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

Pandemic Flu Clinical Assessment, Triage and Treatment Dr Graham Douglas Consultant Physician Aberdeen Royal Infirmary

Influenza “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 Case Definition Clinical diagnosis of ‘typical’ influenza is easy during epidemics/pandemics

Influenza Incubation period: commonly 2-4 days (range 1-7 days) Fever is the most important symptom - may reach 41 o C - peaks within 24 hrs of onset - typically lasts for 3 days (range 1-5 days)

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 ~ 50% Cough & malaise - persist for 1-2 weeks and up to 6 weeks

Influenza ASSESSMENT IN PRIMARY CARE Majority with uncomplicated influenza will make a full recovery Symptomatic management – Rest Fluids Paracetamol Antibiotics rarely useful

Avian Influenza A/H5N1

Influenza 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 ASSESSMENT IN PRIMARY CARE

Influenza There is no validated severity assessment tool developed specifically for Influenza or Influenza-related Pneumonia

Influenza SEVERITY ASSESSMENT CURB – 65 Score Well known and validated for Community Acquired Pneumonia  Confusion  Urea > 7 mmol/l  Respiratory rate >30/mm  Blood pressure (diastolic < 60mmHg)  >65 years of age Score 1 point for each feature

Pandemic Influenza Age and mortality

Influenza SEVERITY ASSESSMENT CRB – 65 Also well validated  0Likely to be suitable for home treatment  1 & 2Consider hospital referral  3 & 4Urgent hospital referral Consider hospital referral if there are bilateral lung crackles

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 – pO 2 <8 despite oxygen Progressive CO 2 retention Severe acidosis – pH<7.26 Septic shock Bilateral shadowing on CXR

Influenza RESPIRATORY Acute Bronchitis COMMON COMPLICATIONS Secondary Bacterial Pneumonia (~20%) Appears 4-5 days after start of ‘flu Microbiology: 1918 H.influenza, S.pneumoniae, βhaem.strept 1957 Staph.aureus (>2/3rds) 1968 S.pneumoniae, Staph.aureus, H.influenzae (48%) (26%) (11%) Community MRSA uncommon in Europe/concern in US

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

Influenza UNCOMMON COMPLICATIONS RESPIRATORY: Primary viral pneumonia - appears common in human cases of H5N1 - rapid respiratory failure; within 48 hours - mortality >40%; within 7 days CVS: Myocarditis/pericarditis CNS: Transverse myelitis/Guillain-Barre Myositis & Myoglobinuria (Influenza is a multi-system disorder)

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

Influenza ANTIBIOTICS – WHICH? Empirical cover - S.pneumoniae, H.influenzae, S.aureus - YES - Legionella ssp, ‘ atypical pathogens’ - NO ANTIBIOTICS – HOW? Oral route for non-severe Co-amoxiclav or Doxycycline IV route for severe infection (CURB 65 > 3)

Antiviral Therapy in ‘Ordinary Flu’  <30h after onset of symptoms - significant effect on reduction of duration of symptoms esp fever (shorten by 1 day)  >30h after onset of symptoms - no significant effect  No known effect on mortality

Oseltamivir Oral Zanamivir Dry powder inhaler Neuraminidase inhibitors

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)

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 hospitalisation  Reduction of complications and therefore need for other drugs especially antibiotics  Reduction in viral secretion & clinical attack rates

Pandemic Influenza RECOMMENDATIONS FOR ANTIVIRAL THERAPY  Patients to receive antivirals if they have all of - Acute influenza-like illness - Fever >38 o C - 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!

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