Section 6 Respiratory
6.1 Upper respiratory tract
Introduction
Urgent conditions requiring immediate attention or intervention are those likely to compromise the airway. Protection and maintenance of airway, breathing and circulation (the ABCs) take precedence over history taking, detailed examination or investigations. Possible causes of airway obstruction are listed in Table 6.1.1.
Triage and initial evaluation
Symptoms and signs of airway obstruction include dyspnoea, stridor, altered voice, dysphonia and dysphagia. Evidence of increased work of breathing includes subcostal, intercostal and suprasternal retraction, flaring of the nasal alae, as well as exhaustion and altered mental state. The presence of these signs may vary with age and accompanying conditions. Cyanosis is a late sign. Further examination will be directed by the presenting complaint and initial findings and includes:
Upper airway obstruction
Obstruction may be physiological, with the patient unable to maintain and protect an adequate airway owing to a reduced conscious state. Mechanical obstruction may be due to pathology within the lumen (aspirated foreign body), in the wall (angioedema, tracheomalacia) or to extrinsic compression (Ludwig’s angina, haematoma, external burns). Obstruction may be due to a combination of physiological and mechanical causes. A summary of potential causes of upper airway obstruction is provided in Table 6.1.1. Despite the plethora of possible causes, the initial treatment to secure the airway is the same.
Investigation
Imaging
Neck X-rays
A lateral soft tissue X-ray of the neck is sometimes helpful once the patient has been stabilized. Metallic or bony foreign bodies, food boluses or soft tissue masses may be seen. A number of subtle radiological signs have been described in epiglottitis (Table 6.1.2).
The ‘thumb’ sign | Oedema of the normally leaf-like epiglottis resulting in a round shadow resembling an adult thumb. The width of the epiglottis should be less than one-third the anteroposterior width of C4. |
The vallecula sign | Progressive epiglottic oedema resulting in narrowing of the vallecula. This normally well-defined air pocket between the base of the tongue and the epiglottis may be partially or completely obliterated. |
Swelling of the aryepiglottic folds | |
Swelling of the arytenoids | |
Prevertebral soft tissue swelling | The width of the prevertebral soft tissue should be less than half the anteroposterior width of C4. |
Hypopharyngeal airway widening | The ratio of the width of the hypopharyngeal airway to the anteroposterior width of C4 should be less than 1.5. |
Computed tomography
In the patient with a mechanical obstruction a computed tomography (CT) scan of the neck and upper thorax may be helpful in diagnosing the cause of the obstruction as well as the extent of any local involvement. It may aid in planning further management, especially if surgical intervention is indicated, for example for a retrothyroid goitre or a head and neck neoplasm.
Trauma
Penetrating trauma
Clinical
Penetration of the airway should be suspected if there is difficulty breathing, a change in voice, pain on speaking, subcutaneous emphysema or bubbling from the wound. This is often associated with great vessel or pulmonary injuries, and the patient may require an emergency airway procedure. Uncontrolled haemorrhage is a potentially life-threatening condition. Other causes include head and neck malignancies eroding vascular structures, or following radiotherapy. Uncontrolled haemorrhage may lead to exsanguination as well as compromising the airway, and requires prompt surgical intervention.
Investigations
Endoscopy
Endoscopy includes both laryngoscopy and bronchoscopy, performed in the operating theatre, as urgent surgical intervention may be required. Fuhrman et al. (see Further reading) suggest a classification system for the severity of blunt upper airway injury based on endoscopic and radiological findings (Table 6.1.3).
Grade | Endoscopic and radiological findings |
---|---|
I | Minor laryngeal haematoma without detectable fracture |
II | Oedema, haematoma or minor mucosal disruption without exposed cartilage, or non-displaced fractures on CT |
III | Massive oedema, tears, exposed cartilage, immobile cords |
Infections
Non-specific upper airway infections
Pharyngitis/tonsillitis
Sore throat is one of the top 10 presenting complaints to EDs in the USA. The differential diagnosis is large and includes a number of important conditions (Table 6.1.4). Pharyngitis has a wide range of causative bacterial and viral agents, most of which produce a self-limited infection with no significant sequelae. The major role for antibiotics in treating pharyngitis is for suspected group A β-haemolytic streptococcal infection (GABHS) or Streptococcus pyogenes. Timely use of appropriate antibiotics reduces the duration of symptoms by an average of 8 hours but increases the rate of adverse effects. Antibiotic use also reduces the incidence of suppurative complications such as otitis media, quinsy and retropharyngeal abscess. If given in the first 9 days they prevent the development of acute rheumatic fever. Antibiotics have not been shown to reduce the incidence of post-streptococcal glomerulonephritis, which is related to the subtype of streptococcus. Antibiotic therapy is also recommended for patients from the following groups: patients with scarlet fever, with known rheumatic heart disease, or from populations with high incidence of acute rheumatic fever, including some Aboriginal populations in Central and Northern Australia.
Infective pharyngitis |
Other abscesses
Parapharyngeal abscesses involve the lateral or pharyngomaxillary space. Presentation and treatment are similar to those of Ludwig’s angina, from which they may develop. As well as the complications of Ludwig’s angina, including airway obstruction and spread to contiguous areas, there is the added risk of internal jugular vein thrombosis and erosion of the carotid artery, which has a mortality of 20–40%.
