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62 Cards in this Set
- Front
- Back
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What is a wheeze?
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A continuous sound within a portion of the breathing cycle generated from within the lungs, often referred to as an adventitial sound. It is caused by a process that reduces the calibre or cross sectional area of trachea or major bronchi.
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What are crackles in the context of lung sounds?
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Discontinuous popping sounds.
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How many generations/divisions are there in the bronchial tree?
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~20-23
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Can you hear airflow in the very peripheral airways?
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No, the calibre of individual airways decreases, while the total cross section area increases with each generation, leading to a very low, inaudible velocity (human ear only hears 1m/s velocity).
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How might a smaller airway issue cause wheezing?
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Dynamic narrowing of trachea or bronchi in expiration. If airflow resistance increases in the bronchioles (e.g. in asthmatic attack), expiration switches from being passive to being active by making pleural pressure positive. This increases alveoli pressure, and down (towards mouth) from where pleural pressure = intraluminal pressure, dynamic airway closure can occur.
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How is the noise itself made in a wheeze?
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High pitch sound is produced when the airway lumen is narrowed to the point where the opposite walls are almost in contact, accelerated gas flow induces oscillation of the airway, dependent on elasticity of the airway wall, causing noise like in a vibrating reed.
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What is stridor?
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The continuous Inspiratory musical respiratory sound heard in patients with an upper airway obstruction. More prominent over the neck than chest. Most commonly caused by laryngeal obstruction or muscle weakness.
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Which portion of the airways tend to collapse in inspiration?
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The upper airways, due to negative intra-airway pressure.
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What conditions might you hear a wheeze in?
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Any which narrows airway calibre e.g. bronchospasm, intraluminal tumours or secretions, foreign bodies, mucosal oedema, external compression of an airway by tumour, dynamic airway compression.
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What is atopy?
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Predisposition to produce IgE antibodies in response to ordinary exposure to allergens in the environment. Commonly see asthma, rhinitis and eczema/atopic dermatitis, food allergies.
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What is a Type I allergy?
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Immediate reaction caused by IgE (IgG too?) binding to mast cells and allergen, crosslinking and causing degranulation of histamine.
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How is IgE synthesis regulated?
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Activated B cells/Plasma cells are directed to make IgE due to IL4 (not IFN-gamma) released by Th2 cells, which also release IL5 which attracts eosinophils. TH1 cells, Tregs produce IFN-gamma which suppresses IgE production.
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What is the order of progression of atopic disease in a growing child?
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Atopic dermatitis and food hypersensitivity in infancy, asthma and allergic rhinitis in preschool and school.
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How is evidence of IgE sensitisation to allergens demonstrated?
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RAST – radioallergosorbent test/ ‘in vitro allergen specific IgE measurement’.
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What is the usual cause of acute episodes of asthma particularly in infancy?
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Respiratory viruses
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What organisms may cause asthma-wheezing in young children?
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The most common are the viruses rhinovirus (the most common) and RSV, less common are the parainfluenza viruses, coronaviruses, enteroviruses and adenoviruses, rarer causes are mycoplasma pneumonia in school aged children, Chlamydia trachomatis in infancy and Chlamydia pneumonia, and bacteria don’t cause cause wheezing.
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What do we use to detect viruses in children with an acute exacerbation of asthma?
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ELISA and PCR
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What type of cytokine and cellular profile do you see in atopic individuals responding to airway viruses?
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Th2 helper cell with IL4 and IL5, but not IL2 or IFN-y, with eosinophilic infiltration secondary to GM-CSF. Rhinoviruses = IL8
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What type of cytokine and cellular profile do you see in a normal, non-atopic response to airway viruses?
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Th1 with IFN-y and IL2.
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How many children have been infected by RSV by the end of their 2nd winter?
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95%
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What is bronchiolitis?
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An acute lower respiratory infection characterised by tachypnoea, hyperinflation and crackles, babies.
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What percentage of children who are infected with RSV develop bronchiolitis?
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40%
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What % of babies who develop bronchiolitis severe enough for hospitalisation develop asthma?
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50%
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What does the evidence suggest about the correlation between RSV and asthma?
