Infectious etiologies represent relatively common causes of upper airway obstructing lesions. Ludwig angina is an infection of the submandibular space.9 The source of infection is usually a second or third mandibular molar tooth, with causative organisms representing typical oral flora: streptococci, staphylococci, and anaerobes. Gram-negative organisms should be considered as potential etiologies in patients with altered oral flora, such as immunocompromised patients and recipients of broad-spectrum antibiotics. Airway obstruction may result from elevation and posterior displacement of the tongue and supraglottic edema. The infection may extend to the lateral and retropharyngeal spaces, and subsequently along the carotid sheath and to the mediastinum.
Affected patients present with dysphagia, neck swelling (“bull neck”) and stiffness, trismus, drooling, and brawny induration of the floor of the mouth. Occasionally, crepitus of the submandibular area is present. Tooth pain or a history of recent tooth extraction is usual, but not invariable. While not all patients with Ludwig angina need to undergo endotracheal intubation or tracheostomy, the decision to observe the airway rather than secure it should not be made lightly, and should be made after consultation with an otolaryngologist. If intubation is deemed necessary, placement via a flexible fiberoptic approach may be useful in decreasing the risk of laryngospasm during the procedure. Treatment consists of antibiotic therapy, and in some patients, surgical drainage. Obviously, any infected teeth should be extracted.
Lymphatic drainage from the oropharynx, teeth, maxillary sinuses, and ears passes through the retropharyngeal space, predisposing it to infections from the ear, nose, and throat.10 While the space itself contains no vital structures, infection may extend into the mediastinum or epidural space, or provoke atlantoaxial dislocation. Whereas this condition usually follows an upper respiratory tract infection, pharyngitis, or otitis media in children, in adults the more common antecedent problems are odontogenic infection or procedures, or oral trauma. Patients present with throat and neck pain, and may have drooling or symptoms of upper airway obstruction. On occasion, infection may spread to the retropharyngeal space from the prevertebral space, such as with tuberculosis of the spine (Pott disease). The diagnosis may be made through a lateral neck radiograph; however, CT is advisable for helping define the boundaries of infection. Importantly, physical examination may fail to reveal any posterior pharyngeal swelling, highlighting the need for a high index of suspicion for this condition and further investigation via endoscopy or imaging. Treatment consists of antibiotics directed at oral flora (streptococci, staphylococci, anaerobes, and in some patients, gram-negative organisms), airway stabilization, and surgical exploration.
Because the lateral pharyngeal space is bounded by the retropharyngeal and submandibular spaces, it serves as a means of transmitting infections from diverse sources, as suggested previously. Again, infections in this space are typically treated with a combination of antibiotics and surgical drainage.
Peritonsillar abscesses are located between the tonsil and the superior constrictor muscle of the pharynx. Affected patients are typically young adults and have a history of prior tonsillitis; not surprisingly, Streptococcus species are most commonly isolated, along with other oral organisms. Presenting symptoms include sore throat, trismus, and voice change. Despite the prevalence of this disorder, there are several aspects of management that remain controversial.11 While steroids are occasionally administered to patients with peritonsillar abscess, there are no studies to support or refute their efficacy. Both needle aspiration and open abscess drainage with tonsillectomy (“quinsy tonsillectomy”) have been advocated as initial treatment, and both are effective. Complications include UAO and rarely, thrombophlebitis of the internal jugular vein, a condition known as Lemierre syndrome. This condition is usually associated with Fusobacterium necrophorum, but other oral flora may be responsible. Bacteremia and septic emboli may result. The role of anticoagulation in Lemierre syndrome is controversial.
Occasionally, tonsillar enlargement from infectious mononucleosis may be so significant as to obstruct the airway. Management consists of close observation of the airway in a monitored setting, and the administration of corticosteroids.
