Transcript Walkerly_Presentation - Registered Nurses` Association of Ontario

Got TB?
An update on Latent Tuberculosis Infection (LTBI) for Family
Practice Nurses from the new release of the Canadian TB
Standards 7th edition.
Shelley Walkerley, NP-PHC, PhD
Stonegate Community Health Centre
Clare Burnell, RN, BScN
Tuberculosis Prevention and Control, Toronto Public Health
Acknowledgements to Elizabeth Rea, MD, MSc, FRCPC, Associate Medical Officer of
Health, Tuberculosis Prevention and Control, Toronto Public Health
May 2, 2014
TB Around the World
1/3 of the world’s population is
infected with the TB bacteria
8.6 million people were diagnosed
with active TB disease in 2012
1.3 million people died from TB
disease in 2012
TB occurs in every part of the
world.
Source: WHO
TB in Canada
≈1500 Active TB Cases occur in Canada
annually
≈ 600 Active TB Cases occur in
Ontario annually
≈ 300 Active TB Cases occur in
Toronto Annually
What is TB?
• Bacteria
(Mycobacterium Tuberculosis)
• Usually affects lungs
• Can be TB disease
or TB infection
TB Body Locations
Transmission
• Airborne
• Active TB disease in lungs throat coughs / sneezes
• Requires close, frequent, prolonged exposure
• Not highly contagious!
NOT transmitted by
TB Infection vs TB Disease
TB Infection
(Latent)
+ TB Skin Test
Not Infectious
No Symptoms
Bacteria = Dormant
Normal Chest X-ray
TB Disease
(Active)
+/- TB Skin Test
Infectious (possibly)
Symptomatic (possibly)
Bacteria = Multiplying
Abnormal Chest X-ray
Why do a TST?
Why do we screen for TB at all?
• not universal – focus on high risk of exposure/progression
• Younger: LTBI and preventive treatment
• Older: active TB disease - early detection and treatment
• Contact follow-up (individual + determining scope of transmission)
Goal determines the test:
•in active TB 25% are TST negative– TST is not for ruling
out active disease!
•If patient is a candidate for LTBI treatment…then do a TST
Decision to test = decision to treat
• Approximately 10% of persons infected with TB will go on
to develop active TB disease:
• 5% within 2 years of infection
• 5% over the remaining life.
• Treatment of LTBI reduces the individual’s risk for
developing active disease by up to 90%
Who Should be Tested?
High risk of having had TB exposure:
•Contacts of infectious TB.
•People who were born in or visited TB-endemic countries; especially
<20 years old and immigrants who have arrived within the last 2 years.
•All refugees >20 years old or <50 years old from countries with a high
incidence of TB, ASAP on arrival in Canada and all adult immigrants
with risk factors.
•Persons from Aboriginal communities with high rates of TB *Nunavut.
•People with x-ray evidence of old, healed TB disease and no history of
treatment.
Who else should be tested?
Occupational/congregate setting risks:
•Health care workers (risk of occupational exposure to TB,
risk of transmission to patients).
•Staff and residents in communal care: LTC, corrections,
shelters, etc.
Medical high risk if exposed:
•People with increased risk of progression to active TB.
Risk Factors for Developing Active TB
in Persons With LTBI
High Risk – screen at any age
•AIDS
•HIV infection
•Chronic Renal Failure/Hemodialysis
•Transplantation
•Silicosis
•Carcinoma of the head/neck
•Recent TB infection (up to 2 years)
•Abnormal CXR: fibronodular disease)
Increased Risk – screen up to 65 yrs
•Treatment with chemotherapeutic agents or
glucocorticoids equivalent to prednisone (≥ 15mg/day)
•Treatment with TNF inhibitors
•Diabetes Mellitus
•< 5 years of age at time of infection
•Cigarette smoking (1+ ppd)
•Heavy alcohol consumption (3+ drinks/day)
•Abnormal chest x-ray (granuloma)
•Underweight (≤ 90% ideal weight, generally BMI ≤ 20)
Low Risk - screen up to 50 yrs
•No known medical risk factor
•Normal chest x-ray
Screening Case
• 25 year-old woman
• Born in Philippines, emigrated to Canada 3 years ago
• Type 2 diabetes, on oral medication
• Enrolling in nursing; TB screening required for school
Reasons to test:
• TB endemic country – high risk of TB exposure
• Diabetes – moderate risk of progression
• Health care worker
Contraindications for TST
Already positive – no need to repeat:
•Documented positive TST in the past
•Tuberculin reactions that have severely blistered in the
past
•Documented active TB in the past
•Clear past history of treatment for TB infection or disease
High likelihood of false negative:
•live-virus vaccinations in the past month (MMR, Varicella,
or Yellow Fever) or major viral infections.
