Respiratory System Flashcards
what is asthma?
an obstructive disease, where there is resisitance to the flow of air through the airways during inspiration and expiration
what does the degree of resistance depend on?
airway diameter
laminar turbulent flow
what is FEV1?
amount breathed out in 1 second
forced expiratory volume
what does the FEV1/FVC ratio indicate?
under 70%= diagnose with asthma
what are the showing signs of asthma?
dyspnoea
wheezing
tight chest
cough
what are the 3 main factors of asthma?
airway constriction (narrowing)
airway hypersensitivity and responsivness
mucous hyper-secretion
what are the causes of asthma?
cytokine response profiles
allergens
pollutants
infection
stress
age
how do the host factors and environmental exposusres become asthma?
altered innate and adaptive immune responses
symptoms and chronic changes
what does inflammation due to asthma cause?
airway obstruction
AHR/ bronchospasm
Airway remodelling (long term changes in the airway
what are some trigger factors of asthma?
allergens
chemicals
drugs
foods
environmental chemicals
cold air
excersise
stress
workplace
how is the IgE antibody associated with asthma?
the propensity to develop IgE antibosies to common antigens
this is associaated to succeptability to develop asthma, allergic rhinitis, eczema
pin prick test for asthma?
early onset asthma will have more of a positive result
1/3 of pop have +ve results
about a 1/3 of them end up getting asthma
what causes extrinsic asthma?
specific triggers
what causes intrinsic asthma?
non-specific triggers
what ar specific triggers of asthma?
allergens, occupational agents (SO2, ciggarette smoke)
what is the process of sensitisation of genitically predisposed individuals to allergens?
allergen–> dendritic cell (antigen presenting cell)–> Th0 helper cell –> immune response –> Th2 lymphocyte –> cytokines–> call in immune cells (mast cells and eosinophils)
what are the 2 phases of an asthma attack?
early phase; increase in resistant airflow
immediate response to release of inflammatory mediators from mast cells
late phase: can occur a long time after allergen exposure
driven by continuation of inflammation chara terised by an influx of eosinophils into the lungs
what is the paradigm of asthma pathophysiology?
mast cell activation/ degranulation
immediate inflammatory responses
late inflammation responses
inflammation reduced airway remodelling
what happens when epithelium breaks down?
smooth muscle grows over–> narrowing the airway
what is the process of mast cell degranulation?
Cross linking IgE receptor by binding antigen results in mast cell to degranulate leading to the release of histamine and other inflammatory mediators.
what happens during mucus plugging?
during inspiration the air moving in can fold the mucus over blocking the bronchus, which mean that the air cannot escape during expiration
what are the theraputic goals of asthma?
Minimal symptoms day & night
Minimal need for reliever medication
No exacerbations
No limitation of activity
Normal lung function
what are the therapeutic treatments given for asthma?
reliever (bronchodilators)
preventer (corticosteroids)`
why are drugs given through the respiratory route?
rapid onset of activity when given for a local affect
smaller dose required
what are the pulmonary drug delivery fundamentals?
patient
formulation
delivery systems
drug physiocochemucal properties
why is density important for aerodymic factors?
Density is important for the aerodynamic factor of the particle
Small aerodynamic is what we want for drugs that are delivered to the lungs
what size particles are going to reach the alveolar duct?
1-2 micron particles
what does every branch in the airways add?
a generation
what are the pulmonary drug delivery devices?
pressurised metered-dose inhalers
dry powder inhalers
nebulisers
electronic ciggarettes
how does the phase of drug change in PMDIS?
held under hih pressure in the canister= liquid
release= lower pressure= gas
what is the cold filling of pMDI canisters?
Drug + excipients + propellant chilled to -60°C and added to canister
Further (chilled) propellant added and canister sealed (with the valve)
what is the pressure filling of pMDIs?
Drug + excipients + propellant added to canister under pressure (through the valve)
Further propellant (under pressure) added
how has the formulation of pMDIs changed over the years?
pMDIs originally contained chlorofluorocarbons (CFCs) but discovered in 1980s that these damaged the ozone layer
CFCs removed from pMDIs during the late 1990s/ early 2000s and replaced with hydrofluoroalkanes (HFAs)
what are the advantages of pMDIs?
Portable (vs. nebulisers)
Low cost
Drug protected from environment in canister
Multiple doses in one device
Reproducible dose
Efficient at drug delivery (cf. oral route)
Disposable
what are the disadvantages of pMDIs?
Incorrect use by patients
Greenhouse gases
Inefficient at drug delivery!
