3.3 The respiratory system
Estimated time for chapter: 100 minutes.
The respiratory system is specialised to enable an adequate supply of oxygen to the tissues. As was described in Chapter 1.2b, oxygen is one of the essential ingredients for the process of cellular respiration. It is also the role of the respiratory system to allow carbon dioxide, a waste product of respiration, to be removed from the body.
In common usage, the term ‘respiration’ refers simply to the act of breathing. However, in physiology there are three aspects to respiration that can be clearly defined. These are external respiration, internal respiration and cellular respiration.
Cellular respiration is the process (described in Chapter 1.2b) by which oxygen and nutrients are converted to cellular energy (adenosine triphosphate (ATP)) and carbon dioxide within the cell itself. It is important to be clear about the distinction between these three processes, as these terms help define the precise roles of the respiratory system.
The respiratory system is conventionally divided into two sections, the upper and lower respiratory tract. A simple representation of the organs of the respiratory tract is given in Figure 3.3a-I. The division between the upper and lower parts occurs at the point at which the trachea splits into the two tubes called ‘bronchi’.
The diagram illustrates that this division occurs at a deep level in the chest, just above the position of the heart. The diagram also illustrates the close physical relationship between the heart and the lungs. In fact, if the heart is removed through dissection, an imprint of its shape is seen in the tissue of the lungs.
The upper respiratory tract leads from the entrance of the respiratory system at the nose to the end of the trachea, the tube which directs the inhaled air into the chest cavity (thorax) towards the lungs.
The function of the upper respiratory tract is to provide a plentiful supply of warm, clean and moist air to the lungs. To help it perform this function it consists of wide air spaces and is lined by a specialised form of epithelium. The respiratory epithelium consists largely of ciliated columnar cells but it also has many mucus-secreting (goblet) cells.
The water-containing mucus moistens the air that rushes through the respiratory tract, and picks up dirt particles and other foreign bodies present in the air. Cilia are structures akin to microscopic hairs on the surface of cells. They are powered by the energetically charged molecule ATP to move in coordinated waves. In the respiratory tract the cilia beat in an upward direction. Their function is to cause an upward movement of the mucus, allowing the foreign material to be moved away from the delicate lung tissue and up to the back of the throat, from where it can be swallowed or expectorated.
The connective-tissue layer below the respiratory epithelium has a number of lymphocytes scattered throughout its length. These respond to foreign antigens by producing antibodies and attracting other immune cells. This is an important aspect of the protection of the respiratory tract from infection.
In the breathing of a healthy person at rest, all air is drawn in through the nostrils into the nasal cavity. This space has a deeply ridged surface which has a rich blood supply. This means that the current of air comes into contact with a large area of warm epithelium before its descent towards the lungs. In addition to the cilia on the epithelial cells, body hairs are present in the opening of the nose to filter out any large foreign particles.
Opening out into the nasal cavity are the sinuses. These are cavities deep within the facial bones that have narrow passageways leading into the nasal cavity. Their function is to give the voice a resonant quality, the loss of which is apparent in anyone who has suffered from a ‘head cold’, when the sinuses become filled with thick secretions. A tiny duct leading from each eye also opens into this space. This continually drains away tears from the eyes. The runny nose that accompanies a bout of crying is a result of the excess tears flooding into the nose through this duct.
The nose is the specialised sense organ for smell. To perform this function, delicate nerves originating from the base of the brain penetrate the bone above the nasal cavity to supply the nasal lining. These are sensitive to the chemicals in the incoming air, which become dissolved in the mucus. The sense of smell is also important to enrich the experience of taste. Occasionally, in a head injury, these nerves become permanently severed, even though there may be no other major brain damage. The person may recover fully but be left without a sense of smell and with a highly impaired sense of taste.
Other nerves in the nose are very sensitive to the irritation that can result from foreign particles and from inflammation of the lining of the nose. These nerves can trigger the protective reflex of the sneeze, which is a very effective mechanism for expelling unwanted material from the nasal cavity.
The pharynx is the space at the back of the nose that connects with the throat. The adenoids (nasal tonsils) are two collections of lymph-node tissue situated at the back of this space. The tonsils (palatine tonsils), which are similar collections of lymphoid tissue, are situated a little lower down. The palatine tonsils can be seen in most people on either side of the space behind the arch of the palate, as illustrated in Figure 3.1a-II, whereas the adenoids are hidden up behind the palatoglossal arch.
