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Tuberculosis diagnosis by dr najeeb


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Tuberculosis diagnosis by dr najeeb

  1. 1. LIAQUAT MEDICAL UNIVERSITYBy: DIAGNOSIS OF TUBERCULOSIS Assist: Prof:Faculty of Community Medicine & Public HealthSciencesLiaquat University of Medical & Health Sciences(LUMHS)Jamshoro, Sind, Pakistan e mail
  2. 2. Why diagnosis important? Diagnosis of tuberculosis in most cases  clinical diagnosis based upon the clinical presentation In 15-20% of p’t with suspected TB  lab confirmation never obtained Early diagnosis and initiation of effective therapy  reducing morbidity and mortality from TB  minimize the spread of infection
  3. 3. Outline Screening for prior infection  Tuberculin skin test Diagnosis of pulmonary TB  Medical history  Physical examination  Chest radiograph  Bacteriologic exam
  4. 4. Screening for prior infection Tuberculin skin test(little value as a case- finding tool )
  5. 5. Screening for prior infection Whom to screen  Highprevalence and high risk population (HIV) How to screen  Mantoux tuberculin test (ie, purified protein derivative or PPD, tuberculin skin test) How to interpret  Determine maximum diameter of induration by palpation
  6. 6. Mantoux Tuberculin Test Preferred method of testing for TB infection in adults and children Tuberculin skin testing useful for  Examining person who is not ill but may be infected  Determining how many people in group are infected  Examining person who has symptoms of TB
  7. 7. Mantoux test  Inject intradermally 0.1 ml of PPD tuberculin  Produce wheal 6 mm to 10 mm in diameter  Represent DTH (delayed type hypersensitivity)
  8. 8. Reading of Mantoux test Read reaction 48-72 hours after injection Measure only induration Record reaction in mm
  9. 9. Classifying the tuberculin reaction >5 mm is classified as positive in  HIV-positive persons  Recent contacts of TB case  Persons with fibrotic changes on CXR consistent with old healed TB  Patients with organ transplants and other immunosuppressed patients
  10. 10. Classifying the tuberculin reaction >10 mm is classified as positive in  Recent arrivals from high-prevalence countries  Injection drug users  Residents and employees of high-risk settings  Mycobacteriology laboratory personnel  Persons with clinical conditions that place them at high risk  Children <4 years, or children and adolescents exposed to adults in high-risk categories
  11. 11. Classifying the tuberculin reaction >15 mm is classified as positive in  Persons with no known risk factors for TB
  12. 12. Factors may affect TST False negative  Faulty application  Acute TB (2-10 wks to convert)  Very young age (< 6 months old)  Live-virus vaccination  Overwhelming TB disease False positive  BCG vaccination (usually <10mm by adulthood)  Nontuberculous mycobacterial infection
  13. 13. Two-Step Testing Use two-step testing for initial skin testing of adults who will be retested within 1-3 weeks  If first test (+), consider the person infected  If first test (-), give second test 1-3 weeks later  If second test (+), consider person infected  If second test (-), consider person uninfected
  14. 14. Diagnosis of Pulmonary TB
  15. 15. Diagnosis of disease  1.Medical 1. Medical history  2. Laboratory 2. Physical  Tuberculin  X-ray exam: examination  Mass miniature radiography 3. Chest radiograph  Sputum exam: 4. Bacteriologic exam  Sputum culture  Biochemical test  AFB  Luciferase assay  Culture  ATP enzyme  Blood C.P ( ESR normocytic anemia and lymphopenia
  16. 16. 1. Medical History
  17. 17. 1. Medical History Symptoms of disease History of TB exposure, infection, or disease Past TB treatment Demographic risk factors for TB Medical conditions that increase risk for TB disease
  18. 18. Medical History High prevalence population  More likely to be exposed to and infected with bacillus  Immigrant from high prevalence area  Resident or worker in jail  Long term care facility  Close contact to p’t with active TB
  19. 19. Medical History High risk population  More likely to progress from infection to active TB  HIV (+) or other immunodeficiency  CRF  DM  IVDA  Alcoholics  Malnourished  Malignancy  Gastrectomy
  20. 20. 2. Physical Examination
  21. 21. 2. Physical Examination Productive, prolonged cough  duration of ~3 weeks Chest pain Haemoptysis Fever/Chills Night sweats Appetite loss Weight loss Easily fatigued
  22. 22. 3. Chest radiography
  23. 23. 3. Chest radiography Classical radiograph appearance  Infiltration  Cavitation  Fibrosis with traction  Enlargement of hilar and mediastinal lymph node In reactivation TB  Classically fibrocavitary apical disease Primary TB  Middle or lower lobe consolidation
  24. 24. Chest radiography Abnormalities often seen in apical or posterior segments of upper lobe or superior segments of lower lobe May have unusual appearance in HIV- positive persons Cannot confirm diagnosis of TB!! cavity in patient‘s RUL classic" for adult-type, reactivation tuberculosis
  25. 25. Classic adult TB CXR PA view  diffuse parenchymal disease with multiple cavities and bulla formation on the left  Sputum smear was positive for AFB
  26. 26. Chest radiography 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 TB
  27. 27.  Mass miniature radiography:- (By Who expert committee ) Indiscriminate TB case finding by it should be abandoned.
