Page 589 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 47: Upper Airway Obstruction 409

cardiac surgery and cause vocal cord paralysis. While unilateral vocal While pulmonary involvement in sarcoidosis is extremely common,
cord paralysis does not by itself embarrass respiration because the con- laryngeal disease is relatively rare. When present, it is usually the supra-
tralateral cord has full mobility, bilateral vocal cord paralysis typically glottic region that is affected, and on occasion upper airway patency
requires surgery. may be threatened. Treatment includes a combination of intralesional
■ MISCELLANEOUS CAUSES and systemic steroids. Relapsing polychondritis is manifest as recurrent
inflammation of the cartilages of the ears, nose, larynx, trachea, and
Functional UAO may result from abnormal closure of the vocal cords joints. Half of affected patients have respiratory tract involvement. UAO
during inspiration, expiration, or both, a condition referred to as vocal may result initially from airway edema, subsequently from increased
cord dysfunction or paradoxical vocal fold motion. Affected patients collapsibility from dissolution of cartilage, and later from fibrosis and
often have a history of difficult-to-control asthma. We have witnessed fixed stenosis. Amyloidosis affecting the larynx and trachea is rare, and
patients with this condition who exhibit significant pulsus paradoxus presents as firm nodules that may coalesce and cause UAO.
and respiratory acidosis during attacks mimicking status asthmaticus. Angioedema: Angioedema is a typically intense, painless swelling of a
Physical examination is revealing in that stridor is heard. Similarly, localized body area caused by leakage of plasma into the affected tissues,
if the patient is intubated for this (unsuspected and isolated) condi- and preferentially involving the face, tongue, larynx, gastrointestinal
tion, the respiratory system mechanics are normal, and wheezing is tract, and extremities. Except in the case of angiotensin-converting
not heard. Complicating the diagnosis of vocal cord dysfunction is the enzyme inhibitor–associated angioedema, this leakage typically derives
fact that a significant portion of patients with this condition also have either from mast cell–stimulated histamine release or from activation of
asthma, which may be severe. Spirometry may show flattening of the the complement system. Mast cell histamine release may occur following
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inspiratory limb of the flow volume loop, indicating a variable extra- IgE-mediated hypersensitivity reactions such as those due to severe food
thoracic obstruction. The diagnosis is confirmed when laryngoscopy allergies, as well as in response to certain substances—such as codeine,
reveals abnormal vocal cord closure, particularly during inspiration. aspirin, and iodinated contrast media—that directly stimulate histamine
Unfortunately, both spirometry and laryngoscopy may be normal, par- release. Treatment of histamine-mediated angioedema includes hista-
ticularly between attacks, and frequently the diagnosis must be made mine blockade (both H - and H -receptor blockers are given), cortico-
2
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on clinical grounds. Potential triggers are numerous and include envi- steroids, and if the airway is compromised or hemodynamic instability
ronmental stimuli such as cold air, smoke, or fumes; gastroesophageal is present, epinephrine.
reflux; laryngopharyngeal reflux; exercise; and stressful situations and/ There are several diseases of the complement cascade that result in
or anxiety. A loss of regulation of normal reflexes controlling the laryn- angioedema. They can be generally classified according to whether they
geal muscles has been postulated. Treatment involves speech therapy are hereditary or acquired. Hereditary angioedema (HAE) is an auto-
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and treatment of any underlying triggers. It is increasingly recognized somal dominant disease characterized by recurrent episodes of angio-
that abnormal vocal cord function may complicate the course of many edema of the skin, upper airway, and gastrointestinal tract. Attacks
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patients with difficult-to-control asthma. 23 may be provoked by dental surgery, general anesthesia, or stress. The
Neoplasms are important causes of laryngeal obstruction, with squa- diagnosis should be considered in individuals with recurrent episodes of
mous cell carcinoma being the most common malignancy of the larynx. angioedema without urticaria, when there is a family history of angio-
Risk factors include tobacco and alcohol use, and patients may present edema, whenever unexplained laryngeal edema is present, or when there
with hoarseness or hemoptysis. The diagnosis is typically established is a history of recurrent nausea and vomiting of unexplained etiology.
