You are in: eMedicine Specialties > Radiology > PEDIATRICS Epiglottitis, AcuteArticle Last Updated: Apr 21, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 9
  Author: Jon E Jaffe, MD, Assistant Professor, Department of Emergency Medicine, Texas A&M University College of Medicine; Consulting Staff, Department of Emergency Medicine, Scott and White Hospital Jon E Jaffe is a member of the following medical societies: American Academy of Emergency Medicine, American Medical Association, Society for Academic Emergency Medicine, and Texas Medical Association Coauthor(s): Mary Kitazono-Hammell, MD, Resident, Department of Radiology, Hospital of the University of Pennsylvania; Sarah Heringer, DO, Consulting Staff, Department of Emergency Medicine, Kaiser Permanente, Sacramento/Roseville; Rodney Lewis Hajdik, MD, Assistant Professor of Diagnostic Radiology, Texas A&M University Health Science Center College of Medicine; Senior Staff, Assistant Residency Program Director, Department of Diagnostic Radiology, Scott and White Clinic Editors: Beverly P Wood, MD, MS, PhD, Professor, Departments of Radiology and Pediatrics, Division of Medical Education, Keck School of Medicine, University of Southern California; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Eugene C Lin, MD, Clinical Assistant Professor of Radiology, University of Washington Medical School Author and Editor Disclosure Synonyms and related keywords: acute epiglottitis, supraglottitis, cherry-red epiglottitis, Haemophilus influenzae type b, Hib, Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus pyogenes, group A beta-hemolytic streptococci, herpes simplex virus, HSV INTRODUCTIONSection 2 of 9
  BackgroundEpiglottitis is a rapidly developing inflammation of the epiglottis and adjacent tissues, usually due to a bacterial infection, that can cause life-threatening airway obstruction. Historically, epiglottitis was a disease of childhood, and the most common pathogen was Haemophilus influenzae type b (Hib). After the introduction of the Hib vaccine in 1985, followed by the recommendation of routine infant vaccination in the United States beginning in 1991, the incidence of epiglottitis dramatically declined in children.1, 2, 3, 4, 5, 6, 7 Today, there is no predominant pathogen implicated in epiglottitis. Hib epiglottis is still occasionally seen, accounting for 6 out of 19 cases in a series (from 1992 to 2002) by Shah and colleagues.5 It occurs in vaccinated and nonvaccinated patients, because the vaccine is not 100% effective. Patient Education For excellent patient education resources, visit eMedicine's Esophagus, Stomach, and Intestine Center. Also, see eMedicine's patient education article Epiglottitis. PathophysiologyThe epiglottis is a thin cartilage covered by a loose layer of stratified squamous epithelium, which creates a potential space. When infection ensues, this potential space expands with inflammatory cells and fluid, and curls posteriorly over the glottic opening, acting as a ball-valve type of airway obstruction during inspiration. Associated swelling of the aryepiglottic folds and arytenoids is frequently seen in children and adults. In adults, the soft palate, base of the tongue, uvula, and vallecula are commonly involved as well, often resulting in supraglottitis.8 FrequencyUnited StatesThe incidence of epiglottitis in children has greatly declined since Hib vaccine came into widespread use, although the vaccine is not 100% effective.1 In children younger than 5 years, the incidence has decreased from approximately 10 cases per 10,000 in the pre-vaccine era to 0.3 cases per 10,000 between 1995 and 2003. In contrast, the incidence of acute epiglottitis has increased in adults, with the reported incidence rising from 0.79 cases per 100,000 in 1986, to 1.8 per 100,000 in 1990, and to 3.1 per 100,000 in 2000.7, 9 InternationalA similar decline in incidence of childhood Hib epiglottitis was seen in other countries following the introduction of routine Hib vaccination. Mortality/MorbidityThe majority of the morbidity and mortality associated with epiglottitis is caused by life-threatening airway obstruction requiring intubation and occasionally tracheostomy. Epiglottitic swelling causing greater than 50% airway obstruction, or extension of swelling to the arytenoids, generally requires immediate intervention. Other complications include the development of an abscess, acute tonsillitis, or bacteremia. The mortality rate is around 1% in children; the rate is 6-7% in adults, which may be partially attributable to a greater difficulty and delay in diagnosing epiglottitis in adults.10 SexEpiglottitis is more common in males than in females, with a male-to-female ratio of about 3:1. Age
