Transcript Suspect case

‫بسم هللا الرحمن الرحيم‬
Severe Acute
Respiratory
Syndrome
Hatami M.D. MPH
2008 (1387)
‫تاريخچه ‪:‬‬
‫آغاز همه گيري ‪:‬‬
‫ّ‬
‫اول نوامبر ‪( 2002‬دهم آذرماه ‪)1381‬‬
‫پايان همه گيري ‪:‬‬
‫ّ‬
‫ل‬
‫نيمه او ماه آگوست ‪(2003‬اواسط مرداد ماه ‪ )1382‬تعداد‬
‫موارد ‪ :‬حدود ‪ 8422‬مورد‬
‫وسعت همه گيري ‪ :‬از بيش از ‪ 30‬كشور جهان به سازمان‬
‫جهاني بهداشت‪ ،‬گزارش شده است‪،‬‬
‫ميزان مرگ ‪ 916 :‬نفر آنان جان خود را از دست داده و ميزان‬
‫كشندگي بيماري را در حدود ‪ 14‬درصد اعالم كردهاند‬
SARS
Case definition
1 – Suspect case
2 – Probable case
3 – Definitive case
1 - Suspect case (1)
1. A person presenting after 1 November 2002 (10
Aban 1381) with history of:
- high fever (>38 °C)
AND
- cough or breathing difficulty
AND one or more of the following exposures
during the 10 days prior to onset of symptoms:
- close contact with a person who is a suspect
or probable case of SARS;
- history of travel, to an affected area
- residing in an affected area
Suspect case (2)
2. A person with an unexplained acute
respiratory illness resulting in death after 1
November 2002, but on whom no autopsy has
been performed
AND one or more of the following exposures
during to 10 days prior to onset of symptoms:
- close contact, with a person who is a suspect
or probable case of SARS;
- history of travel to an affected area
- residing in an affected area
2 - Probable case
A suspect case with:
1- radiographic evidence of infiltrates
consistent with pneumonia or
respiratory distress syndrome (RDS)
on chest X-ray (CXR).
OR
2- autopsy findings consistent with
the pathology of RDS without an
identifiable cause.
Exclusion criteria
A case should be excluded if an alternative
diagnosis can fully explain their illness.
SARS Etiologic Agent
Order: Nidovirales
Family: Coronaviridae
• Torovirus
• Coronavirus
–Grp I
–Grp II
–Grp III
Seasonal pattern
Mode of transmission
Mode of transmission
• Probable major modes of transmission
– Large droplet aerosolization
– Contact
• Direct
• Fomite
• Airborne transmission cannot be ruled out
– ? Role of aerosol-generating procedures
• ? Fecal-oral
Number of cases by reported source
of infection (Singapore)
Spread from Hotel M
Reported as of March 28, 2003
Canada
Guangdong
Province,
China
F,G
A
F,G
18 HCW
11 close contacts
A
Hotel M
Hong
Kong
A
Hong Kong SAR
95 HCW
H,J
H,J
K
B
Ireland
K
0 HCW
I, L,M
C,D,E
I,L,M
>100 close contacts
B
C,D,E
Vietnam
Singapore
37 HCW
34 HCW
21 close contacts
37 close contacts
United
States
1 HCW
‫ّ‬
‫مورد اوليه ‪SARS‬‬
‫(نسل ّاول)‬
‫كاركنان حرفههاي پزشكي‬
‫و اعضاء خانواده بيماران‬
‫(نسل ّ‬
‫دوم)‬
‫اعضاء خانواده كاركنان‬
‫(نسل ّ‬
‫سوم)‬
‫ساير تماس يافتگان در جامعه‬
‫(نسل چهارم)‬
Attenuation
• Attenuation is a phenomenon seen in
some members of the coronavirus
family, where the virulence decreases
when it jumps from person to
person.
• The SARS virus seems to exhibit this
phenomenon (however, there are no
studies yet to prove this).
