radiographic
findings suggestive
of tuberculosis
should have sputum
specimens
submitted for
microbiological
examination.
International Standards for Tuberculosis Care, 2009
Evaluation of Abnormal CXR
Study from India:
2229 outpatients evaluated by CXR/culture
 Of 227 cases deemed TB by CXR alone
• 36% had negative sputum cultures for TB
 Of 162 culture-positive cases of TB
• 20% would have been missed based on CXR alone
 CXR alone is not enough!
Nagpaul DR, Proceedings of the 9th Eastern Region Tuberculosis Conference and 29th National
Conference on Tuberculosis and Chest Diseases. 1974 Delhi, as cited in Toman’s tuberculosis.
Case detection, treatment and monitoring, 2nd Edition: World Health Organization, 2004
Chest Radiography
Purpose:
 Provides additional evidence to aid in diagnosis
of TB disease when only 1 sputum smear is
positive in settings without an EQC laboratory
 Check for lung abnormalities in people who
have symptoms of TB; especially in those with
HIV co-infection
 Evaluate and rule out TB disease in persons
with a newly positive tuberculin skin test
(Mantoux)
 Chest X-ray alone cannot confirm TB disease
Chest Radiography (2)
Chest X-ray findings suggestive of active
PTB disease include:
 Acute upper lobe pneumonia
 Unresolving pneumonia
 Cavitation, cavitary lesion
 Pleurisy, pleural effusion
 Lung infiltrate, especially in upper lung zones
 Intrathoracic adenopathy
International Standards for Tuberculosis Care, 2009
Chest Radiography (3)
Chest X-ray findings suggestive of previous
or presumed inactive PTB include:
 Apical fibrosis
 Upper lobe fibronodular abnormality
 Pleural (fibro) calcification
 Upper lung zone bronchiectasis
 Thoracoplasty or partial pneumonectomy
 Healed primary lesion (Ghon focus/complex)
Can this be TB?
Can this be TB? Miliary TB
Can this be TB?
54-year-old man with
three months of focal
low-back pain
Can this be TB? Extrapulmonary
54-year-old man with
three months of focal
low-back pain
 “Pott’s disease”
 Signs and symptoms of extrapulmonary TB
are site specific
 Sampling of extrapulmonary sites for smear,
culture, and histopathology may confirm
diagnosis
Sputum Smear-Negative Patient
Criteria for diagnosis:
 Have sputum that is smear-negative but culturepositive for M. tuberculosis
OR
 Decision by a clinician to treat with a full course
of anti-TB therapy; AND
 Chest X-ray consistent with TB; AND either:
• Laboratory or strong clinical suspicion of HIV
infection
• Lack of response to broad-spectrum (nonfluoroquinolone) antibiotic (if HIV-negative or
unknown)
Standard 5: Smear-negative Diagnosis
The diagnosis of sputum smear-negative PTB
should be based on the following criteria:
 At least two negative sputum smears (including
at least one early morning specimen)
 Chest radiographic findings consistent with TB
 Lack of response to a trial of broad-spectrum
anti-microbial agents (avoid use of
fluoroquinolones)
For such patients sputum cultures should be
obtained.
International Standards for Tuberculosis Care, 2009
Standard 5: Smear-negative Diagnosis (2)
 In persons who are seriously ill or have
known or suspected HIV infection, the
diagnostic evaluation should be expedited
and if clinical evidence strongly suggests
TB, a course of antituberculosis treatment
should be initiated
International Standards for Tuberculosis Care, 2009
TB Diagnostic Algorithm:
HIV-Negative or Low Prevalence Area
All Pulmonary TB Suspects
Sputum AFB Microscopy
Assess for HIV
Any smear +
Rx: Non-anti TB antibiotics
Improvement?
> 2 smears -
No
Yes
Repeat AFB smear
Order TB culture
> 1 smear +or TB culture +
Yes TB*
Yes TB*
All smears CXR & medical officer’s
judgment
No TB
TB Diagnostic Algorithm:
HIV-Positive and High Prevalence
Ambulatory HIV+ TB Suspect
AFB smears/culture; DST
AFB Positive*
Treat for TB; CPT;
HIV care if positive
AFB Negative *
TB likely
Clinical evaluation; CXR; TST;
may repeat AFB smears/culture
TB not likely
Reassess
for TB
No or poor
response
Treat for bacterial infection and/or PCP;
HIV care if positive; CPT
Reassess if
symptoms recur
CPT = cotrimoxazole prophylaxis
Response
Clinical Presentation and Diagnosis of TB
Remember:
 Symptoms/severity can range from none to
overwhelming
 Tempo of illness: ranges from indolent to fast
 TB can involve any organ or tissue
 Signs/symptoms may be both local and
systemic
 Consider HIV testing in the diagnostic
evaluation
 TB is capable of presenting in many ways
Can this be TB?