AnatomyThe epiglottis is a small flap of tissue in the larynx that guards the airway entrance to the lungs. The larynx also contains the arytenoid cartilages, aryepiglottic folds, vocal cords, and cricoid cartilage. Clinical DetailsThe most common symptoms of epiglottitis include a severe sore throat, odynophagia, drooling (due to inability to swallow), and stridor. Classically, the patient appears anxious and may lean forward, extending his/her neck in an attempt to maintain an open airway. Dyspnea, drooling, a muffled voice, and the rapid onset of symptoms are predictors of impending airway obstruction.2 In children with Hib, the onset is often sudden and progresses rapidly; the disease usually follows a more indolent course in adults, and delayed airway obstruction can occur several days after admission. Preferred ExaminationFindings on lateral neck radiographs are frequently diagnostic. A single, lateral, upright view of the neck in extension, preferably with a closed mouth, is usually adequate. The radiograph should be obtained with portable equipment in the emergency department (ED), because acute airway obstruction may occur at any time. In severe cases, radiographs should not be acquired until the airway is secured. The diagnosis can be confirmed by direct nasopharyngolaryngoscopy, which should be performed only when measures to immediately secure the airway are available in the ED or operating room. Limitations of TechniquesAn inability to hyperextend the patient's neck because of irritability may interfere with diagnostic accuracy. An image obtained with the patient's mouth open may decrease the probability of seeing true obliteration of the vallecula. Direct examination of the pharynx or anxiety caused by diagnostic tests may precipitate acute airway obstruction. If crying occurs, rapid inspiration through the swollen epiglottis can cause the airway to close completely. Finally, a suboptimally low kilovolt setting may cause poor depiction of the soft tissues. DIFFERENTIALSSection 3 of 9
Anaphylaxis Bacterial Tracheitis Croup Diphtheria Mononucleosis Peritonsillar Abscess Pertussis Pharyngitis Retropharyngeal Abscess Other Problems to Be ConsideredAngioneurotic edema RADIOGRAPHSection 4 of 9
FindingsOn plain radiographs, the normal epiglottis is a thin, curved flap of soft-tissue opacity that is separated from the base of the tongue by air in the vallecula (see Image 1). In epiglottitis, the epiglottis appears swollen and enlarged (the thumbprint sign), typically greater than 8 mm in adults (see Images 2-3).11 Often, only a pencil-thin airway or no air column is visible in the shadow of the epiglottis. As edema develops, the epiglottis expands, obliterating the vallecula. Loss of the vallecula has been said to be an independently sensitive and specific sign of adult epiglottitis, although further validation is needed.12 Thickening of the aryepiglottic folds and thickening of the arytenoids are associated findings in 85% and 70% of cases of epiglottitis, respectively. Aryepiglottic fold thickening greater than 7 mm is a particularly sensitive and specific finding in children and adults.11 Prevertebral soft-tissue swelling and hypopharyngeal widening are additional associated findings. In children, ballooning of the hypopharynx, caused by sucking air through an open mouth against an obstruction, is occasionally seen due to laxity of the immature airway. Hypopharyngeal widening and ballooning, however, are nonspecific findings associated with any cause of upper airway obstruction. The following additional parameters for diagnosing epiglottitis in adults have been proposed13, 14:
The presence of any of these signs should raise the suspicion that epiglottitis is present, although diagnostic accuracy increases when multiple findings exist. Degree of ConfidenceSoft-tissue, lateral neck radiography has a sensitivity of 88-100% and a specificity of 87-96% in diagnosing epiglottitis.14 False Positives/NegativesAn enlarged epiglottis may result from various disorders, including irritation from a foreign body or burn, granulomatous disease (eg, sarcoidosis, tuberculosis, Wegener granulomatosis), angioneurotic edema, and tumors, such as epiglottic cysts and neoplasms (eg, lymphomas) CT SCANSection 5 of 9
