Stridor and Sleep Apnoea

Question 1

What is stridor?

Answer 1

Predominantly inspiratory wheeze due to large airways (larynx, trachea, major bronchi) obstruction.

Question 2

What are common causes of stridor in children?

Answer 2

Infections: (croup [viral infection of larynx], epiglottitis, pseudomembranous croup, retropharyngeal abscess [arises in retropharyngeal lymph nodes], diptheria, mononucleosis), foreign body, anaphylaxis/angioneurotic oedema, others e.g. burns.

Question 3

What is the key element in diagnosis of an airway foreign body?

Answer 3

History (acute onset of stridor accompanied by a choking spell, then look at airway films and CXR).

Question 4

What are the causes of stridor in adults?

Answer 4

Neoplasma in larynx, trachea, major bronchi; anaphylaxis; goitre (retrosternal, chronic enlargement of thyroid gland); trauma e.g. strangulation, burns and irritant gases; other e.g. bilateral vocal cord palsy, Wegener’s granulomatosis, cricoarytenoid arthritis (RA), tracheopathia (disease of the trachea).

Question 5

How would you investigate stridor?

Answer 5

Laryngoscopy (beware in acute epiglottitis), bronchoscopy, flow volume loop, CXR, other imaging e.g. CT, thyroid scan.

Question 6

What is the treatment for laryngeal obstruction?

Answer 6

Treat underlying cause e.g. foreign body removal, anaphylaxis. Mask bad ventilation with high flow O2, cricothyroidotomy (incision through cricothyroid membrane), tracheostomy.

Question 7

What are the options for tumour removal in a large airway?

Answer 7

Laser, photodynamic therapy, cryotherapy, diathermy (use of high frequency currents), surgical resection.

Question 8

What could be used to compress a tumour blocking a large airway?

Answer 8

Intraluminal stent.

Question 9

What types of radiotherapy are there?

Answer 9

External beam, brachytherapy [internal radiation therapy].

Question 10

What kind of hypersensitivity reaction is acute anaphylaxis?

Answer 10

Type 1 (immediate, IgE mediated).

Question 11

What are the signs and symptoms of acute anaphylaxis?

Answer 11

Flushing, pruritis (itch), urticaria (hives), angioneurotic oedema (lips, tongue, face, larynx, bronchi), abdominal pain and vomiting, hypotension (vasodlation and plasma exudation) leads to shock, stridor, wheeze and respiratory failure.

Question 12

What is the treatment for anaphylaxis?

Answer 12

IM adrenaline, IV antihistamine, IV corticosteroid, high flow O2, nebulised bronchodilators, endotracheal intubation if necessary.

Question 13

How can you prevent anaphylaxis?

Answer 13

Allergen avoidance, desensitisation (immunotherapy e.g. venom), self administered adrenaline.

Question 14

What are the scores 1-3 in the Epworth sleepiness scale?

Answer 14

0 - would never dose, 1 - slight chance, 2 - moderate chance, 3- high chance.

Question 15

What is a normal Epworth sleepiness scale?

Answer 15

<10/24

Question 16

Describe how snoring happens.

Answer 16

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

Question 17

What is obstructive sleep apnoea?

Answer 17

Intermittent upper airway collapse in sleep.

Question 18

What is the difference between apnoea and hypopnoea?

Answer 18

Apnoea - absence of breathing for a short time. Hypopnoea - breathing that is shallower than normal.

Question 19

What are the risk factors for sleep apnoea?

Answer 19

Enlarged tonsils or adenoids, obesity, retrognathia (retrusion of mandible, locked out of position), acromegaly (excessive enlargement of limbs due to hypersecretion of growth hormone from pituitary gland, hypothyroidism, oropharyngeal deformity, neurological (stroke, MS, myasthenia gravis, myotonic dystrophy), drugs (benzodiazepines, opiates, alcohol), post-operative period after anaesthesia.

Question 20

What are the effects of sleep apnoea on a patient?

Answer 20

Excessive daytime sleepiness, personality change, cognitive/functional impairment, major impact on daytime function.

Question 21

How much can sleep apnoea increase road traffic accidents?

Answer 21

7-fold.

Question 22

How can sleep apnoea increase risk of stroke and cardiovascular events?

Answer 22

Is an independent risk factor for hypertension, activates sympathetic system and raises C reactive protein, impairs endothelial function and glucose tolerance.

Question 23

How can you diagnose sleep apnoea?

Answer 23

Snoring and raised Epworth score, overnight sleep study (involves oximetry, domiciliary recording [airflow, oximetry, thoracic/abdominal movement, full polysomnography [means overnight test to diagnose sleep disorders]).

Question 24

What are the main treatments for sleep apnoea?

Answer 24

Remove underlying cause, CPAP (most effective).

Question 25

What are other treatments for sleep apnoea?

Answer 25

Mandibular advancement device (used in mild OSA), surgery (removing soft tissue at back of throat, good for snoring but avoid if sleep apnoea as future CPAP may be less effective).