11/14/24, 10\:43 AM Stridor

Stridor

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Stridor\: high-pitched sound from turbulent air
life-threatening emergency due to potential airway compromise.
Aetiology\:
Newborn\: laryngomalacia (most common), tracheomalacia, subglottic stenosis.
Child\: croup, epiglottitis, quinsy, deep neck space infections, bacterial tracheitis; foreign body inhalation, anaphylaxis, burns.
Adult\: supraglottitis, bacterial tracheitis, deep neck space infections; tumour, trauma, post-extubation, burns, anaphylaxis,
hereditary angioedema, gastroesophageal re
Symptoms\: sore throat, di
fever; less commonly weight loss and cough.
History\: assess for foreign body ingestion, allergy history.
Clinical examination\: rapid A-E assessment with focus on airway.
Airway\: cyanosis, tripod position, angioedema, drooling, asymmetrical neck swelling,
palpation, restricted neck movements, trismus,
Breathing\: respiratory rate, oxygen saturation, respiratory e
Circulation\: pulse (tachycardia), blood pressure (hypotension).
Disability\: consciousness level (AVPU scale), temperature (fever indicating infection).
Exposure\: evidence of anaphylaxis (urticarial rash, angioedema), potential allergens.
Classi
Inspiratory\: obstruction above or at the vocal cords.
Biphasic\: obstruction below the vocal cords.
Expiratory\: obstruction of trachea or larger bronchi.
Investigations\:
Laboratory\: FBC, U&Es, CRP, ABG (if concerns about oxygenation or respiratory failure).
Imaging\:
Management\:
Initial interventions\: sit patient upright, high
2
dexamethasone), IV broad-spectrum antibiotics (if infection suspected).
Specialist interventions\: airway assessment by specialist, endotracheal intubation, surgical airway (tracheostomy,
cricothyroidotomy) if intubation is not possible.
Further interventions to treat underlying cause once airway is secured.
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Introduction

Stridor is an externally audible, high-pitched sound caused by turbulent air
respiratory tract (pharynx, larynx or trachea). 1,2
It is a life-threatening emergency as there is potential for airway
compromise and respiratory arrest.

Aetiology

The most common causes of stridor can be di
Table 1. Common causes of stridor by age group
Age Infective Non-infective
Newborn No major causes
Laryngomalacia (most common) - a
congenital abnormality of the laryngeal
cartilage that predisposes to the airway
collapsing in during the inspiratory
phase of respiration
3
Tracheomalacia
Subglottic stenosis
Child
Croup (viral
laryngotracheobronchitis)
Epiglottitis
Quinsy (peritonsillar abscess)
Deep neck space infections -
parapharyngeal, retropharyngeal,
submandibular (Ludwig's angina)
Bacterial tracheitis
Foreign body inhalation
Anaphylaxis
Burns
Adult
Supraglottitis/epiglottitis
Bacterial tracheitis
Deep neck space infections
Tumour
Trauma
Post-extubation
Blunt or penetrating trauma
Burn injury
Allergic/immune- anaphylaxis,
hereditary angioedema
Gastroesophageal re
Psychogenic

Clinical features

History

Typical symptoms of stridor include\:
1
Sore throat
Di
Noisy breathing*
Drooling or inability to swallow saliva
Dysphagia
Voice change (aphasia/hoarse voice)
Fever
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Less common symptoms of stridor include\:
Weight loss
Cough (typically presents with croup)
Other important areas to cover in the history include\:
Any history of foreign body ingestion (often seen in children – history from parents)
Allergy history
*Stridor is not to be confused with ‘stertor/snoring’
nares or nasopharynx.
2
- a low pitched sound, generally produced from obstruction of the

