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

Clinical characteristics of ‘Flu’ Dr Dermot H Kennedy Consultant Physician in Infectious Diseases (Retd.) Glasgow

“Influenza A is an unvarying disease due to a varying virus” E. Kilbourne New York 1975 Variation Complicated: - by pandemic virus - by co-infecting bacteria - by risk factors Uncomplicated: - by age - by virus type

THE MENU Clinical features of: Typical influenza A - milder complications Serious complications - respiratory - non respiratory Variation by pandemic outbreak

Clinical Spectrum of Influenza A Incidence / range of systemic features Collated from 10 studies of 520 virologically confirmed adult cases ( after Nicholson Ch. 19 in ‘Human Influenza’ )

MILDER COMPLICATIONS OF INFLUENZA A - TRACHEOBRONCHITIS - OTITIS MEDIA - SINUSITIS - POST INFLUENZAL ASTHENIA AND DEPRESSION

Who is at risk of influenza? ‘Typical’ Influenza A: Age 65yrs Chronic disease : respiratory, cardiac, renal, diabetes, immunosuppression ‘at risk’ settings Risk factor influences presentation / complications Pandemic Influenza As across + young adults +pregnant women Peak mortality 1918

SERIOUS COMPLICATIONS OF INFLUENZA A RESPIRATORY:. 2y bacterial pneumonia. 1y viral pneumonitis. Mixed viral and bacterial pneumonia. Exacerbation of COAD, asthma NON RESPIRATORY:. CNS eg encephalopathy, myositis. CARDIAC eg decompensated CCF

Complications of Influenza A Infection 2y pneumonia due to bacterial suprainfection The problem :

2y BACTERIAL PNEUMONIA Influenza A accounts for 5 →10% of all C.A.P. Biphasic disease – usually Pattern different from “CAP norm”, and between pandemics Pneumococcal pneumonia commonest

2y bacterial pneumonia H.influenza pneumococcus

Staphylococcal pneumonia complicating Influenza A A sinister synergy

Complications of Influenza A Virus Iy Pneumonitis due to virus What is role of cytokine storm?  Often fulminant and fatal  Dyspnoea, wheeze, cyanosis, blood  Diffuse CXR infiltrates (like ARDS)  Pregnant, cardiac, young

Pandemic Influenza 1918/19 Occurred in 3 waves Globally estimated 750m-Ib. ill Morbidity Global mortality 23-50M UK mortality 240K Peak mortality - young adults Mortality

Spanish ‘flu - Heliotrope cyanosis “We have always been thankful when (facial) colour remains red …there is ample room for hope of recovery When the colour of the patient’s face is heloitrope or mauvy-blue the prospect is grave indeed…” 1918/19

H5/N1 - Z genotype traced to geese in Guangdong, China 1996 Features Avian Influenza 1997: Hong Kong - 6/18 fatal (33%) 2003/7: Asia - 175/290 fatal (60%) Majority < 25yr old Severe disease in: older, late presentation + pneumonia, leuko/lymphopenia (16%) Vietnamese cases – encephalopathy + diarrhoea Multi system involvement and Multi organ damage at Post Mortem

COMPARING PANDEMICS AGEYoungElderlyElderly adult (young)(young) ‘notable’ S. pyogenesS. aureusS. aureus BACTERIA + others ’18/’19’57/’58’68 UK MORTALITY 240k33k 30k E+W

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