Module 4 Cfdx

8/13/2019 Module 4 Cfdx

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Project Partners

Collaborative project

Funded by the United States Agency for International Development (USAID)


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Module Overview

Case Finding

Steps in Diagnosing TB

Medical History

Bacteriologic Examination

Drug SusceptibilityTesting

Radiographic Exam

Sputum smear-negativepatient

International Standards 1, 2, 3, 4, and 5


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Learning Objectives

At the end of this presentation, participantswill 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 drugsensitivity testing in the diagnosis and

management of tuberculosis


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Rapid, accuratediagnosis is essential

for individual and

public health

Despite technical

advances, clinical

acumen with a high

index of suspicionremains vital to the

diagnosis of

tuberculosis.THINK TB

Case Finding


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Question


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Opportunities for Case Finding

TB Chest Clinics Hospitals (Public)

Public Health Clinics

Voluntary Counsellingand Testing (VCT)clinics

Prevention of Mother

to Child Transmission(PMTCT) clinics

Correctional facilities(prisons, jails)

Drug Rehab Centres HIV Care facilities

Private medical clinics

Occupational Healthfacilities

Long term carefacilities and shelters


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Steps in Diagnosing TB

Medical HistoryBacteriologic

examination

Drug SusceptibilityTesting

Radiographic exam

Other examinations

based onsite(s)/location(s)involved


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Medical History

Known exposure to a person withinfectious pulmonary TB

Symptoms of TB disease and

approximate date symptoms started

Previous treatment for latent TB

infection or active TB disease Other medical conditions that might

affect treatment approach


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Question


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Standard 1: Prolonged Cough

All persons with anunexplainedproductivecough

lasting two or moreweeksshould beevaluated for

tuberculosis

Intern ational Standards for Tuberculo sis Care, 2006


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Prolonged Cough

Think TB:Prolonged Cough (2 or more weeks) Cough may not be specific for TB, however, long

duration raises the likelihood of TB diagnosis

Is criterion for suspecting TB in most national andinternational guidelines

The likelihood of AFB smear-positive sputum

increases with increasing duration of cough

Wil l no t catch al l TB cases; use best cl in ical

judgment


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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)


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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


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Clinical Presentation

Physical Examination (PE): May be normal in mildmoderate disease

Lungs: rales, rhonchi; absent breath sounds

and dullness to percussion if pleural fluid ispresent

Extrapulmonary (site specific): adenopathy,skin lesions, bone tenderness, neck stiffness,etc.

The PE is most useful when assessing fornon-pulmonary sites of TB


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Bacteriologic Examination


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Standard 2: Sputum Microscopy

All patients suspected ofhaving pulmonary TB who

can produce sputum

should have at least two

sputum specimensobtained for microscopic

examination.

When possible, at leastone early morning

specimen should be

obtained.

International Standard s for Tuberculo sis Care, 2006


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Sputum Microscopy

To confirm a diagnosis of TB, every effortmust be made to identify the causative agent

The AFB smearin 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


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Mase SR, Int J tuberc Lung Dis2007;11(5): 485-95

Average yield of single earlymorning specimen: 86.4%

Average yield of single spot specimen: 73.9%

Performance of Sputum Microscopy

SpecimenNumber

Incremental Yield

(of all smear positive)

IncrementalSensitivity

(of all culture positive)

1 85.8% 53.8%

2 11.9% 11.1%

3 2.4% 3.1%

Total 100% 68.0%


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Culture and Drug Susceptibility Testing

Obtaining culture and drugsusceptibility testing (DST)offers significantadvantages in the diagnosis

and management of TB: Increases case detection

Earlier diagnosis

Identification of drugresistance


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Culture: Advantages

Higher sensitivity than smear microscopy(culture can make diagnosis despite fewerbacilli in specimen)

If TB disease is suspected and sputumsmears are negative, culture may providediagnosis

Allows for identification of mycobacterialspecies

Allows for drug susceptibility testing


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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. Avoiddelaying appropriate TB treatment insuspicious cases while awaiting results.


