Transcript Intradermal injections & Interpretation of Mantoux Tests

Intradermal injections
& Interpretation of
Mantoux Tests
Intradermal Injections
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Why?
Dx. Allergies ie;________________
2.
Dx. Specific diseases ie__________
3.
Dx. Impaired immune system
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Tuberculosis
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Infection caused by the aerobic
bacterium, Mycobacterium tuberculosis
TB kills more than 2 million people per
year
Within 20 yrs-1 billion new cases of TB
200 million will get sick
35 million will die
More dangerous because of:
lack of health services in some parts of world
Spread of HIV/AIDS
Emergence of multi-drug resistant TB
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How? Spread by droplets emitted by
infected people when they are coughing,
sneezing, laughing and singing
Left untreated active TB pt.s could infect
10 to 15 people each year
S & S? -cough, night sweats, chest
pain, tightness, fatigue, anorexia, weight
loss, low-grade fever, often persistent
cough, productive with purulent yellowgreen hemoptysis (bloody) sputum
Most “primary infections” are not active,
but can lay dormant for years
 Can invade almost any tissue in body
 Most common in lungs
 In lungs, small area becomes inflamedcauses immune response-some can
escape & be carried to lymph
 Can be necrotic @ lung site, creates
cavities-can fill with infectious material
 Pt. can cough up some material in
sputum
 Site can heal-scar tissue-(ghon)
tubercule lesion
Some become active
 Infectious process progresses &
develops into active TB
 Primary in lungs spreads
 Outside lungs called Extrapulmonary
TBInfections in kidneys, bones,
meninges, GI tract, lymph nodes,
pericardium
 Pt.s are infectious when symptoms
appear
At Risk groups
In frequent contact with infected
person
 Immune disfunction or HIV
 Living in crowded areas ie_________
 Elderly, homeless
 Minorities
 IV drug abusers, alcoholics
 Foreign immigrants- Mexico,
Philipines, Vietnam
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Diagnosis (DX)
High risk exposure?
 Sputum culture
 Acid-fast smears of potential body flds
S&S
 Chest xrays
 Pneumonia that won’t heal
 TB skin test
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TB Skin Test
Infected pt.s immune response
causes a reaction to the intradermally
injected tuberculin
 ***Tuberculin is a protein fraction of
the tubercule bacillus****
 PROCEDURE IN LAB MANUAL
 0.1 mLs. injected under the skin
 Produces wheal on skin
-called raising a wheal
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When to Assess A Mantoux
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Mantoux test are given as a “two-step” test
5TU’s are injected intradermally on the volar
aspect of the forearm
The area is assess 48 to 72 hours later
If the first step is negative (<10mm) then the
second step is administered 1-4 weeks later
in the opposite arm
The area is assessed 48 to 72 hours later
The only way to diagnose active TB is with
a sputum specimen
Reading the Mantoux Test
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48-72 hours (no longer)
Measuring with calipers in millimetres
Canadian guidelines
Negative – no induration (thickened
local area of skin reaction, don’t
measure redness)
Positive
0-4mm- TB risk factors & immuncomp.
5-9mm- + if pt. close contact with TB
or pt. has an abnormal CXR
10 or > 10mm. + for pt. who is healthy
with no known TB risks
CDC Guidlelines (USA)
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Negative – no induration (thickened local
area of skin reaction, don’t measure redness)
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Positive
5mm. or > in persons with HIV infection,close
contact, CXR of old, healed TB
2. 10mm. considered exposed/infection with high
risk groups including HCW, foreign borne from
hi risk areas-Asia, Africa, Latin America,
medical conditions placing them at hi risk, LTC
3. 15 mm. is always considered positive
**BCG (bacille Calmette-Guerin not TB. If greater
than 10 mm., may be new infection may be +
up to 9mm. as response to vaccine
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Visual guide
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The individual in the following slides
gave permission for the pictures to be
used for teaching purposes. We
assured their anonymity so please do
not ask details regarding the
individual.
A positive Mantoux Skin Test
Note the ERYTHEMA
(redness) around the
outside edges
Note the
INDURATION
(red raised
area) in the
centre
A positive Mantoux Skin Test
Note the ERYTHEMA
(redness) around the
outside edges
Note the
INDURATION
(red raised
area) in the
centre
Measuring Devices
Find the edge of the induration
and mark with a pen
Measure the diameter of the induration
horizontally and record the results in
mm’s
This type of measuring device can but
used but the caliper type shown in the
previous slide is easier to use and more
precise
Measure induration
horizontally not vertically
Measure the
induration only.
Do not measure
the erythema.
Results are recorded in mm’s not
“neg” or “pos”
Contraindications
Severe blistering tuberculin reactions
 Active or past hx of TB
 Extensive burns or skin conditions like
eczema, psoriasis, PUPPP syndrome
 Major viral infections
 Immunization with a live virus in the
past month
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Eligible for testing
Pregnant
 If ill with cold
 Had BCG
 Recent immunization with a non-live
virus vaccine
 Hx. Of postive TB test
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Cause of False negatives
Poor injection technique-non wheal or
bleb
 Immune suppressed ie: elderly,
corticosteriods, cancer tx
 Malnutrition
 Severe illness
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Causes of False Positives
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Had BCG
Non-tuberculous
uncommon
mycobacteria-
Treatment-Antituberculotics
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Isoniazid
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pyrazinamide(Tebrazid)
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rifampin (Rofact)antit & antibiotic
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ethambutol hydrochoride(Etibi)