Stridor and Sleep Apnoea

Question 1

describe stridor

Answer 1

predominantly inspiratory wheeze due to large/upper (larynx, trachea, major bronchi) airways obstruction

Question 2

describe causes of stridor in children

Answer 2

foreign body 
anaphylaxis/angioneurotic oedema
infections;
croup
epiglottitis (hemophilias influenza bacteria)
pseudomembranous croup
retropharyngeal abscess
diphtheria
infectious mononucleosis
other;
physical trauma
burns

Question 3

describe foreign bodies in the airway

Answer 3

children<3 years at high risk
peanuts most common
acute onset of stridor accompanied by choking spell
airway films and CXR

Question 4

describe causes of stridor in adult

Answer 4

neoplasms (most common);
larynx
trachea
major bronchi
anaphylaxis (second most common)
goitre (retrosternal)
foreign body 
trauma (strangulation, burns, irritant gases)
others (bilateral vocal cord palsy, Wegener's granulomatosis, cricoarytenoid arthritis, tracheopathia)

Question 5

describe tracheomalacia

Answer 5

rare

destruction of hyaline cartilage causing negative intra-thoracic pressure when inspiring

Question 6

describe investigations of stridor

Answer 6

laryngoscopy (beware in acute epiglottitis)
bronchoscopy
flow volume loop (smaller the loop, larger the airway obstruction)
CXR
CT, thyroid scan

Question 7

describe treatment of laryngeal obstruction

Answer 7

treat the underlying cause (removal of foreign body, anaphylaxis)
mask bag ventilation with high flow oxygen
cricothyroidotomy
tracheostomy

Question 8

describe treamtment of malignant airway obstruction

Answer 8

tumour removal (laser, photodynamic therapy, cryotherapy, diathermy, surgical resection)
tumour compression (intraluminal stent)
radiotherapy (external beam, brachytherapy)
chemotherapy
corticosteroids

Question 9

describe acute anaphylaxis

Answer 9

type 1 (immediate) hypersensitivity - IgE
flushing, pruritus, urticaria
angioneurotic oedema (lips, tongue and then face, larynx, bronchi)
abdominal pain, vomiting
hypotension (vasodilation and plasma exudation) causing circulatory collapse (shock)
stridor, wheeze, respiratory failure

Question 10

describe causes of anaphylaxis

Answer 10

foods (nuts, shellfish)
insect venom (bee, wasp)
drugs (penicillin, aspirin, anaesthetics)
other (latex)

Question 11

describe treatment anaphylaxis

Answer 11

intramuscular epinephrine (adrenaline) (epi pen) - seconds
IV antihistamine - minutes
IV corticosteroid - hours

supportive;
high flow oxygen
nebulised bronchodilators
endotracheal intubation

allergen avoidaance
desensitisation (immunotherapy) e.g. venom
self administered epinephrine

Question 12

describe Epworth scale

Answer 12

sleepiness scale
score individuals based on their sleepiness
high score indicates pathological sleepiness (sleep apnoea)

Question 13

describe snoring

Answer 13

relaxation of pharyngeal dilator muscles during sleep causing airway narrowing, turbulent airflow and vibration of soft palate and tongue base
airway may become too narrow to breathe and the brain wakes you up recurrently during the night (sleep apnoea)

Question 14

describe obstructive sleep apnoea

Answer 14

intermittent upper airway collapse in sleep
apnoeas or hypopnoeas +/- hypoxaemia
recurrent arousals/sleep fragmentation
1-4% of adults

Question 15

describe risk factors of sleep apnoea

Answer 15

kissing tonsils - children with large tonsils closing the airways, adenoids
obesity
retrognathia - receding jaw
acromegaly, hypothyroidism - excessive growth hormone
oropharyngeal deformity
neurological - stroke, MS, myasthenia gravis, myotonic dystrophy .
drugs - benzodiazepines, opiates, alcohol
post operative period after anaesthesia

Question 16

describe consequences of sleep apnoea

Answer 16

excessive daytime sleepiness
personality change
cognitive/functional impairment
major impact on daytime function
7-fold increase in road traffic accident (driving stimulation is equivalent to being twice legal limit for alcohol)
independent risk factor for hypertension
activated sympathetic system
raised CRP
impaired endothelial function
impaired glucose tolerance
increased risk of stroke and cardiovascular events

Question 17

describe diagnosis of obstructive sleep apnoea

Answer 17

snoring and EDS (raised Epworth score)
overnight sleep study;
oximetry
domiciliary recording (airflow, oximetry, thoracic/abdominal movement)
full polysomnography

Question 18

describe treatment of obstructive sleep apnoea

Answer 18

remove underlying cause
CPAP (continuous positive airway pressure) - most effective therapy (mask when sleeping)
inbuilt technologies with SIM card help monitor compliance, airleak and allow remote titration of pressure

mandibular advancement device;
improves snoring, moderate reduction in AHI, use in mil OSA
surgery (mandibular advancement surgery, UPPP, laser)