Discussion
While the incidence of pediatric epiglottitis has decreased since the introduction of the Haemophilus influenzae type b (Hib) vaccine in 1985, adult epiglottitis continues to represent a potentially life-threatening condition whose incidence has remained constant over the past several decades.1,2 The incidence of supraglottitis in adults is now 2.5 times greater than the incidence in children.3,4
Several important differences exist in the presentation and management of adults who present with inflammation of the epiglottis as compared to children. Children commonly present with an acute onset of symptoms, and due to their smaller and more pliant airway anatomy, they often experience stridor and respiratory distress.3,5 The inflammation in children is typically confined to the epiglottis and aryepiglottic folds, while in adults the inflammation can affect not only the epiglottis, but also supraglottic structures such as the pharynx, uvula, and aryepiglottic folds. For this reason, in adults the condition is often referred to as “supraglottitis.”2,6 Adults with supraglottitis most likely present in their 30s, 40s, and 50s, while children present between the ages of 2 and 5 years old.1,3,7 In adults, men more commonly present with supraglottitis than women.1,2 Cigarette smokers and patients with hypertension, diabetes mellitus (DM), chronic obstructive pulmonary disease, or human immunodeficiency virus/AIDS are at increased risk for supraglottitis.3,4 The mortality rate for adults with supraglottitis ranges from 1.2% to 7.1%.3
Etiology
Prior to the use of the Hib vaccine, Hib was the most common cause of epiglottitis, and remains so for children.1 Currently, the most common cause of supraglottitis in adults is Group A beta-hemolytic Streptococci.2 Other etiologies include other bacteria (Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas species, Klebsiella pneumoniae, Pasteurella multocida, Neisseria species), viruses (herpes simplex, varicella, parainfluenza), trauma, and thermal injuries.1,4,5,8
Signs and Symptoms
Throat pain, dysphagia, odynophagia, and muffled voice are common complaints of adults presenting to the ED with supraglottitis.2,7 Fever is usually, but not always, present; the complaint of cough, however, is rare.2,3,4 Other less frequent complaints include hoarseness and drooling. Adults can also present with cervical lymphadenopathy, anterior neck tenderness, and cellulitis of the neck and chest.2,4 In general, the more severe cases will progress rapidly over a few hours. Due to the larger anatomy in adults, they are more likely than children to experience a gradual progression of symptoms, and supraglottitis will be missed on the initial presentation in up to 50% of adults.3,4 Stridor or respiratory compromise does occur in a minority of adult patients with supraglottitis. The need for artificial airway support (ie, endotracheal intubation, cricothyroidotomy) in adults ranges from 6.6% to 16%.9,10
Making the Diagnosis
The gold standard for diagnosing supraglottitis is direct laryngoscopy.3,4 This point is emphasized in our case report, since the CT scan was concerning for a retropharyngeal abscess, and not supraglottitis. The examination of the oropharynx is generally safer and better tolerated in adults compared to pediatric patients, since airway compromise is much less likely. On occasion, inflammation, erythema, and edema of the epiglottis, aryepiglottic folds, or arytenoid cartilages can be observed.5 More commonly, the supraglottic structures are not visualized, and the posterior oropharynx appears relatively normal. This should serve as a clue for possible supraglottitis.
In suspected cases of adult supraglottitis without emergent airway compromise, lateral soft-tissue radiographs can be obtained to look for the “thumb sign,” indicating a swollen epiglottis. In adult supraglottitis, the width of the epiglottis is usually greater than 8 mm.11 Other abnormal radiographic findings include arytenoid and aryepiglottic fold enlargement, thinning of the airway, and an increase in size of the prevertebral space. Plain film sensitivity rates range from 38% to 98%.
Complete blood count and throat cultures are not particularly helpful in adult cases. Blood cultures, while only about 30% sensitive in adults, should be considered as supraglottitis can result in secondary infection in the central nervous system, lungs, and surrounding structures.3,5
If available, otolaryngology services should be consulted to evaluate the airway, and IV antibiotics, such as a third-generation cephalosporin (eg, ceftriaxone, cefotaxime), should be initiated to include coverage of Hib.3 If methicillin-resistant S aureus is a concern, vancomycin should be added. Clindamycin or metronidazole should also be given if anaerobes are suspected.4,7 The location for performing the nasopharyngeal laryngoscopy varies, depending on the patient’s age (ie, pediatric vs adult), severity of symptoms, presence of airway compromise, and local practice and custom.
Advanced imaging studies (CT scan or magnetic resonance imaging) can help identify the presence of an abscess and delineate the extent of the infection, but are not indicated in the early diagnosis and management of suspected adult supraglottitis.4 As our case demonstrates, CT is neither highly sensitive nor specific for the diagnosis of epiglottitis. The role of ultrasound in the evaluation of suspected epiglottitis is still being developed. One recent study compared 15 healthy volunteers with 15 patients diagnosed with epiglottitis by an otolaryngologist using laryngoscopy.12 A statistically significant difference was observed in the anteroposterior diameter of the epiglottis at the midpoint and both lateral edges between the study subjects and healthy volunteers.12 While there was overlap in the ranges for the midpoint, there was no overlap in both lateral edges between the two groups.12