Stridor and Sleep Apnoea (DISEASE MECHANISMS)

Question 1

What is stridor?

Answer 1

Stridor is a predominantly inspiratory sound due to large airways obstruction

Question 2

What are supraglottic/laryngeal causes of inspiratory stridor?

Answer 2

Laryngomalacia
Supraglottic mass
Glottic lesions
Vocal cord paralysis

Question 3

What can cause stridor in children?

Answer 3

Infections
Foreign bodies
Anaphylaxis / Angioneurmtic oedema
Other (e.g. burns)

Question 4

Which infections can cause stridor in children?

Answer 4

Croup
Epiglottitis
Pseudomembranous croup
Retropharyngeal abscess 
Diphtheria 
Infectious mononucleosis

Question 5

What is croup?

Answer 5

Laryngotracheobronchitis - commonly caused by RSV

Question 6

What are the symptoms of croup?

Answer 6

Fever
Barking Cough
Stridor

Question 7

What is pseudomembranous croup?

Answer 7

Laryngotracheobronchitis of the respiratory epithelium with micro purulent secretions

Question 8

What commonly causes infectious mononucleosis (aka glandular fever/mono)

Answer 8

Epstein Barr Virus (EBV)

Question 9

What is angioneurotic oedema?

Answer 9

Rapid swelling of:
dermis
subcutaneous tissue 
mucosa
submucosal tissues

Question 10

Which group are most as risk for foreign bodies in the airway

Answer 10

Children under the age of 3

Question 11

What is the key element in diagnosis foreign body airway obstruction?

Answer 11

History

Question 12

How do patients with a foreign body airway obstruction usually present?

Answer 12

Acute onset of stridor accompanied by a choking spell

Question 13

How can a foreign body in an airway be detected?

Answer 13

Airway films and CXR

possibly lateral x-ray of the throat

Question 14

What are causes of stridor in adults?

Answer 14

Neoplasma
Anaphylaxis
Goitre
Trauma
Other

Question 15

Which neoplasms could cause stridor in adults?

Answer 15

Larynx
Trachea
Major bronchi

Question 16

Which other causes of stridor are there besides neoplasms anaphylaxis, goitre and trauma?

Answer 16

Bilateral vocal cord palsy
Wegener’s granulomatosis
Cricoarytenoid arthritis
Tracheopathia

Question 17

How can stridor be investigated?

Answer 17

Laryngoscopy 
Bronchoscopy
Flow volume loop by spirometry
CXR
(CT/Thyroid scan)

Question 18

How are laryngeal obstructions treated?

Answer 18

Treat underlying cause
High flow oxygen
Cricothyroidotomy (emergency)
Tracheostomy

Question 19

What is the Heimlich Manoeuvre?

Answer 19

Rapid upward thrust in epigastrium force upward movement of diaphragm and forced expiration

Question 20

How can malignant airway obstructions be treated?

Answer 20

Tumour removal (laser / photodynamic therapy / cryotherapy / Diathermy / surgical resection)
Tumour compression (intraluminal stent)
Radiotherapy
(Chemotherapy / Corticosteroids)

Question 21

What type of hypersensitivity causes anaphylaxis?

Answer 21

Type I hypersensitivity

Question 22

How does acute anaphylaxis present?

Answer 22

Flushing, pruritus, urticaria
Angioneuortic oedema
(Abdominal pain, vomiting)
Hypotension leading to circulatory collapse (shock)
Stridor, wheeze and respiratory failure

Question 23

What are causes of anaphylaxis?

Answer 23

Food allergy
Insect venom
Drugs
Other e.g. latex

Question 24

How is acute anaphylaxis treated?

Answer 24

IM Epi within minutes
IV antihistamine within half hour
IV corticosteroid within hour 
High flow O2
Nebuliser bronchodilators
Endotracheal intubation if necessary

Question 25

How can anaphylaxis be managed long-term?

Answer 25

Avoidance
Immunotherapy
Self-admin epinephrine

Question 26

What causes snoring?

Answer 26

Relaxation of pharyngeal dilator muscles during sleep (esp. REM sleep) causes upper airway narrowing, turbulent airflow and vibration of soft palate and tongue base producing sound

Question 27

What causes sleep apnoea?

Answer 27

Negative pressure from breathing in obstructs airway if the throat is floppy causing microarousal to re-establish airflow

Question 28

What is obstructive sleep apnoea?

Answer 28

Intermittent upper airway collapse in sleep
Can be apnoeas or hypo apnoeas +/- hypoxaemias

Include recurrent arousals and sleep fragmentation

Question 29

What are the risk factors for sleep apnoea?

Answer 29

Enlarged tonsils/adenoids
Obesity
Retrognathia
Acromegaly/Hypothyroidism
Oropharyngeal deformity
Neuro: Stroke / MS / Myasthenia gravis / Myotonic dystrophy
Drugs: Benzodiazepines / opiates / alcohol / post-op period after anaesthesia

Question 30

What is retrognathia?

Answer 30

Jaw is set back and tongue is further back resulting in less space in the oropharynx

Question 31

Why ca sleep apnoea occur after anaesthesia?

Answer 31

Muscle relaxant is part of anaesthetic

Question 32

What are consequences of Sleep apnoea?

Answer 32

Excessive daytime sleepiness
personality change
Cognitive and/or functional impairment 
Major impact on daytime function
7-fold increased risk in RTA
independent risk for hypertension
Activated sympathetic system
Raised CRP
Impaired endothelial function
Impaired glucose tolerance
Increased risk of stroke & CVS events

Question 33

How is obstructive sleep apnoea diagnosed?

Answer 33

Snoring& EDS (raised Epworth score)

Overnight sleep study - domiciliary recording / full poysomnography

Question 34

What is included in domiciliary recording?

Answer 34

Airflow
Oximetry
Thoracic and abdominal movement

Question 35

What is polysomnography used for?

Answer 35

Establish they don’t have narcolepsy or REM sleep disorders

Question 36

How is obstructive sleep apnoea treated?

Answer 36

Remove underlying cause

CPAP (most effective)

Question 37

What does CPAP stand for?

Answer 37

Continuous positive airway pressure

Question 38

What are other treatment options for sleep apnoea besides CPAP?

Answer 38

Mandibular advancement device

Surgery (avoid in sleep apnoea because reduces future CPAP efficacy, used in simple snoring)