Angioedema from a variety of causes can involve the tongue and hypopharynx and threaten airway patency both above and at the level of the larynx. This disorder is discussed below along with other disorders of the larynx. Stevens-Johnson syndrome and toxic epidermal necrolysis are rare vesiculobullous diseases that involve the skin and mucous membranes. Affected patients may develop bullae and edema of the upper airway mucosa, leading to obstruction. Causes typically include medications (with antibiotics, nonsteroidal anti-inflammatory medications, and anticonvulsants frequently being implicated), infections, and malignancies. Depending on their location, facial fractures may lead to UAO through local swelling and a loss of support for the tongue and/or facial skeleton. While oral neoplasms are common, patients typically present for evaluation before the airway can be compromised. Obstructive sleep apnea is a form of chronic UAO that is exhibited only during sleep, and is considered in greater detail in Chap. 109.
Supraglottitis, or infection of the supraglottic portion of the larynx, may cause life-threatening UAO primarily through involvement of the epiglottis. Vaccination against Haemophilus influenzae has successfully decreased the number of cases of epiglottitis in children caused by this organism. As a result, adults comprise a greater proportion of all cases of epiglottitis. In addition to H. influenzae, Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus parainfluenzae, and anaerobes all have been implicated as causes of epiglottitis. Because most physicians who treat adults will work a lifetime without seeing a single patient with the acute onset of sore throat go on to develop UAO, the diagnosis may be missed. The classic presentation is that of a patient sitting upright and leaning forward, drooling; however, these signs may not be present initially. An additional clue is the rapid onset and severity of odynophagia. Signs of toxicity, such as fever and tachycardia, may be present. Otolaryngology and anesthesiology consultation should be obtained if the diagnosis is suspected, while an oral examination should be performed extremely carefully, if at all. The approach to diagnosis depends on the patient's overall clinical status. While lateral films of the neck may reveal the diagnosis, a negative examination does not exclude epiglottitis. A fiberoptic examination can often be performed carefully via the nasopharyngeal route, but should be performed only by a person experienced in treating this problem, preferably a seasoned otolaryngologist or anesthesiologist. Visualization of a swollen, cherry-red epiglottis confirms the diagnosis. This examination is preferentially performed in the operating room, or at a minimum with all necessary airway personnel and equipment available. Although many adults with epiglottitis may be managed with antibiotics and observation in the ICU, the potential for acute airway obstruction should always be considered to be extremely high.12,13 A tracheostomy tray should be at the bedside, and all relevant airway personnel—anesthesia as well as otolaryngology—should be alerted to the patient's condition and location. At no time should the patient be sent unaccompanied to another location in the hospital. While blood cultures may on occasion reveal the etiology, in most cases the specific organism is not identified, and antibiotic treatment is empirical. The response to treatment is typically prompt.
Infections of the larynx may be caused by viruses, bacteria, or fungi. Laryngotracheitis in children (croup) is usually caused by a viral infection, and UAO may result. While viral infections of the larynx are rarely serious in adults, bacterial laryngotracheitis can be life-threatening. Because the causative organisms include Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae, pneumonia may be present as well. Corynebacterium diphtheriae should always be considered in the differential diagnosis despite the relative infrequency with which it is currently encountered in the United States. In particular, nonimmunized persons and those individuals who have not received a booster in the past 10 years are at risk. Diphtheria is also more frequently encountered in communities with low immunization rates, as in some Native American communities. Diphtheria commonly presents initially as tonsillitis and pharyngitis. Subsequent spread inferiorly may cause laryngitis, although occasionally the larynx is the only site of involvement. Clinical manifestations include fever, sore throat, malaise, headache, and vomiting. Physical examination may reveal a tenacious gray or black membrane overlying involved sites, and cervical lymphadenopathy may be present. Delays in treatment increase the likelihood of systemic complications from circulating toxin, such as myocarditis, neuritis, and nephritis. Death occurs in 5% to 10% of cases, either from systemic effects of diphtheria toxin or from UAO, the latter occurring more commonly in infants. Treatment includes antibiotics and equine antitoxin, which can be obtained through the Centers for Disease Control and Prevention. Sensitivity to horse serum should be assessed prior to administration of the antitoxin, and desensitization should be performed as necessary. Because infection does not ensure immunity, immunization is indicated after recovery.14
Fungal laryngotracheitis may be caused by Candida albicans, histoplasmosis, blastomycosis, and coccidioidomycosis. In addition to fever and sore throat, affected patients may develop dyspnea and voice change from vocal cord nodules and/or vocal cord fixation. The diagnostic approach depends on the presentation, as other sites of involvement—for example, pulmonary infiltrates—may be present. Respiratory papillomatosis is caused by human papillomavirus types 6 and 11, and is manifested by multiple—sometimes innumerable—papules in the larynx and trachea.
