Aetiology

Approximately two thirds of cases of dyspnoea in adults are due to a pulmonary or cardiac disorder. In about a third of cases, diagnosis will be multifactorial.^[2]

Epidemiology

Next to pain, breathlessness is the most common symptom for which patients seek help and relief from their doctor. Peak incidence of chronic dyspnoea occurs in the 55 to 69 year-old age bracket.^[2] 70% of all terminal cancer patients suffer breathlessness in their last six weeks.^[4]

History

• Duration of breathlessness and speed of onset, ie acute, chronic
• Timing of breathlessness, eg diurnal variation with asthma
• Any known precipitating events, eg trauma, palpitations, chest pain, exercise
• Try to quantify exercise tolerance (eg breathlessness at rest, with talking, dressing, distance walked or number of stairs climbed).

  MRC dyspnoea score
  Grade	Impact
  1	Not troubled by breathlessness except on vigorous exertion.
  2	Short of breath when hurrying or walking up inclines.
  3	Walks slower than contemporaries because of breathlessness, or has to stop for breath when walking at own pace.
  4	Stops for breath after walking about 100 metres or stops after a few minutes' walking on the level.
  5	Too breathless to leave the house or breathless on dressing or undressing.

  Note: there is no accepted gold standard for measuring breathlessness - unidimensional tools such as the above are recommended for assessing severity but multidimensional tools are required to capture the impact on quality of life.^[5]
  
  
• Smoking history
• Occupation
• Past history of chest or cardiac disease
• History of atopy
• History of anxiety-related disorder
• Family history
• Pets ± contact with birds
• Drug exposure (betablockers, amiodarone, nitrofurantoin, methotrexate, heroin)

Examination

Should include:

• General, eg patient distress, colour of skin and lips, cyanosis, clubbing, lymphadenopathy, tremor, flap
• Trachea - central, deviated to one side
• Shape of chest, eg kyphosis
• Movement of chest - symmetrical, asymmetrical
• Respiratory rate
• Pulse - rate, rhythm
• Percussion note, eg stony dull over a pleural effusion, hyperresonant over a pneumothorax
• Auscultation of chest

  Auscultation of the chest
  Sign	Possible cause
  Wheezing/rhonchi	Asthma COPD Heart failure Bronchiolitis
  Crepitations	Pneumonia Bronchiectasis Fibrosis
  Stridor	Foreign body Acute epiglottitis Anaphylaxis Trauma
  No added sounds	Anaemia Pulmonary embolus Metabolic acidosis Neuromuscular causes

Investigations^[2]

These will be dependent on the findings of the history and examination but may include:

• Lung function tests, eg peak flow measurement, FEV1, FVC, ± reversibility after short-acting beta-agonist inhalation
• Pulse oximetry
• CXR
• FBC
• Arterial blood gases
• Brain natriuretic peptides (BNPs)
• ECG
• Echocardiogram
• High-resolution CT scan
• V/Q scan
• Radioallergosorbent test (RAST) measurement or skin prick testing to common aeroallergens

Management

Dependent on the underlying cause.

• In an acute situation, breathless individuals should be assessed rapidly and treated with high flow oxygen (>60%) unless there is a known history of COPD, in addition to any specific therapy for the underlying condition. If unstable, transfer to hospital should be arranged as an emergency.
• In the chronic situation, the underlying cause should be addressed and treated. Frequently breathlessness is a common end point of non-reversible disease and symptomatic relief should be sought instead.

Strategies for relieving breathlessness (of respiratory origin)

• Reassure and educate the patient and care-givers to increase confidence in their ability to control and interpret symptoms.
• Controlled breathing technique counteracts the fast, shallow, inefficient breathing associated with dyspnoea:
  • Sit upright
  • Control respiratory rate
  • Use diaphragmatic breathing
  • Relax shoulders and upper chest.
• Cognitive behavioural therapy (CBT) seeks to modify the patient's response to the symptom. Anxiety and panic can be reduced often by using techniques such as distraction or relaxation.
• Drug treatment can be used to reduce the sensation of breathlessness. Opiates, such as morphine and codeine, are effective and used in palliative care settings^[6][7] but may further depress breathing so care is required. Similarly, benzodiazepines such as diazepam are used to reduce anxiety associated with breathlessness but also carry the side-effect of respiratory depression. The use of nebulised furosemide is under investigation.^[8]
  Drugs for symptom control of dyspnoea^[9]

  • Oral morphine 2-2.5 mg prn if opioid naive. This dose can be repeated every 4 hours, although frequent dosing may not be required and may be used in anticipation of exercise (take 30 minutes prior to exercise for those with dyspnoea on exertion).
  • If already taking regular analgesic morphine, increase the regular dose by around 30% every 2-3 days until symptoms are controlled or adverse effects limit further increases.
  • Once stable, this can be converted to a modified-release preparation if needed regularly throughout the day. If only one or two doses are needed each day, continue as-required doses of standard-release morphine.
  • Benzodiazepines used when anxiety is an integral part of breathlessness, alone or alongside opiates, e.g lorazepam sublingual 0.5-1 mg prn or diazepam 2-5 mg tds, where there are persistent symptoms. Start at low doses in elderly or debilitated people.
• Pulmonary rehabilitation - individuals with severe breathlessness become less active and their general fitness levels diminish, causing a cycle of worsening breathlessness with less and less physical exertion. Supervised programmes of exercise training have been shown to be beneficial in COPD, improving both dyspnoea and fatigue levels,^[10] and rehabilitation should not be neglected in a palliative setting.^[11]
• Nutrition - patients with severe respiratory disease tend to be cachexic and have such generalised muscle weakness that the work of breathing is extremely demanding. Addressing nutritional needs with a dietician may be helpful.
• Ongoing or intermittent oxygen therapy via a facemask or nasal prongs may be of benefit in some selected cases. In chronic heart and lung disease, benefit is only evident where there is confirmed hypoxia or pulmonary hypertension. Consistent benefit of oxygen therapy in advanced lung cancer or cardiac failure patients has not been shown.^[12]
• Partial ventilation support - continuous positive airway pressure (CPAP) can be used for several hours a day to rest chest muscles but is intrusive and of temporary benefit only.
• Positioning - leaning forward when standing or nursing a bed-bound patient as upright as possible can help to relieve breathlessness.
• Stream of air on the face via a fan or open window.
• Modifying activities of daily living, lifestyle and expectations in line with disability.