The function of the tonsils is to complement the protective function of the lymphocytes in the respiratory epithelium. Their presence is an indication of the need for the lungs to be protected from foreign material. The adenoids are most active in early childhood, because this is the time when immunity to a wide range of infections has to be rapidly developed. After 5 years of the age, in most people the adenoids shrink to a negligible size, although the palatine tonsils persist into adulthood.
The eustachian tube opens from the middle ear into the pharynx close to the location of the adenoids. The middle ear is also lined with respiratory epithelium, and the eustachian tube allows the drainage of mucus from this enclosed space.
The larynx, popularly known as the voice box, is the structure that separates the pharynx from the trachea. Although it is primarily associated with voice production, it also plays a very important protective role. Figure 3.3a-III is a diagrammatic representation of the nasal cavity, pharynx and larynx, which illustrates how these structures relate to each other.
The tube-like larynx has stiff cartilage in its walls which enables it to maintain its shape. The cartilage at the front of the larynx is what can be seen and felt as the ‘Adam’s apple’. Because the thyroid gland sits close to this structure, the medical term for this is the ‘thyroid cartilage’.
The vocal cords are two fine flaps of tissue that are suspended from the surrounding cartilage tube. Figure 3.3a-IV shows a view of the aperture of the larynx. The vocal cords are depicted on either side of the aperture, leaving a triangular space through which the air can pass. Tiny muscles in the larynx contract to change the shape of this triangle between the vocal cords so that the space can vary from being a wide gap to a tiny ‘chink’. The tone of the muscles also affects the tightness of the vocal cords. During quiet breathing the gap is wide to allow a free passage of air in and out of the lungs. During speech, the gap narrows and the cords tighten. The expired air causes vibration of the tightened cords, which produces the sound of the voice. The tighter the cords, the higher the pitch of the voice.
The protective reflex of the cough involves a temporary tightening of the vocal cords so that the gap closes altogether. This occurs during a forced expiration of air. The closed gap means that the pressure of air below the vocal cords is suddenly increased. At this point the muscles relax and the gap widens. This results in a sudden forceful rush of air accompanied by the familiar sound of the cough. Like the sneeze, the cough is stimulated by the irritation of nerves in the larynx and the tubes that branch from the trachea into the lungs. The cough also has the effect of expelling unwanted material from the trachea, larynx and pharynx out through the open mouth.
The other important protective structure in the larynx is a stiff flap of cartilage-containing tissue called the ‘epiglottis’, which sits above the larynx. During swallowing this flap descends to completely cover the gap between the vocal cords. This protects against the inhalation of food during swallowing.
The lower respiratory tract begins where the trachea divides into the two narrower tubes called the bronchi. The bronchi further subdivide, like the branches of a tree, to penetrate the tissue of the two lungs.
The bronchi and the smaller tubes into which they divide (the bronchioles) are structurally similar to the trachea, and are also lined with respiratory epithelium. Therefore, they too are concerned with ensuring the air that reaches the depths of the lungs is as warm, moist and as clean as possible.
The width of these air passages varies according to need. During exercise the bronchi and bronchioles widen, so that a large amount of air can enter the lungs in each breath. At rest, they narrow again because the need for a large volume of air is not so necessary, and because the protective mechanism of these tubes is more efficient when they are narrower.
At the end of each of the tiniest branches of the tree-like air passages that penetrate the lung are masses of tiny air sacs only a few cells in diameter. These are known as ‘alveoli’ (singular ‘alveolus’). The lungs are composed of millions of these tiny air spaces packed together, and all connecting with the outside world through the bronchioles and bronchi. The alveoli are lined with only a single layer of flat squamous epithelium, and are supplied by a dense network of fine blood capillaries.
The blood that enters the capillaries surrounding the alveoli has originated from the pulmonary arteries. These large vessels originate from the right ventricle of the heart and carry deoxygenated blood pumped by the right side of the heart. The blood is deoxygenated because the cells of the body tissues have used up all the oxygen in the process of cellular respiration. As well as being deoxygenated, this blood is also carrying a high concentration of carbon dioxide, the by-product of cellular respiration. In contrast, the air inspired into the alveoli is rich in oxygen from the outside air, and carries very little carbon dioxide. Therefore, there is a tendency for the oxygen in the alveoli to move into the deoxygenated blood in the capillaries. This movement occurs readily, as oxygen can diffuse with no restriction through the cell membranes of the alveolar and capillary walls. At the same time, there is a movement of carbon dioxide out of the capillary blood and into the alveolar air. This exchange of the two gases of respiration occurs very rapidly (see Q 3.3a-2).
