Transcript A typical day in the TB clinic

A typical day in the TB clinic
You see the following patients in the TB clinic. All have normal CXRs:
1.
A 35 year old man from Hartford with a 16 mm positive PPD. He has no
known exposure to MTB, no risk factors, normal exam. He wants to work
in your hospital.
2.
A 64 year old woman from Jamaica with a 12 mm PPD who is referred for
immigration purposes. She has no risk factors and her exam is negative
3.
An 18 year old young woman from Lima, Peru with a 14 mm PPD for
immigration purposes. Her history and exam are negative
4.
A 54 year old man born and raised in Hartford, who has a 20 mm PPD.
He cannot recall having had a previous TST. He used to be an IV drug
abuser. He says his HIV was negative 3 months earlier.
What is the risk of developing TB disease and what is the role, if any, for IGRA
testing in these patients, and how would you treat them?
LTBI vs. TB Disease
LTBI
TB Disease
Tubercle bacilli in the body
Skin test or blood test usually positive
Chest x-ray normal
Chest x-ray abnormal
Bacteriology negative
Bacteriology positive
No symptoms
Cough, weight loss, night sweats
Not infectious, not a case
Often infectious before treatment
Interpretation of TST Results
nyc.gov/health
False-positive and false-negative PPDs
The PPD is only about 70% sensitive
•
•
False positive
– BCG vaccination
– Nontuberculous mycobacterial infection
– Improper administration or interpretation
False negative
– Very young (<6 months old)
– Inability to mount an immune response (e.g., HIV or TB
itself)
– Recent infection (<10 weeks since exposure)
– Very remote infection
– Recent live virus vaccination
– Improper administration or interpretation
Interferon Gamma Release Assays (IGRAs)
• Quantiferon Gold/Gold In-Tube (QFT-GIT)
– 2nd/3rd generation tests
– Available from commercial labs
– ELISA that measures amount of IFN-gamma
released by patient’s cells
• T-Spot.TB
– Approved July 2008
– Elispot
Indeterminate IGRA
• Less frequent with QFT-GIT
• Several possible reasons
– High background IFN-: patient illness, mitogen in
wrong well, defective tubes
– Low mitogen: immune suppression, defective tubes,
overfilling, inadequate shaking
• Options?
– Repeat QFT
– Place TST instead
Comparison of IGRAs and TST
TST
IGRA
• About 70% sensitive
• About 70% sensitive
• Fairly specific
• Not affected by BCG
• Cheap
• Not cheap
• Been around a long time
• New: less experience
• In vivo test
• In vitro testl; requires phlebotomy
• Potential boosting
• No boosting
• Requires 2 patient visits
• Only need 1 patient visit
• Inter-reader variability
• Gives numbers, lessens variability
• Results in 2-3 days
• Results possible in 1 day
• May be more sensitive in
detecting remote infections
• May decline in response to test after
treatment
Potential to cause big problems versus
the hassle required to reduce this risk
Latent Tuberculosis Infection (LTBI)
and progression to real disease
• About 5–10% of persons with LTBI will develop TB disease if
untreated
– 50% in the first two years
– 50% later in life
• The most effective treatment would be to identify and treat LTBI
in all these individuals
• However, treatment of LTBI is:
– Is lengthy: 4 to 9 months, generally
– Is costly: not from medications but because patients have to
come in regularly for monitoring, thereby missing work,
school, etc.
– Carries a very small but real risk for side effects
High Risk for Conversion of LTBI to TB
Disease
• Recent infection, documented conversion (within the last 2 years)
• HIV infection
• Substance abuse (alcohol or drugs)
• Old healed TB lesions on CXR
• Children under 5 years of age
• Certain medical conditions
Medical Conditions
• HIV infection
• <90% of ideal body weight, recent weight loss
• Diabetes mellitus (poorly controlled)
• Chronic renal failure
• Solid organ transplant recipients
• Certain cancers and / or treatment
• Higher-dose steroid treatment (15mg, >4 weeks)
• Tumor necrotizing factor antagonist therapy (TNF-α antagonists)
• History of gastrectomy or jejunoileal bypass surgery
Dealing with the uncertain
The Online TST/IGRA Interpreter:
https://www.tstin3d.com
Statistics and risks derived from website (1)
•
A 35 year old man from Hartford with a 16 mm positive PPD. He has
no known exposure to MTB, no risk factors, normal exam, normal
chest x-ray. He wants to work in your hospital.
•
What do you think? Should he be offered LTBI rx?
•
Stats from history as given above:
–
Likelihood of a true positive PPD: 100%
–
Annual risk of TB disease: 0.1%
–
Lifetime risk of TB disease: 4.5%
–
Risk of hepatotoxicity from treatment: 0.2%
Statistics and risks derived from website (2)
•
A 35 year old man from Hartford with a 16 mm positive PPD. He has
no known exposure to MTB, no risk factors, normal exam, normal
chest x-ray. He wants to work in your hospital.
•
New data: the patient had diabetes:
•
What do you think? Should he be offered LTBI rx?