Disposable!
what is COPD?
a disease state characterised by the presence of chronic bronchitis and/or emphysema associated with airflow obstruction: air flow obstruction is often accompanied by airway hyperreactivity and may be partially reversible
what is chronic bronchitis?
lung damage and inflammation in the airways (bronchi)
what are the symptoms of chronic bronchitis?
chronic cough
sputum production
haemoptysis
initially mild dyspnea
cyanosis
peripheral oedema
what is emphysema?
lung damage and inflammation of alveoli
what are the symptoms of emphysema?
enlargement of the air spaces distal, further away to the terminal bronchioles
dyspnea
minimal cough
pink flush in the face
hyperinflation
tachypnea
what are the COPD functional changes?
Airway obstruction
Air trapping
Hyperinflation
Mucus hypersecretion
Ciliary dysfunction
Gas exchange impairment
Pulmonary hypertension
Cardinal triad of COPD
Dyspnoea
Chronic cough
Sputum production
what is the epidemiology of COPD (smokers)?
Approximately 90% of COPD patients are smokers
although only 15% of smokers develop COPD
In the 10% of non-smokers who suffer from COPD, causative factors include environmental factors (passive smoking, pollutants, inhalation of other toxins) and developmental lung changes
COPD increase with age and are higher in men
Inflammation dominated by neutrophil invasion of the lung tissue
The most important identified genetic risk factor for the evolution of COPD is deficiency of α1-protease (α1-antitrypsin) inhibitor
when should a diagnosis of COPD be considered?
over the age of 35
who have a risk factor (generally smoking)
and who present with:
exertional breathlessness
chronic cough
regular sputum production
frequent winter ‘bronchitis’
or wheeze.
what is the pathophysiology of COPD?
Inflammatory response –’> amplified –> macrophages–> attract immune cells–>increase of neutrophils–>proteases–> alveolar wall destruction and mucus hypersecretion
what is the treatment of COPD?
corticosteroids
long acting beta-agonists
anticholinergics
oxygen
avoid respiratory infections
smoking cessation
what are the tests used to make an asthma diagnosis?
Spirometry
Peak Expiratory Flow
Asthma Control Questionnaire (ACQ)
Asthma Control Test
FeNO
Eosinophil differential count
what are the classifications of uncontrolled asthma?
Uncontrolled asthma describes asthma that has an impact on a person’s quality of life
3 or more days a week with symptoms or
3 or more days a week with required use of a SABA for symptomatic relief or
1 or more nights a week with awakening due to asthma.
what is maintenance and reliver therapy (MART)?
MART is a type of asthma treatment plan.
If a patient is on a MART plan, they have just one inhaler to use as a preventer and a reliever.
A MART inhaler is a combination inhaler that contains:
An inhaled steroid + A long-acting bronchodilator with a fast onset of action (Formoterol)
Not all combination inhalers are licensed for MART
when is it appropriate to use MART?
patients on step 2 or 3 or 4 with a personalised action plan, able to self manage and who are compliant with their own treatment, uncontrolled symptoms
what are the high risk drugs for use in asthma?
selective B2-agonists
inhaled corticosteroids
theophylline
leukotriene receptor antagonists
what is the treatment guidline for COPD?
spirometrically confirmed diagnosis –> assesment of airflow limitation –> assessment of symptoms/ risk of exacerbations –> post-bronchodilator
what are the pharmocological management of COPD?
LAMA (leads to hospitalisation)
a bronchodilator (not leading to hospital admission)
what is the follow up pharmocological treatent for dyspnea?
LABA–> LAMA
–> switching inhaler devices or molecules –> investigate other causes of dyspnea
what is the follow up pharmocological treatment of exacerbation?
LABA–> LAMA–> ICS –> azithromycin –> roflumilast
what are the step of treatment of COPD?
assessment
diagnosis
refer
prescribe
review
what are some of the inhaled antimuscarinics?
sama
lama
what is exacerbtion in COPD?
increased dyspnea, increased sputum volume, increased sputum purulence
what is the management of exacerbation of COPD?
short acting (sama, saba) usually at higher doses through nebuliser
withold lama if sama is given
short course of oral perdnisolone
antibiotics for sings of infection
what are the prevention of exacerbations of copd?
pulmonary rehabilitation
education and self management
integrated care programs
what is custic fibrosis?
It is a genetic disorder affecting the lungs, pancreas, liver, intestine, and reproductive organs.
what are the main clinical signs of cystic fibrosis?
pulmonary disease, with recurrent infections and the production of copious viscous sputum, and malabsorption due to pancreatic insufficiency.
what are the complications of cystic fibrosis?
include hepatobiliary disease, osteoporosis, cystic fibrosis-related diabetes, and distal intestinal obstruction syndrome.
what are the aims of treatment of cystic fibrosis?
Preventing and managing lung infections
Loosening and removing thick, sticky mucus from the lungs
Preventing or treating intestinal obstruction
Providing sufficient nutrition and hydration
what is a key predictor of life expectancy in prople with cystic fibrosis?
lung function
what are the non-drug treatments of cystic fibrosis?
