Common Respiratory Conditions Flashcards
What is dyspnoea?
difficulty breathing
What is perfusion?
amount of blood perfusing a capillary bed
What is Hyper/Hypoventilation?
Portions to ventilations: excessive or decreased
What is Bradypnoea?
Decreased respiration rate
What is Hypoxia?
reduced tissue oxygen
What is hypoxemia?
reduced oxygen levels in the blood
What is hypercapnia?
Increased CO2 levels in the blood
What is Acidosis?
low blood pH (<7.35)
What is Alkalosis?
High pH in the blood (>7.45)
What is Parenchyma?
A generalised term for the tissue of the lungs
What is a restrictive respiratory disease?
A small volume of air is flowing and the total lung capacity is lower.
There is a difficulty in inflating the lungs.
What is an obstructive respiratory disease?
A small volume of air is flowing OUT and the vital capacity is low.
There is an increased lung compliance.
How do restrictive (RR) and obstructive (OR) respiratory diseases differ?
RR there is difficulty inflating the lungs
OR it is easy to inflate the lungs but not easy to expel the air.
Is cystic fibrosis an restrictive or obstructive respiratory disease?
Often termed as obstructive disorder but has some elements of restriction.
What does CFTR stand for?
Cystic Fibrosis Transmembrane Conductance Regulator
What is CFTR?
CFRT is a chloride ion transporter with multiple ‘categories of variant defects’
What is the function of chloride ions?
Chloride ions are pumped out of a cell in the epithelium layer and are secreted onto the epithelial surface
What are some main cellular defects caused by the CFTR variants?
Defects in protein production
Defects in function of the ATP pump (rate of ions is compromised)
Defects in the regulation of the ATP pump (the way ATP binds to proteins)
Defects in protein processing (proteins cannot fold correctly)
What are some organs/systems that cystic fibrosis can affect?
Secondary biliary cirrhosis (auto-immune disorder)
Chronic pancreatitis
Abnormal sweat electrolytes (salty sweat)
Malabsorption of the gut
Lung/respiratory issues (thick mucous, honeycomb lung, lung abscesses)
What are some pathophysiological features in a CF lung?
- Dysregulated /reduced chloride secretion.
- Increased sodium reabsorption into epithelial cells - Water follows the sodium and is reabsorbed into the epithelium
- Mucous becomes ‘thicken’ and more sticky and adherent to the lungs
- pH is lowered in bronchial epithelia . The pH is acidic, compromising the immune defence of the 1st defence barrier
What can be observed from a x-ray of CF lungs?
- Hyperinflation of the lungs
- Chronic sinusitis (immunosuppressant)
- Bronchiectasis (airway widening)
- Peribronchial cuffing (thickened wall due to inflammation)
- Chronic pulmonary inflammation
- Atelectasis (collapsed alveoli due to obstructed bronchiole)
What causes airway widening (bronchiectasis) in CF?
Smooth muscle is lost and the airway looses its tone and strength.
What are some pathophysical complications of CF?
- Chronic airway infection
- Pneumothorax
- Fragile, distended blood vessels
- Pulmonary fibrosis (restrictive)
- Chronic respiratory failure
What factors can cause COPD?
Mainly smoking but also:
history of maternal/paternal/childhood asthma
severe respiratory infections before the age of 5
maternal smoking
What can you observe from an x-ray of someone who has COPD?
Hyperinflation of the lungs - the diaphragm is very flat
Narrow mediastinum due to hyperinflation
Chest is full of lung tissue, there is less space between lungs and mediastinum.
What are the 2 sides of COPD pathophysiologically?
Emphysema and chronic bronchitis
Why is emphysema and chronic bronchitis so common in COPD?
There are large air spaces so the respiratory surface is less.
A lot of elastic has been removed so the elastic recoil is a lot less, making it harder to empty the lungs.
What does a normal bronchial look like?
It has a nice, organised mucola with ciliated surface and organised goblet cells.
The sub mucosal mucous glands push mucus out to the surface
What does a COPD bronchial look like?
We have a thickened mucosa and submucosa, the mucus gland and goblet cell hyperplasia.