The capillaries that leave the alveoli converge to form the pulmonary veins, which return all this blood to the left side of the heart. This blood is now rich in oxygen, and has been cleared of carbon dioxide. The pulmonary veins are the only veins in the body that carry oxygenated blood. All the other veins carry blood away from the body tissues, and this blood is of course deoxygenated.
The air left in the alveolus now contains more carbon dioxide than oxygen, and is expelled to the outside world by the process of expiration, so that the whole process can begin afresh with the next in-breath.
This process of exchange of gases is assisted by the fact that there are millions of alveoli, each with its own rich blood supply. In some conditions, such as emphysema, the delicate structure of the alveoli is damaged and their number is reduced (see Chapter 3.3e). This severely impairs the process of exchange of gases, so that the blood does not get replenished with an adequate amount of oxygen, and carbon dioxide fails to be fully cleared.
The lungs consist of the branching air passages of the bronchi and bronchioles, and the thousands of alveoli clustered around the ends of the bronchioles. The lungs are surrounded and supported by elastic connective tissue, which has the tendency to cause the fully expanded lung to contract. The lungs sit within the thorax, which is protected by the rib cage and its supportive muscles, and they rest on the sheet of muscle below known as the ‘diaphragm’.
The lungs are surrounded by a double layer of protective fluid-secreting serous membrane called the ‘pleura’. In the pleura the secreted fluid forms a thin lubricating layer between the two pleural membranes akin to the fluid that separates the pericardium from the heart. The outer pleural membrane is attached to the inner surface of the rib cage from above and at the sides, and to the diaphragm below. It is this attachment that prevents the elastic lungs from collapsing. Figure 3.3a-VI illustrates the relationship between the pleura and the lungs.
Inspiration involves the inflation of the lungs. Like an expanded bellows, the inflated lung naturally draws air into itself. The lungs are inflated by a lifting and expansion of the rib-cage walls and a descent of the diaphragm. This action occurs as a result of contraction of the diaphragm and of the muscles that link the ribs together.
Expiration involves the deflation of the lungs. This naturally forces air back out of the lungs. In relaxed breathing, expiration requires no muscular effort. A simple relaxation of the rib cage and diaphragm has the effect of reducing the volume of the thorax and thus deflating the lungs.
In normal, quiet breathing the cycle of inspiration and expiration occurs at about 15 times per minute (4 seconds/cycle). There is an automatic reflex that originates from a control centre in the base of the brain that sets this regular rhythm. Nerves travel down from this control centre to stimulate the synchronised and rhythmic muscular contraction of the rib cage and diaphragm (see Q3.3a-3).
All variations in the resting respiratory rate are brought about by changes that take place in the breathing control centre in the brain. The breathing control centre is essential for maintaining homeostasis of the levels of oxygen and carbon dioxide in the arterial blood. The oxygen level must of course be maintained at a high concentration, whereas the level of carbon dioxide must not be allowed to rise too high. To perform this role, the breathing control centre contains cells that are very sensitive to the level of carbon dioxide in the blood. A miniscule rise in the level of carbon dioxide leads to an increase in the breathing rate so that excess carbon dioxide can be ‘blown off’. If the level of carbon dioxide drops, so does the rate of breathing, and the levels in the blood can build up again.
The control centre in the brain is also sensitive to drops in the concentration of oxygen in the blood. However, the responsiveness of the control centre to carbon dioxide also indirectly controls the homeostasis of oxygen in the blood, as increased external respiration will increase oxygen levels, and reduced external respiration will reduce oxygen levels.
Any voluntary wish to modulate the breathing, such as for speech, singing or laughing, generates nerve impulses from other parts of the brain (the cerebral hemispheres) to the control centre of breathing, which then alters the breathing rate accordingly. The sneeze and cough reflexes involve a direct link between the irritated nerve endings and the control centre.
Information Box 3.3a-I The lungs: comments from a Chinese medicine perspective
The Government of Qi refers to the conversion of Gu (food) Qi and Heavenly (Clear) Qi in the Lungs to produce Zong (Gathering) Qi. Zong Qi is important for supporting the Lungs, the Heart and the circulation. It also gives strength to the voice.
The Lungs are seen as the site of the combination of Gu Qi and Heavenly Qi into a readily available source of energy (Zong Qi) for the organs of the Upper Jiao, as well as for the circulation and the voice.
In conventional medicine no distinction is made between different sorts of energy as there is in Chinese medicine with the various type of Qi. There is also no idea that the Lungs play any role in the production of energy over and above their function in external respiration, which is to draw oxygen into the body.
