Viraemia is neither an essential nor a common phase of infection. D. Clinical Features Croup is the commonest clinical manifestation of parainfluenza virus infection in children. Typically, the children exhibit a croupy cough, inspiratory stridor, hoarse voice or cry and respiratory difficulty on inspiration. Patients are usually afebrile. Respiratory rhonchi are heard frequently throughout the lung fields.
Radiological examination is usually normal.
Severe airway obstruction may ensue, necessitating an emergency tracheotomy. Hospitalized patients are usually admitted within 3 - 24 hours after onset of croup. They should be placed promptly into plastic tents with cooled humidified oxygen. Usually, respiratory symptoms subside within 1 or 2 days. Parainfluenza viruses are found uncommonly in association with other respiratory tract infections in children such as tracheobronchitis, bronchiolitis and bronchopneumonia.