Respirology Flashcards
Describe the pathophysiology of asthma
Allergen taking by antigen presenting cell to CD4 Th2 cell -> secretion of IL4 which activates IgE -> IgE attaches to Fc receptor on mast cell -> subsequent exposure of allergen results in mast cell degranulation and release of inflammatory cytokines -> vascular permeability, inflammation, bronchospasm, and airway hyperesponsiveness -> chronic have eosinophils that cause edema, smooth muscle contraction and goblet cell activation
What are some risk factors for asthma?
History of atopy
Urban area
History of bronchiolitis
History of maternal smoke exposure
Discuss the differences between intermittent and chronic asthma
Intermittent: due to small airways where any airway inflammation results in further narrowing and wheezing. Usually only have symptoms with colds and they improve with time
Chronic: due to atopic mechanism following respiratory syncytial virus infection leading to IgE. Have chronic symptoms with exacerbations due to allergens, viral infections or exercise
This the possible investigations for asthma in children
<6 must due therapeutic trial if are having prolonged wheezing or cough with colds
>6 can do pulmonary function testing
>8 can do methacholine challenge
List the common inhaled corticosteroids and their doses for mild, moderate and severe
Fluticasone: 100mcgBID, 125mcgBID, 250mcgBID
Beclamethasone: 100BID, 200BID, 400BID
Budesonide: 200BID, 200TID, 400BID
Take 1-6 weeks before have any affect
Only 15% reach the lungs
Can decrease doses by 25% if are able to handle triggers
Side effects: thrush, Dysphoria, hypothalamic-pituitary axis dysregulation, grow 1cm less in first year but usually make it up
Discuss leukotriene receptor blockers for the treatment of asthma
Block the leukotriene receptor, so are useful with viral URTI as they receptors are more active. Onset in 1 day
Montelukast: 2-5 4mgqHs, 6-14 5mg, >14 10mg
Discuss the use and effectiveness of bronchodilators for asthma
Short Acting Beta2 Agonists: Salbutamol
- QID at onset of colds
- q4h during exacerbations
- before exercise
Long Acting Beta2 Agonists: Salmeterol or Formoterol
- onset within 5-30 minutes and last for 6-12 hours
- addition of long acting improves symptom control and lung function, however must use with inhaled corticosteroid or have increased risk of life-threatening exacerbation
Side effects: tremor, headaches, palpitations
What are two combination inhalers
Advair: Fluticasone and Salmeterol (>6yo)
Symbicort: Budenoside and Formoterol (>12yo)
What is the pathophysiology of cystic fibrosis?
Autosomal recessive inheritance of CFTR gene -> results in Cl not being transported out of the cell -> results in no gradient for Na and water to cross -> increase viscosity of secretions leading to obstruction and mucostasis
List some of the sequelae from cystic fibrosis
Respiratory tract:
- mucostasis results in chronic infections and rhinosinusitis and nasal polyps
- mucostasis results in mucous plugging and bacterial pneumonia (staph -> h flu -> pseudomonas -> nosocomial)
- bronchiectasis due to chronic lung scarring and fibrosis
GI:
- mucostasis leads to pancreatic insufficiency and malnutrition, steatorrhea and failure to thrive
- chronic obstruction of pancreas leads to dysfunction and diabetes
- mucostasis can block bowel leading to meconium ileus, constipation, obstruction or intussusception
- mucostasis block biliary tree leading to liver cirrhosis
Reproductive
- obstruction of vas deferens leading to infertility
- thickened cervical mucous and infertility
List some of the investigations for cystic fibrosis
Diagnostic: - heel prick for highly immunoreactive trypsinogen - sweat chloride test - CFTR gene mutation Pulmonary function test - obstructive disease (low FEV1, low FEV1/FVC, scooped curve) Chest X-ray - hyperinflation - tram tracks from bronchiectasis - increased pulmonary markings
Discuss the management of cystic fibrosis
Chest physiotherapy for secretions (percussion, positive expiratory pressure)
SABA
Inhaled dornase alfa to reduce viscosity of mucous
Inhaled tobramycin for pseudomonas infection
Nutritional counselling and pancreatic enzyme supplementation
Oral or IV antibiotic for exacerbation
Discuss three different types of apnea in children
Central: failure of medulla to coordinate breathing movements
Obstructive: obstruction of airway resulting in failure to ventilate
Mixed: central and obstructive
Discuss the presentation and management of pertussis
Organism:
- Bordetella pertussis
Phases:
Catarrhal phase:
- 1 week of mild URTI symptoms
Paroxysmal phase:
- 6 weeks of paroxysmal coughing with inspiratory whoop and post-tussive vomiting
Convalescent phase:
- 6-10 weeks of gradual decrease in cough (prolonged due to bacteria necrosis to cough receptor)
Investigations:
- in those with >=2 weeks of cough with at least one of: paroxysmal, post-tussive vomiting, cough with inspiratory whoop must perform nasopharyngeal aspirate
- apnea <1
- lymphocytosis
Management:
- isolation for 5 days if receive treatment or after >21 days of symptoms
- Antibiotics if symptom onset less than 3 weeks (usually only prophylactic):
- Azithromycin PO x5, or Clarithromycin PO x7
- Erythromycin PO x7-10
Discuss the presentation and management of tracheitis
Organism: - Staph aureus - group A strep - h flu Presentation: - fever - brassy cough - worsening stridor - large amount of purulent discharge Treatment: - secure airway - cefuroxime