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Case 1

A 32 year old man presents to the clinicwith complaint of cough x 1 month. He is

not severely ill and can be evaluated in an

ambulatory setting

What other history do you ask himabout?

What other signs will you look for duringyour examination to aide in diagnosis?


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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 treatedfor tuberculosis last year. Patient was not

evaluated for TB at that time.

What laboratory tests would do you order?

Case 1 (2)


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Among the results you receive, one ofthree sputum smears is positive for acid

fast bacilli (AFB) on direct microscopy.

What would you do next?

Case 1 (3)


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Collect additional 3 sputa for AFB smearand culture

Obtain chest X-ray

If chest X-ray result consistent with

tuberculosis, treatment for TB should be

initiated without delay

Might also consider adding broad-

spectrum antibiotic (non-fluoroquinolone)

Case 1 Summary


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Standard 3: Extrapulmonary Specimens

For all patients suspectedof having extrapulmonaryTB, appropriate specimensfrom the suspected sitesofinvolvement should be

obtained for microscopy.

Where facilities andresources are available,specimen should also besent for culture andhistopathologicalexamination.



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Pulmonary, 70%

Extrapulmonary, 21%

Both, 9%

Pleural, 18%Lymphatic, 42%

Bone/joint, 11% Genitourinary, 5%Meningeal, 6%

Other, 12%

TB Cases by Form of Disease,

United States, CDC, 2005Peritoneal, 6%

Clinical Presentation: Extrapulmonary

Incidence/site may vary TB can involve any organ

More common in HIV/TB (co-infection)


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Extrapulmonary Tuberculosis

R di hi E i ti


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Radiographic Examination


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Standard 4: Evaluation of Abnormal CXR

All persons withchest radiographicfindingssuggestive

of tuberculosisshould have sputumspecimenssubmitted formicrobiologicalexamination.

Intern ational Standards for Tuberculo sis Care, 2006


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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 Tomans tuberculosis. Case detection, treatment and monitoring,

2ndEdition: World Health Organization, 2004


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Chest Radiography

Purpose: Provides additional evidence to aide in diagnosis

of TB disease when only 1 sputum smear is

positive

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 witha newly positive tuberculin skin test (Mantoux)

Chest X-ray alone cannot confirm TB disease


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Chest Radiography (2)

Chest X-ray findings suggestive of active

PTBdisease include:

Acute upper lobe pneumonia

Unresolving pneumonia

Cavitation, cavitary lesion

Pleurisy, pleural effusion

Lung infiltrate, especially in upper lung zones

Hilar node enlargement or adenopathy



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Chest Radiography (3)

Chest X-ray findings suggestive of previousor presumed inactive PTBinclude:

Apical fibrosis

Upper lobe fibronodular abnormality

Pleural calcification

Upper lung zone bronchiectasis

Thoracoplasty or partial pneumonectomy

Healed primary lesion (Ghon focus/complex)


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Can this be TB?

C ?


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Can this be TB? Miliary TB

C hi b TB?


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54-year-old man with

three months of focal

low-back pain

Can this be TB?


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54-year-old man with

three months of focal

low-back pain

Can this be TB? Extrapulmonary

Potts disease

Signs and symptoms of extrapulmonary TB are site

specific Sampling of extrapulmonary sites for smear, culture, and

histopathology may confirm diagnosis

S S N i P i


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Sputum Smear-Negative Patient

Criteria for diagnosis: At least 3 negative sputum smears

Cultures must be attempted

Chest X-ray consistent with TB

Lack of response to broad-spectrum

(non-fluoroquinolone) antibiotic


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Standard 5: Smear-negative Diagnosis

The diagnosis of sputum smear-negative PTBshould be based on the following criteria:

At least three negative sputum smears (including atleast one early morning specimen)

Chest radiography findings consistent with TB Lack of response to a trial of broad-spectrum anti-

microbial agents (avoid use of fluoroquinolone)

For such patients, if facilities for culture areavailable, sputum cultures should be obtained.In persons with known or suspected HIV infection,the diagnostic evaluation should be expedited.


