To simplify things, others suggest that the upper pre-vertebral soft tissue should be no wider than one vertebral body width. Adequate hyperextension of the head and neck is necessary in order to properly interpret the film if there is no history of trauma. If the head and neck are not properly positioned, the pre-vertebral space will appear to be widened because the neck is not extended enough. Repeating the radiograph with proper positioning may resolve this problem. If proper positioning is not possible or if the clinician is unsure if plain films are definitive, CT of this area can more accurately define any abnormalities of this region.
Most patients presenting with symptoms of croup have viral croup.
While epiglottitis is usually not difficult to distinguish clinically from croup, an early retropharyngeal abscess may be difficult to distinguish from croup. A lateral neck radiograph may reveal this occult diagnosis in selected cases, such as those with high fever, unexpected lymphadenopathy, or those wit h a suspicious bulge in the pharynx. Other causes of partial upper airway obstruction include epiglottitis, croup, peritonsillar abscess, severe tonsillitis, infectious mononucleosis, cystic hygroma, hemangioma, or neoplasms. Retained upper esophageal foreign bodies, trauma to the retropharynx from foreign body ingestion, instrumentation, and C-spine injury can also cause localized swelling or obstruction. View another cause of stridor.