Snapshot A 3-year-old boy is brought to the ER by his mother who is concerned about a "barking cough," mild fever, and hoarse voice. She reports that he had a runny nose last week that has since resolved. Physical exam reveals an inspiratory stridor. An AP neck film is shown. Introduction An acute, inflammatory disease of the larynx primarily within the subglottic space Caused by upper respiratory infection with parainfluenza type 1 (most common cause) parainfluenza types 2 and 3 RSV influenza adenovirus mycoplasma pneumonia Epidemiology affects children ages 3-5 years often presents in fall and winter months Presentation Symptoms prodromal upper respiratory symptoms mild cough sore throat followed by low-grade fever dyspnea inspiratory stridor hoarseness classic "barking cough" symptoms usually worsen at night Physical exam wheezing or rales may be evident on ausculation Evaluation Diagnosis is based primarily on clinical observations and patient history degree of stridor is usually criteria needed for diagnosis AP neck film subglottic narrowing ("steeple sign") neither sensitive nor specific, though often tested on Step 1 and Step 2 exams Differential Epiglottitis, bacterial tracheitis, retropharyngeal abscess Treatment Medical management dependent on severity of disease mild cases supportive care in outpatient setting moderate cases oral/IM corticosteroids may be indicated to reduce inflammatory response recemic epinephrine nebulizer indicated to dilate airways severe cases hospitalization supplement O2 nebulized racemic epinephrine corticosteroids ribavirin may be indicated in immunocompromised patients, though use is controversial Prognosis, Prevention, and Complications Prognosis very good to excellent when diagnosed early and treated appropriately Prevention avoid contact with other infected individuals practice good hand hygeine Complications respiratory obstruction can lead to respiratory failure and death bacterial superinfection can progress to tracheitis