Stridor, anaphylaxis & sleep apnoea Flashcards
Define what stridor is
This is a predominantly inspiratory wheeze due to large airways (larynx/trachea/major bronchi) obstruction
List the main causes of stridor in children
- Laryngomalacia
- Inhaled foreign bodies
- Infections - croup, epiglottitis, retropharyngeal abscess, siptheria, infectious mononucleosis (IM)
- Anaphylaxis
- Trauma e.g. burns
List the main causes of stridor in adults
- Neoplasms - of the larynx, trachea or main bronchi
- Anaphylaxis
- Goitre (retrosternal)
- Foreign body
- Trauma (eg strangulation, burns, irritant gases)
- Other (eg bilateral vocal cord palsy; Wegener’s granulomatosis; cricoarytenoid arthritis (RA); tracheopathia
What is the most common foreign body which gets stuck in the airways ?
Peanuts
What age of child is most at risk of airway obstruction from a foregin body ?
Children < 3
What are the clinical features of an inhaled foreign body ?
Acute onset accompanied by a chocking spell:
- cough
- stridor
- dyspnoea
What investigations should be done in someone suspected of having inhaled a foreign body ?
CXR & airway films
Describe what laryngomalacia is
It is a congenital softening of the tissues of the larynx (voice box) above the vocal cords. This is the most common cause of noisy breathing in infancy.
How does laryngomalacia typically present and when?
Infants typical present at 4 weeks of age with stridor
Is laryngomalacia a serious condition ?
- In most cases, laryngomalacia in infants is not a serious condition — they have noisy breathing, but are able to eat and grow.
- It will resolve for these cases by about 18-20months old
What is a retropharyngeal abscess ?
It is an abscess located in the tissues in the back of the throat behind the posterior pharyngeal wall (the retropharyngeal space).
What are the signs/symptoms of a retropharyngeal abscess ?
- Stiff neck (limited neck mobility or torticollis)
- Some form of palpable neck pain (may be in “front of the neck” or around the Adam’s Apple)
- Malaise
- Difficulty swallowing
- Fever
- Stridor
- Drooling
- Croup-like cough
- Enlarged cervical lymph nodes
What is the difference in ages groups that retropharyngeal abscesses occur compared to a peritonsillar abscess ?
Peritonsillar occur commonly in adolescents and young adults whereas retropharyngeal abscesses occur mainly in children < 5 years of age
How is a retropharyngeal abscess diagnosed ?
- 1st line = lateral neck X-ray
- 2nd line = CT
What is the treatment of a retropharyngeal abscess ?
IV antibiotics & surgical drainage
What investigations may be done in someone presenting with stridor ?
- Laryngoscopy (beware in acute epiglottitis)
- Bronchoscopy
- Flow volume loop
- Chest X ray
- Other imaging (CT; thyroid scan)
What is the treatment of laryngeal obstruction ?
- Treat underlying cause eg foreign body removal, anaphylaxis
- Mask bag ventilation with high flow O2
- Cricothyroidotomy
- Tracheostomy
What manoeuvre is used to attempt to dislodge a inhaled foreign body ?
Heimlich manoeuvre - Rapid upward thrust in epigastrium forces upward movement of diaphragm and forced expiration
Define what anaphylaxis is
- It is a severe, life-threatening, generalised or systemic hypersensitivity reaction.
- Resulting in angioedema causing respiratroy compromise followed by cardiovascular collapse (shock). Often with urticaria
What type of hypersensitivity reaction is anaphylaxis ?
Type 1 (immediate) hypersensitivity (IgE)
List the different causes of anaphylaxis
- Foods eg nuts; shellfish
- Insect venom (bee, wasp)
- Drugs (Antibiotics e.g. penicillin, aspirin, anaesthetics, contrast media etc)
- Other eg latex
What are the clinical features of anaphylaxis ?
- Flushing, pruritus, urticaria,
- Angioneurotic oedema (lips, tongueà face, larynx, bronchi)
- GI symptoms - abdominal pain, vomiting, incontinence
- Hypotension (vasodilatation and plasma exudation) ==> circulatory collapse (shock)
- Stridor, wheeze and respiratory failure
An anaphylactic reaction is highly likely when what 3 criteria is met ?
- Sudden onset and rapid progression of symptoms
- Life-threatening Airway and/or Breathing and/or Circulation problems
- Skin and/or mucosal changes (flushing, urticaria, angioedema)
What also helps support the diagnosis of anaphylaxis ?
Exposure to a known allergen / trigger for the patient helps support the diagnosis
What assessment is key to be done in someone presenting with a potential anaphylactic reaction ?
ABCDE
Considering A of the ABCDE assessment, what airway problems suggest an anaphylactic reaction ?
- Airway swelling e.g. throat and tongue swelling
- Difficulty in breathing and swallowing
- Sensation that throat is ‘closing up’
- Hoarse voice
- Stridor
Considering B of the ABCDE assessment, what breathing problems suggest an anaphylactic reaction ?
- Shortness of breath
- Increased respiratory rate
- Wheeze
- Patient becoming tired
- Confusion caused by hypoxia
- Cyanosis (appears blue) – a late sign
- Respiratory arrest
Considering C of the ABCDE assessment, what circulatory problems suggest an anaphylactic reaction ?