•
Likelihood of a true positive PPD: 100%
–
Annual risk of TB disease: 0.28% (originally 0.1%)
–
Lifetime risk of TB disease: 12.6% (originally 4.5%)
–
Risk of hepatotoxicity from treatment: 1.2%
Statistics and risks derived from website (3)
•
A 35 year old man from Hartford with a 16 mm positive PPD. He has
no known exposure to MTB, no risk factors, normal exam, normal
chest x-ray. He wants to work in your hospital.
•
New data: the patient had documented close contact:
•
What do you think? Should he be offered LTBI rx?
–
Likelihood of a true positive PPD: 100%
–
Annual risk of TB disease: 0.10%
–
Lifetime risk of TB disease: 9.3% (originally 4.5%)
–
Risk of hepatotoxicity from treatment: 1.2%
–
Risk of developing TB in next two years: 5% (originally 1.2%)
Statistics and risks derived from website (4)
•
A 35 year old man from Hartford with a 16 mm positive PPD. He has
no known exposure to MTB, no risk factors, normal exam, normal
chest x-ray. He wants to work in your hospital.
•
New data: patient had documented new infection (< 2 years):
•
What do you think? Should he be offered LTBI rx?
•
Likelihood of a true positive PPD: 100%
–
Annual risk of TB disease: 0.10%
–
Lifetime risk of TB disease: 5.8% (originally 4.5%)
–
Risk of hepatotoxicity from treatment: 1.2%
–
Risk of developing TB in next two years: 1.5% (originally 1.2%)
Statistics and risks derived from website (5)
•
A 35 year old man from Hartford with a 16 mm positive PPD. He has
no known exposure to MTB, no risk factors, normal exam, normal
chest x-ray. He wants to work in your hospital.
•
New data: the patient had a granuloma on chest x-ray
•
What do you think? Should he be offered LTBI rx?
•
Likelihood of a true positive PPD: 100%
–
Annual risk of TB disease: 0.2% (originally 0.10%)
–
Lifetime risk of TB disease: 9% (originally 4.5%)
–
Risk of hepatotoxicity from treatment: 1.2%
–
Risk of developing TB in next two years: 1.5% (originally 1.2%)
Statistics and risks derived from website (6)
•
A 35 year old man from Hartford with a 16 mm positive PPD. He has
no known exposure to MTB, no risk factors, normal exam, normal
chest x-ray. He wants to work in your hospital.
•
New data: Abnormality (more than a granuloma) on chest x-ray:
•
What do you think? Should he be offered LTBI rx?
•
Likelihood of a true positive PPD: 100%
–
Annual risk of TB disease: 1.25% (originally 0.10%)
–
Lifetime risk of TB disease: 56% (originally 4.5%)
–
Risk of hepatotoxicity from treatment: 1.2%
Statistics and risks derived from website (7)
1.
A 64 year old woman from Jamaica with a 12 mm PPD who is
referred for immigration purposes. She has no risk factors and her
exam is negative. She came to USA 10 years ago.
•
What do you think? Should she be offered LTBI rx?
•
Stats:
–
Likelihood of a true positive PPD: 62%
–
Annual risk of TB disease: 0.06%
–
Lifetime risk of TB disease: 0.99%
–
Risk of hepatotoxicity from treatment: 2.3%
Statistics and risks derived from website (8)
1.
A 64 year old woman from Jamaica with a 12 mm PPD who is
referred for immigration purposes. She has no risk factors and her
exam is negative. She came to USA 10 years ago.
•
New data: she is taking a TNF alpha drug:
•
What do you think? Should she be offered LTBI rx?
•
Likelihood of a true positive PPD: 62%
–
Annual risk of TB disease: 0.33% (originally 0.06%)
–
Lifetime risk of TB disease: 5.3% (originally 0.99%)
–
Risk of hepatotoxicity from treatment: 2.3%
Statistics and risks derived from website (9)
•
A 18 year old from Lima, Peru with a 14 mm PPD for immigration
purposes. She has been in USA for 2 years. Her history and exam
are negative
•
What do you think? Should she be offered LTBI rx?
•
Stats:
–
Likelihood of a true positive PPD: 91%
–
Annual risk of TB disease: 0.07%
–
Lifetime risk of TB disease: 5.6%
–
Risk of hepatotoxicity from treatment: 0%
Statistics and risks derived from website (10)
•
A 54 year old man born and raised in Hartford, who has a 20 mm
PPD. He cannot recall having had a previous TST. He used to be
an IV drug abuser. He says his HIV was negative 3 months
earlier.
•
What do you think? Should he be offered LTBI rx?
•
Stats:
–
Likelihood of a true positive PPD: 100%
–
Annual risk of TB disease: 0.25%
–
Lifetime risk of TB disease: 6.5%
–
Risk of hepatotoxicity from treatment: 2.3%
Statistics and risks derived from website (11)
•
A 54 year old man born and raised in Hartford, who has a 20 mm
PPD. He cannot recall having had a previous TST. He used to be
an IV drug abuser. He says his HIV was negative 3 months
earlier.
•
New data: the patient is HIV positive
•
What do you think? Should he be offered LTBI rx?
–
Likelihood of a true positive PPD: 100%
–
Annual risk of TB disease: 8% (originally 0.25%)
–
Lifetime risk of TB disease: 100% (originally 6.5%)
–
Risk of hepatotoxicity from treatment: 2.3%
Questions?