NOT Contraindications for TST
• BCG vaccination in the past
• Common cold
• Immunized with any vaccine on the same day as TST
• Recent vaccination with non-live virus vaccine
• Pregnancy or breastfeeding.
• History of positive TST that is not documented
• Taking low dose corticosteroids (≤ 15 mg/day)
TST Technique
• 0.1 ml of PPD
• Inject intradermally on
volar (inner) aspect of
forearm
• small wheal (6-10 mm)
will disappear in 10-15
minutes.
Reading TST
• Read at 48-72 hours
• Self-reading strongly
discouraged
• Induration, not redness!
• Calipers ideal
• Measure across forearm
• Record in mm
• “no reaction” = 0mm
Interpretation of the TST
Based on all of the following:
•Size of the reaction (induration)
•Predictive value of the test (considering potential causes of
false-negative, false-positive reactions).
•Risk of progression to active TB disease.
On-line TST interpreter available at the McGill University
website: http://www.tstin3d.com
TST Reaction
(mm induration)
Situation in which reaction considered positive
0-4 mm
In general this is considered negative. For contacts under 4
years – window prophylaxis pending definitive TST at 8
weeks post exposure
5-9 mm
•
•
•
•
≥ 10 mm
All others
Close contact of active contagious case
Abnormal chest x-ray with fibronodular disease
Immune suppression
HIV infection
Causes of False-Negative TST
• Active TB!
• Poor injection technique
• Conversion window period: TB exposure <8 weeks ago
• Age < 6 months?
• Anergy (severe illness, dialysis, very elderly, cancer tx,
•
•
•
•
etc)
Immunization within the past 4 weeks with live virus
vaccine (MMR, Varicella, Yellow Fever)
Major viral illness in the past 4 weeks (measles, mumps,
mononucleosis)
Immune suppression
Severe malnutrition
Causes of False Positive TST
•Infection with non-tuberculous mycobacteria (generally
<15 mm)
•Prior BCG vaccination
BCG
Smallpox
BCG: it matters how old at vaccination
BCG Vaccination
Relationship to TST Results
Received in infancy
Unlikely to cause a TB reaction of
≥ 10 mm after ≥ 10 years of age
Received at 1-5 years of age
10-15% will have a positive TST up to
25 years later.
Received at 6 years of age or older
40% chance of having a persistent
positive TST later in life
www.bcgatlas.org
Ignore Prior History of BCG when:
Risk of real TB exposure is high:
•Close contacts of a person with infectious TB disease
•Populations with high prevalence of TB infection, eg
• Immigrants from TB-endemic areas
• Persons from Aboriginal communities with high rates of TB
•Chest x-ray consistent with old healed active TB disease
And/or risk of progression to active TB is high:
•Immunocompromised, including
• HIV infection
• Renal Failure
• Diabetes Mellitus
TST interpretation – a case
• Canadian born 18 year old, no travel, no TB exposure hx
• TST required for volunteering
• No TB signs or symptoms
• 10mm
• CXR normal
• Very low risk – likely “false positive”
TST interpretation – another case
• 37 year man old born in India
• BCG
• Household contact of brother with pulmonary TB
• Well, no medical co-morbidities
• TST = 17 mm
Ignore BCG and interpret as “positive” because
• contact of infectious case
• Lived in TB - endemic country, high risk real TB exposure
• BCG at birth  minimal impact on TST as adult
Two-Step TST
• Distinguishes a booster effect (due to prior infection) from
a conversion due to recent infection
• Should be performed only for people who will be getting
serial TSTs (health care workers; corrections workers, etc)
• If the first test is negative, do a second test 1-4 weeks
later
• Each TST should be read and recorded at 48-72 hours
after planting
Management of a Positive TST
• First rule out active TB disease
• History and physical examination
• Chest x-ray - anterior and posterior (AP) and lateral views
• If symptoms or chest x-ray findings consistent with pulmonary TB,
get 2 -3 sputum samples to send for Acid Fast Bacillus (AFB)
smear and culture.
