Acute Epiglottitis

Acute epiglottitis is a life-threatening emergency. In contrast to LTB, epiglottitis is an inflammation of the supraglottic region, which includes the epiglottis, aryepiglottic folds, and false vocal cords (see Figure 39-1). Epiglottitis does not involve the pharynx, trachea, or other subglottic structures. As the edema in the epiglottis increases, the lateral borders curl and the tip of the epiglottis protrudes posteriorly and inferiorly. During inspiration the swollen epiglottis is pulled (or sucked) over the laryngeal inlet. In severe cases, this may completely block the laryngeal opening. Clinically, the classic finding is a swollen, cherry-red epiglottis.

The major pathologic or structural changes associated with croup are as follows:

Acute Epiglottitis*

Acute epiglottitis is a bacterial infection that is almost always caused by Haemophilus influenzae type B. It is transmitted via aerosol droplets. Since 1985, when vaccinations with H. influenzae type B vaccine became widespread, the number of reported cases of epiglottitis has decreased by over 95%. H. influenzae type B, however, is still responsible for 75% of the epiglottitis cases. Other causes of epiglottitis include aspiration of hot liquid and trauma from repeated intubation attempts.

Epiglottitis has no clear-cut geographic or seasonal incidence. Although acute epiglottitis may develop in all age groups (neonatal to adulthood), it most often occurs in children 2 to 6 years of age. Boys are affected more often than girls. The onset of epiglottitis is usually abrupt. Although the initial clinical manifestations are usually mild, they progress rapidly over a 2- to 4-hour period. A common scenario includes a sore throat or mild upper respiratory problem that quickly progresses to a high fever, lethargy, and difficulty in swallowing and handling secretions. The child usually appears pale. As the supraglottic area becomes swollen, breathing becomes noisy, the tongue is often thrust forward during inspiration, and the child may drool. Compared with LTB, the inspiratory stridor is usually softer and lower in pitch. A cough is usually not associated with acute epiglottis. The voice and cry are usually muffled rather than hoarse. Older children commonly complain of a sore throat during swallowing. A cough is usually absent in patients with epiglottitis. Acute epiglottitis in adults is typically seen in patients with neck trauma (e.g., blunt force neck injury or aspiration of hot liquid), in those who have been intubated repeatedly, and in drug abuse (crack cocaine) cases.

The general history and physical findings of LTB and epiglottitis are compared and contrasted in Table 39-1.

 OVERVIEW of the Cardiopulmonary Clinical Manifestations Associated with Laryngotracheobronchitis and Epiglottitis

The following clinical manifestations result from the pathologic mechanisms caused (or activated) by an Upper Airway Obstruction—the major anatomic alteration of the lungs associated with laryngotracheobronchitis (LTB) and epiglottitis (see Figure 39-1).

(Upper airway obstruction is not one of the major clinical scenarios discussed in Chapter 9.)

CLINICAL DATA OBTAINED AT THE PATIENT’S BEDSIDE

The Physical Examination

Vital Signs

Increased Respiratory Rate (Tachypnea)

Several pathophysiologic mechanisms operating simultaneously may lead to an increased ventilatory rate:

• Increased stimulation of peripheral chemoreceptors

• Anxiety

Increased Heart Rate (Pulse) and Blood Pressure

Chest Assessment Findings

• Diminished breath sounds

Inspiratory Stridor

Under normal circumstances the slight narrowing of the upper (extrathoracic) airway that naturally occurs during inspiration is insignificant. Because the upper airway is relatively small in infants and children, however, even a slight degree of edema may become significant. Thus when the cross-section of the upper airway is reduced because of the edema, the child will generate stridor during inspiration, when the upper airway naturally becomes smaller. It also should be noted that if the edema becomes severe, the patient may generate both inspiratory and expiratory stridor.

Cyanosis

Use of Accessory Muscles During Inspiration

Substernal and Intercostal Retraction

CLINICAL DATA OBTAINED FROM LABORATORY TESTS AND SPECIAL PROCEDURES

Arterial Blood Gases

MILD TO MODERATE LARYNGOTRACHEOBRONCHITIS OR EPIGLOTTITIS

Acute Alveolar Hyperventilation with Hypoxemia (Acute Respiratory Alkalosis)

pH	Paco2		Pao2
↑	↓	↓ (slightly)	↓

SEVERE LARYNGOTRACHEOBRONCHITIS OR EPIGLOTTITIS

Acute Ventilatory Failure with Hypoxemia (Acute Respiratory Acidosis)

pH*	Paco2	*	Pao2
↓	↑	↑ (slightly)	↓

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^*When tissue hypoxia is severe enough to produce lactic acid, the pH and values will be lower than expected for a particular Paco₂ level.

Oxygenation Indices*

	Do2†			O2ER
↑	↓	N	N	↑	↓

---

^*, Arterial-venous oxygen difference; DO₂, total oxygen delivery; O₂ER, oxygen extraction ratio; , pulmonary shunt fraction; , mixed venous oxygen saturation; , oxygen consumption.

^†The Do₂ may be normal in patients who have compensated to the decreased oxygenation status with (1) an increased cardiac output, (2) an increased hemoglobin level, or (3) a combination of both. When the Do₂ is normal, the O₂ER is usually normal.

