Stridor and Sleep Apnoea Flashcards
What is stridor?
Predominantly inspiratory wheeze due to large airway (larynx/trachea/major bronchi) obstruction
What areas of the airway does inspiratory stridor affect?
- Extrathoracic
* Suprglottis/larynx
What are some causes of inspiratory stridor?
- Laryngomalacia
- Supraglottic mass
- Glottic lesions
- Vocal cord paralysis (not if unilateral, as other side can usually compensate)
Name structures labelled A - C
pic of glotts, supra glottis, sub glottis
A - supraglottis
B - subglottis
C - epiglottis
What are causes of stridor in children?
- Infections
- Foreign Body
- Anaphylaxis / angioneurotic oedema
- Other (eg burns)
What is the difference between stridor and asthma?
Stridor - inspiratory wheeze
Asthma - expiratory wheeze
What infections can cause stridor?
- Croup - respiratory syncytial virus (RSV)
- Epiglottitis
- Pseudomembranous croup
- Retropharyngeal abscess
- Diphtheria
- Infectious mononucleosis
What individuals are at higher risk of choking?
Children <3 years at higher risk (common cause is peanuts)
What are the effects of airway foreign bodies in children?
Acute onset of stridor accompanied by a choking spell
What are causes of stridor in adults?
- Neoplasms (larynx, trachea, major bronchi)
- Anaphylaxis
- Goitre (retrosternal)
- Trauma (eg strangulation, burns, irritant gases)
- Other (eg bilateral vocal cord palsy; Wegener’s granulomatosis; cricoarytenoid arthritis (RA); tracheopathia
What is tracheomalacia?
Any inflammatory condition which damages structure of the cartilage – causing collapse of trachea
What is the treatment for tracheomalacia?
Metal stents to maintain patency of the airway
What do investigations of stridor include?
- Laryngoscopy
- Bronchoscopy
- Flow volume loop (obstructive airway disease)
- Chest X ray
- Other imaging (CT; thyroid scan)
What is the treatment for laryngeal obstruction?
- Treat underlying cause e.g. foreign body removal, anaphylaxis
- Mask bag ventilation with high flow O2
- Cricothyroidotomy
- Tracheostomy
What are abdominal thrusts?
Rapid upward thrust in epigastrium forces upward movement of diaphragm and forced expiration
When are abdominal thrusts used?
Foreign body inhalation
café coronary syndrome
What is the treatment of a malignant airway obstruction?
- Tumour removal:
laser, photodynamic therapy, cryotherapy, diathermy, surgical resection - Tumour compression: intraluminal stent
- Radiotherapy: external beam, brachytherapy (internal beam)
- Chemotherapy
- Corticosteroids
What is acute anaphylaxis?
Type 1 (immediate) hypersensitivity reaction (IgE)
What immunoglobulin is involved in type 1 hypersensitive reaction e.g. anaphylaxis?
IgE
What are clinical features of anaphylaxis?
- Flushing, pruritus, urticaria,
- Angioneurotic oedema (lips, tongue, face, larynx, bronchi)
- Abdominal pain, vomiting
- Hypotension (vasodilatation and plasma exudation) leads to circulatory collapse (shock)
- Stridor, wheeze and respiratory failure
What causes hypotension in acute anaphylaxis? And what does this lead to?
- Hypotension is caused by vasodilation and plasma exudation
- It can lead to shock (circulatory collapse)
What are causes of anaphylaxis?
- Foods e.g. nuts, shellfish
- Insect venom (bee, wasp)
- Drugs (e.g. penicillin, aspirin, anaesthetics)
- Other e.g. latex
What is the treatment for anaphylaxis?
- IM Epinephrine (adrenaline)
- IV antihistamine
- IV corticosteroid
- High flow O2
- Nebulised bronchodilators
- Endotracheal intubation if necessary
- Allergen avoidance
- Desensitisation (immunotherapy)
- Self-adminstered epinephrine i.e. Epipen
How is an Epipen used?
- Epipen is removed from packaging
- Grey safety cap is removed
- Black tip of Epipen placed at right angles to the thigh
- Pressed hard into the thigh until the auto-injector mechanism functions (there should be a click)
- Epipen held in place for 10 seconds
- Epipen removed and area massaged for 10 seconds
What is a normal score on the Epworth Sleepiness Scale?
<10 out of 24
What is an abnormal score on the Epworth Sleepiness Scale?
A score of 10 or more
What is the Epworth Sleepiness Scale useful in diagnosing?
- Obstructive sleep apnoea
* Sleep apnoea/hypopnoea syndrome
What causes snoring?
- Relaxation of pharyngeal dilator muscles during sleep (esp. REM)
- Upper airway narrowing causes turbulent airflow and vibration of soft palate and tongue base
What happens to airflow, effort (rib cage), effort (abdomen) and SaO2 in sleep apnoea?
- Airflow flat-lines, then jumps up upon arousal
- Effort by rib cage and abdomen do not flat line as body still trying to breathe - increase in effort upon arousal to increase oxygen levels
- SaO2 low until arousal, where this is a small dip and then an increase where oxygen levels return to normal
What is obstructive sleep apnoea?
Intermittent upper airway collapse in sleep
What can apnoeas or hypopnoeas result in?
Hypoxaemia
Why do people with obstructive sleep apnoea score higher of the Epworth Sleepiness Scale?
Recurrent arousals / sleep fragmentation
What are risk factors for sleep apnoea?
- Enlarged tonsils, adenoids
- Obesity
- Retrognathia
- Acromegaly, hypothyroidism
- Oropharyngeal deformity
- Neurological: stroke, MS, myesthenia gravis, myotonic dystrophy
- Drugs: benzodiazepines, opiates, alcohol,
- Post-operative period after anaesthesia
What are consequences of sleep apnoea?
- excessive daytime sleepiness
- personality change
- cognitive / functional impairment
- Major impact on daytime function
- 7-fold increase in road traffic accidents (equivalent of being twice the legal limit for alcohol)
What are physical consequences of sleep apnoea?
- Independent risk factor for hypertension
- Activated sympathetic system
- Raised CRP (C-reactive protein)
- Impaired endothelial function
- Impaired glucose tolerance
- probable increased risk of stroke and cardiovascular events
How are the consequences of sleep apnoea improved?
CPAP (continuous positive airway pressure)
How is obstructive sleep apnoea diagnosed?
- Snoring & Excessive daytime sleepiness (raised Epworth score)
- Overnight sleep study - oximetry, domicillary recording (airflow, oximetry, thoracic/abdominal movement), full polysomnography
What is the treatment for obstructive sleep apnoea?
- Remove underlying cause (tonsillectomy for enlarged tonsils)
- CPAP (continuous positive airway pressure) - most effective therapy
What is the effect of positive airway pressure on upper airway?
CPAP maintains positive airway pressure eat back of throat to maintain airway patency
What are other treatments for obstructive sleep apnoea excluding CPAP?
Mandibular Advancement Device (holds jaw forwards)
- improves snoring
- moderate reduction in apnoea-hyponoea index (AHI)
- use in mild obstructive sleep apnoea (AHI 5-15/hr)
Surgery (UPPP, laser)
- avoid if sleep apnoea (future CPAP less effective)
- may be used in simple snoring
What are the drawbacks of UPPP as a treatment for sleep apnoea?
Future CPAP less effective
What is UPPP?
Uvulopalatopharyngoplasty - removes excess tissue in the throat to make the airway wider