• Report all positive tests to the local public health
department
Evaluation: 1.Clinical Picture
Symptoms of TB:
• New or worsening cough of at least 2 weeks duration.
• Cough is initially dry and may become productive after
several weeks.
• Fever and night sweats (may be absent in the very
young and elderly)
• Hemoptysis, anorexia, weight loss and chest pain in
more advanced cases.
• Lymph node TB is the most common extra-pulmonary
site
•Most people with TB have normal physical examinations.
Evaluation: 2. Interpretation of CXR
• PA and lateral views
• Chest x-rays should always be interpreted in the context of
history, clinical and laboratory findings.
Evaluation: 3. bacteriological testing
Sputum Collection:
•Collect 3 specimens at least 1 hours apart; early a.m. may
be easiest, collect over several days if necessary
•Collect 5-10 cc of sputum per specimen
•Ideally send to Ontario Public Health Lab
Other sites if necessary: request TB smear/culture
specifically!
•Biopsy (eg of enlarged lymph node)
•Pleural fluid/pleural biopsy (for pleural effusion)
•CSF (if TB meningitis suspected)
Contacts: Young Children and HIV+
• Contacts age <5 or HIV+ should ideally be assessed by a
specialist.
• Babies and toddlers: CXR best quality via hospital
radiology dept
• Window prophylaxis is strongly recommended pending
TST at 8-10 weeks post-exposure - initiate as soon as
active disease is ruled out.
• Educate parents and older children regarding symptoms
of adverse reactions and signs of hepatotoxicity.
Decision to Start LTBI Treatment
Should be based on:
1.Interpretation of TST in context of patient’s history:
• Size of induration in millimetres
• Predictive value of the test
• Risk of progression to active disease
2. Medical Contraindications
• Patients under 65 years old with no comorbidities have low rates of
hepatotoxicity
3. Likelihood of adherence to full length of LTBI treatment
• Patient ability and commitment
• Provider ability to continue monthly follow-up
4. Discussion of risks and benefits with patient
5. Active TB has been ruled out
Decision to treat – general approach
• In general, high /
moderate risk of
reactivation <65 should
be treated
• >65, benefits will likely
only outweigh potential
harms of treatment if at
high risk of reactivation
and no comorbidities
• In patients <65 who are
at slightly increased risk
or low risk, decision
should be primarily the
patient’s
Treatment – a case study
• 54 year-old man
• First Nations Canadian, originally from northern Manitoba
• Mother had pulmonary TB when he was 2 yrs old
• Current smoker, 1 pack per day, 20 pack year history
• Diabetic, on oral meds
• Feeling well, no TB signs or symptoms
• Chest x-ray: ‘Fibronodular densities in both upper lobes, right
greater than left.’
• Had BCG as baby
• TST = 23mm
Recommendations for TLTBI
* medication is free from local PHD
Name
Interval and
Duration
Oral Dosage
Criteria for
Completion
Comments
Isoniazid (INH)
Daily for 9
months
Adult:
5mg/kg/day to a
max of 300mg
daily
9 months (270
doses).
Completing 9
months within a
12 month period is
acceptable
without having to
restart treatment.
• Recommended
treatment regime
• Provides optimal
protection in
preventing
progression.
• Consult specialist
for children,
especially < age 5.
Vitamin B6
(Pyridoxine)
Daily with INH
25 mg
Usually prescribed.
Effectiveness of INH
Consultation or Referral to a TB
specialist is recommended for
persons who are:
Assuming sensitivity to INH and ≥ 80%
compliance:
•INH, when taken for 12 months is
93% effective in preventing
progression to active disease.
•However, INH, when taken for 9
months is 90%; thus recommended
duration.
•INH, when taken for 6 months is 69%
effective.