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RSV is more severe in babies who were already predisposed to asthma/atopy, rather than RSV actually inducing asthma by causing mucosal damage to airways and sensitising airways to aeroallergens.
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What pathological events cause the symptoms in asthma?
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Bronco constriction, mucosal oedema, mucus hyper secretion.
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What are the symptoms of an asthmatic attack?
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Wheeze, breathlessness, tight non- productive cough, respiratory distress. If severe there may be no wheeze and chest tightness, tachypnoea, tracheal tug, intercostals/subcostal recession, accessory muscle use and pulsus paradoxus (severe drop in bp during inspiration) might occur.
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What are common triggers of an asthma attack?
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RSV in children, exercise in adults, dietary triggers, cigarette smoke, bed mites.
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What are the most useful indicators for establishing asthma severity?
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frequency of acute episodes, presence of interval symptoms (exercise and or nocturnal induced), lifestyle disruption (hospitalisation, school/work absence, exercise restriction, growth), frequency of bronchodilator use.
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What factors must be present in a health problem for it to be considered as a national health priority area (NHPA) ?
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pose significant health burden, have potential for health gains and improved outcomes for consumers, have the support of all jurisdictions (commonwealth/state Territory?).
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What are the 7 priority areas for Australian health?
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Asthma, cancer control, CVS health, Diabetes mellitus, Injury prevention and control, Mental health, Arthritis and musculoskeletal conditions.
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How many Australians are estimated to be suffering from asthma?
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2 million/ 11%
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How many asthma deaths are thought to be preventable?
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up to 60%
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How many Australians are admitted into hospital each year for their asthma?
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60 000
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How many primary school children, adolescents and adults are affected by asthma?
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1/4, 1/7 , 1/10
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What are the 5 key strategies of the National Asthma Action Plan?
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1) development of agreed national guidlines and tools for the mgmt, prevention and early detection of asthma based on evidence an d consumer needs. 2) Wide dissemination and consistent application of national guidelines and tools. 3) Integration among health care providers in delivering care based on the guidelines and tools and consumer needs. 4) Evaluation of the development, dissemination and implementation of the evidence-based guidelines and tools 5) Extension of the understanding of, and knowledge about asthma through applied research and access to quality information
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What does the Asthma 3+ Visit Plan involve?
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Improve health for moderate to severe asthma sufferers by 3 GP visits over 4 months including diagnosis and assessment, development of a mgmt plan and patient education and review of the plan. GPs can claim mediocre for this, and it is based on Level I evidence – reduces hospitalisation, unscheduled doctor visits, nocturnal asthma and QOL.
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What are the 6 aims for the Australian centre for Asthma Monitoring (ACAM)?
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1) develop systemic approach to asthma surveillance 2) Monitor and report disease levels, burdern, trends with general pop and subgroups 3) Examine social/geographical and environmental differentials that may influence asthma burden 4)Identify potential for improved prevention and mgmt strategies 5)Track impact of health policy, prevention and mgmt strategies 6) Develop and manage special projects and collaborations for the integration and enhancement of asthma related info.
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What are the 24 asthma indicators identified by ACAM grouped into?
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Disease prevalence, comorbidity, primary care/ed attendance/hospital separation, QOL, Mortality, RF, Mgmt, Health maintenance, Education, Severity, Disability.
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What are the 3 main aspects of the NAC Asthma Management Handbook?
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assess the severity of the patient’s asthma by good history-taking, achieve patient’s best lung function through the use of meds, maintain best lung fn by optimising dosage of meds and trigger avoidance
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What is a written Asthma Action Plan?
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An individual written guidance formulated by patient and doctor to give guidance for identifying signs of worsening controls, and giving instructions for how to respond to a change in asthma control.
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What are the 2 categories of agents used in Asthma management?
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Long Term/preventers, short term/relievers/bronchodilators
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What do cromoglycate and nedocromil do in asthma management?
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Inhaled drugs which block antigen induced bronchoconstriction and exercise induced asthma. Nedocromil has anti-inflammatory properties. May irritate upper airways.
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What do beclomethasone, budesonide, fluticasone and ciclesonide do in asthma management? Which of these is the most potent?
