Transcript INFLUENZA (The Flu) What Nurses Should Know

INFLUENZA (The Flu)
What Nurses Should Know
Felissa R. Lashley, RN, PhD, FAAN, FACMG
Professor, College of Nursing, and
Interim Director, Nursing Center for Bioterrorism and Infectious Disease
Preparedness, College of Nursing
Rutgers, The State University of New Jersey
This module is designed to highlight important information about influenza. The influenza virus, in
addition to being the cause of influenza, an important infectious disease, is also considered to be a
potential agent for bioterrorism and is considered as a possible Category C bioterrorism agent by the
Centers for Disease Control and Prevention (CDC). This module was supported in part by USDHHS,
HRSA Grant No. T01HP01407.
Some General Points
The influenza virus is considered to have
the potential for use as an agent for
bioterrorism, most probably by altering it to
a mutated form with greater virulence,
infectivity, more efficient human-to-human
transmission, and antiviral resistance.
 CDC considers it to be a Category C agent
under others.
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Some General Points cont.
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This module is arranged as follows: etiology,
epidemiology, transmission, incubation period,
overall clinical illness picture, clinical
manifestations, clinical differentiation between
the common cold and flu, complications,
diagnosis, treatment, management including
infection control measures and patient/staff
education, and prophylaxis and vaccination.
 Avian influenza is considered at the end of the
content before the case studies.
 Case studies, test questions and information
sources appear at the end of the module.
Objectives
At the conclusion of this module, the
participant should be able to:
 Identify the viruses that can cause influenza
 Describe signs and symptoms commonly
associated with influenza
 Identify the major complications of influenza
 Describe symptoms that can help differentiate
between upper respiratory infection and
influenza
Objectives cont.
Identify antiviral agents in current use for
prevention of influenza
 Identify antiviral agents in current use for
treatment of influenza
 Name the groups for whom flu vaccination
is recommended
 Describe what is meant by avian influenza
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Etiology
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Influenza viruses types A, B, & C infect humans
Influenza types A & B can cause widespread
outbreaks
Influenza type A tends to be the most severe
Influenza A virus types have most potential for
use as bioterrorism weapon
Influenza viruses are RNA viruses classified in
Orthomyxoviridae family
Can mutate and cross species barrier such as
fowl to humans
Etiology cont.
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Influenza subtypes are referred to by their hemagglutinin
(H) and neuraminidase subtypes (N) which are surface
glycoproteins of the virus
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Examples: Avian influenza virus subtypes A H5N1 and H9N2
which appeared recently in Hong Kong and other areas
Influenza viruses have the ability to develop antigenic
variants through viral mutation. Persons develop
antibodies to specific variants which may not confer
protection against another. This helps explain why there
are seasonal epidemics and provides the basis for
understanding the rationale for what strains of the virus
will be used each year in vaccine production.
Epidemiology
Worldwide distribution
 Outbreaks usually occur suddenly
 Flu spreads through communities resulting
in an epidemic. Cases tend to peak after
about 3 weeks and begin to subside after
another 3-4 weeks
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Epidemiology cont.-2
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Have been several great
influenza pandemics:
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1918-19 “Spanish” flu
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Caused 20-40 million deaths
worldwide
A large proportion of these
deaths was in healthy adults 15
to 35 years of age
1957 “Asian” flu
1968 “Hong Kong” flu
1977 H1N1 influenza A virus
subtype, “Russian” flu
Epidemiology cont.-3
Peak season is November through March
 Each year about 10 to 20% of Americans
develop influenza
 In the US, approximately 100,000 people
are hospitalized with influenza each year,
and about 36,000 die
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Transmission
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Major transmission route is through airborne
large respiratory droplets with particles larger
than 5 microns (μ) in diameter that are expelled
from the respiratory tract of an infected person
when they cough or sneeze
 Direct contact with fomites (inanimate objects)
contaminated with infected droplets or
secretions and then touching ones nose or
mouth
 Transmission from infected birds, poultry or pigs
(less common)
Incubation Period
1 to 4 days with average of 2 days
 Adults are infectious from day before
symptoms begin through about 5 days
after onset; children can be infectious for
10 or more days after onset and those
who are immunosuppressed can shed
virus for weeks or even months.
