When asthma masks other breathing disorders
Patients with unexplained breathlessness or intractable asthma may benefit from a lesson in breathing techniques, writes Dr Mike Thomas
e all know how to breathe properly... don't we? Perhaps not: recent evidence suggests significant numbers of our patients, especially those with asthma, may be breathing badly. They may be getting symptoms that impair their well-being as a consequence. Diagnosis can be difficult, and unfamiliarity with the problem may result in a lost opportunity to help symptomatic patients.
When it is recognised, dysfunctional breathing is treatable by breathing retraining programmes, which have been shown to improve symptoms and quality of life.
We may be used to thinking of functional bowel disorders, such as irritable bowel syndrome, or functional urinary disorders such as detrusor muscle instability, but we may be less
familiar with the concept of functional respiratory disorders.
Functional breathing disorders may be relatively common, and may complicate common conditions like asthma. As symptoms are non-specific and common to many other conditions, dysfunctional breathing may masquerade as other diseases. This can create diagnostic confusion and result in ineffective treatment
Hyperventilation and dysfunctional breathing
We all recognise acute hyperventilation attacks: the spectacle of a panic-stricken patient panting for breath and convinced some terrible medical catastrophe is occurring is alarming for all concerned. Acute hypocapnia and respiratory alkalosis produced by over-breathing may result in tetanic muscle spasms, light-headedness and even loss of consciousness (due to cerebral vasoconstriction).
When recognised and treated appropriately it is usually possible to calm the patient by getting them to take slow, steady breaths to allow the crisis to pass. When all else fails, rebreathing, for example through the traditional 'brown paper bag', will allow carbon dioxide tension to rise and the strange and frightening sensations to subside.
Anxiety is often a trigger, and the resulting unpleasant sensations can feed anxiety and result in a vicious circle that produces the acute crisis.
It may be 'acute' episodes are just the tip of an iceberg, and that many more patients may be over-breathing or breathing abnormally in a more low-key way, resulting in symptoms which, although less acute and dramatic, may still seriously impair their lives (see box 1).
Such patients may only be apparent when carbon dioxide levels are measured or detailed respiratory observations made, not usually possible in the surgery.
Hypocapnia was once thought to be the sole cause and was referred to as 'chronic hyperventilation syndrome'. It is now recognised that other abnormalities in the breathing pattern exist, for example unsteady and irregular breathing, frequent sighing and yawning, and chief use of intercostal and accessory muscles of breathing rather than the diaphragm (normally the main muscle in quiet respiration).
We now know only some symptoms result directly from hypocapnia, and other factors such as central 'neuro-proprioreceptive' mechanisms may be involved.
Other diagnostic terms have been used: 'disproportionate breathlessness', 'breathing pattern disorder', 'behavioural breathlessness'. I favour 'dysfunctional breathing' which refers to abnormal breathing patterns that result in symptoms that go when the breathing pattern is corrected (see box 2), so relies on a response to treatment to confirm the diagnosis.
Spotting dysfunctional breathing in the surgery
in the surgery
Unfortunately there is no simple 'gold standard' test, and diagnosis can be difficult even with access to capnography, lung function labs and blood gases. The main alerting feature for the astute clinician is the symptom pattern a particular constellation of symptoms that can ring alarm bells.
Symptom-based questionnaires such as the Nijmegen questionnaire (see box 3 overleaf) have been shown to be very useful for screening: a score of 23 or above points to a high likelihood of dysfunctional breathing.
As the symptoms are non-specific, GPs always need to consider other diagnoses. No prizes for missing undertreated asthma, ischaemic heart disease or pulmonary emboli. Patients whose symptoms seem unusual in pattern, excessive and disproportionate to their disease severity need to be considered. Examples include the patient who complains of asthma symptoms but doesn't seem to improve on increased medication and never seems to be wheezy when examined; or the patient
whose angina attacks are not relieved by
glyceryl trinitrate and has a normal ECG and cardiovascular examination. The list is long.
Physical examination is generally normal, and normal oxygen saturation on pulse oximetry (if available) can be reassuring in the breathless patient.
An association may be present with anxiety or anxiety-producing situations and recent life events. Physical examination and simple investigations such as peak flow rate are often normal, but asking the patient to hold their breath for as long as possible can often be revealing, abnormally short
breath-holding times of five to 10 seconds are common.
A 'voluntary hyperventilation provocation test' can be useful in confirming to patient and doctor the relationship between abnormal breathing and symptoms; in this test, the patient is asked to hyperventilate for up to two minutes, stopping when they experience unpleasant symptoms. This will often produce the symptoms that made the patient present.
