Viral infections bronchiolitis

Bronchiolitis is an acute viral infection of the lower respiratory tract of infants that affects approximately 50% of children during the first year of life and 100% by 3 years. 

Respiratory syncytial virus (RSV) infection is a major cause of bronchiolitis in infants, whereas influenza A infection usually manifests as an upper respiratory tract infection. The immunological responses of infants to RSV infection and influenza A infection are different. In our studies of the cytokine responses during these infections, we found that the serum concentrations of IL-4, IL-5, RANTES, and soluble intercellular adhesion molecule-1 (sICAM-1) in infants with RSV infection were significantly higher than those with influenza A infection (S8). The concentration of TNF-a in nasopharyngeal aspirates was significantly lower in infants with RSV infection. Therefore, a predominant T helper cell type 2 (Th2) cytokine and related immunological response was observed in infants with RSV infection, whereas a predominantly proinflammatory cytokine response was observed in infants with influenza A infection. This may explain the different clinical manifestations of the two viral infections in infants (S8). 

Bronchiolitis Inflammation of the bronchioles, usually caused by a viral infection... 

Bronchiolitis is an acute viral infection of the lower respiratory tract most commonly affecting infants during the first year of life, with peak attack rates occurring in infants between the ages of 2 and 10 months. Infectious bronchiolitis is unusual in children older than 2 years of age. The occurrence of bronchiolitis peaks during... 

In the well infant, bronchiolitis is usually a self-limiting illness, and reassurance and antipyretics are usually all that are necessary while waiting for resolution of the underlying viral infection. In-hospital support is necessary for the child suffering from respiratory failure or dehydration underlying cardiac and pulmonary diseases potentiate these conditions. 

Ribavirin is a synthetic guanosine analogue, with in vitro activity against a broad spectrum of DNA and RNA viruses, and retroviruses, including HIV. Ribavirin has been used for treatment of a variety of viral infections, including respiratory syncytial virus bronchiolitis and pneumonia, measles, influenza types A and B, Lassa fever, hemorrhagic fever with renal syndrome (Hantaviruses), hepatitis C, and HIV infection. It is used commonly now along with interferon alpha for treatment of hepatitis C infection. There is no known direct nephrotoxicity of ribavirin. 

Respiratory syncytial virus is the most common cause of acute bronchiolitis, an infection that mostly affects infants during their first year of life. In the well infant, bronchiolitis is usually a self-limiting viral illness, whereas in the child with underlying respiratory or cardiac disease or both, the child may develop severe respiratory compromise (failure) necessitating in-hospital treatment, such as rehydration, oxygen, and in select patients, bronchodilators, ribavirin aerosol, or both. 

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