- Signs of shock – pale, clammy
- Tachycardia
- Hypotension
- Myocardial ischaemia / angina
- Cardiac arrest
Considering D of the ABCDE assessment, what disability problems suggest an anaphylactic reaction ?
- Sense of “impending doom”
- Anxiety, panic
- Decreased conscious level caused by airway, breathing or circulation problem
Considering E of the ABCDE assessment, what disability problems suggest an anaphylactic reaction ?
- Skin changes often the first feature
- Present in over 80% of anaphylactic reactions
- Skin, mucosal, or both skin and mucosal changes
- Erythema – a patchy, or generalised, red rash
- Urticaria (also called hives, nettle rash, weals or welts) anywhere on the body
- Angioedema - similar to urticaria but involves swelling of deeper tissues e.g. eyelids and lips, sometimes in the mouth and throat
List the differentials other than anaphylaxis for someone presenting with clinical features of anaphylaxis ?
- Asthma
- Septic shock
- Vasovagal episode
- Panic attack
- Breath-holding episode in a child
- Idiopathic (non-allergic) urticaria or angioedema
What is the initial resucitation treatment of anaphyalxis ?
- IM adrenaline (epinephrine) (dose can be repeated every 5 mins if necessary) + rapid IV fluid challenge (due to large volumes of fluid leaking from patients circulation during anaphylaxis reaction)
- High flow O2
- Consider further bronchodilator therapy with salbutamol (inhaled or IV), ipratropium (inhaled), aminophylline (IV) or magnesium (IV)
What are the different dosages used of IV fluids, adrenaline, cholramphenamine and hydrocortisone used for treatment of anaphylaxis ?
What is the treatment of an anaphylaxis reaction following the initial resucitation treatment ?
IM or IV Antihistamine (chlorphenamine) + IM or IV steroids (hydrocortisone)
Sometimes it can be difficult to establish whether a patient had a true episode of anaphylaxis. What can be done to confirm if someone has a true anaphylactic reaction?
Measuring mast cell tryptase.
Once someone is confirmed to have had an anaphylactic reaction what is prophylactic treatment is then provided ?
- Allergen avoidance (where possible)
- Desensitisation (immunotherapy) eg venom
- Give a self-administered epinephrine (epipen)
Anaphylaxis is one of the few times when you would not have time to look up the dose of a medication.
What are the doses of adrenaline you should give for the following age groups:
- < 6 years
- 6-12 years
- > 12 years
- <6 years - 150 micrograms
- 6-12 years - 300 micrograms
- > 12 years - 500 micrograms
Anaphylaxis is one of the few times when you would not have time to look up the dose of a medication.
What are the doses of hydrocortisone you should give for the following age groups:
- < 6 months
- 6months - 6 years
- 6-12 years
- > 12 years
- < 6 months - 25mg
- 6months - 6 years - 50mg
- 6-12 years - 100mg
- > 12 years - 200mg
Anaphylaxis is one of the few times when you would not have time to look up the dose of a medication.
What are the doses of Chlorphenamineyou should give for the following age groups:
- < 6 months
- 6months - 6 years
- 6-12 years
- > 12 years
- < 6 months - 25 micrograms/kg
- 6months - 6 years - 2.5mg
- 6-12 years - 5mg
- > 12 years - 10mg
Where on the body should you give an IM injection of adrenaline ?
Anterolateral aspect of the middle third of the thigh.
Define what snoring is and what causes it
- It is a snorting or grunting sound when you sleep
- Caused by relaxation of pharyngeal dilator muscles during sleep (esp. REM) resulting in upper airway narrowing, turbulent airflow and vibration of soft palate and tongue base
Define what obstructive sleep apnoea (OSA) is
- This is intermittent upper airway collapse in sleep resulting in apnoeas or hypopnoeas ± hypoxaemia (breathing stops for a bit then starts again)
- This leads to recurrent arousals / sleep fragmentation
What are the risk factors for developing OSA?
- 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 does the partner of someone with OSA often complain of ?
Excessive snoring and may report periods of apnoea.
What are the consequences of OSA?
- Excessive daytime sleepiness
- Personality change
- Cognitive / functional impairment
- Major impact on daytime function
- 7-fold increase in RTA – it is the equivalent to being twice legal limit for alcohol
- Independent risk factor for hypertension
- Activated sympathetic system
- Raised CRP
- Impaired endothelial function
- Impaired glucose tolerance
- (probable increased risk of stroke and cardiovascular events)
How is OSA diagnosed ?
Assessment of sleepiness:
- Epworth Sleepiness Scale - questionnaire completed by patient +/- partner (raised score suggestive)
- Multiple Sleep Latency Test (MSLT) - measures the time to fall asleep in a dark room (using EEG criteria)
Diagnostic test = Overnight Sleep studies (polysomnography)
What is measured on an overnight sleep study ?
- oximetry
- Domicillary recording (airflow, oximetry, thoracic/abdominal movement)
- Full polysomnography
What is the treatment of OSA?
1st line = Remove underlying cause & weight loss + CPAP
Who should be informed if someone has OSA causing excessive daytime sleepiness ?
DVLA
What other treatment may be used instead of CPAP for OSA and when can it be used ?
Intra-oral devices (e.g. mandibular advancement) - may be used if CPAP is not tolerated or for patients with mild OSAHS where there is no daytime sleepiness