Asthma and dysfunctional breathing
How common is dysfunctional breathing? Our own recent work1,2,3 has indicted approximately one in 10 adults may have functional breathing problems, although the prevalence is three times higher in people with asthma. Overall it seems to be more common in women and tends to affect younger rather than older people. There are even reports of similar problems in children and infants.
An unorthodox school of alternative medicine practitioners teach the Butekyo method of asthma treatment, which has received wide lay press publicity including a Panorama TV programme and a series in the Daily Telegraph. This method is based on the scientifically untenable theory that asthma is caused by hyperventilation and represents the body's attempt to conserve carbon dioxide.
There is considerable anecdotal evidence (and a limited amount of scientific evidence) that this method may at least improve asthma symptoms for some people, although not that it can 'cure' asthma.
We have shown that a breathing retraining programme supervised by a respiratory physiotherapist can improve symptoms and quality of life in more than half the patients with asthma and evidence of dysfunctional breathing.
At present we don't know why dysfunctional breathing should be more common in people with asthma, although possibly the higher anxiety levels shown to exist in asthma, and possibly the focus on breathing caused by the illness, may play a role.
Good news is that when spotted this is a treatable condition. In the UK, a suitably trained physiotherapist generally gives treatment. Although it is not part of the 'core' physiotherapy training, there is a special interest physiotherapy group that runs training courses.
Most respiratory units will have a trained physiotherapist who specialises in treating this problem. There are several controlled and observational studies showing benefits from such breathing courses, and an audit of our own unit found that of 281 patients diagnosed and referred for breathing retraining over a two-year period, 98 per cent showed improved symptoms.
The programme usually has three components.
· Education Explanation of normal and abnormal breathing and how abnormal breathing can result in symptoms.
· Reassurance Encouragement to re-attribute symptoms to dysfunctional breathing instead of other frightening explanations. Basic relaxation and anxiety management.
· Diaphragmatic breathing Exercises to
breathe slowly, regularly and with the diaphragm ('push your belly button out as you breathe
in, exhale slowly'), and encouragement to
practise regularly and when symptoms occur.
Although many of us will not have access to a respiratory physiotherapist, much of this can be achieved in a GP consultation given time and motivation.
On a personal note
I'd like to summarise my personal experience of
10 years of seeing, diagnosing, treating and researching this condition. I first became aware of it when I began work as a clinical assistant in our local chest clinic. I was surprised at how often a
patient referred by my GP colleagues with poorly controlled asthma or breathlessness of uncertain cause was found to have functional breathing problems as the main cause for their symptoms.
As time went on I found I was spotting this condition more and more often myself, in the hospital clinic and in my surgery. The response to treatment is often very marked and gratifying, with patients reporting how much better they feel, how they understand their symptoms and now feel in control of them.
It is great to be able to help patients in this way, especially without use of drugs.
My suspicion, backed up by our recent research findings, is that this is an under-diagnosed
condition, and that there may be many people,
both with asthma and without, who potentially
may be helped.
· Chest tightness
l'Air hunger' perceived inability to get air into lungs
· Frequent sighing and yawning
· Chest pain
· Cold peripheries
· Abdominal pain and bloating
Breathing pattern abnormality
· Over-breathing (hyperventilation)
· Irregular breathing high variability in respiratory rate and depth
· Sighing and yawning
· Predominant use of intercostal rather than diaphragmatic muscles
· Typical symptom pattern
· Nijmegen questionnaire score =23
Response to breathing re-training
· Improvement in symptoms, Nijmegen score, quality of life following intervention
3: Nijmegen questionnaire
Please ring the score that best describes the frequency with which you
experience the symptoms listed below
Never Seldom Sometimes Often Very often
Chest pain 0 1 2 3 4
Feeling tense 0 1 2 3 4
Blurred vision 0 1 2 3 4
Dizziness 0 1 2 3 4
Confusion or loss of touch 0 1 2 3 4
Fast or deep breathing 0 1 2 3 4
Shortness of breath 0 1 2 3 4
Tightness across chest 0 1 2 3 4
Bloated sensation in stomach 0 1 2 3 4
Tingling in fingers and hands 0 1 2 3 4
Difficulty in breathing or 0 1 2 3 4
taking a deep breath
Stiffness or cramps in fingers 0 1 2 3 4
Tightness around the mouth 0 1 2 3 4
Cold hands or feet 0 1 2 3 4
Palpitations in the chest 0 1 2 3 4
Anxiety 0 1 2 3 4
· Typical symptom pattern
· Normal physical examination, oximetry
· Nijmegen score =23
· Short breath-holding time (less than 10 seconds)
· Voluntary hyperventilation provocation test
· Response to breathing retraining