This image was sent to me by one of my colleagues. He saw an un-immunized 22-year-old with sore throat and muffled voice:
This CT shows swelling and edema in the epiglottis. CT imaging of this diagnosis can occur in the STABLE epiglottitis patient. It will likely be a patient with unclear pathology and identified on CT rather than a easily clinically identified epiglottitis. Why? Because clinical epiglottitis that is very clearly identified is an airway emergency and they don’t end up in the CT scanner. The classic appearance will be a patient in the “tripod” position, drooling, stridor, hoarse voice, and looking ill. Lateral soft-tissue plain films can also make the diagnosis. Usual suspects causing epiglottitis include: H. Influenza, S. Aureus, Streptococcus sp., and Moraxella Catarrhalis (1).
Epiglottitis affects both children and adults and should be on your differential in an adult with these symptoms. Since childhood vaccinations have become widespread in developed countries the incidence of childhood epiglottitis has decreased. The incidence has remained stable in adults. This patient is interesting because of the un-immunized status.
Some thoughts pertaining mainly to children:
CT imaging of the neck in children is a controversial subject. Remember that the thyroid gland is anatomically present in the radiation area and the future risk of thyroid malignancy isn’t quite known. You must weight the risk of radiation against the benefit of the imaging test in this situation. CT is very good at detecting and characterizing childhood illnesses such as peritonsillar abscess, retropharyngeal abscess, and epiglottitis. If you highly suspect one of these pathologies CT is usually warranted as these diagnoses can cause significant morbidity and will many times need intervention. Keep in mind, however, that soft tissue neck plain radiographs may give you enough information to direct management and has much less radiation burden.
Some radiology signs are applicable to epiglottitis:
1. Thumbprint sign: on lateral CT or Plain film the epiglottitis will resemble a thumb in shape and size rather than the expected thin appearance. This is present on the CT above.
2. Halloween sign: describes the usual appearance of the epiglottis on CT axial cut. See image on Wikipedia®. Halloween Sign.
Author: Russell Jones, MD
Image Contributor: James Chenoweth, MD
1. Epiglottitis. http://www.wikipedia.org.