L7 - Paediatric Asthma Flashcards
Asthma clinical characteristics
Characterised by recurrent episodes of wheeze, cough and breathlessness.
Inflammation of airways.
Bronchial hyper-reactivity
Risk of asthma will increase if…
- Positive family history of asthma and atopy
- Maternal smoking in pregnancy
- Early sensitisation to air borne allergens.
Atopy
Genetic tendency to develop allergic diseases such as:
- allergic rhinitis
- asthma
- atopic dermatitis (eczema)
How may you test for asthma?
Test Peak Flow
- repeat after administration of short acting beta 2 agonist.
What is an example of a first line preventative treatment for asthma?
Inhaled corticosteroid
Advantage of using an inhaler with a spacer
- Delivery of drug to lungs is optimised.
- Children must be shown how to use inhaler and have their technique checked.
Adverse environmental factors leading to asthma
- Contine levels (exposure of nicotine in tobacco)
- Exposure to household mould
- Allergy to pets
Co-morbidities associated with asthma
- Obesity
- rhinosinusitis (inflammation of sinuses and nasal cavity)
- food allergy
- Dysfunctional breathing
- exercise induced laryngeal obstruction
Signs of an asthma attack (6)
- Difficulty talking . walking
- Unable to feed
- Little relief with salbutamol
- Drop in peak flow
- Hard and fast breathing
- Coughing and wheezing a lot.
Describe an example of a personal action plan of a patient during an asthma attack
- 10 puffs of salbutamol
2. If symptoms persist then call ambulance
Episodic viral wheeze could be due to…
- Exercise
- Viral cold
- Exposure to allergens
- Cold air
Sarcoidosis
- Multi-system inflammatory disorder
- which most commonly involves the mediastinal lymph nodes and lungs
What is pulmonary langerhan cell histocytosis?
- Proliferation of Langerhan cells
- Occurs in response to cigarette smoke
Alveolar lipoproteinosis
Rare
Characterised by accumulation of eosinophillic material within alveoli.
Describe different types of lung tumour
Can either be:
1- Primary (most common, majority related to cigarette smoking)
2- Secondary
Common sites of metastases in lung cancer
- Lymph nodes
- Pleura
- Adrenal glands
- Bone
- Brain
Risk factors of lung cancer
- Cigarette smoking
- asbestos exposure
- uranium mining
- radon gas
- pulmonary fibrosis
Describe squamous cell carcinoma
Tumour usually central in location.
Frequency cavitate.
Recognised by presence of keratin.
Cavitation
Phenomenon where rapid changes in pressure in liquid lead to formation of small vapor filled cavities.
Describe an adenocarcinoma
what gives evidence towards an adenocarcinoma?
May be central or peripheral
Acinar or papillary glandular growth pattern.
Evidence of mucin production by cell.
Describe a large cell undifferentiated carcinoma?
These tumours are poorly differentiated.
Show no evidence of squamous or glandular differentiation
Small cell lung carcinomas arise in…
Central bronchus
Contrast Asthma with COPD
Reversibility of airway obstruction in asthma contrasts with COPD.
In COPD - obstruction is either not reversible or only partly reversible at best with a bronchodilator
Describe the pathophysiology of asthma
- Asthmatic’s have activated T cell with T-helper TH2 cells.
- TH2 cytokine released will attract other inflammatory granulocytes (eosinophils, Interleukin 5, granulocyte-macrophage colony)
- stimulating factor which causes esinophils to produce cysteinyl leukotrienes.
- Release granule protein that damages epithelium
IgE on mast cells will trigger…
- Degranulation.
- Release of histamine and Leukotriene B4.
- Both are powerful bronchoconstrictors
Define asthma
Recurrent reversible airway osbtruction with attack of wheeze, shortness of breath and often a noctural cough, severe attacks cause hypoxaemia and are life-threatening.
Activation of TH2 lymphocyte and cytokine generation will promote…
- Differentiation and activation of eosinophil
- IgE production and release
- Expression of IgE receptor on mast cell and eosinophil
Anti-asthmatic drugs
Bronchodilators
Anti-inflammatory agents
Growth factors released from inflammatory cells will…
- Act on smooth muscle cells
- Causing hypertrophy
- Smooth muscle can itself release pro-inflammatory mediators and growth factors
Treatment for very mild asthma
- short acting bronchodilator - usually an inhaled short acting Beta 2 agonist such as salbutamol or terbutaline
Why are corticosteroids the mainstay of drugs in asthma?
Only asthma drugs that potentially inhibit T-cell activation.
Helps reduce the inflammatory response
Role of B-Adrenoreceptor agonists
- Dilate bronchi, direct action of B2 adrenoreceptors of smooth muscle
- Inhibit mediator release from mast cells
- Inhibit TNF-a from monocyte
- Increase mucus clearance action by cilia
How may Beta 2 agonist be administerd?
Aersol
Powder
Nebulised solution
Short term relief from asthma
Salbutamol, terbutaline
- Inhalation
- duration of action 3-5hrs
- peaks in 1st 30mins
Long term relief from asthma
Salmeterol and Formoterol
Inhaled.
Duration 8-12hrs
Examples of muscarinic receptor antagonists
Ipratropium
Bronchodilator
Role of glucocorticosteroids
- Anti-inflammatory
- restrain clonal proliferation of THelper cells by reducing the transcription factor for gene IL-2
- inhibit generation of vasodilator PGE2, PGI2
Describe muscarinic agonists
e.g. ACH
Can cause:
- bradycardia, vasodilation leading to a fall in BP, contraction in visceral smooth muscle (gut, bladder and bronchi). exocrine secretions, pupillary constriction
Describe muscarinic antagonists
- Atropin, tiotropium
Can cause: - inhibition of secretions, tachcardia, relaxation of smooth muscle, inhibition of gastric acid secretion.
Describe methylxanthines
Cause
- mild diuresis
- stimulation of cardiac muscle
- relaxation of smooth muscle (broncial)
- bronchdilator!
What will cause the synthesis of glucocorticoids?
Influence of ACTH secreted from AP will cause synthesis of glucocorticoids.