  28. 28. X-ray-based evaluation causes over-diagnosis of TB 100 Over- 80 diagnosis 60 40 20 0 Diagnosed by X- Actual cases ray aloneNTI, Ind J Tuberc, 1974
  29. 29. 4. Bacteriologic Exam
  30. 30. Specimen Collection Obtain 3 sputum specimens for smear examination and culture Persons unable to cough up sputum  induce sputum  bronchoscopy  gastric aspiration Follow infection control precautions during specimen collection
  31. 31. Three Specimens Three specimens optimal • Spot specimen on first visit; sputum container given to patient • Early morning collection by patient on next day • Spot specimen during second visit
  32. 32. Three sputum smears are optimal 100% 100% 93% 81%Cumulative Positivity 50% 0% First Second Third
  33. 33. Number of sputum samples required overall diagnostic yield for sputum examination related to  the quantity of sputum (at least 5 mL)  the quality of sputum  multiple samples obtained at different times to the laboratory for processing 3 samples obtained at least eight hours apart with at least one sample obtained in the early morning
  34. 34. Number of sputum samples required several studies have suggested that only two samples may be sufficient to capture the majority of cases:  Retrospective study  Nelson, SM, Deike, MA, Cartwright, CP. Value of examining multiple sputum specime specim  overall, 92 percent of cases would have been detected with two specimens a third sputum smear was of no additional value
  35. 35. Smear Examination Strongly consider TB in patients with s smears containing acid-fast bacilli (AFB) Results should be available within 24 hours of specimen collection Presumptive diagnosis of TB Not specific for M. tuberculosis
  36. 36. AFB smearAFB (shown in red) are tubercle bacilli
  37. 37. Reporting on AFB MicroscopyNumber of bacilli seen Result reportedNone per 100 oil immersion fields Negative1-9 per 100 oil immersion fields Scanty, report exact number10-99 per 100 oil immersion fields 1+1-10 per oil immersion field 2+> 10 per oil immersion field 3+
  38. 38. Open tuberculosis A tuberculous ulceration or other form of tuberculosis in which tubercle bacilli are present in the excretions or secretions. Pulmonary tuberculosis, especially with cavitation. 開放性結核就是在病人咳出的痰液中有結 核桿菌的存在
  39. 39. Sputum Cultures 2nd in importance in case- finding programme. Difficult Tedious Expensive Needs special training lengthy ( takes at least 6 - 8 wks ) L. J media Method offered with chest symptoms & sputum smear –ve. Culture of sputum is necessary for carrying out sensitivity tests & monitoring drug treatment ( drug susceptibility test )
  40. 40.  Liquid media ( BACTEL media is used ) production of co2 in 2 wks
  41. 41. Cultures•Gold standard for TB diagnosis•Use to confirm diagnosis of TB•Culture all specimens, even if smear negative•Results in 4 to 14 days when liquid medium systems used Colonies of M. tuberculosis growing on media
  42. 42. Microscopy is more objective and reliable than X-ray Inter-observer 98%100 agreement 80 70% 60 40 20 0 AFB Microscopy X-ray
  43. 43. Microscopy is a more specific test than X-ray for TB diagnosis 100 98% Specificity 80 60 50% 40 20 0 AFB Microscopy X-ray
  44. 44. Diagnosis of Pulmonary TB Cough 3 weeksIf 1 positive, AFB X 3 If 2/3 positive: X-ray and Anti-TB Rx evaluation If negative: Broad-spectrum antibiotic 10-14 daysIf symptoms persist, repeat AFB smears, X-ray If consistent with TB Anti-TB Treatment
  45. 45. Recommended Diagnostic Approach
  46. 46. Thanks for your attention!