Cases from General Practice - Breathlessness Flashcards
When assessing a patient with shortness of breath, what two types of causes should be considered?
- RESPIRATORY
- NON-RESPIRATORY
What parts of the brain are involved in breathlessness?
- Anterior insula, anterior cingulate gyrus and prefrontal cortex involved
- Same areas that feel pain
- Fear and anxiety exacerbate breathlessness
Define dyspnoea.
- Labored breathing
- Subject conscious of shortness of breath
What characteristics are indicative of breathlessness?
- Sensation of ‘air hunger’
- Difficulty in inspiration and expiration
- Feeling chest is filled up
What causes breathlessness?
- Hypoxia / high CO2
- Airway obstruction
- Decreased lung compliance
- Acute right heart strain
- Chest wall stiffness
- Acidosis
- Anaemia
What are the respiratory causes of sob?
- Asthma
- COPD
- Pneumonia
- Pneumothorax
- Lung cancer
What are the non-respiratory causes of SOB?
- Hypovolaemic/cardiac/septic shock
- Anaemia
- Pulmonary oedema
- MSK/neurological conditions
How does hypoxia influence breathlessness?
- Increases respiration and sensation of breathlessness
- Present in patient with pneumonia with low PO2
- Sensation not increased by hypoxia following chest wall paralysis
What is the effects of increased PCO2 on breathlessness?
- Feeling of air hunger and increases respiration
- Effects on chemosensitive areas of brainstem
What are the effects of airway obstruction?
- Breathing against resistance sensed by individual
- Increased input from chest wall muscles and stretch receptors
- Increase in brain activity
Describe hyperinflation.
- Within airway narrowing and collapse, air trapping and increase in residual volume
- Sensation increases during exercise
- Activates pulmonary stretch receptors
Describe sensation from the chest wall.
- Muscle spindle afferents transmit signals reflecting strength of contraction and length of muscle
- Paralysis or vibration over chest wall reduces inputs send to brain
- Common when residual volume increased/inflation
Describe what occurs in decreased lung compliance.
- Local congestion activates J receptors in bronchial wall (exception - in transplants)
- Harder for lungs to expand when full of fluid or inflamed
- More energy required to expand chest wall
Describe J receptors.
- Situated next to capillaries in bronchial wall
- Input to brainstem via vagus
- Activated by congestion, oedema and irritants
- Activation shortens expiration, increases respiration frequency
Describe acute right heart strain.
- Occurs when pulmonary artery occluded even if hypoxia is mild e.g during pulmonary emboli
- Rise in arterial pressure due to right heart failure causes pulmonary vasoconstriction. Symptoms worsen
Describe the role of the chest wall and muscles in breathlessness
- Increased load or effort by the chest wall means increased breathlessness
- Hyperinflation - muscle contraction less efficient. Increased breathlessness
- Ventilation reduced in chest stiffness/weakened breathing muscles
Describe acidosis.
- During metabolic acidosis, increase in respiration and therefore air hunger
Describe dysfunctional breathing.
- During hyperventilation, increased expiration of CO2. Produced alkalosis. Increased effort involved in breathing
- Occurs during spasms of the larynx and reduced size of orifice during inspiration
Describe the sensations of breathlessness.
- Consciously sensed
- Information received from chest wall and lungs
Describe hyperventilation.
- Breathless at rest and on exercise - excess ventilation with decrease in PCO2
- Wide range of causative factors
A patient has a rapid onset of breathlessness. What conditions could this indicate?
- Airway obstruction
- Anaphylaxis
- Shock
- Cardiac Arrythmias
- Pulmonary emboli
A patient has gradual onset of breathlessness developing from hours-days. What conditions could this indicate?
- Community acquired pneumonia
- Influenza
- Silent MI, PE or bleeds
- Spontaneous pneumothorax
- Pulmonary oedema
A patient has gradual onset of breathlessness developing from weeks-months. What conditions could this indicate?
- Anaemia
- Tumour
- Valve disease
- COPD
- Heart failure
What factors and signs often present with SOB and what do they indicate?
- Stridor + SOB = Upper airway obstruction
- Wheeze + SOB = Lower airway obstruction
- Cough = Airway irritation
- Sputum = Infection/inflammation
- Fever = infective cause. Opposite for non-fever
In stridor, what conditions could the different speeds of onset and symptoms indicate?
- Gradual onset + no fever = tumour
- Vary rapid onset + no fever = Aspiration, anaphylaxis
- Rapid- onset + fever = Epiglottitis, croup
In wheeze, what conditions could the different speeds of onset and symptoms indicate?
- Gradual onset + no fever + night sweats + smoker + monophonic = Tumour
- Very rapid onset + no fever + urticaria = Anaphylaxis
- Rapid onset + no fever + no urticaria = Acute asthma
- Gradual onset + no fever + smoker + polyphonic = COPD
What should assessments of patients with acute-on-chronic SOB aim to establish?
- Whether cause is exacerbation of pre-existing condition
- Whether cause is new condition in same body/arising elsewhere
What are the two key questions to ask in chronic illness?
- Is this similar to your normal exacerbation of …?
- If not, what is different this time?
What should be beared in mind during the history of presenting complaint? PART 1
- When were they normal
- What did they first notice
- What does it feel like
- Is it at rest or exercise
- Is there anything else they have noticed at the same time
- How does it affect their day-to-day life?
What should be beared in mind during the history of presenting complaint? PART 2
- Do they smoke?
- Are they on any treatment?
- SYSTEMS REVIEW - any fever, weight loss, sputum or night sweats
What should be established ina physical examination of a patient with SOB? PART 1
- How fast are they breathing?
- Are there any difficulties moving around the room?
- Are they struggling to breath?
- Any cyanosis or paling?
- Are there signs of chest inflation?
What should be established ina physical examination of a patient with SOB? PART 2
- How many words are they saying per breath?
- Does breathing ease when they relax?
- Is breathing noisy or labored?
What are some examination findings that would be red flags?
- Difficulty moving chest and reduced expansion
- Dull percussion
- Crackled breathing
- Labored breathing
- No air entry could mean air trapping or solid lung
What tests could be done to measure extent of breathlessness?
- Measure respiratory rate and oxygen saturation
- Ask them to stand and sit and measure how long it takes
- Breathless score text - MMRC system (measure before and after interventions)