LATERAL NECK RADIOGRAPH

• Haziness in the subglottic area (LTB)

• “Steeple point” or “pencil point” narrowing of the upper airway (LTB)

• Haziness in the supraglottic area (epiglottitis)

• Classic “thumb sign” (epiglottitis)

Although the diagnosis of epiglottitis or LTB can generally be made on the basis of the patient’s clinical history, a lateral neck x-ray examination sometimes is used to confirm the diagnosis. When the patient has LTB, a white haziness is demonstrated in the subglottic area. When the patient has acute epiglottitis, a white haziness is evident in the supraglottic area. In addition, epiglottitis often appears on a lateral neck x-ray film as the classic “thumb sign.” The epiglottis is swollen and rounded, giving it an appearance of the distal portion of a thumb (Figure 39-2). Figure 39-3 shows a lateral neck radiograph of a 27-year-old man with severe epiglottitis caused by crack cocaine abuse and neck and head trauma from a motorcycle accident.

Supplemental Oxygen

Because hypoxemia is associated with both LTB and epiglottitis, supplemental oxygen is required (see Oxygen Therapy Protocol, Protocol 9-1).

Cool Aerosol Mist

Cool aerosol mist therapy (with oxygen) either by face mask or tent is the primary mode of treatment for LTB. It liquefies thick secretions and cools and reduces subglottic edema. Generations of mothers have learned this homespun therapy, and it usually (although not always) works. Warm aerosols also are often effective.

Racemic Epinephrine (MicroNefrin, Vaponefrin)

Aerosolized racemic epinephrine (MicroNefrin, Vaponefrin) usually is administered to children with LTB. This adrenergic agent is used for its mucosal vasoconstriction and is recognized as an effective and safe aerosol decongestant (see Aerosolized Medication Protocol, Protocol 9-4).

Corticosteroids

Corticosteroids have been shown to reduce the severity and duration of LTB. They generally are prescribed when the patient does not respond to cool mist and racemic epinephrine therapy (see Appendix II).

Antibiotic Therapy

Because acute epiglottitis almost always is caused by H. influenzae type B, appropriate antibiotic therapy should be part of the treatment plan. Ampicillin and chloramphenicol often are prescribed to cover the most common organisms that cause acute epiglottitis.

Endotracheal Intubation or Tracheostomy

In the patient with a suspected acute epiglottis, the examination or inspection of the pharyngeal and laryngeal areas is only to be performed in the operating room with a trained surgical team in attendance. This is because the epiglottis may obstruct completely in response to even the slightest touch during inspection. The physician, nurse, and respiratory care practitioner should not leave the patient’s bedside until the endotracheal tube is secured. If the patient is anxious, restless, or uncooperative, restraints and sedation may be needed to prevent accidental extubation. After intubation, the patient should be transferred to the intensive care unit (ICU) and placed on continuous positive airway pressure (CPAP).

Respiratory Assessment and Plan

Over the next 8 hours, the patient progressively improved. At his discharge the next morning, the patient’s mother was instructed in home treatment of LTB, using aerosolized racemic epinephrine prn.

Discussion

Home remedies sometimes do work. Any parent who has had a child with LTB will find this scenario familiar. What may not be as widely recognized is that sometimes warm and sometimes cool aerosols improve this syndrome. When this approach failed, the parents were wise to bring their son to the emergency department for prompt vasoconstrictive therapy accompanied by a cool mist aerosol. This resulted in prompt improvement. In most pediatric units, decongestant aerosol therapy and mist inhalation are part of the Aerosolized Medication Protocol (see Protocol 9-4). Note the emphasis on family education, including the prn use of racemic epinephrine aerosolization for outpatients. These instructions may have kept the patient from ever returning again to the emergency department to be treated for such an episode.

Respiratory Assessment and Plan

While the emergency page for the anesthesiologist and the ENT surgeon went out, a nonrebreathing oxygen mask was immediately “lightly” held to the child’s face by the respiratory therapist. As soon as the physicians arrived (after about 10 minutes), the child was taken to the operating room. The surgeon stood by to perform an emergency cricothyrotomy while the anesthesiologist attempted to intubate the child.

Fortunately, the anesthesiologist was successful in spite of an enlarged, cherry-red epiglottis partially obstructing the larynx. As soon as the endotracheal tube was in place, the child relaxed and soon went to sleep. She was admitted to the intensive care unit (ICU), sedated, and placed on +5 cm H₂O continuous positive airway pressure (CPAP). She was extubated the next day and discharged on the third hospital day. A throat culture taken in the ICU was positive for H. influenzae type B. She was treated orally with amoxicillin.

Discussion

Acute epiglottitis is a life-threatening condition. The key point to remember is to refrain from examining the throat until a staff member qualified in pediatric intubation is nearby. Such manipulation often is unsuccessful, and unless qualified assistance is at hand, the child may asphyxiate. The treatment suitably selected here was placement of a nonrebreathing oxygen mask while the appropriate team was assembled. Typical of this disease is its abrupt onset and, under appropriate therapy, the rapid manner in which it subsides.