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INFLUENZA COMPLICATIONS
Influenza complications
• Bacterial superinfections
– bacterial pneumonia
– croup
– respiratory disorders
• Decompensation of chronic diseases
– pulmonary disease
– heart disease
– renal insufficiency
– metabolic disease
Nicholson KG. Semin Respir Infect 1992; 7: 26–37.
Influenza – respiratory complications
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Upper respiratory tract infection (URTI)
– otitis media
– sinusitis
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Lower respiratory tract infection (LRTI)
– exacerbation of asthma/chronic obstructive pulmonary
disease (COPD)
– croup, bronchiolitis
– primary viral pneumonia (rare*)
– secondary bacterial pneumonia
*5–10% of pneumonia is an influenza complication
Influenza complications
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Primary viral pneumonia
Bacterial secondary pneumonia
Tracheobronchitis
Bronchiolitis
Congestive heart failure
Myocarditis, pericarditis
Complications of sinus, middle ear, musculature
Reye’s syndrome – in children
Ketoacidosis – in diabetics
Acute viral encephalitis – in children
Guillain Barre syndrome
Gastrointestinal bleeding – in children
Decompensation of pre-existing pathology
Excess mortality
Possible association with prenatal exposure and schizophrenia
Groups at higher risk of complications
• Elderly (> 60 years of age), especially in residential care units
• Children and teenagers (6 months–18 years of age) receiving
long-term aspirin therapy
• Pregnant women belonging to high-risk groups
• Patients with:
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chronic respiratory disease, e.g. asthma, COPD
chronic heart disease
chronic metabolic disease, e.g. diabetes mellitus
immunosuppression due to treatment or disease, e.g. HIV
haematological disorders
chronic renal failure
Palache AM. Influenza subunit vaccine - ten years experience. Eur J Clin Res 1992; 3: 117–38.
Age distribution of respiratory
complications
Respiratory
complications (%)
80
60
40
20
0
0–4
5–9
10–19 20–39 40–49 50–59 50–69
> 70
Age groups (year)
Betts FR et al. In: Mandell GL et al., eds. Principles and Practice of Infectious Diseases.
3rd Edn. New York: Churchill Livingstone; 1990: 1306–25.
Influenza complications
in children
• Higher fever than in adults
• Higher incidence of coryza, otitis media and
gastrointestinal manifestations
• Influenza may present as croup or bronchiolitis
• Higher incidence of drowsiness and delirium
• Complications like myositis and pneumonia are more
frequent
Nicholson KG. Semin Respir Infect 1992; 7: 26–37.
Severe symptoms in children
Bronchiolar, pulmonary signs
30%
Vomiting, diarrhoea
40%
Pharyngitis
50%
Fever, rhinitis
90%
Kilbourne ED. Influenza. New York: Plenum Medical Book Company; 1987: 157–66.
Influenza in children with asthma and other
chronic medical conditions
• Retrospective cohort study, Tennessee Medicaid program (1973–1993)
• Children under 15 with medically treated asthma or chronic medical conditions
Yearly excess hospitalisation for
cardiopulmonary disease due to influenza in
different age group per 1000 high risk children
Age group
Under 1 year
1 to < 3 years
3 to < 15 years
Excess hospitalisation
per 1000
19
8
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•Influenza morbidity is high in this class of patient,
and often underestimated
Neuzil KM et al. J Pediatr 2000; 137: 856–64.
Other yearly consequences
of influenza
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Outpatients visits
– 120 to 200 per 1000 atrisk children
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Antibiotic courses
– 65 to 140 per 1000 atrisk children
Influenza in pregnancy
Vulnerability during the second and third trimester
Possible consequences:
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Severe pulmonary complications and death for pregnant
woman
Foetal loss and abortion
Other risks
– foetal complications (growth, weight, etc.)
– brain damage
– neural tube defects
Anonymous. Lancet 1994; 343: 665; Lynberg MC et al. Am J Epidemiol 1994; 140: 244–55; Takei N et al. Eur Arch
Psychiatry Clin Neurosci 1995; 245: 255–9; Wright P et al. Am J Psychiatry 1995; 152: 1714–20.
Pneumonia and influenza associated
death
Associated cardiovascular and
pulmonary disease
870
Associated cardiovascular
disease and diabetes
481
Pulmonary disease
240
Cardiovascular disease
104
Healthy adults
Barker WH et al. Arch Intern Med 1982; 142: 85–9.
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By courtesy of APACI
Asia-Pacific Advisory Committee on influenza
www.apaci-flu.com