Provide advice on airway clearance, nebuliser use, musculoskeletal disorders, physical activity, and urinary incontinence (by specialist physiotherapists).
Regular exercise improves both lung function and overall fitness.
whaat are the drug treatments of cystic fibrosis?
Treatment is based on the prevention of lung infection and the maintenance of lung function.
Patients, who have clinical evidence of lung disease, the frequency of routine review should be based on their clinical condition.
Adults should be reviewed at least every 3 months.
More frequent review is required immediately after diagnosis.
what should patients with cystic fibrosis who have evidence of lung disease be offered?
mucolytic
what is mucolytics?
Dornase alfa is the first choice mucolytic.
If there is an inadequate response, dornase alfa and hypertonic sodium chloride, or hypertonic sodium chloride alone should be considered.
Mannitol dry powder for inhalation is recommended as an option when dornase alfa is unsuitable, when lung function is rapidly declining, and if other osmotic drugs are not considered appropriate.
what should be offered to patient with cytsic fibrosis with a pulmonary infection?
Staphylococcus aureus: Offer an antibacterial oral or IV
Pseudomonas aeruginosa: Offer an oral antibacterial in combination with an inhaled antibacterial.
Aspergillus fumigatus complex: Offer an antifungal drug only to suppress chronic complex respiratory infection in patients with declining pulmonary status.
what are the innervation of the lungs?
Parasympathetic nervous system activation triggers bronchoconstriction
Predominantly VAGAL nerve
Sympathetic nervous system activation triggers bronchodilation
Increased lung capacity
Preparation for exercise
what are the steps to smooth muscle contraction?
Ca2+ ions increase
Extracellular
Sarcoplasmic reticulum
Ca2+ Bind to calmodulin
Ca2+ / calmodulin complex then activates myosin (light chain) kinase (MLCK)
MLCK phosphorylates myosin
Allows myosin heads to bind to actin
Fibres contract (power stroke)
Background level of tone
what is the process of parasympathetic innervation?
Parasympathetic dominant
VAGAL Nerve (cranial nerve X)
M1, M2, M3 present, M3 most important
M3:
Produce mostly stimulatory effects
Glands (secretion)
Smooth muscles of airways (contraction)
(NB Relaxation of vascular smooth muscle - vasodilatation)
what is the processof sympathetic NS innervation?
Sympathetic nerves innervate blood vessels and glands in trachea and bronchus
NOT airway smooth muscle
Many Beta-adrenoreceptors human smooth airway muscle and alveoli
Beta 2
Respond to circulating agonists
Relax bronchial smooth muscle
Mast cells: Inhibit mediator release
Epithelium: enhance muco-cilliary clearance
Reduced calcium
what receptors are contained in brochial smooth muscle?
histamine-bronchoconstriction
leukotrienes -bronchoconstriction
what are the therapeutic aims of asthma and COPD?
relief- rescue patient from bronchospasm
prophylaxis - reduce frequency and severity of attacks, limit structural remodelling
what are the classes of bronchodilaters?
β-adrenoceptor agonists
Xanthines
Muscarinic receptor antagonists
Leukotriene receptor antagonists
Histamine receptor antagonists
what are the classes of anti-inflammatory drugs?
Glucocorticoids
Cromoglicate and nedocromil (Cromones)
Anti-IgE (immunotherapy)
Phosphodiesterase (PDE) inhibitors (also bronchodilator effect) – cover in COPD
what are the mechanisms of beta adrenoceptor agonists?
β2 receptor stimulation
via Gs activates adenylyl cyclase that increases intracellular levels of cAMP - cAMP activates protein kinase A (PKA)
PKA phosphorylates numerous targets leading to bronchodilation (reduction of intracellular Ca2+)
why use inhaled therapy?
lower doses leading to fewer side effects
faster onset of action with inhaled bronchodilators than systemic
what are the different types of beta-adrenoreceptor antagonists?
short acting
long acting
what are the characteristics of short acting beta-adrenoreceptor agonists?
Hydrophilic in nature
Short duration of action (4-6 hours)
As needed, PRN
what are the characteristics of long acting beta-adrenoreceptor agonists?
Lipophilic in nature
Leech out of membrane prolonging duration of action (gen 8-12 hours)
NOT given as needed
Adjunctive therapy
MUST NOT be given in the absence of a corticosteroid
what are the unwanted effects of beta-adrenoreceptor agonists?
Result from Systemic absorption
Commonest-
Tremor
Other-
Nervous tension
Headache
Muscle cramps
Peripheral vasodilatation
High doses-
Hypokalemia after high doses
Tachycardia
Cardiac dysrhythmias