H1N1

H1N1
Diagnosis ,Management and
Treatment

DEFINITION
• A virus responsible for a flu pandemic in 2009 that was
originally referred to as “swine flu" because many of the
genes in this new virus were very similar to influenza
viruses that normally occur in pigs in North America.
• However, the virus is actually a novel influenza A (H1N1)
virus. This virus first caused illness in Mexico and the
United States in March and April, 2009 that spread to
pandemic status over the following months.
• H1N1 flu is spread from person to person, unlike typical
swine flu, although it is not clear how easily the virus is
able to spread among people.

THE INFLUENZA VIRUS

Type A
Typeavian,
A
(Seasonal,
swine
influenza,….)
(Seasonal,
a\ian, swine
influenza,….)
Type B

Type B
(Seasonal influenza)

Can cause significant disease

Generally causes milder
disease but may also cause
severe disease

Infects humans and other
species (e.g., birds; H5N1)

Limited to humans

Can cause epidemics and
pandemics (worldwide
epidemics)

Generally causes milder
epidemics

H1N1
• The 2009 H1N1 virus is a hybrid of
swine, avian and human strains
• India and Pakistan currently
experiencing outbreaks.

MODE OF TRANSMISSION
• How does H1N1 Influenza spread?

• This virus is thought to spread the same
way seasonal flu spreads
• Primarily through respiratory droplets
– Coughing
– Sneezing
– Touching respiratory droplets on yourself, another
person, or an object, then touching mucus
membrdsanes (e.g., mouth, nose, eyes) without
washing hands

SIGNS AND SYMPTOMS
• Symptoms of novel H1N1 flu in people are
similar to those associated with seasonal flu.
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Fever
Cough
Runny or stuffy nose
Body aches
Headache
Chills
Fatigue
In addition, vomiting (25%) and diarrhea (25%) have
been reported. (Higher rate than for seasonal flu.)

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Most people should be able to recover at home, but watch for
emergency warning signs that mean individual should seek
immediate medical care:
In adults:
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Difficulty breathing or shortness of breath

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Pain or pressure in the chest or abdomen

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Sudden dizziness

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Confusion

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Severe or persistent vomiting

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Flu-like symptoms improve but then return with
fever and worse cough

INDIVIDUALS AT RISK FOR
DEVELOPING H1N1 RELATED
COMPLICATIONS
• Children younger than 5, but especially
children younger than 2 years old
• Adults>65 yrs
• Pregnant women

INDIVIDUALS AT RISK FOR DEVELOPING H1N1
RELATED COMPLICATIONS
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People who have medical conditions including:
Asthma
Neurological and neurodevelopmental conditions [including disorders of the brain,
spinal cord, peripheral nerve, and muscle such as cerebral palsy, epilepsy (seizure
disorders), stroke, intellectual disability (mental retardation), moderate to severe
developmental delay, muscular dystrophy, or spinal cord injury].
Chronic lung disease (such as chronic obstructive pulmonary disease [COPD] and
cystic fibrosis)
Heart disease (such as congenital heart disease, congestive heart failure and
coronary artery disease)
Blood disorders (such as sickle cell disease)
Endocrine disorders (such as diabetes mellitus)
Kidney disorders
Liver disorders
Metabolic disorders (such as inherited metabolic disorders and mitochondrial
disorders)
Weakened immune system due to disease or medication (such as people with HIV or
or AIDS, or cancers, or those on chronic steroids)

The CDC criteria for suspected
H1N1 influenza are as follows:
• Clinicians should consider the possibility of
swine influenza virus infections in patients
presenting with febrile respiratory illness who
– live in areas where human cases of swine influenza
A(H1N1) have been identified or
– have traveled to an area where human cases of
swine influenza A(H1N1) has been identified or
– have been in contact with ill persons from these areas
in the 7 days prior to their illness onset

INVESTIGATIONS
• If swine flu is suspected, clinicians should
obtain a respiratory swab for swine
influenza testing and place it in a
refrigerator (not a freezer)
– once collected, the clinician should contact
their state or local health department to
facilitate transport and timely diagnosis at a
state public health laboratory

INVESTIGATIONS
• The Human Influenza Virus Real-Time RT-PCR
Detection and Characterization Panel (rRT-PCR Flu
Panel) is an in vitro laboratory diagnostic test that can
provide results within 4 hours. It is the only in vitro
diagnostic test for influenza that is cleared by the FDA
for use with lower respiratory tract specimens .
• The kit utilizes a 3-module design and can:
• Identify and distinguish between influenza A and B
viruses,
• Classify influenza A viruses by subtype, and
• Detect highly pathogenic avian influenza A (H5N1) virus
infection in human respiratory tract specimens.

