W2L15 Dyspnoea

Question 1

Define the term dyspnoea

Answer 1

Subjective sensation of breathing discomfort: inappropriate relationship between respiratory work and total body work.

Question 2

Can awareness of breathing can occur in normal settings?

Answer 2

Yes

Question 3

What are the 5 clinical causes of dyspnoea? (categories)

Answer 3

Respiratory
• Cardiac
• Chestwallrestriction/muscleweakness • Metabolic/anaemia
• Psychogenic
– This is a diagnosis of exclusion (sick people are often anxious as well)

Question 4

What are the 3 mechanisms of dyspnoea?

Answer 4

1. Increased drive (demand) for ventilation – exercise, metabolic acidosis, hypoxia, anxiety
2. Increased load (work of breathing) - resistive load, elastic load
3. Decreased strength of respiratory muscles

Question 5

What is a good way of eliciting the severity of dyspnoea on hx?

Answer 5

How limited are you? How far can you walk before you have to stop and have a break? How far could you walk before?

Question 6

Where is the anatomical location of the problem? Wheeze

Answer 6

Airways

Question 7

Where is the anatomical location of the problem? Crepitations

Answer 7

Terminal lung units

Question 8

Where is the anatomical location of the problem? Stony dullness

Answer 8

Pleura (pleural effusion)

Question 9

Where is the lung ‘silent zone’?

Answer 9

Pulmonary Vessels

Question 10

Sudden onset SOB in a 23 yo male, severe, present for a few hours. Associated moderate pleuritic chest pain that started with SOB. What is the most likely diagnosis, and 2 other key differentials?

Answer 10

Pneumothorax (air within the pleural space)–> most likely

Arrythmia

PE

Question 11

What are the examination findings of someone with a pneumothorax?

Answer 11

Looks unwell, distressed with increased WOB

High RR, High HR, Normal BP, afebrile, Low (<95%) O2 saturation.

Possible trachea deviation

decreased unilateral chest expansion (on side of pneumothorax), hyperesonant on that side.

Question 12

What us the mechanism of dyspnoea in a pneumothorax?

Answer 12

Hypoxia–> increased drive
Pain and anxiety–> increased drive
collapsed lung–> increased load

Question 13

What is the mechanism of a tension pneumothorax?

Answer 13

Air leaving into pleural space via a one way valve (eg from the lung, air can get in but not out), which progressively pushes more air into the pleural space (SOB)–> lung deflates–> increased pressure–> mediastinum gets pushed to contralateral side (mediastinal shift) and becomes compressed–> BVs including veins move across–> vena cava close/ kink–> reduced venous return to RA–> reduced blood in lungs–> reduced amount of oxygenated blood–> acute reduction in CO–> SHOCK.

Question 14

How do you treat a tension pneumothorax?

Answer 14

Stick in a chest tube into the air filled pleural space to release the pressure.

Question 15

What is the likely presentation/ examination findings of an acute asthma exacerbation?

Answer 15

SOB over hours/ days

widespread wheeze and dry cough

High RR, High HR, Normal BP, moderately low sats/ may be normal (but >95%)

Question 16

What are the expected investigation findings in an acute asthma exacerbation?
CXR
peak flow
ABG and Aa gradient

Answer 16

Normal CXR
Low peak flow (indicates airflow obstruction. <500)
ABG: pH high, CO2 low, O2 low, HCO3 normal= resp aklylosis

Aa gradient: widened (VQ mismatch, not enough ventilation)

Question 17

What is the mechanism on dyspnoea in asthma?

Answer 17

Increased resistive WOB–> increased load.

Question 18

What is the likely presentation/ examination findings of an acute DVT PE?

Answer 18

Sudden onset severe SOB in a person with risk factors (female, recent surgery, hyper coagulable, female, cancer, sedentary etc)

• Right sided pleuritic chest pain
• Mild fever

Leg swelling

Question 19

What are the important differentials in a PE case?

Answer 19

Pneumonia (onset can be very acute), pneumothorax, arrhythmia, AMI, anxiety

Question 20

What are the examination findings in someone with a PE? (obs and exam)

Answer 20

High RR, High temp (mild), High HR, normal BP, Low O2 saturation, chest auscultation normal.

Question 21

What are the findings on investigation in a person with a PE?

CXR, ABG

Answer 21

CXR usually normal

ABG: pH high, CO2 low, O2 low. Hugh Aa gradient (lots of blood is not being oxygenated)

Question 22

What is the mechanism of dyspnoea in a patient with a PE?

Answer 22

VQ mismatch–> hypoxemia–> increased drive.

Question 23

What does a change in sputum colour indicate about a person with COPD and chronic productive cough?

Answer 23

acute bacterial exacerbation.

Question 24

What are the examination findings in a patient with acute exacerbation of COPD

Answer 24

High RR, High temp, High HR, normal BP, Low O2 sats.

Increased WOB and use of accessory muscles

hyperinflation (barrel chest, decreased chest expansion, hyper-resonant percussion)

prolonged expiration with wheeze

Question 25

What are the examination findings in someone with an acute exacerbation of CHF?

Answer 25

Increased WOB
High RR, afebrile, high HR, low BP, low (<95%) O2 saturation
Displaced apex beat
3rd heart sound
stony dull percussion at lung bases and bilateral inspiratory creps just above the dull areas.

Question 26

What are the investigation findings in someone with an acute exacerbation of CHF?

Answer 26

(may have ECG abnormalities eg AF)

ABGs: high Ph, Low CO2, Low O2, Low/ normal HCO3