Clinical Presentation and Diagnosis of Tuberculosis Your name Institution/organization Meeting Date International Standards 1-5.

Clinical Presentation and Diagnosis of TuberculosisYour name Institution/organizationMeetingDate

International Standards 1-5

ISTC TB Training Modules 2009

Clinical Presentation and Diagnosis of TB

Objectives: At the end of this presentation,participants will be able to: Describe the signs/symptoms and risk factors that

should raise suspicion for the diagnosis of TB Understand the importance of sputum smear

microscopy, as well as the need to obtain specimens for microbiologic examination from extrapulmonary sites

Recognize that CXR alone is not sufficient for the diagnosis of TB

List criteria used for the diagnosis of smear-negative TB



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

Overview: General considerations Signs and symptoms Role of AFB smear Radiographic

presentation AFB smear-negative

diagnosis


Standards for Diagnosis


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 TB Think TB

Fundamental Principles


“Classic” TB Clinical Presentation

Insidious onset and chronic course Chest symptoms

• Cough (usually productive)• Hemoptysis• Chest pain (usually pleuritic)

Nonspecific constitutional symptoms (more common in children and HIV)

Extrapulmonary symptoms (if involved)


Nonspecific Systemic Symptoms

Fever in 65-80% of cases

Chills/night sweats

Fatigue/malaise

Anorexia/weight loss

However, 10-20% of TB cases have no symptoms at the time of diagnosis


Diagnosis of TB in HIV

Cannot rely on “typical” indicators of TB

Fever and weight loss are important symptoms

Cough is less common

Chest radiographic pattern more variable

More extrapulmonary and disseminated TB

Differential diagnosis is broader


Standard 1: Prolonged Cough

All persons with otherwise unexplained productive cough lasting two-three weeks or more should be evaluated for tuberculosis


Prolonged Cough

Think TB: Prolonged Cough (2-3 weeks) Cough may not be specific for TB,

however, long duration raises likelihood of TB diagnosis

Criterion for suspecting TB in most national and international guidelines

Percentage of AFB smear-positive sputum increases with increasing duration of cough

Will not identify all TB cases; use best clinical judgment


Clinical Presentation: Risk Factors

Risk for Recent Infection Contact with active TB case Occupational risk – e.g. healthcare worker Crowded conditions – e.g. jails, institutional

residences Recent stay in a healthcare facility


Clinical Presentation: Risk Factors

Risk of Progression to Active TB HIV infection Abnormal CXR suggestive of prior TB (with

inadequate treatment) Children (less than 5 years of age) Underlying medical conditions

• Immunosuppressive therapy

• Malnutrition

• Diabetes, renal failure, and other conditions

• Tobacco use, injection drug use (?)


Clinical Presentation: Physical Examination

May be normal in mild–moderate disease Chest: 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 physical examination is nonspecific, but it is helpful to identify extrapulmonary sites of involvement


Standard 2: Sputum Microscopy

All patients (adults, adolescents, and children who are capable of producing sputum) suspected of having pulmonary TB 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.


Sputum Microscopy

To prove 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


Mase SR, Int J tuberc Lung Dis 2007;11(5): 485-95

Average yield of single early morning specimen: 86.4%Average yield of single spot specimen: 73.9%

Specimen Number

Incremental Yield of smear specimens

(of all smear positive)

Incremental Sensitivity of smear specimens

(compared with culture)

1 85.8% 53.8%

2 11.9% 11.1%

3 2.4% 3.1%

Total 100% 68.0%

Performance of Sputum Microscopy


54-year-old man with three months of focal low-back pain

Can this be TB? Extrapulmonary

“Pott’s disease” Signs and symptoms of extrapulmonary TB are

site specific Sampling of extrapulmonary sites for smear,

culture, and histopathology may confirm diagnosis


Standard 3: Extrapulmonary Specimens

For all patients (adults, adolescents, and children) suspected of having extrapulmonary TB, appropriate specimens from the suspected sites of involvement should be obtained for microscopy, culture, and histopathological examination.


Pulmonary, 71%

Extrapulmonary, 20%

Both, 9%

Pleural, 18%

Lymphatic, 42%

Bone/joint, 11% Genitourinary, 5%

Meningeal, 5%

Other, 13%

TB Cases by Form of Disease,United States, CDC, 2008 Peritoneal, 6%

Clinical Presentation: Extrapulmonary

Incidence/site may vary TB can involve any organ More common in HIV/TB


Extrapulmonary Tuberculosis


Radiographic Presentation of TB


Standard 4: Evaluation of Abnormal CXR

All persons with chest radiographic findings suggestive of tuberculosis should have sputum specimens submitted for microbiological examination.

ISTC Training Modules 2008


Distribution

Apical / posterior segments of upper lobes

Superior segments of lower lobes

Isolated anterior segment involvement is unusual

Can this be TB?

Typical Pattern: Reactivation, Post-primary TB


Reactivation/Post-primary TB

Patterns of disease Air-space consolidation Cavitation, cavitary

nodule Miliary Fibro-nodular densities Nodule (Tuberculoma) Pleural effusions


Can this be TB?

