Pandemic%20Flu

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Hot Topic Meeting by Royal College of Physicians of Edinburgh The Scottish Executive Health Department Pandemic Flu Planning Scotlands Health Response 5th June 2007 Queen Mother Conference Centre
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Pandemic Flu

• Clinical Assessment, Triage and Treatment

Dr Graham Douglas Consultant Physician Aberdeen
Royal Infirmary
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Influenza
Clinical Case Definition
The presence of fever and new (or in those with
chronic lung disease worsening) cough of acute
onset in the context of influenza circulating in
the community NB This definition may need to
be modified once the pandemic appears
Clinical diagnosis of typical influenza is easy
during epidemics/pandemics
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Influenza

• Incubation period commonly 2-4 days (range 1-7
  days)

• Fever is the most important symptom
• - may reach 41oC
• - peaks within 24 hrs of onset
• - typically lasts for 3 days (range 1-5 days)

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Influenza
RANGE OF SYMPTOMS ASSOCIATED WITH UNCOMPLICATED
INFLUENZA INFECTION
Cough 85 Anorexia 60 Malaise
80 Coryzal (cold) symptoms 60 Chills
70 Myalgia 53 Headache 65 Sore throat
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Cough malaise - persist for 1-2 weeks and up to
6 weeks
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Influenza
ASSESSMENT IN PRIMARY CARE
Majority with uncomplicated influenza will make a
full recovery
Symptomatic management Rest
Fluids Paracetamol
Antibiotics rarely useful
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Avian Influenza A/H5N1
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Influenza
ASSESSMENT IN PRIMARY CARE
EXAMPLES OF WHAT SHOULD PROMPT PATIENTS TO
RECONSULT

• Shortness of breath at rest
• Painful or difficult breathing
• Coughing up bloody sputum
• Fever for 4-5 days and not getting better
• Starting to feel better then developing high
  fever
• Drowsiness, disorientation or confusion

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Influenza
There is no validated severity assessment tool
developed specifically for Influenza or
Influenza-related Pneumonia
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Influenza
SEVERITY ASSESSMENT
CURB 65 Score Well known and validated for
Community Acquired Pneumonia

• Confusion
• Urea gt 7 mmol/l
• Respiratory rate gt30/mm
• Blood pressure (diastolic lt 60mmHg)
• gt65 years of age
• Score 1 point for each feature

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Pandemic InfluenzaAge and mortality
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Influenza
SEVERITY ASSESSMENT
CRB 65 Also well validated

• 0 Likely to be suitable for home treatment
• 1 2 Consider hospital referral
• 3 4 Urgent hospital referral

Consider hospital referral if there are bilateral
lung crackles
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Influenza
SEVERITY ASSESSMENT IN HOSPITAL
CURB -65 score 3 or more Severe Pneumonia
CURB -65 score 4 or more Should be considered for
HDU/ITU care
Other general indications for HDU/ITU Hypoxia
pO2lt8 despite oxygen Progressive CO2
retention Severe acidosis pHlt7.26 Septic
shock Bilateral shadowing on CXR
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Influenza
COMMON COMPLICATIONS
RESPIRATORY

• Acute Bronchitis

• Secondary Bacterial Pneumonia (20)
• Appears 4-5 days after start of flu

• Microbiology
• 1918 H.influenza, S.pneumoniae, ßhaem.strept
• 1957 Staph.aureus (gt2/3rds)
• 1968 S.pneumoniae, Staph.aureus, H.influenzae
• (48) (26)
  (11)

• Community MRSA uncommon in Europe/concern in US

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Influenza
COMMON COMPLICATIONS

• CVS
• ECG changes 80
• (Twave inversion minor rhythm disturbances)

• CHILDREN
• Otis media

• EXACERBATION OF PRE-EXISTING DISEASE
• COPD
• Bronchiectasis
• Heart failure
• Diabetes mellitus

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Influenza
UNCOMMON COMPLICATIONS

• RESPIRATORY
• Primary viral pneumonia
• - appears common in human cases of H5N1
• - rapid respiratory failure within 48 hours
• - mortality gt40 within 7 days

• CVS
• Myocarditis/pericarditis

• CNS
• Transverse myelitis/Guillain-Barre
• Myositis Myoglobinuria

(Influenza is a multi-system disorder)
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Influenza
ANTIBIOTICS WHEN?

• Previously well adults
• - Uncomplicated acute bronchitis NO
• - Pneumonia (lung crackles/abnormal CXR) - YES

• High risk patients/pre-existing disease
• - Lower respiratory tract features - YES
• - Pneumonia - YES

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Influenza
ANTIBIOTICS WHICH?

• Empirical cover
• - S.pneumoniae, H.influenzae, S.aureus - YES
• - Legionella ssp, atypical pathogens - NO

• Co-amoxiclav or Doxycycline

ANTIBIOTICS HOW?

• Oral route for non-severe

• IV route for severe infection (CURB 65 gt 3)

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Antiviral Therapyin Ordinary Flu

• lt30h after onset of symptoms
• - significant effect on reduction of duration of
• symptoms esp fever (shorten by 1 day)

• gt30h after onset of symptoms
• - no significant effect

• No known effect on mortality

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Neuraminidase inhibitors

• Oseltamivir
• Oral

• Zanamivir
• Dry powder inhaler

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Pandemic Influenza
EFFICACY OF ANTIVIRALS

• Oseltamivir active in vitro and in vivo against
• previous pandemic strains
• H2N2 (1957), H3N2 (1968), N1N1 (1977) etc

• But only 1 mutation required for full resistance

• Rates of development of resistance to oseltamivir
  in clinical isolates
• - Trials in adults 0.33
• - Trials in children 4-18

• ? Combining neuraminidase inhibitors with M2 ion
  channel inhibitors (Amantadine Rimantadine)

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Pandemic Influenza
POSSIBLE BENEFITS OF ANTIVIRAL USE IN THE
PANDEMIC

• Reduction of illness duration by an average of
  24hr and therefore more rapid mobilisation of
  essential workers

• Reduction in viral secretion clinical attack
  rates

• Reduction in hospitalisation

• Reduction of complications and therefore need for
  other drugs especially antibiotics

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Pandemic Influenza
RECOMMENDATIONS FOR ANTIVIRAL THERAPY

• Patients to receive antivirals if they have all
  of
• - Acute influenza-like illness
• - Fever gt38oC
• - Within 30hrs of onset

• Oseltamivir (Tamiflu) 75ug bd for 5 days
• - reduce dose in renal failure
• - adjust dose by body weight in children
  (liquid)
• - avoid in children under 1 year

• Currently stockpile for 25 population in
  Scotland
• Logistics!

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Hot Topic Meeting by Royal College of Physicians of Edinburgh The Scottish Executive Health Department Pandemic Flu Planning Scotlands Health Response 5th June 2007 Queen Mother Conference Centre