Government of respiration refers to external respiration. Here is a direct parallel with the understanding of conventional medicine. Strictly speaking, the role of the breathing control centre in the brain would also be seen in Chinese medicine as part of the Lung functions, as it plays an important part of the control of external respiration.
The dispersing function refers to the ability of the Lungs to spread Wei Qi and body fluids to all body parts. This protects the body from external pathogens and keeps the skin and muscles moist and warm. It is also important for the control of sweating. The lungs are not seen to have this sort of function in conventional medicine. Instead, the defensive and warming roles would be attributed to the immune system and circulatory system, respectively. Conventionally, the skin is seen as the organ that deals with sweating.
The descending function refers to the descent of Qi, which is important to enable clearance of fluids via the Kidneys and Bladder, and also for defecation. If impaired, the loss of this function may give rise to oedema, retention of urine and constipation.
However, in conventional terms there is no link between the lungs and the kidneys or the large intestine. Although the lungs can become ‘waterlogged’ in a case of pulmonary oedema, this usually is the result of a condition that primarily affects another part of the body,such as heart failure.
Again there is little correspondence with conventional medicine, as the skin and body hair are not seen as linked to the function of the lungs. Although the common skin condition of eczema is commonly associated in conventional medicine with asthma, these are still seen as separate conditions. The reason they are understood to be linked lies in a deficiency of the immune system, not the lungs.
Although conventional medicine makes no explicit link between the lungs and emotions or spirit, it is recognised that emotions have an effect, via the breathing control centre in the brain, on the respiratory rate and rhythm.
In summary, the Lungs in Chinese medicine have a much broader role than their purely physical counterpart in conventional medicine. It seems that the role of the Lungs in Chinese medicine also embraces aspects that would be attributed in conventional medicine to the cardiovascular, urinary, gastrointestinal and immune systems as well as the skin.
The functions of the Lung according to a conventional and Chinese perspective can be summarised in the form of a correspondence table (for an introduction to the Organ correspondence tables, see Appendix I). This table illustrates the idea that the functions of the air-filled sacs, which conventional medicine calls the lungs, may be the domain not only of the Lung Organ in Chinese Medicine, but also of the Kidney and Liver Organs. It will follow from this that diseases of the lungs may manifest in Chinese medicine syndromes involving the Lung, Liver and Kidney Organs.
|Functions of the lung||Functions of the Lung Organ|
|‘The Lungs are like a minister from whom policies are issued’|
Self-test 3.3a The physiology of the respiratory system
2. List three parts of the respiratory tract that would protect a person from smoke inhalation (NB: There are more than three.) Remember that smoke consists of tiny particles that are very irritating to the respiratory epithelium.
1. The primary role of the respiratory system is external respiration. This involves the drawing in of clean, warm, moist air into the air spaces of the lungs so that the exchange of oxygen and carbon dioxide can take place between the outside air and the blood.
Estimated time for chapter: 30 minutes.
The bulk of minor respiratory disease, particularly infectious disease affecting the upper respiratory tract, is managed in the UK entirely by the GP. More severe problems affecting the nose and throat may be referred for the opinion of a specialist in diseases of the ear, nose and throat.
If a surgical operation is necessary, the chest physician will refer the patient to a thoracic surgeon. Very often the thoracic surgeon is also skilled in the surgery of the heart, in which case the proper title is ‘cardiothoracic surgeon’.
This is an examination performed by an ear, nose and throat specialist to examine the vocal cords. It involves the skilled insertion of an instrument, which carries a tiny mirror, into the mouth and thence into the pharynx. Laryngoscopy is usually painless.
A patient with infection or a possible tumour will be requested to produce a sample of phlegm. This can reveal the presence of infectious organisms, and occasionally in cancer can contain cancerous cells. In the case of infection, the sample can be used to test for sensitivity to a range of antibiotics.
Lung-function tests are performed when disease of the lower respiratory tract is suspected. These tests require the patient to blow into a machine that measures the force and volume of the out-breath, and detects the changes that are characteristic of the diseases which lead to restricted breathing, such as asthma and emphysema. These tests are straightforward and painless for the patient to perform.
The most simple of these tests is the peak expiratory outflow assessment, which is done using a peak-flow meter. This is a hand-held tool that the patient can be taught to use at home. Its main purpose is to assess the severity of asthma in a patient on ongoing treatment. It does not provide as detailed or helpful information as the more complex tests available in a hospital outpatient department.
