內文：
Abstract
To present the essential elements of an infection control/ exposure control plan for the oral healthcare settings with emphasis on
tuberculosis Introduction
˙In 2005, the Centers for Disease Control and prevention (CDC) published new guidelines for prevention the transmission of Mycobacterium tuberculosis (MBT)
→Apply to healthcare workers (HCWs)
˙The magnitude of the risk varies by :
occupational group, prevalence, population Etiology and Epidemiology
˙Robert Koch first described MBT →carried in airborne particles (droplet nuclei) generated when
patients cough, sneeze,shout, sing, talk
˙Droplets nuclei are between 1-5 microns in diameters
→can remain in air for ours and can be
carried by air throughout a room or building
˙The probability of a person becoming infected depends on the concentration of droplets nuclei in the air and the duration of exposure
˙Environmental factors
→confined space, inadequate ventilation, recirculation of air
˙When hosts inhale droplets nuclei
→the bacilli travel through upper respiratory tract, bronchi, to alveoli where a local infection is established
˙The immune response is predominantly cell-mediated (CD4+ and CD8+ T-cell)
˙Pulmonary macrophages present antigens to
→major-histocompatibility-complex (MHC) class II molecules (active CD4+
T-cells) and MHC class I molecules (active CD8+ T-cells)
˙within 2-10 weeks
→the immune response will limit further multiplicaiton of MBT
→if the quantity and virulence of TB bacilli is high, then the bacilli may disseminate throughout by lymphatic and hematogenous spread
˙TB causes approximately two million death annually
˙In 2005, 14097 cases were reported to CDC represented 2.9% decease than 2004
˙In 2005, TB case rate of 4.8 per 100000 represented 3.8% decline compared with 2004
˙The rate of TB in foreign-borne persons was 7.8 times that of those born in U.S.
˙Classic symptoms include chronic ill health, coughing with hemoptysis, low-grade fever, weight loss, and night sweats.
˙About 15% of patients with TB disease present with an extrapulmonary site of infection
˙Expectoration of the infected sputum may cause tuberculous
tracheitis,laryngitis, and tuberculous ulcers on the tonsils and nasal cavity
˙When the cervical lymph nodes are involved,they may caseate forming tuberculous abscesses or fibrosis and calcification
Oral manifestations of TB
˙The estimated prevalence of oral tuberculous lesions ranges from 0.05 to 5%
˙Oral lesions are usually secondary, reflecting with infected sputum and hematogenous spread
˙Patients with TB disease and HIV-infection, the palate and dorsum of the tongue were the most frequent sites of oral involvement
˙Pain and cervical lymphadenopathy are common findings
Diagnosis
Latent TB Infection
˙The tuberculin skin test (TST)
→The antigen is injected intracutaneously into the forearm
˙TST evokes the delayed hypersensitivity reaction mediated by T-cells
˙The test is read at 48-72 hours, and the diameter of the induration of erythema is measured
˙While the relative specificity of the TST is high →false positive and false negative
→false positive : sensitization with MBT
→false negative : immunocompromised, recent exposure, very young child
QuantiFERON -TB Gold (QFT-G) test (for LTBI)
˙Detects the release of interferon-gamma in fresh heparinized blood from sensitized persons when it is incubated with mixtures of synthetic peptides representing two proteins present in MBT
TB disease
˙Definitive diagnosis requires the demonstration of MBT in the patient’s tissues or secretions.