CHEST X-RAY FINDINGS
• In the 2012 study

Chest radiological findings
of influenza A H1N1 pneumonia. Nicolini A, Ferrara
L, Rao F, Senarega R, Ferrari-Bravo M

• Bilateral ground-glass opacities and areas
of consolidation were the predominant
radiological findings of influenza A (H1N1)
virus pneumonia.

TREATMENT

NON PHARMACEUTICAL
INTERVENTIONS
• 1. Delay disease transmission and
outbreak peak
• 2. Decompress peak burden on
healthcare infrastructure
• 3. Diminish overall cases and health
impacts

VOLUNTARY ISOLATION
• Separation and restricted movement of ill
persons with contagious disease (often in a
hospital setting and Primarily individual
level)
– Isolate severe and mild cases
– Location of isolation (home, hospital) depends on
several factors (severity of illness, the number of
affected persons, the domestic setting)
– Do not wait for lab confirmation
– Plan for large number of severe cases
– Provide medical and social care

VOLUNTARY ISOLATION
Infection Control of Ill Persons in a Healthcare Setting
• Patients with suspected or confirmed case-status should be placed in
a single-patient room with the door kept closed. If available, an
airborne infection isolation room (AIIR) with negative pressure air
handling with 6 to 12 air changes per hour can be used. Air can be
exhausted directly outside or be recirculated after filtration by a high
efficiency particulate air (HEPA) filter. For suctioning, bronchoscopy,
or intubation, use a procedure room with negative pressure air
handling.
• The ill person should wear a surgical mask when outside of the
patient room, and should be encouraged to wash hands frequently
and follow respiratory hygiene practices. Cups and other utensils
used by the ill person should be washed with soap and water before
use by other persons. Routine cleaning and disinfection strategies
used during influenza seasons can be applied to the environmental
management of swine influenza.

VOLUNATARY QUARANTINE
• Separation and restricted movement of well
persons presumed exposed
– Identification of contacts

• Often at home, but may be designated
residential facility or hospital
• Applied at the individual or community level
• Regular health monitoring is essential part of
quarantine
– Self-health monitoring and reporting

Hand Washing
• Wet hands with clean (not hot) water
• Apply soap
• Rub hands together for at least 20 seconds
• Rinse with clean water
• Dry with disposable towel or air dry
• Use towel to turn off faucet
• Alcohol based hand rubs can be used, more
costly than hand washing

Guidelines for general population
• Covering nose and mouth with a tissue when coughing
or sneezing
– Dispose the tissue in the trash after use.

• Handwashing with soap and water
– Especially after coughing or sneezing.

• Cleaning hands with alcohol-based hand cleaners
• Avoiding close contact with sick people
• Avoiding touching eyes, nose or mouth with unwashed
hands
• If sick with influenza, staying home from work or school
and limit contact with others to keep from infecting them

Patients Cared for at Home
• Potential for transmission
• Must educate family caregivers
• Fever / symptom monitoring
• Infection control measures
– Hand washing
– Use of available material as mask

ISOLATION PRECAUTIONS

PERSONAL PROTECTIVE
EQUIPMENT

PERSONAL PROTECTIVE
EQUIPMENT
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For specific work activities that involve contact with people who
have ILI(influenza like illness), such as escorting a person with ILI,
interviewing a person with ILI, providing assistance to an individual
with ILI, the following are recommended:
workers should try to maintain a distance of 6 feet or more from the
person with ILI;
workers should keep their interactions with ill persons as brief as
possible;
the ill person should be asked to follow good cough etiquette and
hand hygiene and to wear a facemask, if able, and one is available;
workers at increased risk of severe illness from influenza infection
(see footnote 3 of table 1) should avoid people with ILI (possibly by
temporary reassignment); and,
where workers cannot avoid close contact with persons with ILI,
some workers may choose to wear a facemask or N95 respirator on
a voluntary basis.

Droplet precautions: Surgical
Masks

N-95 Filtering Masks

Management

• (H1N1) infection need to be seen by a
health care provider. For most people,
the illness appears to be mild and selflimiting.
• Minority of people with influenza A(H1N1)
has had severe illness with complications.