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Overall Clinical Illness Picture
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Influenza infection can run a spectrum from
asymptomatic or mild illness through fulminant primary
viral pneumonia
For most uncomplicated cases, influenza resolves
spontaneously in a few days but cough and malaise often
last 2 weeks or more
Major clinical pictures:
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Rhinotracheobronchitis
Primary viral pneumonia
Respiratory viral infection followed by secondary bacterial
pneumonia
There is no “stomach” flu - these manifestations are from other
disorders
Major influences on clinical illness
development and complications of influenza
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Age - elderly (over 65 years of age) and young children particularly
younger than 5 years of age and especially those 6 to 23 months
are particularly vulnerable
Presence of other chronic underlying illnesses such as chronic
cardiac or pulmonary disease
Compromised immune status such as from immunosuppressive
drugs, or conditions such as malnutrition or pregnancy
Lack of access to health care
Crowded living conditions that facilitate transfer of respiratory
pathogens that can include congregate and institutional settings
especially if precautions such as respiratory hygiene dn cough
ettiquette are not observed
Health care workers may be at higher risk for transmission
Clinical Manifestations
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Abrupt onset of constitutional
and respiratory symptoms
Fever, duration typically 1 to 5
days, with an average of 3
days and peak within 12 hours
after symptoms. Typical
temperatures are 38 to 40 deg.
C.
Myalgia
Headache
Chills
Cough, usually unproductive
Sore throat
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Malaise
Rhinitis
May have eye tearing, burning,
photophobia or eye pain
Children may have otitis media
and nausea and vomiting as
well as febrile convulsions in
addition to other symptoms
Elderly persons may present
with minimal respiratory
symptoms but show lassitude,
high fever and confusion
Respiratory symptoms may
increase as fever decreases
Clinical Differentiation Between the Common Cold
and the Flu
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(see Table 1 at end of module)
The following symptoms
are more commonly seen
in influenza rather than
the common cold:
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High fever lasting 3 to 4
days
Headache
Myalgia
Fatigue and weakness
Extreme exhaustion
Severe chest discomfort
and cough
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The following symptoms
are more commonly seen
in the common cold
rather than influenza:
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Stuffy nose is common
Sneezing is common
Cough is generally mild to
moderate
Symptoms such as fever,
headache, aches and pains
and exhaustion are rare in
those with colds.
Complications may be respiratory
or non-respiratory or both
Major respiratory complications include:
 Primary viral pneumonia
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Occurs most frequently in elderly or persons with
cardiopulmonary disease
Can occur in healthy immunocompetent persons or pregnant
women
Usually develops rapidly, within 1 day or onset of illness
Symptoms include rapidly progressing fever, tachypnea,
tachycardia, cyanosis and hypotension
Signs include bilateral crepitant rales on chest examination,
chest x-rays showing nonconsolidating pulmonary infiltrates, but
sometimes areas of consolidation, blood gas studies show
hypoxemia, blood counts may show leukocytosis with a left shift
Mortality is high, and extensive fibrosis and interstitial
inflammation may develop
Complications cont.-2
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Secondary bacterial pneumonia
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Occurs most frequently in elderly or persons with
pulmonary disease
Typical course of influenza illness seems to be
improving but fever with shaking chills returns,
pleuritic-type chest pain, productive cough with
bloody or purulent sputum
Signs include local areas of lung consolidation on
chest X-ray, sputum culture and Gram stain may
reveal predominance of bacterial pathogen, most
commonly Streptococcus pneumoniae,
Staphylococcus aureus, Haemophilus influenzae, or
Moraxella catarrhalis
Mortality can approach 7%
Complications cont.-3
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Combined bacterial-viral pneumonia
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Coinfection can yield varying symptoms which
may be like primary viral pneumonia at first
Coinfection with S. aureus may carry a
particularly high mortality rate
Exacerbation of chronic pulmonary
disease such as asthma or in persons
with cystic fibrosis
Complications cont.-4
Major non-respiratory complications include:
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Cardiac complications particularly electrocardiographic
abnormalities and myocarditis
Central nervous system complications such as seizures, especially
in children, and acute encephalitis
Reye’s syndrome, a neurologic and metabolic disorder occuring
mainly in children and adolescents from 2 to 16 years of age. It
appears more closely associated with influenza B than influenza A
and has a mortality rate of 10% to 40%. Not prescribing aspirin for
patients, especially children and adolescents with viral infections
has decreased the incidence of Reye’s syndrome.
Myositis may occur primarily in children and particularly after
influenza B along with myoglobinuria and rhabdomyolysis leading to
acute renal failure.
Diagnosis
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Important to make diagnosis as quickly as possible
Facilitated by community surveillance knowledge about
influenza outbreak patterns in the community
May be made on basis of clinical signs and symptoms
along with knowledge about influenza patterns in the
community. Thus in the setting of a confirmed influenza
outbreak in a given community, persons who are not
residents of institutions and who have muscle aches,
fever and two respiratory symptoms probably have
influenza according to Shorman & Moorman, (2003).
