W2L15 Dyspnoea Flashcards
Define the term dyspnoea
Subjective sensation of breathing discomfort: inappropriate relationship between respiratory work and total body work.
Can awareness of breathing can occur in normal settings?
Yes
What are the 5 clinical causes of dyspnoea? (categories)
Respiratory
• Cardiac
• Chestwallrestriction/muscleweakness • Metabolic/anaemia
• Psychogenic
– This is a diagnosis of exclusion (sick people are often anxious as well)
What are the 3 mechanisms of dyspnoea?
- Increased drive (demand) for ventilation – exercise, metabolic acidosis, hypoxia, anxiety
- Increased load (work of breathing) - resistive load, elastic load
- Decreased strength of respiratory muscles
What is a good way of eliciting the severity of dyspnoea on hx?
How limited are you? How far can you walk before you have to stop and have a break? How far could you walk before?
Where is the anatomical location of the problem? Wheeze
Airways
Where is the anatomical location of the problem? Crepitations
Terminal lung units
Where is the anatomical location of the problem? Stony dullness
Pleura (pleural effusion)
Where is the lung ‘silent zone’?
Pulmonary Vessels
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?
Pneumothorax (air within the pleural space)–> most likely
Arrythmia
PE
What are the examination findings of someone with a pneumothorax?
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.
What us the mechanism of dyspnoea in a pneumothorax?
Hypoxia–> increased drive
Pain and anxiety–> increased drive
collapsed lung–> increased load
What is the mechanism of a tension pneumothorax?
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.
How do you treat a tension pneumothorax?
Stick in a chest tube into the air filled pleural space to release the pressure.
What is the likely presentation/ examination findings of an acute asthma exacerbation?
SOB over hours/ days
widespread wheeze and dry cough
High RR, High HR, Normal BP, moderately low sats/ may be normal (but >95%)
What are the expected investigation findings in an acute asthma exacerbation?
CXR
peak flow
ABG and Aa gradient
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)
What is the mechanism on dyspnoea in asthma?
Increased resistive WOB–> increased load.
What is the likely presentation/ examination findings of an acute DVT PE?
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
What are the important differentials in a PE case?
Pneumonia (onset can be very acute), pneumothorax, arrhythmia, AMI, anxiety
What are the examination findings in someone with a PE? (obs and exam)
High RR, High temp (mild), High HR, normal BP, Low O2 saturation, chest auscultation normal.
What are the findings on investigation in a person with a PE?
CXR, ABG
CXR usually normal
ABG: pH high, CO2 low, O2 low. Hugh Aa gradient (lots of blood is not being oxygenated)
What is the mechanism of dyspnoea in a patient with a PE?
VQ mismatch–> hypoxemia–> increased drive.
What does a change in sputum colour indicate about a person with COPD and chronic productive cough?
acute bacterial exacerbation.
What are the examination findings in a patient with acute exacerbation of COPD
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