Distribution: Any lobe involved (slight lower lobe predominance)

Air-space consolidation Cavitation is uncommon

(< 10%) Adenopathy is common

(esp. in children and HIV) Miliary pattern

Atypical pattern: Primary TB


Can this be TB? Miliary 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


CXR Issues

Reliance on chest radiograph alone results in both over-diagnosis and missed diagnosis of TB and other diseases

Radiography needs to be held to high standards of technical quality and interpretation

Results of poor imaging quality may be harmful to patient care


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 177 culture-positive cases of TB• 18% 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


The diagnosis of sputum smear-negative pulmonarytuberculosis should be based on the following criteria: At least two negative sputum smears (including at

least one early morning specimen) Chest radiography findings consistent with

tuberculosis Lack of response to a trial of broad-spectrum

antimicrobial agents (Note: Because the fluoroquinolones are active against M. tuberculosis complex, and thus may cause transient improvement in persons with tuberculosis, they should be avoided.)

Standard 5: Smear-negative Diagnosis

(1 of 2)


(Continued) For such patients, sputum cultures should

be obtained. 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 tuberculosis, a course of antituberculosis treatment should be initiated.

Standard 5: Smear-negative Diagnosis

ISTC Training Modules 2008

(2 of 2)


Clinical assessment, HIV test1, sputum smear microscopy

At least 2 sputum specimens AFB negative

HIV + and/or severe illness2 HIV-, mild/moderate illness2

1. Recommended in countries or areas with adult HIV prevalence >1% or prevalence among TB cases >5%

2. Severe illness = respiratory rate >30 breaths/min, temperature >39°C, pulse >120 beats/min, unable to walk unaided, symptoms/signs progressing rapidly

TB Diagnostic AlgorithmSPUTUM SMEAR-NEGATIVE TB


HIV + and/or severe illness

SPUTUM SMEAR-NEGATIVE TB

Clinical/radiographic findings NOT suggestive of TB

Negative culture

Consider other diagnoses

Not TB

• Clinical/radiographic findings suggestive of TB

• Positive or negative culture

Treat (empiric TB treatment before confirmed diagnosis if severe illness)

• HIV staging • Evalutate for ARVs • CPT prophylaxis

Repeat clinical assessment Chest radiograph Sputum culture (or other test)

Parenteral broad-spectrum antimicrobials (excluding fluoroquinolones)

TB Diagnostic Algorithm

TB


HIV–, mild/moderate illness

SPUTUM SMEAR-NEGATIVE TB

Broad-spectrum antimicrobials(excluding anti-TB drugs and fluoroquinolones)

Consider other diagnosis

Repeat clinical assessment Chest radiograph Sputum culture (or other test)

Treat

TB Diagnostic Algorithm

NO IMPROVEMENT

Not TB Not TBTB

Clinical/radiographic findings NOT suggestive of TB

Negative culture

Clinical/radiographic findings suggestive of TB

Positive culture

IMPROVEMENT



Additional points:

Symptoms/severity: 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



Summary: Think TB 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


* Abbreviated versions

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) in a quality-assured laboratory.

Standard 3: Specimens from suspected extrapulmonary TB sites should be obtained for microscopy, culture and histopathological exam.


Summary: ISTC Standards Covered*

* Abbreviated versions

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 pulmonary TB should be based on the following: at least two negative sputum smears (including at least one early morning specimen); CXR finding consistent with TB; lack of response to broad-spectrum antibiotics (avoid fluoroquinolones), and culture data. Empiric treatment if severe illness.


Alternate Slides


Purpose of ISTC


ISTC: Key Points

21 Standards (revised/renumbered in 2009) Differ from existing guidelines: standards

present what should be done, whereas, guidelines describe how the action is to be accomplished

Evidence-based, living document Developed in tandem with Patients’ Charter

for Tuberculosis Care Handbook for using the International

Standards for Tuberculosis Care


Audience: all health care practitioners, public and private

Scope: diagnosis, treatment, and public health responsibilities; intended to complement local and national guidelines

Rationale: sound tuberculosis control requires the effective engagement of all providers in providing high quality care and in collaborating with TB control programs

ISTC: Key Points


Questions



1. A 32 year-old man complains of cough and malaise for the past three weeks. His wife is currently being treated for active tuberculosis. Of the following choices, your first step would be:

A. Begin an empiric trial of treatment with a fluoroquinolone antibiotic for a possible community-acquired pneumonia

B. Obtain a chest film to confirm your suspicion for TB which will make sputum testing unnecessary

C. Obtain two sputum specimens for AFB microscopy (including at least one early morning specimen)

D. Both answers A and C



2. In high prevalence areas, the AFB sputum microscopy smear:

A. Is highly specific for TB

B. Identifies those at greatest risk of dying from TB

C. Identifies those most likely to transmit disease

D. All of the above



3. A 54 year-old woman complains of cough, fever, and unexpected weight loss over the past month. She admits smoking 10 cigarettes per day for over 20 years. Two sputum smears were negative for AFB. You would consider each of the following except:

A. An empiric trial of antibiotics (non-fluoroquinolone)

B. Obtaining a chest film for further evaluation

C. A trial of bronchodilator medication alone and follow-up in 3 months

D. Sending sputum specimens for AFB culture

Clinical Presentation and Diagnosis of Tuberculosis Your name Institution/organization Meeting Date International Standards 1-5.

Documents

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