•
•
•
•
HIV positive
Contacts of multidrug-resistant TB
Children
Pregnant women at high risk for TB
disease
• Abnormal chest x-ray
Treatment – case study #2
• High risk for TB exposure, moderate risk for reactivation
• Active TB ruled out – 3 sputums smear/culture neg
• LTBI treatment recommended and accepted
• INH 9 months
• Smoking cessation
• What monitoring does he need?
• Does he need repeat LFTs during treatment?
INH: Adverse Reactions and Monitoring
Adverse
Reactions
Monitoring
Comments
•
•
•
•
•
•
•
•
•
•
•
Hepatitis risk and age:
↑ Liver enzymes
Hepatitis
Peripheral neuropathy
CNS
GI
Hematological
Hypersensitivity
Drug Interactions (see
CPS)
Baseline AST/ALT
Monthly clinical monitoring
Monthly AST/ALT for patients
with:
• Liver disease
• Age ≥ 35
• Alcohol abuse
• Prior INH hepatitis
• Pregnant or within 3
months postpartum.
Age
<20
20-34
35-49
50-64
≥ 65
Risk
0.1-0.2%
0.3%
0.5%
1.0-3.0%
2.0-5.0%
•Hepatitis risk increases with daily
alcohol intake or viral hepatitis
•INH hepatitis is almost always
reversible
•INH given alone to people with
active TB disease can lead to INHresistant TB.
Second line alternative for treatment of LTBI
Name
Interval and
Duration
Oral Dosage
Criteria for
Completion
Comments
Isoniazid and
Rifampin
(INH/RMP)
Daily for 3-4
months
Adult:
NA
Consider
collecting
sputum and
pending for
culture results
prior to
initiation to
avoid inducing
drug
resistance.
INH
5mg/kg/day to
a max 300mg
daily
RMP
10mg/kg/day
to a max
600mg daily
Effectiveness of INH/RMP
Consultation or Referral to a TB
specialist is recommended for
persons who are:
• Published efficacy of 3 months of
INH/RMP is 64%
• Efficacy and safety is similar to 6-9
months of INH alone
Use this regime in consultation with a
specialist.
Rifampin : Adverse Reactions and Monitoring
Adverse Reactions
Monitoring
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•
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•
•
•
•
•
•
CNS
Dermatological
Hypersensitivity
Hepatitis
GI
Hematological
Renal
Drug Interactions (see
CPS)
•
Comments
Baseline bilirubin, serum •
creatinine, CBC,
platelets and liver
•
enzymes
Repeat measurements if: •
• Baseline are
abnormal
• Patient has
symptoms of an
adverse reaction.
•
Colours body fluids
reddish-orange
May permanently
discolour contact lenses
By accelerating estrogen
metabolism, Rifampin
may interfere with
effectiveness of birth
control pills; alternative
contraception should be
advised.
Contraindicated in
severe chronic liver
disease.
LTBI treatment refused, contraindicated or stopped
early…
• Counsel about the symptoms of active TB and advise to
return for medical assessment if those symptoms arise.
• Flag the chart – if symptoms compatible with TB occur in
the future, get specimens for TB smear and culture
• Routine CXR or follow-up is not recommended.
Interferon Gamma Release Assays (IRGAs)
• Two types of IGRAs are approved by Health Canada for
use: QuantiFERON-TB Gold In-Tube (QFT) and TSPOT.
• Currently these tests are not covered by OHIP.
• QFT testing is available on a limited basis through
Gamma-Dynacare Medical Laboratories.
Role of Public Health
Reportable
• Health Promotion & Protection Act (HPPA)
• Both TB infection and disease are reportable to Public Health
Contact Follow-up
• Active case investigation (source, transmission)
• Contact identification and follow-up
Drug Ordering
• Provision of LTBI medications to Health Care Providers
• Supply TB Clinics & Pharmacies
Education & Consultation
• Client education (new LTBI diagnosed)
• HCP consultation
Websites
www.publichealth.gc.ca
www.cdc.gov/tb/
www.who.org
www.on.lung.ca
www.bcgatlas.org
www.phac-aspc.gc.ca
www.tstin3d.com
www.respiratoryguidelines.ca/tb-standards-2013
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