Breathlessness and Cyanosis

Question 1

Define the following:
a) dyspnoea
b) tachypnoea
c) hyperventilation
d) hyperpnoea

Answer 1

a) difficulty breathing
b)increased rate of breathing (can occur with anxiety but also can indicate lung disease and/or metabolic disease)
c) overbreathing resulting in decreased alveolar and arterial pCO2 (associated with increased resp rate)
d) increased level of ventilation (volume of air) as occurs with metabolic acidosis

Question 2

What are the 2 key types of cause of sudden onset breathlessness

Answer 2

Pulmonary (pneumothorax; inhaled foreign body; anaphylaxis)

Cardiovascular (PE, MI)

Question 3

Give 4 broad groups of causes that could underlie a breathlessness with a onset over hours

Give examples for each area

Answer 3

Pulmonary (acute bronchitis; pneumonia; asthma)

Cardiovascular (LVF; pericardial tamponade; high altitude)

Psychogenic (anxiety; panic attacks)

Metabolic (diabetic ketoacidosis; uraemia; poisons)

Question 4

Name 3 poisons that could cause breathlessness with an onset over hours

Answer 4

salicylate
methyl alcohol
ethylene glycol

Question 5

Name 3 poisons that could cause breathlessness with an onset over hours

Answer 5

salicylate
methyl alcohol
ethylene glycol

Question 6

Give 5 broad groups of causes that could underlie a breathlessness with a onset over days to months

Give examples for each area

Answer 6

Pulmonary (TB; chronic bronchitis; emphysema; bronchiectasis; pleural effusion; interstitial lung disease)

Cardiovascular (heart failure; recurrent PE; pulmonary hypertension)

Neuromuscular (Myasthenia gravis; MND; myopathies)

Mechanical (chest wall and skeletal abnormalities; morbid obesity)

Metabolic (thyroid disease; anaemia)

Question 7

What are the key things you need to ask about when taking a history of a breathless patient

Answer 7

Speed of onset
Associated symptoms
Medications
Past Hx

Question 8

Which associated symptoms do you need to be aware of when assessing breathlessness in a Hx

Answer 8

Cough and sputum
Wheeze
Chest pain
Haemoptysis
Peripheral oedema

Question 9

What are key things to look for when examining a breathless patient

Answer 9

cyanosis
oxygen saturations
PEF
chest sounds/ observations

Question 10

What investigations do you want to do on a breathless patient

Answer 10

Radiology - CXR, thoracic CT
Respiratory function tests - PFTs, 6 MWT, CPET
Blood gas

Question 11

What should blood pH be

Answer 11

7.35-7.45

Question 12

What is the normal range for PO2 and PCO2 in the blood?

Answer 12

PO2= 11-15kPa

PCO2= 4.5-6kPa

Question 13

What is the normal range of
a) [H+] and
b) [HCO3-] in the blood

Answer 13

a) 35-45nmol/L

b) 22-30mmol/L

Question 14

What causes type 1 resp failure

Answer 14

acute hypoxaemia and diseases that damage lung tissue eg:
- pulmonary oedema
- pnuemonia
- idiopathic pulmonary fibrosis (+interstitial lung disease)
-asthma

Question 15

What causes type 2 resp failure

give examples of when this occurs

Answer 15

ventilatory failure - when alveolar ventilation is insufficient to excrete the volume of CO2 produced by tissue metabolism

-COPD
-chest wall deformities
-respiratory muscle weakness (Guillan-Barre/ myasthenia gravis…)
-depression of respiratory centres (eg opiate overdose)

Question 16

How could metabolic acidosis cause breathlessness

Answer 16

increased acid production and/or decreased elimination would mean the HCO3- buffer gets used up so has to compensate via hyperventilation causing PCO2 to fall

Question 17

Give 3 causes of metabolic acidosis

Answer 17

Diabetic ketoacidosis
Renal failure
Lactic acidosis

Question 18

What is lactic acidosis and what are the different types of lactic acidosis

Answer 18

acidosis from increased lactate production due to reduced tissue perfusion or reduced ability of cells to use O2