Iatrogenic and Traumatic Causes
Related to Endotracheal Intubation
A variety of upper airway problems can follow endotracheal intubation and are listed in Table 34-1. Several of these problems merit further discussion here. Laryngospasm consists of uncontrolled glottic closure, and respiratory distress with inability to ventilate the patient may result. It can be provoked by a variety of stimuli, including stimulation of the glottic aperture and/or superior laryngeal nerve during intubation, medications including general anesthetics and opioids, and the presence of secretions or blood in the upper airway. Careful suctioning of the mouth and endotracheal tube prior to extubation may reduce the likelihood of laryngospasm after extubation, in addition to improving pulmonary toilet. When laryngospasm occurs, gentle mask ventilation with 100% oxygen should be performed. If the laryngospasm fails to break and ventilation is not possible, the short-acting paralytic succinylcholine may be administered followed by mask ventilation or endotracheal intubation. It should be emphasized that in the ICU, laryngeal edema is a much more likely cause of postextubation stridor than laryngospasm.
Table 34–1. Upper Airway Disorders Related to Endotracheal Intubation ||Download (.pdf)
Table 34–1. Upper Airway Disorders Related to Endotracheal Intubation
- Related to insertion
- Epistaxis (with nasotracheal intubation)
- Tooth avulsion and aspiration
- Hypopharyngeal trauma
- Laryngospasm (either from airway manipulation or medications)
- Laryngeal trauma
- Mucosal trauma
- Vocal cord paralysis and/or arytenoid dislocation
- Related to long-term intubation
- Endotracheal tube obstruction from secretions or kinking
- Vocal cord injury: edema, ulceration, granuloma, and paralysis possible
- Laryngomalacia from ischemic cuff injury
- Subglottic stenosis
- Tracheal stenosis
- Related to extubation
- Excess secretions
- Residual sedation
- Previous undiagnosed laryngeal edema or other upper airway injury or disorder
Long-term endotracheal intubation may cause a variety of injuries to the upper airway. Fortunately, current endotracheal tube cuffs have a higher volume and lower pressure than were used a number of years ago, decreasing problems related to long-term intubation. Whether or not an individual patient will develop subglottic or tracheal stenosis is difficult to predict. While duration of intubation has been shown in some studies to be correlated with laryngeal or tracheal stenosis, the relationship is not strong. Similarly, while increased tube caliber, frequency of insertion, the severity of respiratory failure, female gender, and the presence of diabetes or immunocompromise have all been suggested as exacerbating factors, the data on this topic are inconsistent.1 The decision to perform a tracheostomy therefore depends on the expected duration of need for an artificial airway, and the extent to which conversion to tracheostomy will facilitate other aspects of care; for example, liberation from mechanical ventilation, or recovery from more proximal upper airway injury or toxic therapy (e.g., surgery or irradiation for neoplasm). In general, the usual recommendation of considering tracheostomy for all patients intubated for 2 to 3 weeks who are not likely to recover soon is a prudent one. As mentioned previously, possibility of subglottic or tracheal stenosis should be considered when encountering breathless patients who have undergone long-term intubation previously. In such cases, the diagnosis of UAO may easily be overlooked. Voice change and stridor are clues to the diagnosis. CT of the upper airway with three-dimensional reconstruction can be very useful in such cases, if patient stability permits.