Viral pathogenesis - general
local replication
dissemination
immune
response
end-organ
involvement
Adaptive
Innate
cytokines
phagocytes
NK cells
primary viremia
secondary viremia
Incubation Period
• 2-10 days
• Infected people do not pass on the
virus to others during the
incubation period.
• They become infectious only when
the first symptoms appear: cough,
sneezing – which spread droplets
containing virus particles.
Clinical manifestations
• Incubation period 2-10 days
• Onset of fever, chills/rigors, headache,
myalgias, malaise
• Respiratory symptoms often begin 3-7
days after symptom onset
Clinical manifestations
• Sudden onset of high fever
• Characteristic chest X-rays 3-4 days after
onset of symptoms
• 10-15% of cases require intensive care
and mechanical ventilation
• Case fatality about 10%
• Intensive and good supportive care
Symptoms Commonly Reported By
Patients with SARS1-5
Symptom
Fever
Cough
Dyspnea
Chills/Rigor
Myalgias
Headache
Diarrhea
Range (%)
100
57-100
20-100
73-90
20-83
20-70
10-67
Common Clinical Findings in Patients
with SARS
Finding
Examination
Rales/Rhonci
Hypoxia
Laboratory
Leukopenia
Lymphopenia
Low platelet
Increased ALT
Increased LDH
Increased CPK
Range (%)
38-90
60-83
17-34
54-89
17-45
23-78
70-94
26-56
Symptoms Reported by Patients With
Diagnostic SARS-CoV Laboratory
Testing, United States, 2003
Symptom
Coronavirus Positive
(n=6) %
Coronavirus Negative
(n=28) %
Fever
100
96
Cough
100
93
Dyspnea
100
61*
Myalgias
83
75
Chills/Rigor
83
68
Headache
67
68
Diarrhea
67
25*
Coryza
17
43
Sore Throat
17
43
Clinical Findings in Patients With
Diagnostic SARS-CoV Laboratory Testing,
United States, 2003
Symptom
Coronavirus
Positive
(n=6) %
Coronavirus
Negative
(n=28) %
83
23*
Hypoxia
83
29*
Infiltrates
100
30*
Laboratory
Leukopenia
17
5
Lymphopenia
83
53
Low platelets
17
5
Increased ALT
60
17
Examination
Rales/rhonci
‫تشخيصهاي افتراقي‬
‫‪SARS‬‬
‫ّ‬
‫برخي از عوامل مولد پنوموني آتيپيك‬
‫‪1‬ـ‬
‫‪2‬ـ‬
‫‪3‬ـ‬
‫‪4‬ـ‬
‫‪5‬ـ‬
‫‪6‬ـ‬
‫‪7‬ـ‬
‫مايكوپالسما پنومونيه‬
‫كالميديا پنومونيه‬
‫كالميديا پسيتاس ي‬
‫كوكسيال بورنتي‬
‫ويروسها‬
‫پنوموسيستيس كاريني‬
‫لژيونالئي پنوموفيال‬
Diagnostic Approach to Patients with
Possible SARS
• Consider other etiologies
–Diagnostic workup
1 - Chest radiograph
2 - Blood and sputum cultures
3 - Testing for other viral pathogens
(e.g. influenza)
4 - Consider urinary antigen testing
for Legionella spp. and Streptococcus
pneumoniae
Diagnostic Approach to Patients with
Possible SARS
5 - Save clinical specimens for possible
additional testing
Respiratory
Blood
Serum
6 - Acute and convalescent sera (>21 days
from symptom onset) should be collected
7 - Contact Local and State Health
Departments for SARS-CoV testing
Laboratory Assays for SARS
• Detection of virus
–
–
–
–
EM in clinical specimens (CoV-like particles)
Isolation of virus
Detection of viral antigens
Detection of viral RNA (PCR)
• Respiratory secretions
• Stool specimens
• Urine specimens
• Tissue – lung and kidney
• Detection of SARS-specific antibody
– IFA
– ELISA
– Neutralization
Characteristics of SARS-CoV
PCR
• Limited experience/data
• Specimens
– 1 - Upper respiratory maybe ~50% positivity in acute-phase
specimens
– 2 - Stool possibly higher sensitivity later in illness, e.g., 10-14
days
– 3 - Sputum/BAL probably higher rate of positivity
– 4 - Other specimens, urine, blood, tissues, ?