Clinical examination

Stridor warrants a rapid A-E assessment, primarily focusing on assessment of the airway.
4
Airway
By de
features of airway compromise and potential underlying causes of stridor.
Inspection\:
Signs of cyanosis\: indicative of signi
Position of the patient\: patients may often sit in a ‘tripod’ position (sat forward, neck extended with their arms by their
side to aid in breathing)
5
Evidence of angioedema\: suggestive of an anaphylactic reaction
Drooling\: associated with epiglottitis
Asymmetrical neck swelling\: suggestive of deep neck space infection
The
Palpation\:
Pain on palpation
Palpable neck swellings
Movement\:
Restricted neck movements\: associated with deep neck space infection
Trismus\: di
Flexible nasendoscopy (FNE) may be performed by the ENT SHO or SpR as part of the A-E assessment in order to visualise
the vocal cords and assess for evidence of swelling or a foreign body.
Breathing
Following a thorough airway assessment, the features of the patient's breathing must be evaluated, including\:
Respiratory rate, oxygen saturation, respiratory e
Auscultation\: wheeze may be a sign of obstruction distal to the large bronchi and might be suggestive of possible
anaphylaxis
Reduced air entry is also a concerning
Circulation
Circulation may be assessed as follows\:
Pulse\: patients with stridor may be tachycardic due to the increased respiratory e
further exacerbated by the administration of nebulised adrenaline (see below).
Blood pressure\: hypotension may be suggestive of systemic vasodilation due to anaphylaxis or an infective cause
Disability
Consciousness - in the context of stridor, a patient’s consciousness level may be reduced secondary to hypoxia or
hypercapnia. The AVPU scale can be used to assess the patient's level of consciousness\:
Alert\: the patient is fully alert, although they may still be distress or dis-orientated
Verbal\: the patient makes some kind of response when you talk to them (e.g. words, grunting)
Pain\: the patient responds to a painful stimulus
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Unresponsive\: the Glasgow Coma Scale (GCS) can be used for a more detailed assessment of consciousness
Temperature\: fever may indicate infectious cause
Exposure
Finally, full 'top-to-toe' exposure of the patient is essential, evaluating the following\:
Evidence of anaphylaxis such as an urticarial rash or angioedema
Potential allergens

Classi

The character of the stridor gives an indication as to the location of the obstruction\:
Inspiratory\: obstruction above or at the level of the vocal cords (glottis or supraglottic)
Biphasic\: obstruction below the vocal cords (subglottic)
Expiratory\: obstruction of the trachea or larger bronchi
1,5,6

Investigations

Further investigations should be considered after the airway is secured.

Laboratory investigations

Relevant laboratory investigations in the context of stridor, include\:
Bloods\: FBC, U&Es, CRP (infection)
ABG\: if concerns regarding oxygenation or respiratory failure

Imaging

Relevant imaging in the context of stridor includes\:
Flexible nasendoscopy (as above)
CT neck\: although this is not an acute investigation, it may be performed if there is clinical suspicion of an abscess or
malignancy
7

Management

Specialists should be involved early in the management of stridor including ENT and critical care sta

Initial interventions

Whilst awaiting specialist input, a number of interventions can be considered to help stabilise the patient\:
Sit patient upright
High 2
(humidi
Heliox (helium mixed with Oxygen) is sometimes used if available to help to reduce work of breathing
Nebulised adrenaline\: assess response and repeat if necessary
IV high dose steroids (e.g. dexamethasone)
IV broad-spectrum antibiotics\: if there is a suspicion of infection (consult local guidelines)

Specialist interventions

The airway should be assessed by a specialist (e.g. anaesthetist or ENT doctor) to allow consideration of further
interventions including\:
Endotracheal intubation
If intubation is not possible, a surgical airway may be necessary (e.g. tracheostomy, cricothyroidotomy)
8
Once the airway is secured, further interventions to de
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References

Sicari V, Zaboo C. S t r i d o r . Updated in 2020. Available from [LINK]
Rose J. A c u t e S t r i d o r i n C h i l d r e n . Published in 2019. Available from [LINK]
Boardman SJ. L a r y n g o m a l a c i a . Last updated in 2019. Available from [LINK]
The American College of Surgeons. A d v a n c e d T r a u m a L i f e S u p p o r t C o u r s e m a n u a l T e n t h E d i t i o n . Published in 2018.
Available from [LINK]
Mohamad N et al. A c u t e S t r i d o r-D i a g n o s t i c C h a l l e n g e s i n D i
Published in 2012. Available from [LINK]
Valman HB. S t r i d o r . Published in 1981. Available from [LINK]
Brady MF, Burns B. A i r w a y O b s t r u c t i o n . Updated in 2020. Available from [LINK]
Price TM, McCoy EP. E m e r g e n c y f r o n t o f n e c k a c c e s s i n a i r w a y m a n a g e m e n t . Published in 2019.

Reviewer

Miss Eleanor Crossley
Otolaryngology Registrar

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Contents

Introduction
Aetiology
Clinical features
Classi
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