Asthma

Question 1

Asthma brief:

Answer 1

Most common chronic respiratory disorder in childhood affecting 15-20% of children. Implies reversible airway obstruction. Diagnosing asthma in preschool children is often difficult - half of all children have wheeze at some point during first 3 years of life.

Question 2

What are the 3 patterns of wheeze?

Answer 2

1) Transient early wheezing
2) Viral induced wheezing
3) Persistant and recurrent multi-trigger/IgE associated wheeze

Question 3

Asthma brief?

Answer 3

• Frequent wheeze triggered by many stimuli
• The presence of IgE to common allergens such as pollen, pets, dust is associated with persistence of wheezing beyond pre-school years.
• Recurrent wheezing associated with evidence (skin-prick or IgE blood test) of skin allergy to one or more inhaled allergens is ATOPIC ASTHMA.
• Atopic wheezers have persistent symptoms and decreased lung function.
• Atopic asthma is strongly associated with other atopic diseases such as eczema, rhino-conjunctivitis and food allergy.

Question 4

Risk factors for asthma?

Answer 4

1) Family history of asthma or atopy
2) Low birth weight
3) Pollution
4) Atopy

Question 5

Pathophysiology of asthma?

Answer 5

• Up to 40% of all children are atopic
• Genetic predisposition, atopy and environmental triggers all contribute to bronchial inflammation.
• Bronchial inflammation results in oedema and excessive mucus production, with infiltration of cells (eosinophils, mast-cells, neutrophils, lymphocytes).
• This causes bronchial hyper-responsiveness causing exaggerated twitchiness to inhaled stimuli.
• Airway narrowing (bronchoconstriction)occurs causing reversible airflow obstruction (peak flow variability).
• Narrowing is responsible for symptoms (wheeze, cough, breathlessness, chest tightness)

Question 6

What are some environmental triggers for asthma/atopy?

Answer 6

1) Pollen
2) Pollution
3) Pets
4) Dust
5) Exercise
6) Cold air
7) Smoking

Question 7

Clinical presentation of asthma?

Answer 7

1) Polyphonic wheeze on expiration
2) Dyspnoea/SOB
3) Cough worse at night
4) Interval symptoms between acute exacerbations
5) Symptoms worse at night and may have triggers - pets, exercise, dust, cold air
6) Examination of chest usually normal but in long standing asthma - hyperinflation of chest, polyphonic expiratory wheeze and a prolonged expiratory phase

Question 8

Differentials for asthma?

Answer 8

1) Viral induced wheeze
2) Bronchiolitis
3) Pneumonia/TB - confirmed on CXR
4) (Croup)
5) Recurrent aspiration of feeds
6) Inhaled foreign body
7) Cystic fibrosis

Question 9

Diagnosis of asthma?

Answer 9

1) History of recurrent wheeze (should be suspected in any child with wheeze more than once) - exacerbations usually precipitated by viral respiratory infections.
2) Skin prick testing for common allergens can aid in diagnosing atopy.
3) NO CXR!!!!!!!!!!!!!!!
4) If uncertain - peak expiratory flow rate can help: uncontrolled asthma leads to increased variability in PEFR - both diurnal (worse in mornings) or day to day variable.
- FEV1:FVC <70%
5) RESPONSE TO TREATMENT!!!! Measure PEFR after inhaling bronchodilator (10-15% increase)

Question 10

Treatment of Asthma (OVER 5 YRS)?

Answer 10

1) SABA - Salbutamol (reliever)
2) SABA + ICS (budesonide/beclametasone)
3) SABA + ICS + LABA (Salmeterol) if LABA is ineffective use LRA (Montelukast) or Theophylline
4) ICS MAX DOSE, + SABA + LABA/LRA/theophylline
5) Add daily oral steroid of prednisolone and refer for specialist care - may need immunosuppressant or immunomodulation (Anti-IgE) therapy

Question 11

Treatment of Asthma (Under 5 YRS)

Answer 11

1) SABA
2) SABA + ICS (budenoside or beclametasone)
3) SABA + ICS + LRA, and refer to specialist if child under 2yrs.
4) Refer to resp paediatrician

Question 12

Bronchodilators info:

Answer 12

SABA - Salbutamol - rapid onset of action and effective for 2-4 hours, ‘reliever’.
LABA - Salmeterol - First choice add on therapy for children over 5 yrs, effective for 12 years. SHOULD NOT BE USED WITHOUT ICS.

Question 13

ICS info:

What are some side effects of ICS?

Answer 13

E.g. Budenoside, Beclametasone
Prophylactic drugs ‘preventers’, that are only effective if taken regularly. Act to decrease airway inflammation resulting in decreased symptoms, exacerbations and bronchial hyperactivity.

Systemic side effects:

1) Impaired growth
2) Adrenal suppression
3) Altered bone metabolism (in high doses) - dose linked with bone mineral density that can affect patient in later life. Weight bearing exercise has great effect on BMD so correct asthma with ICS and do weight bearing exercise.

MINIMISE DOSE AND MONITOR GROWTH CHARTS.

Question 14

LRA info:
What is the main side effect of Montelukast?
What alternative is there to LABA and LRA and what are the side effects?

Answer 14

Montelukast oral - first choice add on therapy for children under 5 years, can also be used in children over 5 if LABA is not effective.
Side effect: NIGHT TERRORS

Theophylline is used as an alternative to Montelukast but not commonly used in children due to side effects of vomiting, insomnia, headache and poor concentration.

Question 15

What are some reasons that treatment is not effective?

Answer 15

1) COMPLIANCE
2) Diagnosis
3) Environmental triggers - allergy to pets or passive smoking
4) Choice of drugs/devices - TECHNIQUE
5) Bad disease

Question 16

What factors would you look at in a severity assessment for asthma?

Answer 16

1) Resp rate poor indicator of severity compared to tachycardia, use of accessory muscles and chest recession.
2) Breathlessness interferes with talking - severe
3) Children require admission after high dose bronchodilator therapy if they have not responded well (breathless and tachycardia), exhausted with sats <92% on air, still have marked reduction on predicted peak flow.

Question 17

Moderate, severe and life threatening aspects of an acute asthma attack?

Answer 17

Moderate:
O2 sats is not <92% on air
Peak flow is not less than 50% of predicted
No clinical features of severe asthma

Severe:

1) Too breathless to talk
2) Use of accessory neck muscles and chest recession
3) O2 saturations <92%
4) Peak flow <50% predicted
5) Resp rate: 2-5yrs >50/min, over 5 yrs >30/min
6) Pulse rate: 2-5yrs >130/min, over 5 years >120/min

Life threatening:

1) Silent chest
2) Poor respiratory effort and ALOC
3) Cyanosis
4) O2 sats <92% and peak flow <33% predicted

Question 18

Management of acute asthma attack?

Answer 18

O SHIT ME:
O - 100% high flow oxygen - initial
S - Nebulised Salbutamol - repeat every 20-30mins PRN -initial
H - IV Hydrocortisone or Oral Prednisolone - initial
I - Nebulised Ipratropium Bromide - add-on
T - IV Theophylline or Aminophylline - add-on
M - IV Magnesium Sulphate - add-on
E - Escalate - Call all senior clinicians and consider CPAP

Can give IV theophylline with Ondansetron (antiemetic) beware of seizures, vomitting, and fatal cardiac arrhythmias with IV Theophylline/Aminophylline.

Continure bronchodilators 1-4hrs PRN, and discharge when stable on 4 hour treatment, continue oral prednisolone for 3 days. Not responding to Tx- refer to PICU or HDU - IV aminophylline/Salbutamol, IV magnesium Sulphate.