• Interpretation of Results
– Negative -- does not rule out SARS-CoV infection
– Positive – possibility of false positive (test error/contamination)
Diagnosis
• SARS is a clinical and epidemiologic
diagnosis
• Laboratory testing can diagnose
SARS-CoV infection during the
acute illness
• Laboratory testing can not rule out
infection until the convalescent
phase of illness
Radiographic Features of SARS
• Infiltrates present on chest radiographs
in > 80% of cases
• Infiltrates
– initially focal in 50-75%
– interstitial
– Most progress to involve multiple
lobes, bilateral involvement
Radiographic Features of SARS
Treatment of Patients with SARS
• Most effective therapy remains unknown
– Optimize supportive care
• Treat for other potential causes of
community-acquired pneumonia of
unknown etiology
Treatment of Patients with SARS
• Potential Therapies Requiring Further
Investigation
– Ribavirin
– ?other antiviral agents
– Immunomodulatory agents
• Corticosteroids
• Interferons
• Others?
Clinical Features Associated
with Severe Disease
• Older Age
• Underlying illness
• ? Lactate dehydrogenase levels
• ? Severe lymphopenia
Infection Control
• Early recognition and isolation is key
– Heightened suspicion
– Triage procedures
• Transmission may occur during the early
symptomatic phase
– Potentially before both fever and respiratory
symptoms develop
Treatment of Patients with SARS
• Isolation
– Hand hygiene
– Contact Precautions (gloves, gown)
– Eye protection
– Environmental cleaning
– Airborne Precautions (N-95 respirator,
negative pressure)
Treatment of Patients with SARS
Key Objectives
• Early detection
• Containment of
infection
• Protection of
personnel and the
environment of care
• Hand hygiene
Key Strategies
• Administrative
measures
• Infection precautions
– Standard
– Contact (droplet)
– Airborne
• Environmental
cleaning/disinfection
SARS Transmission During
Aerosol-Generating Procedures
• Transmission of SARS to healthcare
personnel during aerosol-generating
procedures may be particularly efficient
• Clusters detected in Toronto, Hong Kong,
Singapore and Hanoi
• Intubation, suctioning and nebulization
specifically implicated
Why? How?
• Patient infectivity higher?
• Is it: Droplet? Contact? Airborne?
• Is it failure to wear protective
equipment?
• Is it failure of protective equipment?
Until Risks During AerosolGenerating Procedures Better
Defined…..
• Limit cough-inducing procedures
• Avoid use of non-invasive positive
pressure ventilation (e.g., CPAP, BiPAP)
• Protect the environment
– Use closed suctioning devices
– HEPA filtration on exhalation valve port
Protect Healthcare Personnel
DuringAerosol-Generating
Procedures
• Limit personnel to those essential for
performing procedure
• Wear appropriate personal protective
equipment
– Gowns and gloves
– Sealed eye protection (i.e., goggles)
– Respiratory protection device
Respiratory Protection During
Aerosol-Generating Procedures
• Proper fit is essential
– Reassess respirator fit among personnel who may be
involved in intubation of SARS patients
• Consider better fitting respiratory protection
devices
– Disposable respirators with better seal, e.g., N99,
N100
– Half- or full-face elastomeric (rubber)
– Powered air-purifying respirators (PAPR)
Management of SARS Exposures
in Healthcare Settings
• Surveillance of healthcare personnel
– Develop list of personnel who have contact
with SARS patients (I.e., enter room,
participate in care)
– Encourage reporting of unprotected
exposures
– Monitor absenteeism for SARS-like illness
• Management of asymptomatic exposed
HCWs
Management of Asymptomatic
Exposed Healthcare Workers
• No evidence of transmission from
asymptomatic persons
• Symptomatic HCWs have transmitted
• Active surveillance of HCWs who have
unprotected exposure is recommended
– Monitor temperature and symptoms before
reporting to duty
• Ten-day exclusion from duty for HCWs who
have unprotected exposures during aerosolgenerating procedures
Addressing the limited
supply of respirators
• Should respirators be reused?