TB Diagnostic Algorithm:


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Yes

All Pulmonary TB Suspects

Sputum AFB MicroscopyAssess for HIV

Rx: Non-anti TB antibiotics

Improvement?

Repeat AFB

Order culture

1 or more smear + All smears -

CXR & medical officers

judgmentYes TB* Yes TB

*No TB

TB Diagnostic Algorithm:HIV Negative or Low Prevalence Area

2 or 3 smears +

Only 1 smear +

2 or 3 smears -

No

TB Diagnostic Algorithm:


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TB Diagnostic Algorithm:High HIV Prevalence

Ambulatory TB Suspects

AFB smears/culture, HIV test

HIV positive or ?

AFB Positive* AFB Negative *

Treat for bacterial infection and/or PCP

HIV care if positive; CPT

TB likely

Reassess

for TB

Treat for TB; CPTHIV care if positive

AFB smears/culture, CXR,

TST, clinical evaluation

TB not likely

No or poorresponse

ResponseCPT = cotrimoxazole prophylaxisReassess if

symptoms recur

C f


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Clinical Presentation and Diagnosis of TB

Remember:

Symptoms/severity (can be)none tooverwhelming

Tempo of illness: ranges from indolent to fast

TB can involve any organ or tissue

Signs/symptoms may be both local andsystemic

Consider HIV testing in the diagnosticevaluation

TB is capable of presenting in many ways

C thi b TB?


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Can this be TB?

C thi b TB?


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Can this be TB?

Distribution:Any lobe

involved (slight lower lobepredominance)

Air-space consolidation

Cavitation is uncommon

(< 10%) Adenopathy is common

(esp. in children and HIV)

Miliary pattern

Atypical pattern:Primary TB

Cli i l P t ti d Di i f TB


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Clinical Presentation 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 ofsuspicion

AFB smear in high-prevalence areas is highlyspecific and most rapid tool for diagnosing TB

Radiographic patterns may help in TB diagnosisif suspicion high and AFB smear is negative, buta radiograph alone is not enough to makediagnosis

S ISTC St d d C d*


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* Abbreviated versions

Summary: ISTC Standards Covered*

Standard 1:Unexplained productive cough lasting2-3 weeks or more should be evaluated fortuberculosis.

Standard 2:All TB suspects should have at least

2-3 sputum specimens obtained for microscopicexamination (at least one early morningspecimen if possible).

Standard 3:Specimens from suspectedextrapulmonary TB sites should be obtained formicroscopy, and if possible, for culture andhistopathological exam.

S ISTC St d d C d*


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Summary: ISTC Standards Covered*

Standard 4:All persons with chest radiographicfindings suggestive of TB should have sputumspecimens submitted for microbiologicalexamination.

Standard 5:The diagnosis of smear-negativepulmonary TB should be based on the following:at least two negative sputum smears (includingat least one early morning specimen); CXR

finding consistent with TB; and lack of responseto broad-spectrum antibiotics (avoidfluoroquinolones). Obtain cultures as available.

Think TB* Abbreviated versions


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Additional Cases

Can this be TB?


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Can this be TB?

Can this be TB?


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Can this be TB?

Distribution

Apical / posterior segmentsof upper lobes

Superior segments of lower lobes Isolated anterior segment

involvement is unusual (think M.aviumcomplex or other disease)

Typical Pattern:Reactivation,Post-primary TB

Reactivation/Post primary TB


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Reactivation/Post-primary TB

Patterns of disease Air-space consolidation

Cavitation, cavitarynodule

Endobronchial spread

Miliary

Bronchostenosis

Tuberculoma

Pleural effusions

Can this be TB?


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Can this be TB?

Can this be TB?


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Can this be TB?

Findings suggestive ofprior TB

Ca+ granulomaGhon lesion

Ca+ granuloma and hilar nodecalcificationRanke complex

Apical pleuralthickening

Fibrosis andvolume loss

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Module 4 Cfdx