 Overview
Tuberculosis (TB) is caused by infection
with the bacterium Mycobacterium
tuberculosis.
Infection occurs through inhalation of
the bacterium, which then travels to
the alveoli of the lungs. In most people
who become infected, the body is able
to contain the bacteria and prevent it
from multiplying. The bacterium can live
in the lungs of an infected person for
years, even a lifetime, without the person
exhibiting any symptoms. This state is
called latent TB infection. A person
with latent TB is not infectious to others
but the infection can develop into active
TB disease in the future and usually
exhibits a positive reactive tuberculin
skin test.
People with latent
TB infection
- have
no symptoms;
- don't feel sick;
- can't spread TB to others;
- can have
a positive tuberculin skin test
reaction; and
- can develop TB disease later in
life if they
do not receive treatment for latent
TB infection.
Most people who have latent TB infection
never develop active TB, but if they
do not receive treatment for latent TB
infection about 10 percent of latent TB infections
can develop active disease over a lifetime.
This can happen when the person’s
immune system is weakened allowing the
bacteria to become active and cause TB
disease (e.g., individuals with HIV,
diabetes, certain hematologic disorders
such as leukemias and lymphomas, prolonged
corticosteroid use, and other conditions).
Only a person with active TB can transmit
the disease.
People with active
TB disease
- have symptoms (e.g., a productive
cough, night sweats, fever, weakness
or fatigue, weight loss, pain
in the chest);
- feel sick;
- can spread TB to others; and
- can have
a positive tuberculin skin
test reaction.
The Centers for Disease Control and Prevention
(CDC) has developed recommendations for
preventing transmission of Mycobacterium
tuberculosis in health-care settings.1
For more detailed information refer to
the CDC’s
report  .
Routine Medical History
Ask all patients about past history of
TB or exposure to TB. Ask about TB signs
and symptoms and medical conditions that
increase their risk for TB disease when
taking their medical history. A diagnosis
of respiratory TB should be considered
for any patient with symptoms including
coughing for more than 3 weeks, loss
of appetite, unexplained weight loss,
night sweats, bloody sputum or hemoptysis,
hoarseness, fever, fatigue or chest pains.
The ADA’s Health History Form contains
these kinds of questions.
Return
to Top
Dental
Treatment and TB
Because
a person with latent TB is not infectious,
he or she can be treated in the dental
office under standard infection control
precautions.2
Any patient
with symptoms suggestive of active
TB disease should be removed from
the area of other patients or staff,
instructed to wear a surgical or
procedure mask, assessed for the
urgency of their dental care and
promptly referred for medical care. Standard precautions
are insufficient to prevent transmission
of the bacterium. Elective dental
treatment should be deferred until the
patient has been declared non-infectious
by a physician. Urgent dental care for
a person with suspected or active TB
should be provided in a facility that
has the capacity for airborne infection
isolation and has a respiratory protection
program in place. OSHA describes a standard
for respiratory protection, which should
be consulted if setting up a program
(CFR 1910.134 Respiratory Protection).
When treating a patient with active
TB, dental health care personnel should
use respiratory protection (e.g., fitted,
disposable N-95 respirators). Standard
surgical face masks are not designed
to protect against TB transmission.
Return
to Top
Risk
Assessment
The CDC recommends that dental
offices perform an annual risk assessment.
Risk assessment involves:
1) Risk Classification—identifying
the number of cases of active TB
encountered in the office. The CDC classifies
a low-risk setting as one where less
than 3 patients with active TB are seen
each year. An office that saw more than
or equal to 3 patients with active TB
in the past year is classified as a medium-risk
setting. An office where there is evidence
of a transmission of TB within the past
year or one of the staff has a confirmed
diagnosis of active TB is temporarily
classified as potential ongoing
transmission.
2) Community Awareness—being
aware of the TB risk level in the
surrounding community. Contact the local
or state health department to find out
the number of TB cases in the community.
Just because a dentist practices in a
community with a high number of TB cases
does not mean that that dentist’s
office is medium risk. The likelihood
of encountering TB cases in that particular
practice determines its risk category.
The level of risk for encountering active
TB in the dental office determines the
types of administrative, environmental,
and respiratory protection controls needed.
Annual risk reassessment can also serve
as an ongoing evaluation tool of the
quality of the office’s TB infection
control practices and allows identification
of any needed improvements in infection
control measures.
Return
to Top
Training
The CDC recommends that dental office
personnel receive training and education
on M. tuberculosis and TB disease
that emphasizes the increased
risks posed by an undiagnosed
person with TB disease in a dental-care
setting and the specific measures
to reduce this risk. Training
and education materials are available
at
http://www.cdc.gov/nchstp/tb/pubs/pem.htm and http://www.findtbresources.org .
Return
to Top
Dental
Healthcare Workers and TB
Skin Test
The CDC’s Advisory Committee on
Immunization Practices does not recommend
routine immunization (Bacille-Calmette-
Guérin [BCG]) of U.S. health care
workers against TB. However, the CDC
does recommend that all persons in the
dental office who have the potential
for exposure to M. tuberculosis through
air space shared with persons with infectious
TB disease (which essentially means all
personnel) receive a two-step baseline
tuberculin skin test (TST) at the beginning
of employment in low-risk settings, every
12 months in medium-risk settings and
every 8–10 weeks in the event of potential
ongoing transmission until no further
evidence of ongoing transmission is apparent.
By doing so, TST conversions (from a
negative to positive result) following
an exposure incident can be distinguished
from positive TST results resulting from
previous exposures. After baseline testing
additional TB screening is not necessary
in low-risk settings unless an exposure
to M. tuberculosis occurs.
Individuals with a positive TST should
consult with their physician to determine
whether any treatment is required.
Return
to Top
Endnotes
1. Centers for Disease Control and Prevention:
Guidelines
for Preventing the Transmission of Mycobacterium
tuberculosis in Health-Care Settings,
2005. MMWR 2005; 54(RR17);1-141
2. Centers for Disease Control and Prevention:
Guidelines
for Infection Control in Dental Health-Care
Settings—2003; 52(RR17);1-61
Return
to Top
Additional
Resources
Return
to Top |