Diagnosis cont.
Laboratory diagnostic methods include:
 Viral culture (need expert technicians and
time but excellent specificity and
sensitivity), reverse transcriptase
polymerase chain reaction (laborintensive, costly but quick with excellent
specificity and sensitivity), serology, rapid
antigen testing, and immunofluroescence
assays.
Treatment (this is not comprehensive and is not
meant as recommendations)
Certain antiviral agents may be used
 Newer antiviral agents include zanamivir and oseltamivir (Tamiflu). Both are
effective against influenza A and influenza B. These also need to be
administered within the first 48 hours of symptoms. Both are category C
agents in pregnancy and there is a risk for adverse effects in those with
underlying respiratory disease. It is administered via oral inhalation.
Oseltamivir may result in nausea and vomiting side effects so needs to be
taken with food. It is administered orally. Transient neuropsychiatric events
have been described in adolescents and some adults taking oseltamivir.
These two agents were the only ones licensed for flu prevention and
treatment in 2008.
Management including Infection
Control Measures
Management includes:
 Symptomatic treatment such as encouraging
fluids and rest; the treatment of symptoms with
over-the-counter medications but not aspirin in
children or adolescents
 Comfort measures
 Specific management approaches depend upon
symptoms, complications and characteristics
and condition of the individual patient
Management including Infection
Control Measures cont.-2
Infection Control Measures
 Appropriate prophylaxis and immunization is an important part and is
discussed below
 Respiratory hygiene and cough etiquette programs are now a part of
standard precautions
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Initiate at first point of contact with even a potentially infected person
Includes education which may be visual and\or verbal at an appropriate
educational level with cultural considerations of patients and the people who
accompany them
Should include informing personnel if they have any symptoms of respiratory
infection, having tissues provided to patients and visitors, throw tissues away
after use in proper container, instructing them to cover their mouth and nose
when coughing or sneezing, providing alcohol based hand rubbing dispensers
and supplies for handwashing and educating patients and staff in their use,
encourage handwashing after coughing or sneezing, offering masks to persons
who are coughing, encouraging coughing persons to sit at least 3 feet away from
others, instruct patients and providers not to touch eyes, nose or mouth and
have health care personnel observe Droplet Precautions in addition to Standard
Precautions. Health care workers should use standard precautions with all
patients.
Management including Infection
Control Measures cont.-3
Infection Control Measures cont.
 Standard Precautions are detailed in a
separate module
 Droplet Precautions are detailed in a
separate module
Management including Infection
Control Measures cont.-4
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Persons with respiratory infection symptoms should not
visit patients
Health care workers with respiratory infection symptoms
should be excluded from work for the duration of the illness
In health care settings, influenza testing should be done
early in the outbreak to obtain the type and subtype of virus
responsible
Droplet Precautions with suspected or confirmed influenza
should be implemented and authority to do so should be
decided with nursing staff inclusion
As detailed further under Droplet Precautions, suspected or
confirmed influenza patients should be separated from
asymptomatic patients
Management including Infection
Control Measures cont.-5
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Health care staff movement between units and buildings
should be restricted
In a setting or unit with influenza, patients without influenza
should receive influenza antiviral prophylaxis unless
contraindicated
Influenza antiviral therapy should be administered to those
who are acutely ill with influenza within 48 hours of onset of
illness unless contraindicated
Current inactivated influenza vaccine should be
administered to unvaccinated patients and health care
personnel if not contraindicated
Influenza antirviral prophylaxis should be offered to
unvaccinated personnel for who it is not contraindicated
and who work in the affected unit or who are caring for
high-risk patients
Management including Infection
Control Measures cont.-6
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Limit or eliminate elective medical and surgical
admissions and restrict cardiovascular and
pulmonary surgery to emergency cases only
when influenza outbreaks especially those
characterized by high attack rates and severe
illness, occur in the community or acute care
facility
 Recommendations for peri-and post-partum
settings may be found at
http://www.cdc.gov/flu/professionals/peripostpart
umguid.htm
Prophylaxis and Vaccination
Antiviral agents may be used for prophylaxis,
often in combination with the flu vaccine in an
outbreak situation
 Drugs used most often in the U.S. for prevention
of flu are zanamivir and oseltamivir and are used
particularly for those at high risk for
complications from the flu or to prevent a person
in close proximity from passing the flu to a high
risk person
Prophylaxis and Vaccination cont.
