Complications
Complication table for2009 Influenza A (H1N1) virus
| Complication | Timeframe | Likelihood |
- acute respiratory failure
-
see our comprehensive coverage of Acute respiratory failure
Many cases of severe pneumonia from H1N1 influenza requiring hospitalisation or ICU care were reported worldwide during the 2009 pandemic. Many of these cases involved people younger than 50 years of age. However, overall, severe pneumonia and acute respiratory distress syndrome from the H1N1 swine influenza are relatively uncommon.
Patients with acute respiratory failure require admission to the hospital, possibly in an ICU, with close respiratory monitoring. In such cases, patients should undergo routine blood tests, CXR, and viral and bacterial tests, including testing for influenza infection. Presumptive treatment for influenza and bacterial infection should be started while awaiting definitive test results. If influenza is suspected, patients should be placed in respiratory isolation.
| short term | low |
- neurological complications
-
Neurological complications (including seizures, weakness, encephalopathy, and encephalitis) have been reported with seasonal influenza infections, particularly in children. Similar findings have been described during the 2009 H1N1 swine influenza pandemic; several cases in both adults and children have been reported to the US Centers for Disease Control and Prevention. Although most cases have been self-limited and resolved without any neurological sequelae, there have been a small number of case reports of long-term neurological deficits in children.
| short term | low |
|
| short term | low |
- secondary bacterial pneumonia
-
see our comprehensive coverage of Overview of pneumonia
This is a known complication of seasonal influenza infection, with frequent pathogens being Streptococcus pneumoniae and Staphylococcus aureus. The true incidence is unknown because patients with bacterial pneumonia often do not undergo routine testing for influenza infection, and by the time they present with secondary bacterial pneumonia, influenza virus may not be detectable. Bacterial infections have been co-isolated in patients with H1N1 swine influenza. In cases of H1N1 requiring ICU-level care, bacterial co-infection has been associated with increased necessity for vasopressors and mechanical ventilation and possible increased mortality. It is recommended that patients who present with prolonged symptoms following onset of influenza-like symptoms (>5 days), whose influenza-like illness does not resolve, or who require admission to the hospital, should be managed presumptively for bacterial pneumonia.
| variable | medium |
Last updated: Dec 30, 2011