Endotracheal tube obstruction from secretions may be an insidious cause of UAO that may progress occasionally to a circumstance in which ventilation becomes impossible. Its occurrence may be prevented through frequent suctioning. The development of obstructed respiratory system mechanics—a high peak to plateau airway pressure gradient—in a patient without a history of obstructive lung disease, or in the absence of wheezing, suggests the diagnosis. While difficulty passing a suction catheter is highly suggestive, we have removed endotracheal tubes that are nearly completely occluded through which a suction catheter was able to be passed. If time permits, bronchoscopic examination quickly establishes the diagnosis. Chap. 36 outlines the approach to high peak airway pressures in further detail; here, we stress that prompt removal of the endotracheal tube, with manual mask ventilation of the patient while awaiting reintubation, can be lifesaving.
Stridor has been reported to occur following 2% to 16% of extubations in the ICU, with laryngeal edema most frequently responsible.15 Limited investigations in adults do not support the prophylactic administration of corticosteroids in order to reduce the incidence of reintubation.16 Even if corticosteroids are effective at reducing laryngeal edema, the low incidence of reintubation for this disorder in adults means that an extraordinary number of patients would have to be treated in order to demonstrate a benefit in reducing this occurrence. For this reason, a randomized controlled trial of corticosteroids to treat patients with postextubation stridor is not likely to be performed. Our practice is to administer a short (48 hours) course of parenteral corticosteroids such as dexamethasone in such cases. More important is notification of relevant airway personnel and close observation; aerosolized racemic epinephrine may be useful in decreasing laryngeal edema through local vasoconstriction.
Aspirated foreign bodies lodge in the upper airway much less commonly in adults than in children.17 Still, asphyxiation may follow foreign body aspiration in adults, while large objects aspirated into the esophagus can occasionally obstruct the upper airway. Risk factors in adults include diminished level of consciousness; impaired swallowing mechanism or diminished upper airway sensation as a result of neuromuscular disorder, prior cerebrovascular accident, or advanced age; and inability to chew food properly because of poor dentition. Food particles and medical or dental appliances are most frequently aspirated. Symptoms include cough and dyspnea, and stridor may be present. Chest radiography or lateral films of the neck may reveal the diagnosis. In the case of impending respiratory arrest, the Heimlich maneuver may be lifesaving. Otherwise, the patient should undergo endoscopy in most cases with a rigid endoscope. Flexible fiberoptic endoscopy is generally inadvisable for foreign body removal because the airway cannot be protected if the object lodges in the glottis during removal; however, experienced operators may elect to attempt removal in carefully selected patients.
Upper airway injury may result from inhalation of toxic chemicals, or more commonly from thermal injury. Upper airway burn injury should be suspected whenever a patient has survived a fire or explosion in an enclosed space, and when chemicals or plastics have burned. Physical examination findings that suggest the presence of upper airway injury include the presence of burns or soot on the face, singed nasal hairs, erythema of the oropharynx, and hoarse voice. Sometimes the external signs are relatively mild despite significant inhalation injury. Thus any patient suspected of incurring inhalation injury should undergo fiberoptic laryngoscopy. Affected patients may experience life-threatening UAO from airway edema and mucosal sloughing anytime from initial presentation to 24 hours later. In addition, upper airway edema may be exacerbated by the considerable amount of fluids required to resuscitate patients with extensive burns.18 When the airway needs to be secured, endotracheal intubation is preferred over tracheostomy because of the higher incidence of tracheal stenosis associated with the latter therapy when performed in burn patients. Because corticosteroids increase the incidence of infectious complications and may increase mortality when administered to burn patients, we do not recommend their use here.
Traumatic neck injury may directly injure the larynx.7 Such an injury should be suspected whenever there are ecchymoses or tenderness over the thyroid or cricoid cartilages. In addition to pain, patients may have stridor, hoarseness, and hemoptysis. Cervical spine injury should be excluded, while endotracheal intubation must be done with care to avoid exacerbating any existing injury. Stabilization of the neck and avoidance of neck extension during airway manipulation are mandatory. In a crisis, tracheostomy may be necessary to establish an airway. The evaluation and treatment of laryngeal injury is beyond the scope of this review.