Who needs assessment
• All individual with Symptoms and has comorbid factors.
• All individuals with moderate to severe
disease
• All individual with symptoms beyond 48
hours

Co Morbid conditions
Those considered vulnerable to severe outcomes & should be a focus
of early identification, assessment and treatment, include the
following:
• Chronic respiratory conditions, eg asthma, COPD, OSA
• Pregnant women, esp. in second or third trimester
• Obesity (BMI > 30) & morbid obesity (BMI > 40)
• Other predisposing conditions, such as chronic cardiac disease, and
chronic illnesses including diabetes mellitus, renal failure,
haemoglobinopathies, immunosuppression.
• Adults > 65 years of age esp. those with other chronic diseases

How to recognize disease severity in an
individual with Sympyoms

• Use of clinical assessment tool

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Respiratory impairment: any of the following
Tachypnoea, respiratory rate > 24/min
Inability to complete sentence in one breath
Use of accessory muscles of respiration, supraclavicular recession
Oxygen saturation < 92% on pulse oximetry
Chest pains
Evidence of clinical dehydration or clinical shock
Systolic BP < 90mmHg and/or diastolic BP < 60mmHg
Capillary refill time > 2 seconds, reduced skin turgor
Altered Conscious level (esp. in extremes of age)
New confusion, striking agitation or seizures
Other clinical concerns:
Rapidly progressive (esp. high fever > 3 days) or serious atypical
illness
Severe & persistent vomiting and diarrhea

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Severe illness following influenza occurs in at least 3
ways:
1. severe 1° viral infection with ARDS occurring relatively
early in illness related to viral pneumonia (within 1 st 4
days)
2. bacterial pneumonia,
pneumonia complicating initial bronchitis
caused by influenza
3. destabilization of pre-existing chronic condition. This
may present as respiratory distress related to
exacerbations of COPD, asthma or CCF. Influenza can
also cause acute destabilization of diabetes, CRF,
chronic liver disease etc

Who needs admission
• All patients fulfilling criteria of Influenza
with any of the parameters listed in the
clinical assessment tool for moderate to
severe influenza (with or without comorbidities)

Who can be discharged
• Patients with suspected influenza
manifesting with mild disease will not
require admission to hospital
• Patients should be clinically assessed and
the admission decision will be based on
the severity of the illness

• All individual with suspected influenza
and does not require admission, but
need to be informed of how to
recognize disease deterioration..

Home assessment
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Respiratory Difficulties: Shortness of breath, rapid breathing
or Purple or blue discoloration of lips

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Coughing out blood or blood streaked sputum

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Persistent chest pains

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Persistent diarrhea and / or vomiting

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Fever persisting beyond 2 days or recurring after 2 days

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Abnormal behavior , confusion, less responsive , convulsion

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Dizziness when standing and/or reduced urine production

Lab Test
• Who needs to be tested?
• What test?
• How about rapid test

Laboratory testing (RT-PCR) for Influenza A H1N1 to assist
with clinical management is indicated for those who meet
the case definition and are:
• symptomatic patients with moderate to severe
disease who will require hospitalization

Confirmed Case novel Influenza
A/H1N1 Infection
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Individuals with moderate - severe
symptoms and +ve laboratory test ,
either by

a) RT-PCR
b) Viral culture

Rapid test
• Rapid test : use to detect the presence of Influenza A
virus in respiratory specimens.
• A positive rapid test means-presence of Flu A virus.
• Does not differentiate between seasonal flu or Influenza
A-H1N1.
• Detection rate varies from one test kit to another.
• A negative test does not rule out Influenza virus
infection

Treatment
RECOMMENDATION:
Antiviral Treatment is recommended for:
All hospitalized patients (ie. those with moderate
to severe disease) with confirmed or suspected
novel influenza A H1N1. Empirical therapy for
suspected patients with severe disease should be
considered if the turnaround time for H1N1 confirmation
is prolonged. The antiviral treatment maybe stopped if
the results are negative.
All individual with co-morbid factors whether they are
admitted or not.

