What is the clinical significance of the "thumb sign" on lateral neck radiographs?

The "thumb sign" on lateral neck radiographs is a clinical indicator specifically associated with epiglottitis. This radiographic finding appears as a rounded, enlarged epiglottis, resembling a thumb or a thumbprint. The significance of this sign lies in its association with the inflammation and swelling of the epiglottis, which can potentially lead to airway obstruction in young children.

Epiglottitis is a serious condition that can progress rapidly, making early diagnosis and intervention crucial. The appearance of the sign helps clinicians identify patients who may require immediate medical attention, such as airway management or antibiotics, to prevent respiratory failure.

While other conditions like tonsillitis, tracheitis, and croup may present with overlapping symptoms, they do not produce the "thumb sign" on imaging studies, making this finding a distinctive marker for epiglottitis specifically.