Asthma
- Created by: BeckiSweet95
- Created on: 24-11-19 17:51
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- Asthma
- What is Asthma?
- A chronic inflammatory disorder of the bronchi
- Characterized by episodic, reversible bronchospasm
- Caused by a bronchoconstrictor response to various allergens/irritants
- Clinical diagnosis based on recognition of characterized symptoms without other explanations
- Pathophysiology
- When an antigen is inhaled this causes an immune response.
- Airway becomes leaky due to inspired antigen - allows white blood cells to the tissues
- Antigen exposure triggers activation of dendritic cells and macrophages
- Macrophages engulf and eliminate the antigen.
- Antigen presenting cells (APC), present the antigen to T helper cells.
- Th2 cells stimulate activation of IgE and eosinophils
- Eosinophils cause tissue injury through release of neuropeptides
- Contribute to bronchial hyperresponsiveness
- IgE cells bind to the antigen, and then bind to the surface of mast cells
- Mast cells are then activated and release histamine
- Histamine causes bronchoconstriction and airway oedema.
- Bronchioles produce excess mucus to trap the antigen.
- Can cause mucus plugs which obstruct the airway
- Airway obstruction via inflammation increases airflow resisttance and decreases flow rate
- This can trap air which causes decreased diffusion in the alveoli, resulting in VQ mismatch.
- Airway obstruction via inflammation increases airflow resisttance and decreases flow rate
- Can cause mucus plugs which obstruct the airway
- Bronchioles produce excess mucus to trap the antigen.
- Histamine causes bronchoconstriction and airway oedema.
- Mast cells are then activated and release histamine
- Eosinophils cause tissue injury through release of neuropeptides
- Th1 and Th2 cells contribute to bronchoconstriction.
- Th1 activate lymphocytes and produce proteins
- Th2 are needed for differentiation and proliferation of B cells
- Th2 cells stimulate activation of IgE and eosinophils
- Antigen exposure triggers activation of dendritic cells and macrophages
- When asthma is not managed well, epithelial tissue can peel away
- This reduces cilliated epithelium, meaning mucus is not moved away
- Airway remodelling causes the smooth muscle in the bronchioles to become thickened
- Lumen is now narrowerer than usual
- Risk Factors
- Exposure to allergens/irritants
- Genetics
- If a parent has asthma, their child will be more susceptible to it
- Excercise
- Excercise causes people to breathe more quickly through their mouths
- Cold, dry air travels to the lungs
- This irritates the airway, causing smooth muscle to tighten, increasing the chances of an asthma flare up
- Cold, dry air travels to the lungs
- Excercise causes people to breathe more quickly through their mouths
- Stress
- Can make the inflammatory response more prominent to environmental triggers
- Frequent respiratory infections
- Recurrent respiratory infections with wheezing episodes during early life are a risk factor for development of asthma in later life.
- Infections are linked with asthma exacerbation.
- If there is damage to the epithelial barrier, this is a risk of more severe infections
- Treatments
- Respiratory Assessment
- Chest observed for pattern of breathing, symmetry of chest movement and sounds such as wheezing
- Monitoring
- ECG
- Monitor heart rate. Side effect of salbutamol is tachycardia
- Blood Gas
- Monitor oxygen and carbon dioxide in the blood
- Peak flow
- Measure how quickly air can be expelled from the lungs
- Indicates narrowing of the bronchiolles
- Measure how quickly air can be expelled from the lungs
- ECG
- Medications
- Inhaled corticosteroids taken daily
- Reverse inflammation of the airway
- Sulbutamol inhaler
- Opens the airway during symptomatic episodes
- Ocygen
- Reverse hypoxia during attack
- Magnesium sulfate
- Given during an attack. Relaxes bronchiolle muscles and expands the airway
- Inhaled corticosteroids taken daily
- Education
- Correct inhaler technique
- Advice on avoiding triggers
- Follow Up
- GP
- Monitor patient
- Prescribe medications
- GP
- Respiratory Assessment
- Symptoms
- Cough
- Inflammation of bronchial tubes prompts a non-productive cough
- Wheeze
- Narrowing of the lumen and obsturction caused by excess mucus production causes the wheeze sound
- Tachycardia
- Heart rate increases to compensate for lack of oxygen in the blood
- Tachypnoea
- Respiratory rate increases in attempt to increase oxygen in the blood.
- Shortness of breath
- The lungs can't hold as much air due to inflammation and mucus buildup
- Cough
- Child Development
- What is Asthma?
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