Drugs
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Type of Antiviral: Oseltamivir is the preferred choice; zanamivir might be
used as an alternative. The quality of evidence if considered on a
continuum, is lower for zanamivir compared to oseltamivir.
Since functional groups of the 2 neuraminidase-inhibitors have differences in
their binding sites, mutants resistant to 1 drug maybe susceptible to the
other.
Oseltamivir dosage:
• Duration 5 days
• Adults & adolescents > 13 yrs:
75 mg bd
(in severe cases, dosage can be doubled to 150 mg bd)
• For children (according to weight): <15kg: 30mg bd
15-23kg: 45mg bd
23-40kg: 60mg bd
> 40kg: 75mg bd
Renal adjustments: patients with a serum creatinine clearance between 10 30 ml/min: treated with 75 mg daily for 5 days

• Zanamivir dosage:
10mg (2 puffs) bd for 5days (Adults & children)
(Children < 5 yrs may have difficulty with Diskhaler )
• In patients with bronchospasm: Zanamivir is not
recommended for the treatment of patients with
underlying airways disease (eg. asthma or COPD).
Patients with pulmonary dysfunction should always
have a fast-acting bronchodilator available and
discontinue zanamivir if respiratory difficulty develops.
• No dosage adjustment is required in patients with renal
impairment

Patient presenting with ILI
symptoms within 2 days of
onset of illness

Assessed by Primary doctor
Does patient have any
symptoms and signs of moderate
or severe illness (Clinical
assessment Tool)

If NO moderate/severe illness;
Does patient have a comorbidity associated with
increased risk of influenza
complications?

If patient HAS moderate or
severe illness;
Admit to nearest hospital for
screening and treatment

If patient has co-morbidity ;
Start oseltamivir / zanamivir at
standard doses for 5 days & continue
home care with Home assessment
Tool monitoring

If patient has NO comorbidity;
Does patient have fever > 38°C
after 48hours from onset of
illness ?
Are symptoms rapidly
progressive even within first
2days?

If patient develops moderate or
severe illness with Home
Assessment Tool, seek medical
reassessment
If patient improves, complete
course of antivirals

If YES to either of the above; start
oseltamivir / zanamivir at standard doses
for 5 days & continue with Home
Assessment Tool

Prevention
• The best way for people to protect
themselves…
– Handwashing and using disinfectants
– Taking antivirals Tamiflu or Relenza
– Getting a vaccine

Who should get vaccine
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According to guidelines drafted by the Centers for Disease Control
and Prevention (CDC), there are five key populations that should be
vaccinated against the H1N1 virus:
Pregnant women
People who live with or care for children younger than 6
months of age
Children and young people between the ages of 6 months and
24 years
Health care workers and emergency medical service providers
People between 25 and 64 years of age who have chronic
medical disorders or compromised immune systems.

Preexposure chemoprophylaxis
• Preexposure antiviral chemoprophylaxis
should be used only for persons who are
at very high risk (e.g., severely
immunosuppressed patients) for
influenza-related complications who
cannot otherwise be protected during
times when a high risk for exposure exists

Postexposure
chemoprophylaxis
• Decisions on whether to administer
antivirals for chemoprophylaxis should
take into account the exposed person's
risk for influenza complications, the type
and duration of contact,and clinical
judgment

Postexposure
chemoprophylaxis
• Generally, postexposure chemoprophylaxis
for persons should be only used when
antivirals can be started within 48 hours of
the most recent exposure.
• Chemoprophylaxis with antiviral
medications is not a substitute for
influenza vaccination when influenza
vaccine is available

• Patients receiving postexposure antiviral
chemoprophylaxis should be informed that
chemoprophylaxis lowers but does not
eliminate the risk for influenza, that
susceptibility to influenza returns once the
antiviral medication is stopped, and that
influenza vaccination is recommended if
available

• An emphasis on early treatment is an
alternative to chemoprophylaxis in
managing certain persons who have
had a suspected exposure to
influenza virus.

Masks
• Facemasks help stop
droplets from being
spread by the person
wearing them. They also
keep splashes or sprays
from reaching the mouth
and nose of the person
wearing the facemask.
They are not designed to
protect you against
breathing in very small
particles and viruses.

• A respirator (for
example, an N95 or
higher filtering
facepiece respirator)
is designed to protect
you from breathing in
very small particles,
which might contain
viruses.

Obesity and H1 N1
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Obesity (BMI > to 30-39.9) noted in about 15% of pts

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Morbid obesity (defined as BMI > 40) in about 8% of pts

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Although the importance of obesity as a contributing factor to novel
H1N1 complications is currently unknown, many obese persons
have other known underlying diseases that put them at risk for flu
complications.

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Series of 10 pts with influenza A (H1N1) virus infection and ARDS at
a tertiary-care ICU in Michigan. Of the 10 pts, 9 were obese ([BMI]
≥30), including 7 who were extremely obese (BMI ≥40)