– Disposal after one-time use preferred
– Use up higher level respirators first
– Reuse preferred to no respirator
• Consider using surgical mask to protect
respirator from contact with respiratory droplets
• Carefully handle contaminated respirator
– Use surgical masks only when respirators
are unavailable
Cleaning and Disinfection of the
SARS Patient Environment
• Environment may be a key to transmission
• Clean/disinfect frequently touched surfaces
daily in in-patient areas
– Bed rails, over-bed table, door knobs, lavatory
surfaces
• Perform more thorough cleaning at transfer or
discharge
• Use EPA-registered hospital detergent
disinfectant
• No need for air “fogging” or washing of ceilings
and walls
Infection Control Principles
Applied in the Home
•
•
•
•
Early detection of infection
Containment of infection
Protection of household members
Limiting contamination in the home
environment
Key Time Periods
• 10 days after last exposure –
– Duration of post-exposure monitoring period
• “72 hour rule”
– Period for reassessing early symptoms of
SARS
• 10 days after resolution of fever
– Duration of post-SARS confinement
Guidance for Persons
Exposed to SARS
• Asymptomatic exposed persons
– No change in daily activities
– Monitor for respiratory symptoms and fever (i.e.,
measure temperature twice daily) for 10 days after
last exposure
• Fever or respiratory symptoms develop
– Notify healthcare provider
– Limit interactions outside the home
– Reassess in 72 hours
72 Hour Reassessment
Management of
Persons who
may have been
exposed to
SARS1
Develops fever
AND respiratory
symptoms within
10 days (i.e.
meets case
definition)
Persons who may
have been exposed
Does not develop
fever or
respiratory
symptoms within
10 days
Develops fever OR
respiratory
symptoms within 10
days (i.e. does not
meet case definition)
Use isolation precautions2 for 72 hours
Does not progress to
meet
case definition, but has
persistent fever or
unresolving respiratory
symptoms
Progresses to
meet the case
definition
Use isolation
precautions2 until
10 days after
resolution of fever,
provided
respiratory
symptoms are
improving or
absent
Continue isolation
precautions
for an additional 72
hours, then perform
clinical evaluation
perform clinical
evaluation
Does not
progress to
meet case
definition4
Symptoms
improve or
resolve
Discontinue
isolation
precautions3
Isolation
precautions not
recommended3
Infection Control for Persons
with SARS
• Avoid interactions outside the home
(school, work, day care, church,
shopping)
– Wear surgical mask and avoid public
transportation if travel outside home is
necessary
• Limit persons coming into the home
Infection Control Advice to
SARS Patients
• Wear a surgical mask when in the presence of
other household members
• Contain respiratory secretions in facial tissue
and place in lined container for disposal with
household waste
• Perform hand hygiene frequently and
especially after touching respiratory secretions
and other body fluids (e.g., urine, stool)
Advice to Household Members
of SARS Patients
• Wear surgical mask when around SARS
patient (if patient cannot wear mask)
• Perform hand hygiene frequently (hand
washing with soap and water or use of
alcohol-base gel)
• Consider wearing disposable gloves for
direct contact with body fluids of SARS
patients
Other Infection Control
Measures in the Home
• Do not share personal items until
thoroughly washed with soap and water
(towels, linen, eating utensils)
– Consider separate sleeping arrangements
• Clean surfaces that are touched
frequently or come into contact with
body fluids (e.g., food preparation areas,
phones, lavatories)
SARS Admissions