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through a combination of direct visualization and CT. The evaluation Type I HAE is the most common form and is caused by decreased pro-
and management of tumors of the head and neck is beyond the scope duction of C1 esterase inhibitor. Patients with type II HAE have func-
of this review. tionally impaired C1 esterase inhibitors. Type III HAE is rare and occurs
As mentioned previously, bilateral vocal cord paralysis invariably only in women and is associated with normal C1 inhibitor levels and
results in UAO, although the presentation is often delayed. Previous thy- function. Corticosteroids, antihistamines, and epinephrine are generally
roidectomy is often responsible for the condition, although malignancy, considered to be ineffective in acute attacks in patients with HAE, but
neck irradiation, neck trauma, and prior intubation are additional causes. should not be withheld until the diagnosis is secured. This condition has
Several systemic diseases are associated with upper airway obstructing seen an increase in available therapies in recent years. Plasma derived C1
lesions. Airway involvement in Wegener granulomatosis is common, inhibitor is first-line therapy for acute attacks of angioedema, with many
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although frequently subclinical. Manifestations include ulcerations, decades of use in Europe establishing its efficacy and safety, and with the
mass lesions from proliferating granulation tissue, and circumferential preparation relatively recently becoming available in the United States.
narrowing, particularly in the subglottic region. Treatment typically There now exist two additional targeted therapies: ecallantide, an inhibi-
involves a combination of immunosuppression—usually prednisone and tor of kallikrein, and icatibant, a bradykinin receptor antagonist. 29,30
cyclophosphamide—and surgery. Tracheostomy is frequently necessary Rigorous data comparing these three therapies are lacking. Strategies for
when subglottic stenosis is severe. preventing attacks commonly involve attenuated androgens, antifibri-
Rheumatoid arthritis presents several potential problems where the nolytic agents, and C1 inhibitor therapy and vary depending on disease
upper airway is concerned. Arthritis of the temporomandibular joint severity and whether a provocative stimulus is anticipated. Solvent/
may limit the degree to which the mouth can be opened, frustrating detergent treated plasma or fresh frozen plasma may be considered prior
attempts at oral intubation. Cervical spine arthritis, particularly of to major procedures or intubation if plasma derived C1 inhibitor is not
the atlantoaxial joint, should be considered a serious impediment to available, but carry small theoretical risks of infection and paradoxical
manipulation of the cervical spine. In particular, neck extension may worsening of angioedema. Patients suspected to have HAE should be
lead to catastrophic cervical spinal cord injury when significant atlanto- referred to clinicians with experience in treating this condition.
axial disease is present. When patients with rheumatoid arthritis develop Acquired angioedema (AAE) is associated with autoimmune disor-
hoarseness, vocal cord nodules or cricoarytenoiditis are frequently ders, lymphoproliferative diseases, various carcinomas, and a number
responsible. The latter is often associated with significant pain. Over of chronic infections such as those caused by human immunodeficiency
time, the vocal cords may fuse in the midline. While treatment with virus and hepatitis B and C viruses. Affected patients have circulating
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systemic and intralesional corticosteroids is the rule, surgical removal of antibodies directed either against specific immunoglobulins expressed
the arytenoids or tracheostomy may be necessary. Of note, cricoaryte- on B cells or against C1 esterase inhibitor. Plasma-derived C1 inhibitor
noiditis occurs infrequently in patients with systemic lupus erythemato- has been shown to be efficacious in this condition but some patients
sus, although in affected patients the presentation is more acute, and the become unresponsive to this therapy over time. Some patients expe-
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response to steroid therapy is more gratifying. 27 rience recurrent angioedema, yet have no known cause. Most such

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