Paediatric respiratory Flashcards
(38 cards)
Definition of croup
Narrowing of the larynx and subglottis caused by inflammation
AKA laryngo-tracheobronchitis
Cause of croup
Most commonly viral (parainfluenza virus) Occasionally allergic (episodic, no preceding viral-type illness)
Clinical features of coup
Hoarse voice Brassy/Barking cough Stridor Breathlessness Preceding viral illness few days prior Symptoms occur in the middle of the night, child well during the day
Management of croup
Usually do not require specific therapy
If stridor at rest:
- Oral dexamethasone (4-6 hours to take effect, observe and ensure no stridor at rest before d/c)
- nebulised adrenaline if severe respiratory distress (only lasts couple of minutes)
- if requires oxygen (rare), admit to a paediatric ICU + intubate and ventilate
(supplemental oxygen means pre-terminal, as there is very severe narrowing)
Common causes of Bronchiolitis
RSV - most common and most severe Most common respiratory viruses can cause bronchiolitis - influenza A - influenza B - parainfluenza - human metapneumovirus - rhinovirus
Clinical features of bronchiolitis
Preceding URTI 2-3 days increasing wheeze and respiratory distress over few days Cough Increased work of breathing Poor feeding (infants) Gradual resolution over few days Cough may take weeks-months to resolve
Management of bronchiolitis
No role for antivirals or antibiotics
Trial bronchodilators if older than 6m, especially if history suggestive of atopy
+/- hypertonic saline (evidence unclear)
Supportive care if required: oxygen, small frequent feeds, CPAP rarely needed, stomach decompression if respiratory distress after feeds or NG tube feeding
Incidence of cystic fibrosis in Australia
1/2500 births
Screening for Cystic fibrosis
Two-stage:
- Immunoreactive trypsinogen (IRT) on heel prick - misses approx 15%
- Sweat test (gold standard)
Defect in cystic fibrosis
Cystic fibrosis transmembrane conductance regulator gene (CFTR) on chromosome 7
Leads to sodium channel defect - Na not excreted into secretions - no osmotic gradient for water to enter secretions - thick, sticky secretions
Most common mutation in cystic fibrosis
Delta F508 (70%) >1800 different mutations have thusfar been identified, usually less severe presentations
Management of acute asthma
Salbutamol and ipratropium bromide(atrovent) by MDI + spacer (nebuliser if on high flow oxygen) - 3 doses every 20 minutes
If not improved - continuous salbutamol
Magnesium sulphate (up to 2 doses)
If still refractory, call for help from anaesthetist, aminophylline or IV salbutamol
CPAP/intubation as indicated
Once stabilised, give oral prednisolone 2mg/kg - observe for 4-6 hours, d/c home if requiring salbutamol MDI 3 hourly or less (only 1mg/kg/day prednisolone if needed after initial dose)
Doses for drugs in asthma attack
Under 6: Salbutamol MDI: 6 puffs Salbutamol neb: 2.5mg Ipratropium MDI: 4 puffs Ipratropium neb: 250 mcg
Over 6: Salbutamol MDI 12 puffs: Salbutamol neb: 5mg Ipratropium MDI: 8 puffs Ipratropium neb: 500 mcg
Dose of adrenaline nebuliser in croup management
0.5mgs/kg up to maximum of 5mg
Long term asthma management
Trigger avoidance
Ventolin PRN (if mild, infrequent)
Ventolin x2 before sport if exercise induced
If more frequent/severe:
Add preventer: inhaled corticosteroid (fluticasone, budenoside etc.) OR montelukast (leukotriene antagonist)
IF preventer insufficient:
double dose
Add long-acting agent (montelukast or LABA - salmeterol)
Why are bronchodilators usually ineffective in bronchiolitis
Babies are born with only cholinergic receptors in their airways, no adrenergic receptors, and their smooth muscle is less responsive.
Over the first 18 months, there is a transition to adrenergic receptors in the airways, thus bronchodilators can be trialled in children older than 6m as may be some effect due to transition period
Fluids to prescribe in acute respiratory distress
Normal saline + 5% dextrose
Volume: 2/3 maintenance fluids (4,2,1 rule)
Give only 2/3 due to risk of SIADH from respiratory distress, prevent pulmonary oedema which will lead to poorer oxygenation
Overall cause for hypoxia in children
V/Q mismatch
Definition of a stridor
An inspiratory noise caused by an extrathoracic obstruction of the airways
Causes of stridor
Intraluminal: foreign body, haemangioma, vocal cord palsy
Luminal: croup, malacia,
Extraluminal: Vascular ring, cystic hygroma
Assessing severity of acute asthma attack
Mild: normal mental state, speak in sentences, no acc. muscle use, sat over 95% on air
Mod: normal mental state, some acc. muscle use, tachycardia, short sentences
Severe: Agitated/distressed/confused, moderate to marked acc. muscle use, speak in words, sats not maintained on room air (less than 92%)
Saturation at which to oxygenate a child
90-92%
Categories of asthma
Infrequent episodic (75%)
- 1-5 exacerbations per year, only requiring treatment during episode, asymptomatic between episodes, most only have one episode per year
Frequent episodic (22%)
- more than 6 episodes per year (every 6-8 weeks), some minimal interval symptoms (e.g. with exercise or at night), may benefit from low-dose preventer, particularly during winter/leading up to trigger period)
Persistent/Chronic (3%)
- symptoms most days, acute episodes often more severe than intermittent, always on a preventer, often higher levels and/or more than one, followed by GP and paediatrician
Role of ipratropium bromide (artrovent) in asthma
Not often used in home setting
Used in “rescue doses” in first hour of exacerbation with salbutamol