If possible, separate wards/areas for each of the following
categories :
• Patients with colds, sniffles and runny noses should be
isolated in a single room / area
• Suspect cases
– Place in a single room
• Probable cases
– If cohort nursing : keep probable and suspect cases
apart
– May share room with other probable cases : where possible use
a single room for all patients
Components of SARS Isolation
• Facility
• Administrative
Controls
• Organization of
Isolation Area
• Protective
Equipment
• Hand Hygiene
• Patient transport
• Laboratories
• Mortuary Care
• Cleaning and
Disinfection
• Waste and Linen
Handling
• Patient and family
education
Facility
• Isolated from other patient / staff movement
• Good ventilation
– Air movement: corridor to room to outdoors
•
•
•
•
•
Sinks and running water
Adequate bathroom facilities
Capacity to handle waste and laundry
Sufficient rooms for expected number of patients
Contingency plans for converting other areas to
isolation facilities
General Principals of isolation unit
ISOLATION
WASH/TOILET
A
F
ISOLATION ROOM
Negative pressure/
(e.g. blow air out of
E
window with fan)
CHANGE
ROOM
D
A
E
A.
B.
C.
D.
E.
F.
GENERAL
ACCESS AREA
D
A
B
C
Disinfection station.
Container for disinfection of reusable items, eg goggles
Biohazard bag for used PPE disposal.
Wall-mounted alcohol hand-wash dispensers.
Windows…external only. Keep clear of public.
Storage for general ward clothes, new PPE.
Administrative Controls
• Limit, and control points, of entry to SARS
ward(s)
–
–
–
–
One entrance
“Guard” to control entrance
Log of permitted visitors (Staff & visitors)
Visitors must be restricted or preferably forbidden
with no exceptions
– Limit patient travel/transport outside unit
– Minimize the number of staff exposure to cases
Administrative Controls
• Assignment of responsibility
– Determining patient placement
– Overseeing implementation and enforcement of
infection control measures
– Enforcing access restrictions
– Supply acquisition and distribution
– Surveillance of Health Care Workers
Clinical Surveillance of Staff
• Maintain list of all staff who worked with SARS patients
or on the SARS ward
– Systematically monitor for fever
– Twice daily temperature for staff working in the area (baseline
CXR may be needed )
• Screen for symptoms of SARS-like illness among staff
reporting for duty
• List contact information for:
– Persons visiting or caring for SARS patients
– Contacts of HCWs in close contact with SARS patients
Organization of SARS Isolation Area
• Signs: SARS Isolation Area
• Designated area for clean protective equipment
– Instructions for using protective equipment
– Accessible to personnel
– Sufficient inventory to meet daily needs
• Separation of clean and dirty supplies including
an area for containment of waste and soiled linen
– Color-coded bags and containers for contaminated
waste and laundry
Protective Equipment
•
•
•
•
•
•
N-95 Mask must be worn
Goggles (protective glasses)
Disposable or Reusable Gowns
Disposable Gloves
Head and/or shoe covers
Shoe covers should be worn when shoes not
suitable for cleaning
Key Points
• Wear disposable gowns, gloves and goggles for close
patient contact
• Wash hands using liquid soap and water when leaving
the anteroom
• Use an 70% alcohol-based hand rub solution after hand
washing
• Wash hands when leaving the unit
Standard Precautions
Designed to reduce the risk for
occupational exposure to SARS infection
from both recognized and unrecognized
sources of infection
Exposures
• Patient:
• Health Care Worker:
– Blood
– Blood
– Body fluids
including excreta
– Skin lesions
– Body fluids including
excreta
– Mucous membranes
– Skin lesions