Obstructive Conditions

Asthma

This is a disease which is due to reversible airway bronchoconstriction, most often due to allergic stimuli.

– Whereas the symptoms and development are very similar to adults, the diagnostic criteria and management are different for childre

Diagnosis:

For patients 5-16 years:

– Bronchodilator reversibility test: a positive test is improvement in FEV1 of 12% or more

– FeNO only requested if normal spirometry or negative BDR test

– FeNO: a level of >= 35 parts per billion (ppb) is considered positive

For patients < 5:

– Diagnosis based on clinical judgement

Acute Management:

If Moderate:

–> Give salbutamol, one puff every 60s up to 10 puffs via spacer or fitting mask (if < 3years)

If Acute Severe or Life Threatening:

–> Transfer to hospital and give high flow Oxygen therapy to maintain SpO₂ 94-98%

– 1st line = Salbutamol nebulized with O₂ (+ repeat every 20-30 minutes) + oral prednisolone

– If no response, add ipratropium bromide to the nebuliser

– 2nd line = IV salbutamol (15ug/kg over 10 mins) then aminophylline

– 3rd line = IV magnesium sulphate (40mg/kg/day)

Discharge when stable on 2-4hrly inhaled bronchodilators, PEF >75% best predicted and SpO2 >94%

– Arrange follow up in GP within 2 days and paediatric asthma clinic 1 month after 

Chronic Management:

i) For ages 5-16:

– Start with short acting B₂ agonist for symptom relief. If symptoms >3 times/week or at night:

– Step 1 –> SABA + low dose inhaled corticosteroid (ICS)

– Step 2 –> SABA + low-dose ICS leukotriene receptor antagonist (LTRA)

– Step 3 –> SABA + paediatric low-dose ICS + LABA

– If still unresolving –> refer patient for specialist care

Cystic Fibrosis

This is an autosomal recessive condition due to a delta F508 mutation in CGTR gene on Chromosome 7

– This is a cAMP- regulated Cl- channel. The mutation causes poor chloride secretion across epithelium leading to production of very thick, sticky mucus which clogs airways/tracts

– In the UK, most common mutation is the deltaF508 mutation (deletion of phenylalanine), which results in misfolding of the CFTR protein and failure to migrate from the endoplasmic reticulum

– It affects 1 per 2500 births and the carrier rate is 1 in 25

– Newborns in the UK are screened for CF by tests for IRT (immunoreactive trypsinogen) in the blood

Diagnosis:

Most cases are detected during new-born screening programmes

– Sweat test – measures Cl- in sweat, elevated in cystic fibrosis (>60mEq/L)

False Positives: Malnutrition, adrenal insufficiency, hypothyroidism

False Negative: Skin oedema, seen in pancreatic exocrine insufficiency

Management:

This uses an interdisciplinary approach to manage symptoms as no definitive cure

– Respiratory: twice daily chest physiotherapy and multiple courses of antibiotics for recurrent infections

– GI: pancreatic enzyme replacement, liver transplant, and high calorie/fat diet 

Primary Ciliary Dyskinesia (PCD)

This is a rare autosomal recessive disorder where there is a genetic defect in the cilia which line the respiratory tract, the fallopian tubes, and the flagella of sperm cells.

– The mutation leads to dysfunctional proteins which make up the cilia and flagella meaning they are unable to waft mucus and other chemicals properly

– Poor functioning leads to impaired muco-ciliary clearance giving recurrent infections

– If untreated, leads to chronic inflammation of the respiratory tracts leading to severe bronchiectasis

– In addition, dysfunction of cilia during embryological development mean that transcription factors may not flow in the right direction, which can lead to organs being developed in the opposite direction.

– This can lead to dextrocardia/situs inversus (known as Kartagener Syndrome)

Symptoms:

– Recurrent productive cough

– Purulent nasal discharge

– Chronic ear infections

– Infertility –> due to poor sperm mobility

– Dextrocardia/situs inversus seen in 50% of patients with PCD

Diagnosis:

Microscopy of the cilia of nasal epithelial cells brushed from the nose

Management:

– Daily physiotherapy to clear secretions

– Regular proactive treatment of recurrent infections with antibiotics