Dental Management of Patients with Asthma & COPD Flashcards
List the composition of upper respiratory tract of a child:
- Large occiput
- Short neck
- Large tongue (relative to head size)
- Narrow nasal passages
- Epiglottis positioned higher
- Decreased airway characteristics
List composition of lower respiratory tract of a child
- Short and narrow trachea
- Sternum less rigid
- Horizontally positioned ribs
- Increased alveolar surface area, small total volume of gas exchange
Define Asthma according to Greenwood 2003
Chronic inflammatory disorder characterised by generalised airway obstruction and bronchospasm.
Define asthma according to Zhu and Hidalgo et al. 1996
Initially a reversible bronchoconstriction caused by airway hypersensitivity
Define asthma according to WHO
A disease characterised by recurrent attacks of breathlessness and wheezing, which vary in severity and frequency from person to person. In an individual, they may occur from hour to hour and day to day.
Prevalence of asthma?
Very common chronic obstructive disease of childhood + adulthood.
- 2014/15: 10.8% of all Australians with asthma (2.5 million)
- M = F for all ages, M > F for 0-14 yo
- 2013/14: 37,700 hospital admissions for asthma, 389 deaths
- ABTSI: 1.9x more likely to have asthma than non-ABTSI
Rank of asthma as non-fatal hospital burden in ages 5-14
No. 1
Rank of asthma as non-fatal hospital burden in ages 15-49
8th
rank of asthma as non-fatal hospital burden in ages 50-69
11th
Rank of asthma as non-fatal hospital burden in ages 70+
14th
Rank of asthma as non-fatal hospital burden in all ages
7th
Mild asthma?
Wheezing < 2 days/week, exercise tolerance
Moderate asthma
Wheezing 2-5 days/week, nocturnal symptoms, limited exercise tolerance
Severe asthma
Daily wheezing, exercise intolerance, frequent nocturnal symptoms
Global initiative for asthma (2016)
- Severity + responsiveness to meds
- Controlled, partially controlled, uncontrolled
Triggers for asthma?
Exercise, seasonal, drug-induced
Mild-moderate episode of asthma
- Cough (continuing), wheeze, chest tightness, shortness of breath
- Tachycardia, tachypnoea, use of accessory muscles (typically lasts for minutes
Severe episode of asthma
- Respiratory distress with tachypnea, nasal flaring
- Intercostal mm. retractions, cyanosis, pulsus paradoxus (typically lasts for hours to days)
Aetiology of asthma
- Genetic predisposition
- Gene-by-environment interactions
Risk/triggering factors for asthma
- Maternal smoking
- Low socioeconomic status
- Extended breastfeeding
- Early viral respiratory infections
- Exposure to allergens
- Pollution
- Antibodies, NSAIDs
- Exercise
How to diagnose asthma
- Clinical examination + various non-specific respiratory function tests
Defining features of asthma in >5 year old
- Positive history of respiratory symptoms (wheeze, shortness of breath, chest tightness, cough)
- Expiratory airflow limitation
It is difficult to diagnose asthma in <5 year olds as early S+S mimic several respiratory conditions.
True
Asthma is often diagnosed after successful treatment of an acute attack with?
Beta-2 agonists
Pathophysiology of acute airway inflammation
Release of chemical mediators from activated resident cells (mast cells) undergoing histamine degradation
Pathophysiology of subacute airway inflammation
Early cellular infiltrate (mainly eosinophils), releasing mediators with toxic effects on the respiratory epithelium
Pathophysiology of chronic inflammation
- Irreversible airway obstruction due to eosinophils + lymphocytes (mainly CD4+ T lymphocytes) mediating a persistent, ongoing inflammation that results in a vicious cycle of extensive tissue damage and repair.
- Subepithelial thickening, mucous gland hypertrophy, bronchial muscle wall hypertrophy
- Decreased airway diameter -> airway resistance -> difficulty with expiration
Medical management and pharmacological management of asthma
- Avoidance of precipitating factors
Pharmacological management: - Bronchodilators (short + long acting beta2 agonists, anticholinergic agents, theophylline)
- Anti-inflammatory agents (inhaled + systemic corticosteroids, nedocromil sodium)
- Mast cell stabilisers (cromolyn sodium, nedocromil sodium)
- Leukotriene antagonists (antileukotriene, e.g. Montelukast)
Preventative medication for asthma
- Bronchodilators (long-acting, e.g. salmeterol)
- Inhaled low-dose corticosteroids
- cromolyn sodium / nedocromil sodium (usually an alternative to steroids)
- Systemic corticosteroids (last resort for unresponsive cases)
- Most children have an asthma plan prepared by their doctor
Acute management for asthma
- Short-acting bronchodilators (e.g. salbutamol)
- Remove aggravating factors
Definition of COPD according to Qaseem et al. 2011
Broad category of irreversible respiratory diseases characterised by reduced expiratory flow
Definition of COPD according to Hupp 2006
COPD includes conditions such as emphysema and chronic bronchitis, both with different clinical presentations but that can coexist together causing irreversible structural changes to the airways.
Devlin’s definition of emphysema
Emphysema is characterised by permanent enlargement of airspaces distal to the terminal bronchioles. The elastic recoil of the alveoli is compromised affecting the tendency of the lungs to force air out. Gas exchange becomes insufficient due to the inability of lungs to expire air passively.