PATHOPHYSIOLOGY OF INFLUENZA

Pathophysiology Binding and destruction of epithelial cells from nasopharynx to alveoli SYSTEMIC BODY REACTION Fever, muscle pain, etc. LOCAL INFLAMMATORY REACTION Upper respiratory infection Body response Droplets Aymard M. Vaccine 1995: 47–70. 24

Uncomplicated influenza 37 39 41 temperature (°C) Oral 1 2 3 4 5 6 7 8 9 10 Time in days (RMKTCID 50/ml) LOG10 nasopharyngeal virus titer Incubation period Virus isolation Fever curve Complications Sore throat, myalgia Headache Cough Malaise, prostration Coryza Onset of illness Kilbourne ED. Influenza. New York: Plenum Medical Book Company; 1987: 156–218. 26

Overview – clinical symptoms Abrupt onset of symptoms Abrupt onset of fever, drop in temperature after 2 days, increase again Severe myalgia Sore throat Dry cough Retrosternal pain Severe malaise lasting several days

Symptoms of influenza Percentage of cases Cough Malaise Feverishness 10 20 30 40 50 60 70 80 90 100 Cough Malaise Feverishness Sudden onset Chills Headache Anorexia Coryza Myalgia Sore throat Sputum Dizziness Hoarseness Chest pain Vomiting Diarrhoea Abdominal pain Fever > 37.8°C Percentage of cases Nicholson KG et al., eds. Textbook of Influenza. Malden, Massachusetts: Blackwell Science; 1998.

Fulminant influenza DEATH Reported during pandemics The fulminant form can affect everyone Pulmonary manifestation Antibiotics are ineffective Influenza viral pneumonia Fever Cough Dyspnoea Cyanosis DEATH Aymard M. Vaccine 1995: 47–70. 27

By courtesy of APACI Asia-Pacific Advisory Committee on influenza www By courtesy of APACI Asia-Pacific Advisory Committee on influenza www.apaci-flu.com