Respiratory: Stridor Flashcards
What is stridor?
A high pitched, harsh, musical inspiratory sound
What causes stridor?
Turbulent airflow passing through a partial obstruction of the upper airway (lower portion - upper trachea and larynx)
Is it usually inspiratory?
Yes but can be biphasic
Can it be heard without stethoscope?
Yes
What can severe obstruction also lead to?
Increased HR, RR and agitation
What suggests impeding complete airway obstruction?
Central cyanosis
Drooling
Reduced level of consciousness
What is stertor?
Low pitched snoring or gasping
What causes stertor?
Partial obstruction of airway above level of larynx. Produced by vibrations of the naso- pharynx, pharynx and soft palate
What are the 4 main groups of causes of upper airway obstruction and stridor?
Acute - infectious and non infectious
Persistent - congenital and acquired
What acute, infectious causes of stridor are there?
Croup - laryngotracheobronchitis Bacterial tracheitis Epiglottitis, supraglottitis Peritonsillar, retropharyngeal or parapharyngeal abscess Measles
What non infectious, acute causes of stridor are there?
Laryngeal or oesophageal foreign body Anaphylaxis Inhalation of smoke or hot fumes Trauma to throat Hypocalcaemia
What congenital causes are there?
Laryngomalacia Laryngeal web, cleft, cyst, haemangioma Tracheal stenosis Vascular ring Cystic hygroma
What acquired causes are there?
Post traumatic stenosis Papilloma Mediastinal mass - tumour, lymphatic Damage to spinal cord, vagal or glossopharyngeal nerve or vocal cord Bulbar neuropathy
What is the mechanism of hypoxia?
Hypoventilation (not V/Q mismatch as in LRTI)
What is laryngomalacia?
Congenital abnormality of larynx - does not form right and ends up being soft and floppy.
The aryepiglottic folds are shorter than normal and end up pulling the epiglottis down into a distinctive omega shape.
The cartilages are softer.
What happens when a child breaths with laryngomalacia?
The floppy structures get sucked into the airway causing stridor
At what age do children with laryngomalacia typically present?
4 weeks
Does laryngomalacia typically self correct?
Yes - usually around 12-18 months as muscles strengthen over time.
Is treatment needed for laryngomalacia?
Rarely
Surgery - cut the aryepiglottic folds to help open up the airway
What is the most reliable measure of hypoxaemia?
Oxygen sats by pulse oximetry BUT in contrast to lung disease, it is a later feature of upper airway obstruction
What can precipitate total obstruction of upper airway?
Examination of throat using spatula
Lying the child down
Doing X-ray or IV access
