86 - Physiology of Breathlessness Flashcards
What can cause a weak, hoarse voice?
Impingement upon recurrent laryngeal nerve.
Effect of impinged recurrent laryngeal nerve on coughing
Paralyses larynx. Impaired cough.
Definition of breathlessness
Recognition be the subject of an inappropriate relationship between respiratory work and total body work.
Things contributing to work of breathing
1
2
1) Stretching work (elastic)
2) Airflow work (resistive)
Resistive work of breathing
Resisting friction of air going through airways (normally very low, as flow of air is normally laminar).
Things that increase sensation of SOB
Increased load (increased work of breathing) Increased drive (EG: anxiety, hypoxia, anaemia, metabolic acidosis)
Broad categories of disorders that can lead to dyspnoea 1 2 3 4 5 6
Respiratory Cardiac Muscle weakness Metabolic Anaemia Psychogenic
Respiratory causes of dyspnoea 1 2 3 4 5
1) AIRWAYS DISEASE
a) Upper airways - tumour, foreign body, angioneurotic odema, CROUP
b) Lower airways - asthma, COPD, bronchiolitis
2) ALVEOLAR DISEASE
Pneumonia, lung collapse, pulmonary odema, pulmonary fibrosis
3) PULMONARY VASCULAR DISEASE
Pulmonary embolism, vasculitis, primary pulmonary hypertension
4) PLEURAL and CHEST WALL DISEASE
Pleural effusion, pneumothorax, chest wall deformity
5) RESPIRATORY MUSCLE DISEASE
Respiratory muscle weakness, phrenic nerve palsy
Things that can cause SOB, cough, sputum, wheeze or stridor
Airways problem.
Sputum comes up from airways.
Wheeze (lower airway obstruction), stridor (upper airway obstruction) from airways.
When are CT scans used for airway problems
Bronchiectasis, cancer
Appearance of lower airway obstruction on a flow/volume loop
Lower peak flow, sharp drop off after this
What does reduced diffusing capacity tell you?
Impairment of blood/alveolar membrane
SOB, cough, crepitations diagnosis
Crepitations from alveolar membrane dysfunction. Can be from air bubbling through fluid (oedema), sudden opening of airways during inspiration (stiff lungs, interstitial lung disease).
Indicates that problem is in terminal bronchioles, alveoli.
SOB+/- haemophtysis, pain
Could be pulmonary embolism, pulmonary hypertension, pulmonary vasculitis (rare).
Pain could be from pleural inflammation.
Use risk factors (contraceptive pill, smoking, immobility, etc) to refine diagnosis.
MUD
Medically undiagnosed dyspnoea