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Influenza vaccine
 Current vaccines are inactivated influenza vacine
administered by injection (Fluzone) and live attenuated,
intranasal vaccine (FluMist)
 In late July, 2008, the Advisory Committee in
Immunization Practices (ACIP) issued their updated
recommendations on prevention and control of influenza.
The entire document is in Morbidity and Mortality Weekly
Reports, Recommendations and Reports, 57 (early
release) , 1-60, July 17, 2008
Prophylaxis and Vaccination cont.-3
Recommendations for 2008-2009 Influenza season are given
below
 It is recommended that all children aged 5-18 years old receive
vaccination .
 Children younger that 6 months should not be vaccinated.
 Children and adolescents at higher risk for influenza complication
are those:
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aged 6 months – 4 years;
who have chronic pulmonary (including asthma), cardiovascular (except
hypertension), renal, hepatic, hematological or metabolic disorders (including
diabetes mellitus);
who are immunosuppressed (including immuno-suppresion caused my
dedications or by human immunodeficiency virus);
who have any condition (e.g., cognitive dysfuction, spinal cord injuries, seizure
disorders, or other neuromuscular disorders) that can compromise respiratory
function or the handling of respiratory secretions or that can increase the risk for
aspiration;
who are receiving long-term aspirin therapy who therefore might be at risk for
experiencing Reye syndrome after influenza virus infection;
who are residents of chronic-care facilities; and,
who will be pregnant during the influenza season.
Source: CDC, MMWR 57, 2008 pg 2
Prophylaxis and Vaccination cont.-4
For adults for the 2008-2009 flu season recommendations are
for any adult and for and for all adults in the following groups
because of higher risk:
•
Persons aged >= 50 years;
• Women who will be pregnant during the influenza season;
• Persons who have chronic pulmonary (including asthma), cardiovascular (except
hypertension), renal, hepatic, hematological or metabolic disorders (including diabetes
mellitus);
• Persons who have immunosuppressions (including immunosuppression caused by
medications or by human immunodeficiency virus);
• Persons who have any condition (e.g., cognitive dysfunction, spinal cord injuries, seizure
disorders, or other neuromuscular disorders) that can compromise respiratory function or the
handlig of respiratory secretions or that can increase the risk for aspiration;
• Residents of nursing homes and other chronic-care facilities;
• Health-care personnel;
• Household contracts and caregivers of children aged <5 years and adults aged >= 50 years,
with particular emphasis on vaccinating contracts of children aged <6 months; and,
• Households contracts and caregivers of persons with medical conditions that put them athigh
risk for severe complication from influenza.
Source: CDC, MMWR 57, 2008 pg 2
Nasal Spray Vaccine
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Live, attenuated vaccine administered by nasal
spray
Option for those healthy people ages 2 to 49
years old
Option for health care workers who take care of
sick persons or care for babies under 6 months
of age and who are healthy between 2 and 49
years of age
Not to be used in pregnancy
Not to be used by those who care for or live with
someone with a compromised immune system
or children less than 2 years of age
Table 1. Is It a Cold or the Flu?
Source: National Institute of Allergy and Infectious Diseases
Symptoms
Cold
Flu
Fever
Rare
Characteristic; high (102-104
deg. F): lasts 3-4 days
Headache
Rare
Prominent
General Aches, Pains
Slight
Usual; often severe
Fatigue, Weakness
Quite mild
Can last up to 2-3 weeks
Extreme Exhaustion
Never
Early and prominent
Stuffy Nose
Common
Sometimes
Sneezing
Usual
Sometimes
Sore Throat
Common
Sometimes
Chest Discomfort, Cough Mild to moderate,
hacking cough
Common; can become
severe
Special Notes on Avian Influenza
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Avian influenza viruses refers to those that are carried by
birds, usually wild birds that when infected, shed virus in
saliva, nasal secretions and feces. Birds or fowl become
infected when they come into contact with secretions or
excretions from infected birds most often through fecaloral transmission. Transmission also occurs through
contact with surfaces or materials such as feed, water,
cages or dirt that are contaminated with the virus.
Contaminated cages, for example, can carry the virus
from one place to another.