There are a number of iatrogenic causes of UAO. A hematoma in the neck may cause UAO through direct compression, as may rarely occur following surgery. Inadvertent carotid artery puncture during central line placement may cause a rapidly expanding hematoma with airway compromise, particularly if the patient has a bleeding diathesis. Recurrent laryngeal nerve injury may occur during neck dissection or cardiac surgery and cause vocal cord paralysis. While unilateral vocal cord paralysis does not by itself embarrass respiration because the contralateral cord has full mobility, bilateral vocal cord paralysis typically requires surgery.
Functional UAO may result from abnormal closure of the vocal cords during inspiration, expiration, or both. Affected patients often have a history of frequent treatment for severe “asthma” exacerbations, at times even undergoing intubation. We have witnessed patients with this condition who exhibit significant pulsus paradoxus and respiratory acidosis during attacks mimicking status asthmaticus. Physical examination is revealing in that stridor is heard. If the patient is intubated, the respiratory system mechanics are normal, and wheezing is not heard. Complicating the diagnosis is the fact that a significant portion of patients with this condition also have asthma, which may be severe.19 Spirometry may show flattening of the inspiratory limb of the flow volume loop, indicating a variable extrathoracic obstruction. The diagnosis is confirmed when laryngoscopy reveals abnormal vocal cord closure, particularly during inspiration. Unfortunately, laryngoscopy may be normal, particularly between attacks, and frequently the diagnosis must be made on clinical grounds. While psychiatric disorders and a history of abuse have been reported to be present in a number of cases, these findings are not invariable, and a loss of regulation of normal reflexes controlling the laryngeal muscles has been postulated.20 Treatment involves speech therapy and treatment of any underlying psychiatric disorder.
Neoplasms are important causes of laryngeal obstruction, with squamous cell carcinoma being the most common malignancy of the larynx. Risk factors include tobacco and alcohol use, and patients may present with hoarseness or hemoptysis.21 The diagnosis is typically established through a combination of direct visualization and CT. The evaluation and management of tumors of the head and neck is beyond the scope of this review.
As mentioned previously, bilateral vocal cord paralysis invariably results in UAO, although the presentation is often delayed.22 Previous thyroidectomy is often responsible for the condition, although malignancy, neck irradiation, neck trauma, and prior intubation are additional causes.
Several systemic diseases are associated with upper airway obstructing lesions.23 Airway involvement in Wegener granulomatosis is common, although frequently subclinical. Manifestations include ulcerations, mass lesions from proliferating granulation tissue, and circumferential narrowing, particularly in the subglottic region. Treatment typically involves a combination of immunosuppression—usually prednisone and cyclophosphamide—and surgery. Tracheostomy is frequently necessary when subglottic stenosis is severe.
Rheumatoid arthritis presents several potential problems where the upper airway is concerned. Arthritis of the temporomandibular joint may limit the degree to which the mouth can be opened, frustrating attempts at oral intubation. Cervical spine arthritis, particularly of the atlantoaxial joint, should be considered a serious impediment to manipulation of the cervical spine. In particular, neck extension may lead to catastrophic cervical spinal cord injury when significant atlantoaxial disease is present. When patients with rheumatoid arthritis develop hoarseness, vocal cord nodules or cricoarytenoiditis are frequently responsible. The latter is often associated with significant pain. Over time, the vocal cords may fuse in the midline.24 While treatment with systemic and intralesional corticosteroids is the rule, surgical removal of the arytenoids or tracheostomy may be necessary. Of note, cricoarytenoiditis occurs infrequently in patients with systemic lupus erythematosus, although in affected patients the presentation is more acute, and the response to steroid therapy is more gratifying.25
While pulmonary involvement in sarcoidosis is extremely common, laryngeal disease is relatively rare. When present, it is usually the supraglottic region that is affected, and on occasion upper airway patency may be threatened. Treatment includes a combination of intralesional and systemic steroids. Relapsing polychondritis is manifest as recurrent inflammation of the cartilages of the ears, nose, larynx, trachea, and joints. Half of affected patients have respiratory tract involvement. UAO may result initially from airway edema, subsequently from increased collapsibility from dissolution of cartilage, and later from fibrosis and fixed stenosis. Amyloidosis affecting the larynx and trachea is rare, and presents as firm nodules that may coalesce and cause UAO.
