22 When airways go wrong Flashcards
Types of respiratory diseases:
- Obstructive
- restrictive
- Infection and inflammation
What happens in obstructive diseases?
- Airway resistance is increased
- due to narrowing of the airways
- outflow pressure is reduced
- due to loss of elastic recoil?
What is airway resistance
the ease with which air can flow into and out of the lungs
What is outflow pressure?
The rate at which we can exhale
What effects do restrictive diseases have?
Reduced compliance
- loss of elasticity
- reduced vital capacity
What is compliance
The extent to which our lungs increase in volume in response to a given pressure change
How do we measure airway resistance?
Using FEV1 (the forced expiratory volume in the 1st second) - taken as a percentage of the total vital capacity
What is a normal FEV1
80% of vital capacity
What do we use FEV1 for?
- measuring airway resistance
- diagnosing airway resistance
- monitoring it
Name the obstructive pulmonary diseases:
- Bronchitis (acute and chronic)
- emphysaema
- asthma
what happens in chronic obstructive pulmonary disease:
- covers emphysaema and chronic bronchitis
- narrowing of the airways –> increased airway resistance
- mucus build up
- loss of elastic recoil –> reduced outflow pressure and gas exchange
- over inflation of the chest coz of increased residual volume
What kind of respiratory tract diseases can you get?
upper and lower
- upper is more common and easier to treat
- lower is more severe so more intense treatment
How many people die annually from COPD?
3 million
-3rd leading cause of death in the world
Acute Bronchitis:
- your standard phlegmy cough
- caused by bacteria or virus
- lasts for days or weeks
Chronic bronchitis: what happens
- irritants cause inflammation of the bronchi
- bronchi narrow
- over production of mucus
- airways become plugged
- airways become more prone to infection causing inflammation
Chronic bronchitis: causes
80% smoking, sometimes environmental irritants
Chronic bronchitis: treatments
- stop smoking
- bronchodilators (can be preventative) open up airways to aid airflow
- antibiotics to treat underlying infection
Chronic bronchitis: symptoms
- shortness of breath
- airway obstruction
- wheezing due to turbulent airflow
- chest pain - over exertion of muscles in breathing (not quiet breathing anymore, accessory muscles used)
- productive cough - can look for bacteria present in mucus of cough
Chronic bronchitis: lasts for
3 consecutive months in 2 years
Emphysaema: causes
smoking or an alpha1 trypsin deficiency (2% of COPD patients)
20% of smokers will develop emphyseama
Emphysaema: treatments
- stop smoking
- alpha1 antitrypsin supplements
- O2 supplement
- lung transplant
Emphysaema: what happens
-irritants in smoke cause neutrophils and macrophages to release elastase
-elastase breaks down alveolar walls reducing surface area
-significantly high compliance
-increased residual volume and FRC because damaged alveoli retain air
-chronically over inflated lung
-reduced vital capacity
-inefficient gas exchange
-Hyperventilation because of excess CO2 in lungs (to get rid)
(-alpha1 antitrypsin inhibits elastase action)
Emphysaema: symptoms
- hyperventilation
- inflated chest
- shortness of breath
- muscle wastage due to inefficient gas exchange and hyperventilation
what does high compliance indicate?
loss of elastic recoil
Asthma: Symptoms
-bronchoconstriction
-over production of mucus
-oedema (collection of mucus in cavities)
both cause increased airway resistance
Asthma: Treatments
Bronchodilators: -relievers -act immediately e.g. salbutamol -preventors -take two weeks to effect -contain steroids -dull down mast cell response Anti-inflammatories: Given in an asthma attack to re-inflate the airways
Asthma: Mechanisms
- mast cells stimulated by allergen
- release histamine and other cytokines
- bronchoconstriction
- mucus production
- oedema
- smooth muscle contraction narrowing airways
Asthma: Causes
- hypersensitive reaction to allergens
- exercise and cold air
- genetics
- stress
- air pollution
Name the restrictive diseases:
- fibrosis
- respiratory distress syndrome (IRDS, ARDS, SARS)
Acute Fibrosis: causes
-severe trauma or infection
Chronic fibrosis: causes
- industrial or environmental pollutants
- prescription drug taken over a long period of time
- disease process
Acute fibrosis causes
protein exudation - causes fluid build up (oedema) in the alveoli
Chronic fibrosis causes:
inflammatory processes which cause fibrosis
What is fibrosis
- replacement of lung tissue with connective tissue (collagen) and fibrotic tissue
- reduces gas exchange
- reduces compliance, makes lungs stiffer
Fibrosis: treatments
There are no treatments
Fibrosis: causes
- environmental or industrial pollutant inhalation
- cigarette smoke
- auto immune disease
Upper respiratory infections effect the
nasal cavity, pharynx and larynx
Lower respiratory tract infections include
-tuberculosis pneumonia and chronic bronchitis
Lower respiratory tract infections effect the
lungs, trachea and bronchi
how often does an adult get a upper respiratory tract infection?
2-4 times a year
How long does a normal cough last
15-18 days
How long does a productive cough last?
13-17 days
More women than men get productive coughs. T or F?
T
More men than women get productive coughs. T or F?
F
Pneumonia caused by:
bacteria
- usually streptococcus
- can be staphylococcus aureus or klebsiella
- effects the alveoli and bronchioles but can effect the lung
What happens in pneumonia?
Protein exudate fluid fills the alveoli, inhibiting gas exchange and this causes them to become airless and firm (consolidation)
consolidation
Protein exudate fluid fills the alveoli, inhibiting gas exchange and this causes them to become airless and firm
two types on pneumonia?
- bronchopneumonia
- alveoli in some of the bronchioles are affected
- lobar pneumonia
- alveoli in a certain lobe all become fluid filled
Tuberculosis stats:
new cases 2012:
active chronic cases 2012:
deaths:
8.8 million new
8 million active
1.2-1.5 millon deaths
TB is caused by
mycobacterium inhaled, extremely infectious, shows up red in sputum
How many phases are there in TB? Name them.
2
Latent
Active
Describe the Latent phase of TB
- mycobacterium innitiate response which causes the formulation of a granuloma in lung tissue
- isolated (only effect this lung tissue)
- not infectious
Describe the active phase of TB
- only occurs in 10% of people
- spreads to the bronchioles and into the circulation
- breaks down lymphnodes in order to enter the lymph
- spreads systematically
How does TB spread around the body
- Initially it replicates on the macrophages
- thought to spread due to inefficient immune response
- spreads to bronchioles
- moves to lymph and collagen gets deposited around the bacterium destroying lymph nodes and alveoli
- moves into the lymph and spreads systematically
Treatments for TB
Very difficult to treat due to antibiotic resistance
What percentage of people move from the latent phase to the active phase of TB?
10%
Why does Tb transition phases?
Due to an inefficient immune response