FindingsThe use of computed tomography (CT) scanning is risky in the diagnosis of epiglottitis, but it may help in the evaluation of complications, such as abscess formation (see Image 4), as well as in the exclusion of various conditions, including the presence of a peritonsillar or deep neck space abscess, lingual tonsillitis, or an ingested foreign body. CT scanning should be approached with caution, however, because the supine position increases the risk of acute respiratory distress. The most common CT scan findings include thickening of the epiglottis, aryepiglottic folds, platysma muscle, and prevertebral fascia; obliteration of the pre-epiglottic fat planes; and reticulation of the subcutaneous fat. Emphysematous epiglottis is further characterized by soft-tissue lucencies representing gas within a swollen epiglottis. The finding of multiloculated fluid-density collections should raise the suspicion that an abscess exists. False Positives/NegativesEdema and thickening of the supraglottic tissues with obliteration of the surrounding fat planes can also be seen in patients who have received radiation therapy to the neck. In addition, an enlarged epiglottis can result from a variety of inflammatory and infiltrative disorders, as previously discussed. MRISection 6 of 9
FindingsAs with CT scanning, magnetic resonance imaging (MRI) is not recommended for initial diagnosis but may be useful for excluding potential mimickers of epiglottitis or for identifying complications. Particular caution should be taken to ensure patient safety, because patients must be supine for a lengthy period of time without direct surveillance. Few studies have reported MRI findings in acute epiglottitis. T1- and T2-weighted imaging shows thickening of the epiglottis, and there is marked enhancement of the epiglottis and often of the adjacent aryepiglottic folds following gadolinium administration. Areas of nonenhancement may represent necrosis or phlegmon. Cervical lymphadenopathy may also be seen. INTERVENTIONSection 7 of 9
The first priority is to ensure that the patient's airway is secured.2, 7, 10 The treating or referring clinician or specialist must be notified immediately if acute epiglottitis is suspected; the specialty of the responsible treating physician may vary from institution to institution. An endotracheal or nasotracheal tube is often needed to maintain the airway, although selected cases may be managed expectantly in an intensive care unit (ICU) setting. Respiratory distress, stridor, an inability to swallow secretions (drooling), and rapid progression of symptoms are the main indications for intubation. Tube placement should be done by an anesthesiologist or critical care physician and by an otolaryngologist. In case of precipitous airway obstruction, cricothyrotomy or tracheostomy may be necessary. The patient is best treated in a controlled environment, most often in the ICU or ED, where equipment for intubation, cricothyrotomy, or needle-jet ventilation is available at the patient's bedside. Careful monitoring is essential, and isolation is important, because many cases of epiglottitis are infectious and easily spread. With the decline of Hib, blood cultures and throat swabs are often low yield and should not delay intravenous antibiotic administration. Antibiotics should cover H influenzae and S aureus (methicillin-resistant S aureus, or MRSA), as well as Streptococcus and Pneumococcus species. Effective antibiotics include ampicillin (200 mg/kg/d in 4 divided doses) with chloramphenicol (75-100 mg/kg/d in 4 divided doses), ceftriaxone (80-100 mg/kg/d in 2 divided doses), and cefotaxime (50-180 mg/kg/d in 4 divided doses). Although frequently used, steroids have not conclusively been shown to decrease the need for intubation or to shorten the hospital stay. Patients must remain intubated and mechanically ventilated until the swelling and inflammation decrease. Children with Hib epiglottitis can usually be extubated in 24-48 hours. In the reported cases of epiglottitis caused by beta-hemolytic streptococci, the average duration of intubation was 6 days. Laryngoscopy may be helpful in deciding when extubation is appropriate. Only the immediate household contacts of a patient infected with Hib should be treated with rifampin for prophylaxis. Medical/Legal Pitfalls
MULTIMEDIASection 8 of 9
REFERENCESSection 9 of 9
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