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Although bacterial infections of the larynx can result in “false croup, ” the condition is caused almost exclusively by viruses, esp. parainfluenza, respiratory syncytial, and influenza viruses.
Diagnosis is based on characteristic clinical findings and x-ray examination of the neck, which may show subglottic narrowing of air within the trachea.
Supportive measures include rest and supervised hydration. Positioning in an infant seat or in Fowler’s position is helpful. Although cool mist is often provided via inhalation, its effectiveness is unproven. Oral corticosteroids are routinely prescribed and have proved beneficial in mild as well as moderate to severe cases (less sleep loss, better clinical outcomes in early days). Hospitalization may be necessary for more severe cases; nebulized racemic epinephrine and oxygen therapy may be needed. Intubation is rarely required unless the patient shows evidence of respiratory fatigue or hypoxia. Antibiotics are seldom needed because the viruses involved do not predispose to secondary bacterial infections. The vast majority of children, even those hospitalized, recover without complications.
A quiet, calm environment is maintained; all procedures are explained to the family, and support and reassurance are provided to the child and family to reduce fear and anxiety. Ventilation and heart rate are monitored, as are cough, hoarseness, breath sounds, and ventilatory rate and character. The affected child is observed carefully for retractions, inspiratory stridor, cyanosis, labored breathing, and restlessness. Antipyretics and sponge baths are provided for fever; infants and young children with temperatures above 102°F (38.9°C) are observed for seizures. If the child becomes dehydrated, oral or intravenous rehydration is administered. Sore throat is relieved with water-based ices such as fruit sherbets, and thicker fluids are avoided if the child is producing thick mucus or has difficulty swallowing. Hand hygiene is scrupulously practiced when caring for the child to avoid transmitting respiratory syncytial virus (RSV) or parainfluenza infections to other children. Parents must also wash hands frequently and thoroughly.
diphtheritic croupLaryngeal diphtheria.
Symptoms include those of laryngitis: loss of voice; noisy, difficult, and stridulous breathing; weak, rapid pulse; livid skin; and moderate fever.
Several viruses may cause this disease. These include parainfluenza, respiratory syncytial virus, and various influenza viruses.
Antibiotics are indicated only if there is secondary bacterial infection; corticosteroids are of no benefit. If hypoxia is present, inhalation of a 40% concentration of well-humidified oxygen is indicated. This is best accomplished by a face mask.