Type A: +tissue hypoxia (eg circulatory failure)
Type B: no tissue hypoxia (eg toxicity)

Question 19

What tends to cause metabolic alkalosis

Answer 19

loss of acid or XS alkali administration leads to decreased [H+] with a small increase in PCO2 and [HCO3-]

Question 20

What is base excess

Answer 20

calculated estimated of the non-respiratory influences on total buffering capacity

Question 21

When is CRP raised

Answer 21

In bacterial infections and inflammatory disease - levels rapidly fall to baseline following resolution of injury/infection

Question 22

Name a key autoimmune condition where CRP is not raised

Answer 22

SLE

Question 23

What are 4 broad differential diagnoses for pulmonary infiltrates in asthmatic patients

Answer 23

Infection (look for cough, sputum, fever, pleuritic chest pain and bronchial breathing)

Inflammation

Haemorrhage (vasculitis in Churg-Strauss syndrome)

Malignancy

Question 24

What should you look at on the imaging of a patient presenting with acute breathlessness

Answer 24

lung parenchyma (alveolar filling, interstitial thickening, airway disease)

pulmonary vascular (large vessel obstruction - PE)

cardiac causes (pleural oedema, pericardial effusion)

pleural problems (pneumothorax; haemothorax/ pleural effusion)

Question 25

Describe what consolidation looks like in a CXR

Answer 25

homogenous opacity

obscures vessels

poorly defined margins

air bronchograms without volume loss

air acinograms

poorly defined nodules

Question 26

What is lobar pneumonia

Answer 26

pneumonia involving all or a large part of a lobe

Question 27

What is bronchopneumonia

Answer 27

mixed alveolar and airway inflammation

Question 28

What does interstitial pneumonia look like

Answer 28

oedema and interstitial thickening

Question 29

Give 4 radiographic features of bronchopneumonia

Answer 29

bronchial wall thickening with ill-defined nodular opacities

patchy inhomogeneous consolidation involving several lobes

often volume loss of lobe or segment as airways involved

may progress to lung abscess or pneumatocoele

Question 30

Give 3 complications of pneumonia

Answer 30

abscess

empyema

fibrosis - organising pneumonia

Question 31

What do you look for on the imaging of someone with chronic breathlessness

Answer 31

-lung parenchyma (alveolar thickening; interstitial thickening, emphysema)

-pulmonary vascular (large vessel obstruction - chronic thromboembolism; pulmonary hypertension)

-cardiac (myocardial; valvular)

-Pleural (effusion, thickening)

Question 32

What does interstitial fibrosis look like on a CT

Answer 32

interstitial thickening

architectural distortion

tractional airway dilatation

honeycombing

ground-glass opacity

Question 33

What does interstitial lung disease do

Answer 33

mainly affect alveolar structure (alveolar filling; interstitial fibrosis)

reduces elasticity of the lung (bc scar tissue is inelastic; restrictive deficit on spirometry)

increases distance from alveolus to capillary (impairs gas transfer, breathless on exertion, oxygen desaturation on exercise)

Question 34

Which type of pulmonary fibrosis has the poorest outcome

Answer 34

idiopathic

median survival is 3 years from diagnosis

Question 35

What are the risk factors for idiopathic pulmonary fibrosis

Answer 35

• sex (male>female by 2:1)

-age (>60yrs)

-smoking (2.8x increase)

-occupation (hard woods, metal exposure)

-GORD?

Question 36

Give 3 key features of Usual Interstitial Pneumonia

Answer 36

subpleural distribution

honey combing

increased risk of lung cancer

Question 37

What is pneumoconiosis

Answer 37

permanent alteration of lung structure due to inhalation of mineral dusts (asbestos, silica, coal, cobalt, beryllium)

Question 38

Name 5 asbestos related diseases

Answer 38

asbestosis

mesothelioma

lung cancer (smoking has a multiplicative effect)

pleural fibrosis

fibrous pleural plaques

Question 39

Give 2 ways to sample the lung tissue

Answer 39

BAL or lung biopsy