Tuberculin Skin Testing, Mantoux Test

Tuberculin skin Testing Mantoux tuberculin skin test: 

Dr.T.V.Rao MD Tuberculin skin Testing Mantoux tuberculin skin test Dr.T.V.Rao MD 1

Tuberculosis: PRIMARY Infection: 

Tuberculosis: PRIMARY Infection 95% of cases begin with pulmonary focus usually a SINGLE focus hypersensitivity develops 2 to 6 weeks until then, focus may grow larger hypersensitivity brings caseation

PRIMARY Infection: Lympho-hematogenous spread: 

PRIMARY Infection: Lympho-hematogenous spread 8-14 weeks after onset of TB usually occult Mantoux positive during this phase body wide seeding occurs during this phase bone, kidney, meninges etc. 3% of children with nl CXR’s develop calcifications in lung apices (SIMON FOCI)

PowerPoint Presentation: 

USUAL PROGRESSION OF PRIMARY INFECTION infection Lympho-hematogenous spread healed PRIMARY infection Dr.T.V.Rao MD 4

PowerPoint Presentation: 

PROGRESSIVE PRIMARY DISEASE pleural effusion cavitation lymph node involvement Dr.T.V.Rao MD 5

Tuberculin Skin Testing: 

Tuberculin Skin Testing The Mantoux tuberculin skin test (TST ) is the standard method of determining whether a person is infected with Mycobacterium tuberculosis . Reliable administration and reading of the TST requires standardization of procedures, training, supervision, and practice. Dr.T.V.Rao MD 6

Diagnosis of latent TB with the Tuberculin skin test: 

The issues: Applying the tuberculin skin test Reading the test Interpreting the test – including in children Management of positive TST Diagnosis of latent TB with the Tuberculin skin test Dr.T.V.Rao MD 7

Indications for skin test screening: 

Indications for skin test screening Persons with signs and/or symptoms suggestive of tuberculosis disease Recent contacts of persons known or suspected to have tuberculosis Persons with undiagnosed upper lobe fibrotic lesions Persons infected with HIV Alcoholics and intravenous drug abusers Persons with medical conditions known to increase the risk of disesase if infection has occurred: silicosis, gastrectomy, jejunoileal bypasss, significant weight loss below IBW, chronic renal failure, diabetes mellitus, high dose corticosteroid treatment or other immunosuppressive therapy, leukemia, lymphoma, malignancy Groups at high risk of infection: Latin America, Oceana, medically underserved populations, residents of long term care facilities Groups that would pose a significant risk to others if diseased: employees of health care facilities, schools, child care facilities ATS/CDC Dr.T.V.Rao MD 8

The TB Skin Test: MATERIALS: 

The TB Skin Test: MATERIALS OLD TUBERCULIN culture of TB bacillus in glycol peptone broth TB “tine” test PURIFIED PROTEIN DERIVATIVE (PPD) TB bacillus grown in Long’s media, filtered after heating adopted by WHO as standard in 1950 PPD-S 1952 dose = 5 IU Dr.T.V.Rao MD 9

The TB (Mantoux) Skin Test: 

Intra-dermal quality control important trained practioner necessary Delayed hypersensitivity cell mediated 48-72 hours False negative immuno-compromized conditions measles/measles immunizations Nonspecific reactions increase >10 IU cross reactions, atypical MB The TB (Mantoux) Skin Test Dr.T.V.Rao MD 10

Applying the tuberculin skin test: 

Dr.T.V.Rao MD 11 Applying the tuberculin skin test Courtesy of Dr. Marc Steben

Applying the tuberculin skin test: 

Dr.T.V.Rao MD 12 Applying the tuberculin skin test

Reaction to the tuberculin skin test: 

Dr.T.V.Rao MD 13 Reaction to the tuberculin skin test Courtesy of Dr. Marc Steben

Reading the tuberculin skin test: 

Dr.T.V.Rao MD 14 Reading the tuberculin skin test Courtesy of Dr. Marc Steben

Reading the tuberculin skin test: 

Read 2-3 days after placing the test Feel for induration Color change without induration is not included in the measurement Use a ruler or calipers Have someone else check if unsure Always document the exact size (mm) – not just “positive” or “negative” Reading the tuberculin skin test Dr.T.V.Rao MD 15

a Positive skin test only indicates: 

A positive TB skin test only tells that a person has been infected with TB bacteria. It does not tell whether the person has latent TB infection (LTBI) or has progressed to TB disease. a Positive skin test only indicates Dr.T.V.Rao MD 16

Reading the skin testing in tuberculosis: 

The reaction should be measured in millimetres of the induration (palpable, raised, hardened area or swelling). The reader should not measure erythema (redness). The diameter of the indurated area should be measured across the forearm (perpendicular to the long axis). Reading the skin testing in tuberculosis Dr.T.V.Rao MD 17

PRIMARY Infection: Lympho-hematogenous spread: 

PRIMARY Infection: Lympho-hematogenous spread 8-14 weeks after onset of TB usually occult Mantoux positive during this phase body wide seeding occurs during this phase bone, kidney, meninges etc. 3% of children with nl CXR’s develop calcifications in lung apices (SIMON FOCI)

Reading the tuberculin skin test: 

Read 2-3 days after placing the test Feel for induration Color change without induration is not included in the measurement Use a ruler or calipers Have someone else check if unsure Always document the exact size (mm) – not just “positive” or “negative” Reading the tuberculin skin test Dr.T.V.Rao MD 19

Factors causing decreased ability to respond to tuberculin: 

Factors causing decreased ability to respond to tuberculin Factors related to the person being tested Infections Viral (measles, mumps, chickenpox) Bacterial (typhoid fever, brucelosis, typhus, pertussis, overwhelming TB, Fungal (South American blastomycosis) Live virus vaccinations (MMR) Metabolic derangements (chronic renal failure) Nutritional factors (severe protein depletion) Diseases affecting lymphid organs (Hodgkin’s lymphoma, chronic lymphocytic leukemia, sarcoidosis) Dr.T.V.Rao MD 20

Factors causing decreased ability to respond to tuberculin (CONTD): 

Factors causing decreased ability to respond to tuberculin (CONTD) Drugs (corticosteroids, other immunosuppressive agents) Age (newborn, elderly) Recent overwhelming infection with M. tuberculosis Stress (surgery, burns, mental illness, graft versus host reactions) Factors related to the tuberculin used Factors related to the method of administration Factors related to reading the test and recording results Dr.T.V.Rao MD 21

MILIARY Disease Generalized Hematogenous Tuberculosis: 

MILIARY Disease Generalized Hematogenous Tuberculosis generalized dissemination through bloodstream caseous focus ruptures into blood vessel growth of tubercle within the blood vessel may be acute, occult or chronic uniformly fatal if not treated rare usually occurs in the first 4 months after primary infection Dr.T.V.Rao MD 22

PowerPoint Presentation: 

MILIARY Disease millet seed appearance on X-ray Mantoux positive? Most children still have active primary complex when miliary disease strikes most develop meningitis

Evaluation of a patient with positive TST: 

Evaluate for active TB Re-check symptoms and exam – cough, fever, weight loss, enlarged lymph nodes, dyspnea Chest X-ray, if possible Evaluation of a patient with positive TST Dr.T.V.Rao MD 24

PowerPoint Presentation: 

Dr.T.V.Rao MD 25 Programme Created by Dr.T.V.Rao MD for Medical and Health Care Workers in the Developing World Email doctortvrao@gmail.com