Bear with me on this one; I've not gone all new age and pseudo-science. But this is worth a second look.
Approximately 300million people worldwide have been diagnosed with asthma, mostly in developed countries. Surprisingly, asthma is considered responsible for up to 250,000 deaths annually. That's a very serious tally for something that is widely misunderstood as a bit of wheezing.
Asthma is defined as chronic (long-lasting) inflammation of the airways. The severity of this varies over time and with external factors, causing fluctuating degrees of wheezing, breathlessness, fatigue, coughing and so forth.
Currently asthma is treated with steroids administered via an inhaler. In severe or long-standing cases, and where co-morbidities exist, these may be used prophylactically. Possible allergens and irritants are also investigated as removable triggers.
For years small numbers of chiropractors have been claiming to be able to treat asthma using spinal manipulation. They state that spinal subluxations (used to mean mal-position rather than partial dislocation) are a major component of disease, including asthma, preventing the body from repairing itself by impinging on "neurological flow".
Frankly, these chiropractors have been widely ostracised for prattling absolute jibberish and fleecing patients out of loads of money.
Research on the topic tends to indicate this was a good move by the chiropractic profession; In its naturally conflicting way, current research neither advocates nor condemns chiropractic treatment for asthma, citing lack of evidence.
Of the existing studies, most are poorly designed and the majority conclude that chiropractic and sham-chiropractic treatments have the same outcomes for asthma patients.
For years small numbers of chiropractors have been claiming to be able to treat asthma using spinal manipulation. They state that spinal subluxations (used to mean mal-position rather than partial dislocation) are a major component of disease, including asthma, preventing the body from repairing itself by impinging on "neurological flow".
So that's a no then? Chiropractic cannot help asthma.
Well, hold the phone. There's more.
Out of curiosity, while treating asthmatic patients for other complaints I have been asking whether their asthma symptoms have changed. Remarkably, all those asked have reported dramatic improvement, and even complete regression, of symptoms.
Alongside this, and with the help of a couple of willing asthmatics, I am running a small case series (to be published at a later date). So far, all cases have demonstrated quite incredible improvement in reported symptoms.
Clearly, jumping to conclusions at this time would be ludicrous; however, some basic physiology may actually explain these observations.
During an asthma attack, inflammation, increased mucus secretion, and smooth muscle spasm constrict airways in the lungs. These are automatic actions in response to a stimulus. This stimulus can vary, but may be increased dopamine, cortisol and adrenaline levels resulting from heightened stress, or something as simple as dust or smoke.
Just for simplicity, we'll leave stress to one side for a moment.
Stimuli, such as dust, are detected by nerves within the posterior pulmonary plexus (a group of nerves in the lungs). This information is then relayed to the thoracic sympathetic chain (another collection of nerves), which then communicates with the spinal cord.
The levels of the spinal cord receiving this input are in the upper thoracic spine (T1-5). The spinal cord then relays this information to the brain, which stimulates increased mucus production, bronchial spasm etc, via the vagus nerve.
Crucially, in normal cases, the nerves in the pulmonary plexus only activate when stimulation is great enough to represent a threat. This is controlled by a neurological mechanism called "threshold", whereby a certain degree of stimulation is required before a message (called an action potential) can sent.
Inadequate stimulation means no message is sent, and this is termed a failed initiation. A series of failed initiations have the effect of sensitising a nerve, meaning that less future stimulation is needed to generate an action potential. This is known as sensitisation and means normal stimuli can activate a nerve. In the case of asthma patients, an example could be cold air triggering bronchial constriction.
The process of sensitisation is very common, contributing to a wide range of painful conditions. In conditions such as carpal tunnel syndrome, for example, up to 85% of cases are attributed to nerve sensitisation.
Typically, postural or degenerative changes within the spine exert physical pressure on adjacent nerves causing continual failed initiations. As a result, normal stimuli become sufficient to generate an action potential, most often perceived as pain.
Within the lung, however, these stimuli are interpreted as irritation, leading to the protective responses we describe as an asthma attack.
Treating postural changes (using primarily upper thoracic spinal manipulation) removes a source of nerve stimulation, thus requiring more stimulation for it to signal again. Decreasing the responsiveness of nerves within the lung means that normal stimuli such as cold air are not perceived as threatening and are less likely to cause an asthma attack.
Chiropractic treatment helps a number of conditions by the same principle, with sciatica and thoracic outlet syndrome obvious examples. Having looked at the comparable anatomy and physiology, it doesn't seem a vast leap to expect results when treating asthma.
There are, however, some flaws with this theory:
Most significantly, it does not take into account the afferent (sensory) role of the vagus nerve. The vagus nerve is involved in autonomic responses, giving the urge to cough when stimulated. While the importance of afferent vagus nerve activity has not been determined in relation to asthma, it is not affected by chiropractic treatment and so may remain a cause of symptoms.
It is also over simplistic to assume that all asthma cases are due to sensitisation of pulmonary nerves. Asthma is a multi-factorial disorder and the treatment of postural changes may not have any impact at all on symptoms.
As mentioned earlier, I have been "experimenting" with asthmatic patients in a very informal way with some very positive results. While the results are virtually meaningless due to lack of scientific rigour, it does seem there might be a plausible (if not water-tight) reason for these observations.
But if the neurological argument does not stack up, what else could be responsible for patient reported improvements?
The word that is most likely to be on most people's tongues (and mine!) is placaebo. This is a striking phenomenon in which patient belief affects outcome, and has been attributed with some startling effects. In all likelihood this plays a major part in any improvements in asthma symptoms, perhaps being the sole cause.
Stress is also an interesting factor to discuss here. It can precipitate asthma attacks, as well as exacerbate them and increase a person's sensitivity to irritants. Stress comes in many forms, but taking time out of your day to see a chiropractor can be a very stress relieving thing. There is also something uniquely reassuring in being able to talk at length about how your complaint affects you, undergoing a full, hands on examination, and subsequently having your condition and potential treatment explained in depth.
A final potential factor in asthma response to chiropractic treatment is the mechanical effect manipulation has on the thoracic cage. Costovertebral (rib) and intervertebral (spinal) joints should articulate with every breath. Due to a variety of reasons, it is exceptionally common for some of these joints to articulate poorly. This makes breathing harder, leading to recruitment of accessory respiratory muscles which enhance the problem, with an overall effect of decreased lung capacity and efficiency. Freeing up these stiff joints with manipulation allows air to be inhaled/exhaled more easily.
In all likelihood all of the factors discussed above contribute in cases where asthma symptoms improve with chiropractic treatment. This, combined with the multifactorial nature of asthma, means that seeing a chiropractor may not help every time or ever completely you're your asthma.
But there are some pretty good reasons why it might be worth a look.
If having read this you are interested in discussing anything covered, please feel free to contact me.
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