Download Dr. Ramesh TB Presentation

Tuberculosis Update
Epidemiology and Prevention
Dr. Jaishri Ramesh
Alliance Occupational Medicine
Objectives
• Describe select trends in tuberculosis (TB)
incidence in the United States and California
• Present select Santa Clara County specific TB
data
• Discuss TB Transmission
• Discuss TB Pathogenesis and clinical
presentation – infection vs disease
• Describe characteristics that impact TB
transmission
• The role of TB Control
Tuberculosis Etiology
• Tupberculosis (TB) , one of the oldest known diseases is
still one of the major causes of global mortality.
• TB is primarily a bacterial pulmonary disease that has
many manifestations, affecting bone, CNS, spinal and
many other organ systems.
• TB is caused by an acid fast bacteria Mycobaterium
tuberculosis
• Species: The Mycobacterium tuperculosis complex
(MTC) consist of Mycobacterium africanum,
Mycobacterium bovis, Mycobacterium canettii,
Mycobacterium micotti, Mycobacterium tubersulosis
Tuberculosis Epidemiology
Key Facts/Global Impact
• TB is second only to HIV/AIDS as the greatest killer
worldwide due to a single infectious agent.
• In 2012, 8.6 million people fell ill with TB and 1.3 million
died from TB.
• Over 95% of TB deaths occur in low & middle income
countries, and it’s among the top three causes of death
for women aged 15-44.
• In 2012 an estimated 530,000 children became ill with
TB + 74,000 HIV negative children died of TB
World Health Organization
Key Facts/Global Impact
(cont.)
• TB is a leading killer of people with HIV causing one fifth
of all deaths.
• Multi drug resistant TB (MDR-TB) is present in virtually
all countries surveyed.
World Health Organization
Key Facts/Global Impact
(cont.)
Good News!
• The estimated number of people falling ill with TB each
year is declining, although very slowly which means that
the world is on track to achieve the Millennium
Development Goal to reverse the spread of TB by 2015.
• The TB death rate dropped 45% between 1990 and
2012.
• An estimated 22 million lives saved through the use of
“Stop TB Strategy” recommended by WHO.
World Health Organization
Center for Disease Control
Tuberculosis (TB) incidence overall and among U.S.- and foreignborn persons, by year — United States, 2000–2015*
osis (TB) incidence overall and among U.S.- and foreign-born persons, by year — United States, 2000–2015*
Center for Disease Control
Center for Disease Control
0
5
0
4,000 1930
1980
1970
1960
1950
1940
8,000
TB Cases California 1985-2015
California Department of Public Health
California Department of
Public Health
Case Rate per 100,000
Number of Tuberculosis Cases
and Case Rates: CA, 2004-2013
*
Number of Cases
Case Rate per 100,000 Population
National Case Rate (3.0 per 100,000)
California Department of Public Health
TB Rates by Racial/Ethnic
Group California 2015
California Department of Public Health
Trends in TB Cases Santa
Clara County 2006-2015
TB Case Rates for California
and San Francisco Bay Area
Counties 2015
Case #1
• One of our employer contacts for a large
company called to state that she received a call
from the SCC TB nurse informing her that one of
her employees was diagnosed with active TB
and that they are in the process of identifying the
“contacts” of the Index case who would receive
letters from the SCC TB RN to go to Alliance
Occupational Medicine for Exposure Protocol.
• She called again 1 week later to inform us that
19 contacts (other employees) were identified
and would be coming in.
• Are these Recordable injuries?
TB Transmission
How is TB spread?
• TB is spread from person to person by inhaling
droplets of infected material produced when a
person with “contagious” TB exhales forcefully
(such as coughing, sneezing, singing, or
laughing).
• Small children are less likely to transmit the
bacteria.
TB Transmission (cont.)
• Person with active
pulmonary TB exhales TB
bacilli in “droplet nuclei”
• Droplet nuclei are inhaled
by person sharing the same
airspace
• Infection begins when
droplet nuclei reach the
alveoli
• Small number enter the
bloodstream and spread
throughout the body.
TB Pathogenesis
• Within 2-10 weeks
the immune system
intervenes by
producing immune
cells that surround
the bacilli forming a
hard shell. (latent
TB infection)
30%
Latent TB Infection
• When a person has Latent TB infection, TB
germs in their body are inactive or sleeping. The
body’s defenses wall-off the germs and keep
them from growing.
• A person with Latent TB infection:
–
–
–
–
Does not feel ill and has no symptoms
Is not contagious
Usually has a positive TB skin test
Usually has a normal chest x-ray
TB Pathogenesis
• TB disease will develop when the
immune system cannot keep the
tubercle bacilli under control and
they begin to multiply (active TB
disease)
• TB disease can develop very soon
after infection or many years after
infection
• TB disease may occur in any organ
of the body
Does everyone who is exposed to TB
become infected and get sick?
