2 2 TB Diagnosis by xV43uA2v

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									Diagnosis of TB
           Learning Objectives
• List the 4 principle components of a TB
  evaluation

• Describe the criteria which differentiate
  PTB+ from PTB-

• Describe the 3 major indications for culture
  and DST
    Common Sites of TB Disease

•   Lungs
•   Pleura
•   Central nervous system
•   Lymphatic system
•   Genitourinary systems
•   Bones and joints
•   Disseminated (miliary TB)
       Systemic Symptoms of TB

•   Fever

•   Chills

•   Night sweats

•   Appetite loss

•   Weight loss

•   Fatigue
        Evaluation for TB

1. HIV test

2. Medical history

3. Physical examination

4. Bacteriologic or histologic exam

   (Chest radiograph if indicated)
               Medical History
• HIV status

• Symptoms of disease

• History of TB exposure, infection, or disease

• Past TB treatment

• Demographic risk factors for TB

• Other medical conditions that increase risk for TB
  disease (e.g., diabetes)
Symptoms of Pulmonary TB

•   Productive, prolonged cough
    (duration of 2-3 weeks)

•   Chest pain

•   Hemoptysis (bloody sputum)

•   Signs may vary based on HIV status
    Specimen Collection Procedure

•    Obtain 3 sputum specimens for smear examination
     and culture

         •Spot, first morning, spot
•    Follow infection control precautions during
     specimen collection
      Sputum Smear Examination


• Specimens should be sent to the lab immediately
to preserve the quality of the specimens

•   Always aim for three specimens at each exam

• Always store at a cool temperature and away
from sunlight to preserve the quality of specimens

• 3 respiratory specimens will detect 90% of smear-
positive cases
      AFB smear-microscopy




Acid-fast bacilli (AFB) (shown in red) are tubercle bacilli
Acid fast smear showing TB bacilli
                     Smear-positive PTB vs.
                      Smear-negative PTB-

• PTB+ (Pulmonary TB smear-positive)
    –One AFB-positive smear; i.e. any patient with at
    least one positive smear result (irrespective of
    quantity of AFBs seen on microscopy)




Recommendations to improve the diagnosis of smear negative pulmonary and
extrapulmonary TB among adults in HIV prevalent and resource constrained settings.
Draft for discussion by Strategic and Technical Advisory Group of Stop TB Department of
WHOJune 2006
        Smear-positive PTB vs.
         Smear-negative PTB-
• PTB- (smear-negative)
  Any pulmonary TB case that does not meet the definition
    of being smear-positive. This includes:
  1. Patients with three negative smear results and
    radiological findings and doctor’s decision to treat for TB
  2. Patients with negative smear results and a positive
    culture result for M. tuberculosis
  3. Patients who are unable to produce sputum and with
    highly suspicious radiological and clinical findings and
    doctor's decision to treat for TB
          Other Acid Fast Bacilli
• Mycobacteria other than those comprising the M.
  tuberculosis complex are called Non-Tuberculous
  Mycobacteria (“NTM”) or Mycobacteria Other Than
  Tuberculosis (“MOTT”).

• These mycobacteria may cause pulmonary disease
  resembling TB. Increasingly, cases from these organisms
  are being reported in patients with weakened immune
  systems, especially due to HIV.

• It is important to note that infection with MOTT also may
  produce AFB-positive sputum smear results and positive
  Mantoux skin test readings mimicking M. tuberculosis.
  Culture can distinguish between M. tuberculosis and MOTT.
  Disease due to MOTT is usually unresponsive to first-line
  anti-TB drugs.
              Chest Radiograph

•   Diagnosis of PTB solely on basis of
      CXR not encouraged

•   May have unusual appearance in
    HIV-positive persons

•   CXR is helpful in HIV+, smear-
      negative patients                   Arrow points to cavity in
                                          patient's right upper lobe.

•   Cannot confirm diagnosis of TB
                       Cultures

• Should be requested for ALL
  retreatment patients
  – Relapse
  – Failure
  – Return after default
                                      Colonies of M. tuberculosis
• Culture is indicated for            growing on media
  – New and retreatment PTB cases
    still smear- positive at end of
    intensive phase
  – Symptomatic contacts of known
    MDR cases
                      Diagnosis in Children
     1. Patient history
           • Contact to PTB+
           • Symptoms consistent with TB
           • HIV test
     2. Clinical Exam
     3. TST
     4. Bacteriological confirmation
     5. Investigations for PTB and EPTB
Guidance of National Tb Programmes for the Management of TB in Children
WHO/HTM/TB/2006.371
    Key Risk Factors in Children
Risk Factors For Children Include:

•   Household contact with a newly diagnosed
    smear-positive case
•   Age less than 5 years
•   HIV infection
•   Severe malnutrition.
   Key Features of TB in Children
The presence of three or more of the following should strongly suggest a
  diagnosis of TB:

• Chronic symptoms suggestive of TB

• Physical signs highly of suggestive of TB

• A positive tuberculin skin test

• Chest X-ray suggestive of TB

(The presentation in infants may be more acute, resembling acute severe
   pneumonia and should be suspected when there is a poor response to
   antibiotics. In such situations, there is often an identifiable source case,
   usually the mother.)

								
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