The organised border is missing. the pseudostratified columnar epithelial cells that are ciliated turn into squamous cells and the cilia disappear, loosing the mucus elevator.
What are COPD risk factors?
Tobacco smoking
Air pollution
Occupational dusts and chemicals
Childhood risk factors
How does smoking cause emphysema?
Smoke particles and chemicals are inhaled.
The neutrophils and macrophages engulf the smoke and as a result, change their behaviour to become ‘activated’ defensively
Serine elastase is released by neutrophils and macrophages. Serine breaks down the elastic tissue
Elastin of the lung is destroyed by the serine.
Reactive oxygen species are released by the cells, inhibiting the a1-antitrypsin. This inactivation leads to uncontrolled loss of elastic tissue.
What happens pathologically to your bronchioles as you continue to smoke?
Basal, Squamous, Goblet cell metaplasia
Thickened basement membrane
Mucus gland hyperplasia.
Pitting of mucosa
Generalised oedema
Why is there fibrosis when you smoke?
Fibrosis can occur due to the fibroblasts being recruited (as a result of the inflammation process).
The fibroblasts start to lay down strong, heavy fibres and fibros in the tissue, affecting the flexibility of the bronchioles.
How can you estimate the severity of a person’s chronic bronchitis?
By looking at the ratio of the mucus gland thickness and submucosa thickness, however this is an invasive technique.
Normal ratio = < 0.4
Severe ratio = > 0.7
What are some etiological factors that can cause an obstructive lung condition?
Character of the air being breathed in
Acid reflux
Post nasal drip
What is the immediate inflammatory response of asthma?
An allergen enters the system. The allergen binds to the immunoglobulins on the mast cells which degranulate. This leads to the inflammatory response and inflammatory mediators to be released.
What are some inflammatory mediators involved in the inflammatory response of asthma?
Histamine
Bradykinin
Leukotrienes
What is the delayed inflammatory response of asthma?
The eosinophils and other inflammatory cells start to release factors which reduce ciliary function and can lead to epithelial damage (degration of the collated cells)
The nervous system activated sensory nerve endings to produce an afferent nerve discharge back to the CNS which sends back efferent nerve discharge from the ANS, stimulating symptoms such as mucus secretion and bronchoconstriction
What are the acute/reversible effects of a small diameter of the airways?
Narrowed irregular lumen Sticky mucus Epithelial damage Increased vagal tone Reduced airflow Wheezing
What are the long term effects of a small diameter of the airways?
Smooth muscle hypertrophy Mucus gland hypertrophy Inflammatory cell infiltration Edema of bronchial wall Scarring Subepithelial fibrosis
What are intrinsic disorders?
Changes ‘inside’ of the lung that affects the compliance
What are extrinsic disorders?
Issues outside of the lungs that affect the ribcage, the fat/muscle that surrounds the ribcage and the connective tissue
What can the interstitial space in a restrictive respiratory disorder be associated with?
Fibrosis (collagen) between the alveoli
Fibroblast foci
Formation of scar tissue
Define fibrosis?
Excessive electric recoil, pulling the airways open, enlarging airways and hence losing the ability to fully inflate the lungs.
What are some symptoms of a restrictive respiratory condition?
Dyspnea Dry, unproductive cough Rapid shallow breathing Reduced chest movement Cracks and wheezes (lung crepitations ) Clubbing of fingers
What does Fick’s Law predict about interstitial lung disease?
Predicts that if we have a thicker membrane, it will take longer for gas molecules to diffuse across the membrane, compromising the diffusion capacity.
Results in a lower oxygen saturation in the blood
What main organs help to regulate the acid-base balance?
Kidneys (100mEq per day)
Lungs (10,000mEq per day)
What are symptoms of respiratory acidosis (pH <7.35)
Hypoventilation
Lung disease
Opiate driven hypoventilation
What are the symptoms of respiratory alkalosis (pH >7.45)
Hyperventilation
Anxiety
High altitude
What does ageing do to the respiratory system?
Decreases the respiratory surface area
Increases alveolar size
Increase of bronchiole diameter
Dysregulation of fibroblast function
Decrease in thoracic compliance