• Approximately 70% of exposed people will NOT
become infected.
• Approximately 30% of exposed people will
become infected.
– 5% of infected people will develop TB disease within
1-2 years of infection.
– 95% will contain the infection
• 5% will get disease later in life
• 90% will never develop disease
Risk Factors for Progression to Disease:
•
•
•
•
•
•
•
•
HIV infection
Injection of illicit drugs
Recent infection (within the past 2 years)
Chest radiograph findings suggestive of
previous TB
Diabetes mellitus
Silicosis/certain types of cancers
Prolonged therapy with corticosteroids
Low body weight (10% or more below ideal)
TB Pathogenesis
Progression to TB Disease
TB infection
and diabetes
TB infection
No risk factors
TB
Disease
(10% over
a lifetime)
TB infection
(no TB disease)
TB infection
(no TB disease)
TB infection
And HIV
TB
Disease
(30% over
a lifetime)
TB infection
(no TB disease)
TB
Disease
(7-10% per
year.)
Active TB Disease
• When a person has active TB Disease:
• The germs in their body have awakened and
are multiplying
• They may feel sick
• They may be contagious
• The TB skin test is usually positive
• Chest x-ray is usually abnormal
• Sputum culture is usually positive.
Symptoms of TB Include:
•
•
•
•
Fatigue
Weight loss (unexplained)
Loss of appetite
Cough
- Persistent for 3 weeks or longer
• Fever and/or chills
• Night sweats
What Determines Whether TB
Will Spread?
Characteristics of the person with TB disease
Characteristics of the exposure
Characteristics of the person who is exposed
The Characteristics of the
Person with Disease
• Location: Pulmonary (lung) TB is the most common and contagious
type of TB
• Amount of M. tuberculosis: The more germs in the person’s lung the
greater the number of infectious droplets come out when the person
coughs. Laboratories can check the sputum under a microscope. If
the sputum smear is “positive” for TB bacteria, the person is highly
infectious.
• Symptoms: coughing. The more a person coughs, the more particles
are expelled into the air. Some people with TB have very few
symptoms, and are less likely to infect others.
The Characteristics of the
Exposure
• Location of the exposure: Closed rooms without
significant air circulation or filtration are the most
risky.
• Closeness and time: The closer one is physically
and the longer the time spent together the more
likely transmission will occur.
Characteristics of the Person
Exposed
• Individual factors: some people are more
vulnerable to being infected with TB than others.
• Prior TB infection: someone who has been
previously infected is less likely to become
infected from a new exposure
Tuberculosis Diagnosis:
Tuberculosis Skin Tests
•
The diagnosis of TB should not be based on the result
of a tuberculin skin test
•
A positive tuberculin skin test only indicates a greater
likelihood of TB infection, not necessarily TB disease
•
A negative tuberculin skin test does not exclude TB.
There are many reasons for a false-negative tuberculin
skin test
TB Blood Tests
Interferon – Gamma Release Assays or IGRAs
• Measure how the Immune System reacts to
Mycobacteria TB
• An IGRA measures how strong a person’s
immune system reacts to TB bacteria by testing
the person’s blood in the laboratory.
• 2 IGRAs are approved by FDA in the US.
– Quantiferon, TB Gold in tube test (QFT-GIT)
– T-Spot, TB test (T-Spot)
TB Blood Tests (cont.)
• Positive IGRA: This means that the person has
been infected with TB bacteria. Additional tests
like a CXR are needed to determine if the
person has latent TB infection or TB disease.
• Negative IGRA: This means that the person’s
blood did not react to the test and that latent TB
infection or TB disease is not likely.
TB Blood Tests (cont.)
IGRAS are the preferred method of TB infection
testing for the following:
• People who have received BCG (Vaccine for TB
disease)
• People who have a difficult time returning for a
2nd appointment to look for a reaction to the 1st.
There is no problem with repeated IGRAs.
PRINCIPLES OF
TUBERCULOSIS CONTROL
Elements of TB Control
• Preventing morbidity and mortality from
tuberculosis
• Preventing transmission/infection
• Preventing progression from infection to disease
• Surveillance
Preventing Morbidity &
Mortality
• Identifying and treating persons with active or
suspected TB disease
– Reporting
– Case management
– Home assessment
– DOT
Preventing Transmission/Infection
• Case finding & prompt treatment of
cases/suspects
• other
– isolation of infectious persons
– institutional infection control
– minimizing contact
– covering cough
– personal respiratory protection during contact
Prevention of Progression to
Disease
• Contact Screening
– contact investigations
– source case investigations
– follow through completion of therapy
• Population Screening
– Class B immigrants
– School mandates
Surveillance
• Uses
– monitoring disease trends
– targeting prevention efforts
– evaluating interventions
• Data
– # of cases
– rates
– demographics
TB Control Receives Case
Reports
• All cases and suspect cases must be
reported to the local health department (LHD)
w/in 1 working day of making or presuming a
TB diagnosis
• Cases and suspects are assigned to a nurse
for case management.