Angioedema is a typically intense, painless swelling of a localized body area caused by leakage of plasma into the affected tissues, and preferentially involving the face, tongue, larynx, gastrointestinal tract, and extremities. Except in the case of angiotensin-converting enzyme inhibitor–associated angioedema, this leakage typically derives either from mast cell–stimulated histamine release or from activation of the complement system. Mast cell histamine release may occur following IgE-mediated hypersensitivity reactions such as those due to severe food allergies, as well as in response to certain substances—such as codeine, aspirin, and iodinated contrast media—that directly stimulate histamine release. Treatment of histamine-mediated angioedema includes histamine blockade (both H1- and H2-receptor blockers are given), corticosteroids, and if the airway is compromised or hemodynamic instability is present, epinephrine.
There are several diseases of the complement cascade that result in angioedema. They can be generally classified according to whether they are hereditary or acquired. Hereditary angioedema (HAE) is an autosomal dominant disease characterized by recurrent episodes of angioedema of the skin, upper airway, and gastrointestinal tract.26 Attacks may be provoked by dental surgery or general anesthesia. Type I HAE is the most common form and is caused by decreased production of C1 esterase inhibitor. Patients with type II HAE have functionally impaired C1 esterase inhibitors. Corticosteroids, antihistamines, and epinephrine are generally considered to be ineffective in acute attacks in patients with HAE, but should not be withheld until the diagnosis is secured. Purified C1 esterase inhibitor concentrate seems to be both effective and safe in treating exacerbations of HAE, but is not widely available outside of Europe.27 Fresh frozen plasma infusion may be considered as a means of administering C1 esterase inhibitor, but carries the potential risk of paradoxical worsening of angioedema through C4-mediated tissue damage. Generally, this treatment is reserved as a means of preventing angioedema in patients undergoing major surgical or dental procedures, when C1 esterase inhibitor is not available. Attenuated androgens and antifibrinolytic agents are used as prophylactic therapy. Although the latter is somewhat less effective, they are useful alternatives to androgens in children.
Acquired angioedema (AAE) is associated with autoimmune disorders, lymphoproliferative diseases, various carcinomas, and a number of chronic infections such as those caused by human immunodeficiency virus and hepatitis B and C viruses. Affected patients have circulating antibodies directed either against specific immunoglobulins expressed on B cells or against C1 esterase inhibitor. There is some evidence that antihistamines, corticosteroids, and epinephrine are somewhat more effective in treating AAE than HAE.
Immunosuppressive therapy may prevent attacks by decreasing autoantibody production. Some patients respond to attenuated androgens, although usually not if antibodies to C1 esterase inhibitor are present. Antifibrinolytic agents may be tried if androgens are ineffective.
Some patients experience recurrent angioedema, yet have no known cause. Most such patients also have urticaria. The evaluation of these patients is beyond the scope of this review.
Angioedema occurs in a small fraction (0.1% to 0.5%) of patients receiving angiotensin-converting enzyme inhibitors (ACEIs). Still, because of the widespread use of these agents, a significant percentage of all cases of UAO are caused by ACEIs. Attacks typically occur shortly after initiation of therapy, but may occur years later. The angioedema seems to respond poorly if at all to treatment with corticosteroids, antihistamines, and epinephrine; although studies demonstrating the efficacy of these agents are lacking, they are frequently administered anyway. The pathophysiology is unclear; although accumulation of bradykinin has been implicated as the cause, the occurrence of angioedema in some patients who have been switched from ACE inhibitors to angiotensin receptor antagonists, which do not inhibit the catabolism of bradykinin, raises questions about the mechanisms by which each agent causes angioedema.28 We believe that angiotensin receptor antagonists should be used in patients who have had a prior episode of angioedema attributed to ACEI therapy only when there is no other reasonable alternative.