What are respiratory causes of shortness of breath
Asthma
COPD
Pulmonary fibrosis
Lung cancer
Pulmonary embolism
Pneumothorax
LRTI
What are some cardiovascular or systemic causes of dyspnoea
Congestive heart failure
Pulmonary oedema
Valvular defects
Acute coronary syndrome
Anaemia
Renal/ liver failure
What investigations can you do to help narrow differential diagnosis of dyspnoea
Chest X ray
ECG
Spirometry
FBC
Urea, glucose, electrolytes
What are the types of lung conditions
Restrictive and obstructive
What causes dyspnoea is restrictive lung disease
Normal lung tissue is lost (and sometimes replaced)
- that reduced the healthy lung tissue volume and inhibits inflation of lungs (can’t get air in)
What are examples of restrictive lung disease
Pulmonary fibrobrosis - replaces lung tissue
Sarcoidosis - replaces lung tissue with granules
NM Disorders
Congestive cardiac failure and obesity stop= stop lungs fully inflating
How does obstructive lung disease cause dyspnoea
Narrowing of vessels (due to destruction/ damage)
- increases resistance => makes it difficult to exhale and slows flow of air
Examples of obstructive lung disease
CF
Bronchiecstasis
A1AT deficiency
Asthma
COPD
How does a restrictive condition change FVC and FEV1
Reduces FVC, total lung capacity and can reduce FEV1
- but FEV/FVC ration is normal
How can obstructive lung disease change FEV and FVC
No impact on FVC, total lung capacity but reduced FEV and FEV/ FVC ratio
What are the two pathophysiologies associated with COPD
Chronic Bronchitis and emphysema stem
What is chronic bronchitis
Chronic inflammation causes an increase in goblet cells and mucous gland hypertrophy
=> more mucous secretion
=> this narrows airway and causes a cough
How does emphysema occur
Chronic inflammation causes macrophages and neutrophils to be recruited to the lungs
=> neutrophil elastase breaks down elastin fibres in alveolar
=> loss of elastic recoil, alveolar shape
=> lung hyperinflation
How does hyperinflated chest appear on a chest X-ray
Vertically elongated heart
Flattened diaphragm
More than 7 anterior ribs visible
Bulae- air holes
How do cigarettes induce COPD
Cigarette smoke contains oxidants and activate lung macrophages
=> macrophages recruited eutrophication and release proteases
=> neutrophils release proteases and ROS
=> causes parenchmyal lung damage=> emphysema
And inflammation => bronchitis
How can smoking cessation help COPD
It can reverse bronchitis which can alleviate some lung damage and symptoms
What are some options for smoking cessation
Vapes
NRT - meds with low levels of nicotine but no poisonous inhaled chemicals
Varenicline (Champix) - acts as a NRT and blocks dopamine pathway for addiction
Bupropion (Zyban) - impact addiction pathway
How can nutrition help with COPD
Low carb diets reduces the CO2 generated and need for excess expiration
Fruits and veg that are anti-oxidant can help with oxidant damage
Anti inflammatory foods
How can COPD patients avoid LRTI
Vaccinations
Wearing masks
How does the nervous system innervate the lungs
Parasympathetic nerve release ACh which causes contraction and narrowing
Adrenaline and NA act on B2 receptor (via external sympathetic influences) and dilate and widen airways
What are SABA bronchodilators
Short acting beta agonists (eg salbutamol)
Activate Beta 2 receptors and dilate airways
Rescue therapy
How do LABA bronchodilators work
Long acting beta agonist (e.g. salmeterol, formeterol)
Bing to beta 2 agonist and elicit longer effect (maintenance)
How does SAMA bronchodilators work
Short acting muscarinic antagonist (be ipratropium bromide)
Block Muscarinc M3 receptor causes airways to not contract
What is LAMA
Long term muscarinic anatagonist eg Tiotropium
Maintence therapy