Can this be TB?
Atypical pattern:
Primary TB
 Distribution: Any lobe
involved (slight lower
lobe predominance)
 Air-space consolidation
 Cavitation is uncommon
(< 10%)
 Adenopathy is common
(especially in children
and HIV)
 Miliary pattern
ISTC Standard 18
All providers of care for patients with TB should
ensure that persons who are in close contact with
patients who have infectious TB are evaluated and
managed in line with international recommendations.
The determination of priorities for contact investigation
is based on the likelihood that a contact:
1. Has undiagnosed TB
2. Is at high risk of developing TB if infected
3. Is at risk of having severe TB if the disease
develops
4. Is at high risk of having been infected by the index
case
ISTC Standard 18 (2)
The highest priority contacts for evaluation are:
 Persons with symptoms
suggestive of
tuberculosis
 Children aged <5 years
 Contacts with known
or suspected immunocompromise, particularly
HIV infection
 Contacts of patients with MDR/XDR tuberculosis
 Other close contacts are a lower priority group
Contact Investigation
 There is a high likelihood that a person
with smear-positive PTB will transmit
tuberculosis. Therefore, prompt and
thorough contact investigation is essential
for the control of TB
 Contact investigations should start with
the persons most likely to be infected
(those who most frequently come in
contact with the person who has
infectious TB)
Contact Investigation (2)
 Actively seeking out and evaluating
contacts to persons with smearpositive PTB is an important TB
control strategy for two reasons:
• It identifies persons with previously
undetected tuberculosis, allowing initiation of
treatment and halting further transmission
• It identifies persons with TB infection who
would benefit from isoniazid preventive
therapy (IPT) to prevent future TB reactivation
Case Finding and Diagnosis of TB
Summary:
 A prolonged duration of cough should raise TB
suspicion and trigger a diagnostic evaluation
 TB risk factors and exposure increase level of
suspicion
 AFB smear in high-prevalence areas is highly
specific and most rapid tool for diagnosing TB
 Radiographic patterns may help in TB
diagnosis if suspicion high and AFB smear is
negative, but a radiograph alone is not enough
to make diagnosis
Summary: ISTC Standards Covered*
Standard 1: Unexplained productive cough lasting
2-3 weeks or more should be evaluated for
tuberculosis.
Standard 2: All TB suspects should have at least
2 sputum specimens obtained for microscopic
examination (at least one early morning
specimen if possible).
Standard 3: Specimens from suspected
extrapulmonary TB sites should be obtained for
microscopy, culture, and histopathological
exam.
* Abbreviated versions
Summary: ISTC Standards Covered* (2)
Standard 4: All persons with chest radiographic
findings suggestive of TB should have sputum
specimens submitted for microbiological
examination.
Standard 5: The diagnosis of smear-negative PTB
should be based on the following: at least two
negative sputum smears (including at least one
early morning specimen); CXR finding consistent
with TB; and lack of response to broad-spectrum
antibiotics (avoid fluoroquinolones). Obtain
cultures. Seriously ill or HIV + patients should
have an expedited diagnostic evaluation and if
there is strong clinical evidence, treatment should
be initiated.
* Abbreviated versions
Summary: ISTC Standards Covered* (3)
Standard 18: All providers of care for patients with TB
should ensure that persons who are in close
contact with patients who have infectious TB are
evaluated and managed in line with international
recommendations. The highest priority contacts for
evaluation are:
 Persons with symptoms suggestive of tuberculosis
 Children aged <5 years
 Contacts with known or suspected
immunocompromise, particularly HIV infection
 Contacts of patients with MDR/XDR tuberculosis
 Other close contacts are a lower priority group
* Abbreviated versions
 Think TB
Additional Cases
Can this be TB?
Can this be TB?
Typical Pattern:
Reactivation,
Post-primary TB
Distribution
 Apical / posterior segments
of upper lobes
 Superior segments of lower
lobes
 Isolated anterior segment
involvement is unusual (think M.
avium complex or other disease)
Reactivation/Post-primary TB
Patterns of disease
 Air-space consolidation
 Cavitation, cavitary
nodule
 Endobronchial spread
 Miliary
 Bronchostenosis
 Tuberculoma
 Pleural effusions
Can this be TB?
Can this be TB?
Findings suggestive of
prior TB
 Ca+ granuloma – Ghon lesion
 Ca+ granuloma and hilar node
calcification – Ranke complex
 Apical pleural
thickening
 Fibrosis and
volume loss