tuberculin skin testing

8/2/2019 Tuberculin Skin Testing

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Dr.T.V.Rao MD

TUBERCULINTUBERCULIN SKIN TESTINGSKIN TESTING

MANTOUX TUBERCULIN SKIN TESTMANTOUX TUBERCULIN SKIN TEST

DR.T.V.RAO MD 1


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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 bringscaseation


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PRIMARY INFECTION:

LYMPHOLYMPHO--HEMATOGENOUS SPREADHEMATOGENOUS SPREAD

8-14 weeks after onset of TB

usually occult

Mantoux positive during thisphase

body wide seeding occursduring this phase

bone, kidney, meninges etc.

3% of children with nl CXRsdevelop calcifications in lungapices (SIMON FOCI)


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USUAL PROGRESSIONUSUAL PROGRESSION

OFOFPRIMARYPRIMARY

INFECTIONINFECTION

infection

Lympho-hematogenousspread

healed PRIMARYinfectionDR.T.V.RAO MD 4


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PROGRESSIVE PRIMARYPROGRESSIVE PRIMARY DISEASEDISEASE

pleural effusionpleural effusion

cavitationcavitation

lymph node involvementlymph node involvement

DR.T.V.RAO MD 5


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TUBERCULIN SKIN TESTING

The MantouxtuberculinMantouxtuberculinskintest (TSTskintest (TST) is thestandard method of

determining whether aperson is infected withMycobacteriumtuberculosis. Reliableadministration and readingof the TST requires

standardization ofprocedures, training,supervision, and practice.

DR.T.V.RAO MD 6


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Theissues:

Applying the tuberculin

skin test

Reading the test

Interpreting the test

including in children

Management of positive

TST

DIAGNOSIS OF LATENT TB WITHDIAGNOSIS OF LATENT TB WITH

THE TUBERCULIN SKIN TESTTHE TUBERCULIN SKIN TEST

DR.T.V.RAO MD 7


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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 orother immunosuppressive therapy, leukemia, lymphoma, malignancy

Groups at high risk of infection:

Latin America, Oceana, medically underserved populations, residents of longterm care facilities

Groups that would pose a significant risk to others if diseased: employees of healthcare facilities, schools, child care facilities

ATS/CDCDR.T.V.RAO MD 8


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THE TB SKIN TEST: MATERIALS

OLD TUBERCULINOLD TUBERCULIN

culture of TB bacillus in glycol peptone brothculture of TB bacillus in glycol peptone broth

TB tine testTB tine test

PURIFIED PROTEIN DERIVATIVE (PPD)

TB bacillus grown in Longs media, filtered after heatingTB bacillus grown in Longs media, filtered after heating

adopted by WHO as standard in 1950adopted by WHO as standard in 1950

PPDPPD--S 1952S 1952

dose = 5 IU

DR.T.V.RAO MD 9


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Intra-dermal

qualitycontrolimportant

trained practionernecessary

Delayed hypersensitivity

cellmediated

48-72 hours

Falsenegative

immuno-compromized conditions

measles/measlesimmunizations

Nonspecificreactions

increase >10 IU

crossreactions,atypical MB

THE TB (MANTOUX) SKIN TEST

DR.T.V.RAO MD 10


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Dr.T.V.Rao MD11

APPLYING THE TUBERCULIN SKIN TEST

Courtesy of Dr. Marc Steben


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Dr.T.V.Rao MD12

APPLYING THE TUBERCULIN SKIN TEST


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Dr.T.V.Rao MD13

REACTION TO THE TUBERCULIN SKIN TEST



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Dr.T.V.Rao MD14

READING THE TUBERCULIN SKIN TEST



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Read 2-3 days after placing the

test

Feel for induration

Color change without indurationis 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 TESTREADING THE TUBERCULIN SKIN TEST

DR.T.V.RAO MD 15


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A positive TB skin test

only tells that a person

has been infected with

TB bacteria. It doesnottell whetherthe

personhaslatent TB

infection (LTBI) orhas

progressed to TBdisease.

A POSITIVE SKIN TEST ONLY INDICATESA POSITIVE SKIN TEST ONLY INDICATES

DR.T.V.RAO MD 16


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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 measuredacross the forearm

(perpendicular to the long

axis).

READING THE SKIN TESTING INREADING THE SKIN TESTING IN

TUBERCULOSISTUBERCULOSIS

DR.T.V.RAO MD 17


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PRIMARY INFECTION:PRIMARY INFECTION:

LYMPHOLYMPHO--HEMATOGENOUS SPREADHEMATOGENOUS SPREAD 8-14 weeks after onset of TB

usually occult

Mantouxpositive duringthisphase

body wide seeding occursduring this phase

bone, kidney, meninges etc. 3% of children with nl CXRs

develop calcifications in lungapices (SIMON FOCI)


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Read 2-3 days after placing the

test

Feel for induration

Color change without indurationis 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


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FACTORS CAUSING DECREASED ABILITY TOFACTORS CAUSING DECREASED ABILITY TO

RESPOND TO TUBERCULINRESPOND TO TUBERCULIN

Factorsrelated tothepersonbeingtestedFactorsrelated tothepersonbeingtested 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)

Nutritionalfactors(severe protein depletion)

Diseases affecting lymphid organs (Hodgkins lymphoma, chronic

lymphocytic leukemia, sarcoidosis)

DR.T.V.RAO MD 20


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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

Factorsrelated tothemethod ofadministration

Factors related to reading the test and recording results

DR.T.V.RAO MD 21


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MILIARYMILIARY DISEASEDISEASE

GENERALIZED HEMATOGENOUS TUBERCULOSIS

generalized disseminationthroughbloodstream

caseousfocusrupturesintoblood vessel

growthoftubercle withintheblood vessel

maybeacute,occultorchronic

uniformlyfatalifnottreated

rare

usuallyoccursinthefirst 4 monthsafterprimaryinfection

DR.T.V.RAO MD 22


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MILIARYMILIARY DiseaseDisease

millet seed appearancemillet seed appearance

on Xon X--rayray

Mantouxpositive?Mantouxpositive? Most children still haveMost children still have

active primary complexactive primary complex

when miliary diseasewhen miliary disease

strikesstrikes

most develop meningitismost develop meningitis


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EvaluateforactiveEvaluateforactiveTBTB

Re-check

symptoms andexam cough,fever, weight loss,enlarged lymphnodes, dyspnea

Chest X-ray,ifpossible

EVALUATION OF A PATIENT WITH

POSITIVE TST

DR.T.V.RAO MD 24


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DR.T.V.RAO MD 25

Programme Created by Dr.T.V.Rao MDProgramme Created by Dr.T.V.Rao MD

forMedicaland Health Care WorkersinforMedicaland Health Care Workersinthe Developing Worldthe Developing World

Email

[email protected]@gmail.com

tuberculin skin testing

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