CT neck with IV contrast
Gold standard
Gold standard
Neck in extension at end inspiration
The prevertebral space should be less than 7mm at C2, 14mm at C6 in children regardless of the age
The prevertebral space should be less than 22mm at C6 in adults
The prevertebral space should be less than one-half the width of the corresponding vertebral body
If equivocal XR, order CT
Retropharyngeal abscess
Streptococcal pharyngitis 
Peritonsillar cellulitis
Neisseria gonorrhoeae
Epiglottitis
Diphtheria 
Peritonsillar abscess
Bacterial Tracheitis