Epiglottitis
Sore throat and odynophagia are the most common presenting symptoms. Drooling and stridor are infrequent. Factors shown to be associated with an increased risk of airway obstruction include stridor, dyspnoea, sitting upright, and short duration of symptoms. A number of X-ray changes have been described in epiglottitis, which are listed in Table 6.1.2. Management requires admission and i.v. ceftriaxone or cefotaxime. The role of steroids and nebulized or parenteral epinephrine (adrenaline) is controversial. Chloramphenicol may be used in patients with cephalosporin sensitivity. Most adults can be treated conservatively without the need for an artificial airway.
Alcaide ML, Bisno AL. Pharyngitis and epiglottitis. Infectious Disease Clinics of North America. 2007;21:449-469.
American Heart Association. Guidelines for cardiopulmonary resuscitation and emergency cardiac care. Circulation. 112, 2005. Supplement
Ames WA, Ward WMM, Tranter RMD, et al. Adult epiglottitis: an under-recognized, life-threatening condition. British Journal of Anaesthesia. 2000;85:795-797.
Atkins BZ, Abbate S, Fischer S, et al. Current management of laryngotracheal trauma: case report and literature review. Journal of Trauma. 2004;56:185-190.
Atkins BZ, Abbate S, Fischer S, et al. Current management of laryngotracheal trauma: case report and literature review. Journal of Trauma. 2004;56:185-190.
Bisno AL, Gerber MA, Gwaltney JM, et al. Infectious Diseases Society of America. Practice guidelines for the diagnosis and management of group A streptococcal pharyngitis. Clinical Infectious Disease. 2002;35:113.
Centor RM, Witherspoon JM, Dalton HP, et al. The diagnosis of strep throat in adults in the emergency room. Medical Decision Making. 1981;1:239-246.
Cicala RS. The traumatized airway. In: Benumof JE, editor. Airway management: principles and practice. Mosby-Year Book: St Louis; 1996:736.
Cooper RJ, Hoffman JR, Bartlett JG, et al. Principles of appropriate antibiotic use for acute pharyngitis in adults: Background. Annals of Internal Medicine. 2001;134:509-517.
Del Mar CB, Glasziou PP, Spinks AB. Antibiotics for sore throat. Cochrane Database of Systematic Reviews. (4):2006. CD000023. DOI: 10.1002/14651858.CD000023.pub3. Accessed December 2007
Fuhrman GM, Stieg FH, Buerk CA. Blunt laryngeal trauma: Classification and management protocol. Journal of Trauma. 1990;30:87-92.
Frantz TD, Rasgon BM, Quesenberry CP. Acute epiglottitis in adults. Journal of the American Medical Association. 1994;272:1358-1360.
Gonzales R, Bartlett JG, Besseer RE, et al. Principles of appropriate antibiotic use for treatment of acute respiratory tract infections in adults: Background, specific aims, and methods. Annals of Emergency Medicine. 2001;37:690-697.
Gonzales R, Bartlett JG, Besser RE, et al. Principles of appropriate antibiotic use for treatment of nonspecific upper respiratory tract infections in adults: Background. Annals of Emergency Medicine. 2001;37:698-702.
Gonzales R, Steiner JF, Sande MA. Antibiotic prescribing for adults with colds, upper respiratory tract infections and bronchitis by ambulatory care physicians. Journal of the American Medical Association. 1997;278:901-904.
Howes DS, Dowling PJ. Triage and initial evaluation of the oral facial emergency. Emergency Medicine Clinics of North America: Oral-Facial Emergencies. 2000;8:371-378.
Hurley MC, Heran MKS. Imaging studies for head and neck infections. Infectious Disease Clinics of North America. 2007;21:305-353.
Linder JA, Chan JC, Bates DW. Evaluation and treatment of pharyngitis in primary care practice: the difference between guidelines is largely academic. Archives of Internal Medicine. 2006;166:1374-1379.
McCollough M. Update on emerging infections from the centers for disease control and prevention: commentary. Annals of Emergency Medicine. 1999;34:110-111.
Minard G, Kodak KA, Croce MA, et al. Laryngotracheal trauma. American Surgeon. 1992;58:181-187.
Nemzek WR, Katzberg RW, Van Slyke MA, et al. A reappraisal of the radiologic findings of acute inflammation of the epiglottis and supraglottic structures in adults. American Journal of Neuro Radiology. 1995;16:495-502.
Richardson MA. Sore throat, tonsillitis, and adenoiditis. Medical Clinics of North America: Otolaryngology for the Internist. 1999;83:75-84.
Schamp S, Pokieser P, Danzer M, et al. Radiological findings in acute adult epiglottitis. European Radiology. 1999;9:1629-1631.
Scott PMJ, Loftus WK, Kew J, et al. Diagnosis of peritonsillar infections: a prospective study of ultrasound, computerized tomography and clinical diagnosis. Journal of Laryngology and Otology. 1999;113:229-232.
Stewart MH, Siff JE, Cydulka RK. Evaluation of the patient with sore throat, earache, and sinusitis: an evidence based approach. Emergency Medicine Clinics of North America: Evidence Based Emergency Medicine. 1999;17:153-188.
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Thierbach AR, Lipp MDW. Airway management in trauma patients. Anesthesiology Clinics of North America. 1999;17:63-82.
Victorian Medical Postgraduate Foundation. Therapeutic Guidelines: Antibiotic Version 12, 2006.
6.2 Asthma
Pathophysiology
Pathophysiologically the effects of acute asthma are:
There is increasing evidence that there are different phenotypes of both acute and chronic asthma. For acute asthma, a rapid onset may be closer to anaphylaxis in pathology, with minimal inflammation, and may respond more quickly to treatment.