 Avian influenza viruses vary in their degree of
pathogenicity
"Hong Kong" Flu
First documented direct transmission of an avian influenza
(influenza A) virus (H5N1) to humans occurred in 1997
in Hong Kong
 Severe respiratory disease occurred in 18 healthy young
adults and children and 6 died
 The outbreak was controlled by slaughter of the poultry
population. More than 1.2 million chickens and 0.3
million other poultry were killed and imports of chickens
from Hong Kong and China were banned by other
countries. Quarantine and depopulation or culling of
birds are common ways of control for the outbreak
"Hong Kong" Flu-2
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Live poultry markets were source of the avian
influenza virus strain H5N1 in this outbreak. In
both influenza and SARS, the so-called “wetmarkets” have been implicated as sources. This
illustrates a cultural influence on emergence of
infectious diseases since the preference of many
Asian people for buying fresh foods at these
markets have resulted in an increase in these
types of markets. In New York City, these
increased in number from 44 in 1994 to 80 in
2002.
Additional Recent Avian Flu
Outbreaks
In 1999, avian influenza viruses, H9N2,
were isolated in Hong Kong from children
with mild influenza
 In 2003, the avian influenza virus strain,
H5N1, again emerged in 2 family
members in Hong Kong after traveling in
China. One died.
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Additional Recent Avian Flu
Outbreaks-2
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In 2003, the avian influenza virus strain H7N7
occurred in poultry farms in the Netherlands,
spreading to Germany and Belgium. Infection,
mainly conjunctivitis occurred in 83 humans with
1 death. The outbreak was controlled by
destroying over 30 million domestic poultry
 In 2003, the avian influenza virus, H9N2 was
identified in a child in Hong Kong with influenza
who recovered
Additional Recent Avian Flu
Outbreaks-3
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In 2003, an outbreak of avian influenza virus,
H5N1, occurred in South Korea, and in 2004
emerged in Vietnam and Thailand. Human
cases presented with severe respiratory
infection and out of 23 known and confirmed
cases, 18 died. Many countries banned the
import of poultry products from the Asian
countries affected. Other countries in which
poultry were infected included Japan, Laos,
China, Cambodia, and Indonesia.
Additional Recent Avian Flu
Outbreaks-4
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In 2004, an outbreak of avian influenza, H7N7
occurred in British Columbia, Canada. Infection
has been reported in 5 humans whose major
illness was conjunctivitis.
 In 2004-2005, east Asia again saw an outbreak
of H5N1, particularly in Thailand, Cambodia, and
Vietnam.
 By June 19, 2008, there were 385 reported
human cases of avian flu and 243 reported
deaths.
 Concern about pandemic flu has resulted in
global efforts at prevention.
Documented human-to-human transmission of H5N1
has been noted but is limited. Of concern is that the
virus could mutate to allow sustained person-to-person
transmission.
Transmission includes:
Symptoms
 Direct exposure to
 Fever, over 38 deg. C or
infected birds/poultry
100.4 deg. F
 Exposure to surfaces
 Shortness of breath
contaminated with
 Cough
infected bird/poultry
 Diarrhea
excretions, mostly
through fecal-oral
transmission
 Rare human-to-human
transmission
Suspecting Avian Influenza (H5N1)
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Laboratory testing should be prompted for a hospitalized
or ambulatory patient with
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temperature over 38 deg. C AND
with any one or more of the above symptoms AND
a history of contact with domestic poultry such as a visit to a
poultry farm or bird market
Laboratory testing should be prompted for hospitalized
patients
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with radiologically confirmed acute respiratory distress
syndrome, pneumonia or other severe respiratory illness for
which an alternate diagnosis has not been established AND
history of travel to an area with documented H5N1 avian
influenza within 10 days of the beginnings of symptoms.
Isolation Precautions
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For hospitalized patients who have or are
suspected of having avian influenza A
(H5N1), isolation precautions are same as
for severe acute respiratory syndrome
(SARS). These include:
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Careful hand hygiene before and after all
patient contact
Use gloves and gown for all patient contact
Wear eye protection when within 3 feet (and
perhaps 6 feet) of the patient
Isolation Precautions-2
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Place patient in an airborne infection isolation room (AIIR).
When entering the patient's room, use a fit tested respirator at
least as protective as an N95 filtering-facepiece respirator
approved by the National Institute for Occupational Health and
Safety (NIOSH)
Outpatients or hospitalized patients discharged in less than 14
days should be isolated in the home setting on the basis of
principles for home isolation of SARS patients
These precautions should be continued for 14 days after
onset of symptoms until an alternative diagnosis is
established or diagnostic test results indicate that the
patient is not infected with inflenza A virus (CDC, 2004).
Also see: http://www.cdc.gov/flu/avian/index.htm, and
http://www.cdc.gov/ncidod/dhgp/pdf/isolation2007.pdf