Upper respiratory tract - Clinical Tree

Essentials

1
Management of the airway, breathing and circulation (ABCs) takes precedence over the history, examination and specific treatment of upper airway obstruction.
2
Direct laryngoscopy can be an important technique for both the investigation and management of upper airway obstruction.
3
Chest thrusts and back blows can be useful first aid techniques in foreign-body upper airway obstruction.
4
Acute viral respiratory infections are a frequent reason for seeking medical attention. Over-prescribing of antibiotics continues to be a major problem.
5
Bacterial infections and collections are uncommon but may compromise the upper airway.
6
A high index of suspicion is needed to diagnose blunt trauma injuries to the larynx and trachea and potential associated injuries of the cervical spine.
7
The rates of adult supraglottitis are increasing and the clinical presentation may be nonspecific. Airway interventions are not usually needed.

Introduction

The upper respiratory tract extends from the mouth and nose to the carina. It comprises a small area anatomically but is of vital importance. The majority of presentations are not life threatening; however, those that are require immediate evaluation and treatment.

Emergent conditions are those likely to compromise the airway. Protection and maintenance of the ABCs take precedence over history taking, detailed examination or investigations. Non-urgent presentations include rash or facial swelling not involving the airway, sore throat in a non-toxic patient and complaints that have been present for days or weeks with no recent deterioration. Pharyngitis and tonsillitis are common causes for presentation in both paediatric and adult emergency practice.

Triage and initial evaluation

Initial evaluation is aimed at differentiating those patients needing urgent management to prevent significant morbidity and mortality from those needing less urgent treatment. Triage must be based on the chief complaint and on vital signs, since the same clinical presentation may result from a range of pathologies. For example, stridor can be due to trauma, infection, drug reactions or anatomical abnormalities such as tracheomalacia.

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. Cyanosis is a late sign. The spectrum of signs varies with age and accompanying conditions.

Further examination will be directed by the presenting complaint and initial findings and includes the following:

General appearance—facial symmetry, demeanour
Vital signs—temperature, heart rate, respiratory rate, blood pressure and pulse oximetry
Head and face—rash, swelling, mucous membranes, lymphadenopathy
Oropharynx—mucous membranes, dental hygiene, tongue, tonsils, uvula

Upper airway obstruction

Upper airway obstruction may be acute and life threatening or may have a more gradual onset. It is essential that the adequacy of the airway be assessed first. Any emergency interventions required to maintain the airway should be instituted before obtaining a detailed history and examination. This may range from relieving the obstruction to providing an alternative airway.

Pathology

Obstruction may be physiological, with the patient unable to maintain and protect an adequate airway due to a decreased conscious state. Despite the plethora of possible causes, the initial treatment of securing the airway is the same regardless of the cause. Mechanical obstruction may be due to pathology within the lumen (aspirated foreign body), in the wall (angio-oedema, tracheomalacia) or by extrinsic compression (Ludwig angina, haematoma, external burns). Obstruction may be due to a combination of physiological and mechanical causes. Possible causes of airway obstruction are listed in Box 6.1.1 .

Box 6.1.1

Causes of upper airway obstruction

Altered conscious state

Head injury
Cerebrovascular accident
Drugs and toxins
Metabolic—hypoglycaemia, hyponatraemia, etc.

Foreign bodies

Infections

Tonsillitis
Peritonsillar abscess (quinsy)
Epiglottitis
Ludwig angina
Other abscesses and infections

Trauma

Blunt or penetrating trauma resulting in oedema or haematoma formation
Uncontrolled haemorrhage
Thermal injuries
Inhalation burns

Neoplasms

Larynx, trachea, thyroid

Allergic reactions

Anaphylaxis
Angioedema

Anatomical

Tracheomalacia—congenital or acquired (secondary to prolonged intubation)
Other congenital malformations

Functional upper airway obstruction syndrome

Acute-on-chronic causes

Patients with chronic narrowing of the airway (e.g. due to tracheomalacia) may present with worsening obstruction from an acute upper respiratory tract illness or injury.

Clinical investigations

Investigations are secondary to the assessment and/or the provision of an adequate airway. Once the airway has been assessed as secure, the choice of investigations is directed by the history and examination.

Endoscopy

Direct laryngoscopy by an experienced operator is the single most important manoeuvre in patients with acute upper airway obstruction. It may concurrently form part of the assessment, investigation or treatment. By visualizing the laryngopharynx and upper larynx, the cause of the obstruction can be seen. Any foreign bodies may be removed or, if necessary, a definitive airway, such as an endotracheal tube, may be introduced. In the case of the stable patient with an incomplete obstruction, this should be attempted only when full facilities are available for intubation and the provision of a surgical airway. It may be more appropriately deferred until expert airway assistance is available.

Bronchoscopy may be required to assess the trachea and distal upper airway but it is not part of the initial resuscitation. If the patient is stable, it is more appropriate to transfer him or her to the operating suite or intensive care unit (ICU) for this procedure.

Blood tests

Some blood tests may be useful in guiding further management. These include a full blood count, blood gases and blood cultures. The tests required will be guided by the clinical presentation. Initial treatment in the emergency department should not await their results.

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 for supraglottitis ( Table 6.1.2 ).

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 and extent of the obstruction. It may aid in planning further management, especially if surgical intervention is indicated, for example, for a retrothyroid goitre or head and neck neoplasm. However, care should be taken to secure the airway in cases of impending obstruction prior to CT.

Treatment

Management initially consists of securing the airway. This is described in more detail elsewhere in this book, but simple interventions include chin lift or jaw thrust and an oropharyngeal airway. More sophisticated procedures—such as the laryngeal mask, endotracheal intubation (nasal or oral) or surgical airway—may be required.

A surgical airway is rarely necessary in the emergency department, although it is important that equipment be available and that the techniques are understood and have been practised. These include needle insufflation (oxygenation, not ventilation) and cricothyrotomy. A number of commercial kits are available; however, recent emphasis favours simple techniques such as ‘knife-finger-bougie’. Whatever technique is chosen, the key remains planning and practice. Further management will depend on the underlying pathology.

Foreign-body airway obstruction

Foreign-body aspiration is often associated with an altered conscious state – for example, in alcohol or drug intoxication, cerebrovascular accident (CVA) or dementia. Elderly patients with dentures are at increased risk.

Laryngeal foreign bodies are almost always symptomatic and are more likely to cause complete obstruction than foreign bodies below the epiglottis. Foreign bodies in the oesophagus are an uncommon cause of airway obstruction but, if lodged in the area of the cricoid cartilage or the tracheal bifurcation, can compress the airway, causing partial airway obstruction. Oesophageal foreign bodies may also become dislodged into the upper airway.

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