˙Bacteriologic which includes obtaining a specimen of sputum, detection of acid-fast bacilli (AFB) in stained (Ziehl-Neelsen method) smears examined microscopically
˙DNA probes specific for the genus Mycobacterium now are used routinely to identify
˙Standard
antimycobacterial treatment regimens include antibiotics that target unique targets such as the synthesis of NAG-arabinogalactan
and the early steps in mycolic acid synthesis
Isoniazid safe used
TTrreeaattmmeenntt ooff TTBB DDiisseeaassee
Treatment of Susceptible TB Disease
Treatment of Resistant TB Disease
Treatment of TB Disease in Patient with HIV Infection
Treatment of TB disease in the Pregnant Patient
TBTB IInnffeeccttiioonn--CCoonnttrrooll SSttrraatteeggiieess iinn OOrraall HHeeaalltthhccaarree SSeettttiinnggss
OHCWs and patients with infectious TB disease will generate droplet nuclei by coughing, sneezing, laughing, and talking
A TB infection-control plan that is part of its written infection control/exposure control protocol
Inadequate to prevent the spread of organisms through droplet nuclei 1-5µm in diameter, and additional measures (e.g. transmission-based precautions) are necessary to prevent the spread of MBT
TB infection-control component should be based on a three-level hierarchy of administrative, environmental, and respiratory-protection controls
AdAdmmiinniissttrraattiivvee CCoonnttrroollss
The first and most important level
To reduce the risk of exposure to persons who might have infectious TB disease
TBTB RRiisskk AAsssseessssmmeenntt ffoorr tthhee OOrraall HHeeaalltthhccaarree SSeettttiinngg
Every oral healthcare setting should conduct initial and ongoing (annual) evaluations of TB risk for the setting
TB risk assessment for the community will determine the types of administrative, environmental, and respiratory-protection controls that are needed for the particular setting
Consult with the local or state health department
TBTB IInnffeeccttiioonn--CCoonnttrrooll PPrrooggrraamm tthhee OOrraall HHeeaalltthhccaarree SSeettttiinngg
With patients with undiagnosed or unsuspected infectious TB disease
Specific precautions: prevalence of TB in the community, patient population served, and the type of services provided in a particular setting
TBTB iinnffeeccttiioonn--ccoonnttrrooll pprroottooccooll
Prompt identification of patients with suspected or confirmed infectious TB disease
Separation of patients with suspected and confirmed TB disease from other OHCWs and patients
Referral for a medical evaluation and/or required oral healthcare procedures to a facility with appropriate environmental controls and respiratory-protection controls
IIddeennttiiffiiccaattiioonn ooff PPaattiieennttss wwiitthh SSuussppeecctteedd oorr CCoonnffiirrmmeedd TTBB DDiisseeaassee
Reviewing medical histories (initial and periodic update), including a review of organ systems
• Their history of exposure to TB, LTBI, and any history of TB disease
• Any medical conditions that increase the risk of TB disease
• Any signs and symptoms of TB disease
Patients with a history of LTBI and confirmed TB disease should be questioned about the status of their antimycobacterial treatment
Provisional diagnosis of respiratory TB disease should be considered for any patient with signs and symptoms of infection in the lungs or airways, coughing for
>3 weeks, loss appetite, unexplained weight loss, night sweats, bloody sputum or hemoptysis, hoarseness, fever, fatigue, and chest pain
IsIsoollaattiioonn ooff PPaattiieennttss wwiitthh SSuussppeecctteedd oorr CCoonnffiirrmmeedd TTBB DDiisseeaassee ffrroomm OOtthheerr PPaattiieennttss anandd OOHHCCWWss
Isolated from other patients and OHCWs and instructed to observe strict respiratory hygiene and cough etiquette procedures
Should wear a surgical mask
When coughing or sneezing, they should turn their heads away from other persons and cover their mouth and nose with their hands or preferably a disposable facial tissue
RReeffeerrrraall ooff PPaattiieennttss wwiitthh SSuussppeecctteedd oorr CCoonnffiirrmmeedd TTBB DDiisseeaassee ffoorr aa MMeeddiiccaall EvEvaalluuaattiioonn aanndd//oorr RReeqquuiirreedd UUrrggeenntt DDeennttaall CCaarree
Routine dental care should be postponed until a physician confirms the patient