INFECTION AND
ENVIRONMENTAL CONTROLS
FOR TUBERCULOSIS
Regulation of Tuberculosis
Infection Control
•
•
•
•
•
CDC - Centers for Disease Control
OSHA and Cal/OSHA - Occupational Safety and
Health Administration
OSHPD - Office of Statewide Health Planning and
Development
ASHRAE - the American Society of Heating,
Refrigerating and Air-Conditioning Engineers, Inc.
AIA – American Institute of Architects
Facilities at Increased Risk of
Tuberculosis Transmission
•
•
•
•
Healthcare
Correctional
Drug and alcohol treatment
Shelters serving homeless and HIV-infected
persons
Hierarchy of Infection Control
Measures
• ADMINISTRATIVE CONTROLS to reduce risk
of exposure
• ENGINEERING CONTROLS to prevent spread
and reduce concentration of droplet nuclei
• PERSONAL RESPIRATORY PROTECTION in
areas where there is increased risk of exposure
Administrative Controls
• Control infection
- Early detection, isolation, and treatment
• Prevent the spread of infection, systems to:
- Provide respiratory protection
- Reduce air contamination
• Educate staff, visitors, clients!
If you have a COUGH…
• PLEASE COVER YOUR
MOUTH (Cough into your
upper sleeve not your
hand)
• Ask the receptionist
for a MASK
Education and Training
Cal OSHA requires that workers be trained on:
• Signs, symptoms, transmission, risk factors
• TB screening and prophylaxis for latent TB infection
(LTBI)
• Engineering and work practice controls
• Personal protective equipment, use and limitations
• Employer and employee responsibilities for reducing risk
of TB
• Employees must have the opportunity to ask questions
at the training
Engineering Controls
The Engineering Model
Patient emits infectious droplets which float in the
air indefinitely unless removed or killed
Clean Air In
Contaminated
Air Out
Engineering Controls
Contain contaminated air :
• Negative pressure rooms, sputum induction
booths
Reduce concentration of infectious droplet nuclei:
• Dilution ventilation
• HEPA filters
• UV fixtures
Direct Flow of Air
• Introduce air near staff
• Exhaust near patient
Clean Air In
Contaminated
Air Out
Dilution Ventilation
• Supplies clean air
• Mixes with room air
• Exhausts contaminated air
• One room air change removes 63% of droplets,
if mixing is perfect
• Six air changes per hour (ACH) removes 99.9%
of droplets in 69 minutes
Dilution Ventilation Effectiveness
•
Maximize air changes
•
Optimize room air mixing
•
Direct flow of air
– Over staff
– Across patient
– Then exhaust
Contaminated Return Air
•
Exhaust directly to atmosphere away from air
intakes (25 ft)
•
Use HEPA filtration if air is re-circulated
High Efficiency Particulate Air
(HEPA) Filters
• Removes 99.97% of 0.3 µm particles
• Used to clean air before:
– Recirculation to other parts of
facility
– Recirculation to same room
– Exhaust to atmosphere
Personal Protective Equipment
An Effective Respirator for
Tuberculosis
• Filters particles of 1 micrometer with an
efficiency of 95% (NIOSH, 95% = N 95)
• Comes in various sizes and shapes to fit
different faces
An Effective Tuberculosis
Mask WORKS When…
•
There is a correct fit
•
The mask is conscientiously placed
•
The mask is given proper care
How do we assure that these
essential elements are met?
What To Do?
• Call Public Health early
• Allay fears/anxiety
– Education/Information
– Refer to PMD if necessary
• Above all, maintain patient confidentiality
Protocol for Evaluation &
Treatment of TB Exposure
•
•
•
•
Initial Evaluation – History & Physical
TB test – PPD or IGRA
CXR if positive TB test
Repeat TB test if initial test negative 10-12
weeks
• CXR if 2nd test positive
• Evaluation for latent TB treatment
Any Questions?
Thank you!
Dr. Jaishri Ramesh
Alliance Occupational Medicine
1901 Monterey Rd. San Jose, CA. 95112
2737 Walsh Ave. Santa Clara, CA. 95054
315 S. Abbott Ave. Milpitas, CA. 95035
[email protected]
(408) 228-8400