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Inhaled corticosteroids with a potent topical anti-inflammatory activity to reduce airway hyperresponsiveness (AHR) over the long term. Fluticasone is twice as potent as beclomethasone and budesonide.
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What are the side effects of inhaled corticosteroids?
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Sore throat, oral candidiasis, dysphonia in upper airways, if very high doses inhaled can cause systemic side effects such as easy bruising. Undergo first past metabolism in liver so if swallowed does not really have systemic effects.
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How much of an inhaled drug might actually reach the target in the lungs?
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20%, as 80% is usually deposited in the oropharynx or swallowed unless devices such as a spacer are used which allow more to travel to lungs.
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What are montelukast and zafirlukast and how do they work?
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Oral anti-leukotriene drugs used in asthma prevention which block the actions of leukotrienes at receptor sites of airway smooth muscle. Especially useful against Ag challenge and exercise induced bronchospasm
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What are LABA?
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Inhaled Long acting Beta agonists e.g. salmeterol and eformoterol which bind to beta receptors in smooth muscle of airways to induce relaxation of bronchioles. Often used in conjunction with Inhaled CorticoSteroids, so lower ICS doses are required.
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How many people are affected by atopic eczema?
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10% of population, 20% Australian children
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Where do you find atopic eczema on the body?
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Begins on face, then localises to extensor surfaces of limbs before settling in the flexures, where it often continues in the cubital and popliteal fossa into adulthood.
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How many cases of atopic eczema are adult onset?
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10%
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What are the key clinical features of eczema?
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Itch, associated with skin dryness and thickening (lichenification) due to repeated rubbing and scratching.
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What protein is thought to be mutated in associated with atopy?
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Filigrin mutations, reducing skin barrier function.
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What is a common complication arising from scratching in atopic eczema?
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Secondary infection due to breaking of skin surface and the altered innate immunity in the skin which renders atopic individuals more susceptible to infections.
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What principles are followed in the treatment of atopic eczema?
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Avoid exacerbation eg use bath oil instead of soap. Topical corticosteroids used daily, daily or more use of emollients, wet dressings of cotton over the steroids can help improve over a few days, antibacterial therapy if prone to infection, UVB phototherapy if severe or resistant eczema, immunosuppressive if severely atopic.
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What are examples of the Obstructive Airways Diseases?
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Asthma, Emphysema, Chronic bronchitis, bronchiectasis.
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What is obstruction of airways caused by in asthma?
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mucus, epithelial sloghing, epithelial hyperplasia, inflammatory swelling/oedema, granulation tissue, hypertrophy/plasia of smooth muscle and submucous glands, loss of elastic recoil due to inflammation and overdistaention.
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What will be the macroscopic appearance of the lung in a severe untreated asthmatic?
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Overinflation with rib impressions and petechiae, mucus plugging or bronchi and bronchioles, bronchitis, atelectastis, bronchectasis, Pneumothorax/pneumomediastinum.
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What will be the likely histological features within the lumen of a severe asthmatic’s lung?
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mucus plugs in bronchi and bronchioles with whorls of mucus/epithelium (Curshmann’s spirals) Eosinophils and Charcot leyden crystals (made from broken down eosinophils), epithelial sloughing
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What will be the likely histological features within the epithelium to submucosa of a severe asthmatic’s lung?
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sloughing of epithelium, hyperplastic epithelium, increased goblet cell numbers, thickened epithelial basement membrane, oedema and cellular infiltrate in bronchial mucosae including eosinophils neutrophils B cells and mast cells, increased size of submucosal glands, hypertrophy of bronchial smooth muscle in wall.
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What are the major histological features in the lung parenchyma of a severe asthmatic’s lungs?
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Over distention due to over inflation
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What pathology can occur secondary to the development of mucus plugs?
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aspergillus colonisation of the mucus plugs.
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What are possible clinic-pathological outcomes in a severe asthmatic?
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ventilation-perfusion mismatch, bacterial infections with superimposed chronic bronchitis/bronchiectstasis/pneumonia/aspergillosis infection, cor pulmonale possibly leading to heart failure
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