Patients with suspected or confirmed TB disease requiring urgent dental care must be promptly referred on an oral healthcare facility that meets the requirements for an airborne infection isolation (All) room
While performing procedures on such patients, OHCWs should use at least an N95 disposable respiratory
T
TBB EEdduuccaattiioonn aanndd TTrraaiinniinngg PPrrooggrraamm ffoorr OOHHCCWWss
The level of training will vary according to the risk classification of the setting
SSccrreeeenniinngg ffoorr LLTTBBII aanndd TTBB DDiisseeaassee iinn OOHHCCWWss
The administration, reading, and interpretation of TST or other tests are to be performed by trained personnel as follows:
TBTB IInnffeeccttiioonn--CCoonnttrrooll SSttrraatteeggiieess iinn OOrraall HHeeaalltthhccaarree SSeettttiinnggss Administrative Controls
Preventive Therapy
Workplace Restrictions for OHCWs
Environmental Controls
Respiratory Protection Controls
PPrreevveennttiivvee TThheerraappyy
Should be offered to all personnel with baseline-positive TST or BAMT results if they are younger that 35 years
Should further be offered to the all personnel, regardless of age, who conversion of their TST or BAMT results
Be provided through the local or state health department or by other healthcare providers
P
Poosstt--eexxppoossuurree MMaannaaggeemmeenntt ooff OOHHCCWWss
After an exposure to MBT, TST or BAMT testing should be done on personnel known to have had negative results on previous testing
If the initial post-exposure test is negative, repeat the test 12 weeks after exposure
Do not perform TST or BAMT testing or chest radiographs on personnel with previous positive test results, unless they have symptoms suggestive of TB disease
W
Woorrkkppllaaccee RReessttrriiccttiivvee ffoorr OOHHCCWWss
Personnel with TB disease should be excluded from the workplace until documentation is provided from their healthcare provider that
• They are receiving adequate therapy
• Their cough has resolved
• They have had three consecutive sputum smears collected on different days with negative results for AFB
Personnel with TB disease who discontinue treatment before cured should be promptly evaluated for their infectious state
Do not restrict personnel from their usual duties if they are receiving preventing therapy because of positive TST results
Instruct them to seek prompt evaluation if symptoms suggestive of TB disease develop
I
Immmmuunnooccoommpprroommiisseedd OOHHCCWWss
Referred to their personal health professionals
Offer accommodations for work settings in which they would have the lowest possible risk for occupational exposure to MBT
EEnnvviirroonnmmeennttaall CCoonnttrroollss
Are physical or mechanical measures intended to prevent the spread and reduce the concentration of infectious droplet nuclei 1-5μm in diameter in ambient air
Patients with suspected or confirmed TB disease requiring urgent dental care must be treated in a room meeting requirements for airborne infection isolation
All rooms provide negative pressure in the room so air flows under the door gap into the room
They have an air exchange rate of 6-12 ACH, and a direct exhaust of air from the room to the outside of the building, or provide for a recirculation of air through a high efficiency particulate air filter
ReRessppiirraattoorryy PPrrootteeccttiioonn CCoonnttrroollss
Use of respiratory equipment in situations that pose a high risk for exposure
Performing urgent dental care on a patient with suspected or confirmed TB disease must wear at least an N95 disposable respirator
N95 disposable respirators are nonpowered, air-purifying, particulate-filter respirator
The N (not resistant to oil)-series respirators are available with filtration
efficiencies of 95% (N95), 99% (N99), and 99.7% (N100) when challenged with 0.3μm particles
SuSummmmaarryy
The risk of MBT transmission in the oral healthcare setting is low, but the consequences of exposure can be substantial
TB infection-control surveillance
Post-exposure management strategies
TB infection-control protocol for patients with suspected or confirmed TB disease
題號 題目
1 Where is the most common extrapulmonary sites in the head and neck involved by TB?
(A) tongue
(B) cervical lymph nodes (C) nasal cavity
(D) ear
答案(B) 出處：Oral & Maxillofacial Pathology (P.173)