Serum samples can be used to examine for antigens of infectious agents and for antibodies to confirm the presence of infection. Certain antibodies can also indicate the tendency to allergy, which is common in asthmatics.
This test is performed on all patients with suspected lower respiratory tract disease. Most serious disease, such as pneumonia, cancer, emphysema and lung fibrosis, will show characteristic changes on a chest X-ray image. However, in asthma, even when severe, the chest X-ray image usually appears normal.
Figure 3.3b-I shows a CT scan of the lungs in a patient with advanced lung cancer. This is a ‘slice’ of the upper chest presented as if the patient is lying on their back with their feet facing the viewer. The white structures are bones, and the sternum, one vertebral body, some ribs and the scapulae are visible. The very black areas are regions of normal air spaces in the lungs. The cancer is clearly seen as a grey shadow invading the normal lung tissue.
This invasive test involves the passage of a flexible telescope into the wider air passages of a sedated patient. The tube can be inserted as far as the larger bronchioles. Tumours can be seen directly by means of this technique.
Alternatively, salt water can be squirted down the tip of the tube to retrieve cells from the deeper parts of the lungs in cases of possible infection or cancer when sputum does not reveal any features of disease. This technique is known as ‘bronchoalveolar lavage’.
Biopsy involves the removal of a piece of lung tissue for examination under the microscope. The biopsy can be taken from the bronchi or bronchioles through the bronchoscope. Biopsy of the pleura can be taken through a small incision in the skin overlying a gap between the ribs. Sometimes a thoracic surgeon is required to open up the chest to remove tissue from deep in the chest.
Fluid can also be drawn from between the pleura by means of a syringe needle inserted between the ribs into the space. This is used only in those conditions that have caused fluid to accumulate in this space, known as pleural effusion. Such conditions include cancer of the bronchus, pneumonia and pulmonary oedema.
Self-test 3.3b The investigation of the respiratory system
1. Harry is 53 years old and has been smoking all his adult life. Recently he has become more breathless, and over the past 2 weeks has noticed blood in his sputum. His GP is concerned that Harry might have developed cancer and refers him for assessment by a chest physician. What tests do you expect Harry might have to undergo?
1. Harry will first be given a thorough physical examination. His fingers will be examined for clubbing and his tongue will be checked for cyanosis. The lymph nodes in the neck will be palpated to exclude any enlarged irregular nodes, which may occur in lung cancer. The rate and quality of his breathing will be assessed visually.
The physician will percuss Harry’s chest for areas of dullness, which can signify an underlying mass in the lung tissue. He or she will then use a stethoscope to listen (auscultate) to see if the breath sounds are smooth and symmetrical.
If the examination or chest X-ray reveals features suggestive of cancer, Harry will have to undergo a bronchoscopy. A biopsy might be taken at the time of this test of any suspicious looking areas of the bronchi or bronchioles.
Estimated time for chapter: 100 minutes.
Minor diseases of the upper parts of the respiratory tract such as experience of coughs, colds, and flu, are a well-recognised part of normal life. Conditions that affect the structures progressively further down the respiratory tract, such as the tonsils, larynx and trachea, are seen in conventional medicine as more serious conditions. Nevertheless, on the whole, most acute conditions of the upper half of the respiratory tract are relatively benign.
With the exception of some forms of tonsillitis and pharyngitis and the childhood infection acute epiglottitis, all the common infections of the upper respiratory tract are initially caused by viruses. There is a wide range of viruses that has been identified to affect the respiratory epithelial cells. Viruses tend to enter the upper respiratory tract through inhalation of infected droplets of moisture. The inhaled virus is able to penetrate and damage the cells, and this leads to inflammation (redness and swelling) and the production of sometimes profuse watery secretions. Fever is a common symptom of these infections, although frequently it is mild in nature. Breathlessness (which is significant if respiration rises to over 30 breaths/minute in adults) is not a feature of upper respiratory conditions. Breathlessness suggests a more serious lower respiratory condition or obstruction to the upper airways, and if severe merits same-day referral for a medical opinion.
The different syndromes that result from upper respiratory infection seem to be dependent on the characteristics of the virus. Some primarily affect the throat and the nasal lining, leading to the symptoms of the common cold, whereas others tend to affect lower structures, causing tonsillitis or laryngitis for example. The evidence for this is that a virus that is ‘going around’ will cause the same sorts of symptoms in most people who contract the infection.
Usually, viral infections of the upper respiratory tract are short lived. In some people the infections can progress to affect further regions of the respiratory system, including the lower respiratory tract. In these cases, it is often believed that a further bacterial infection has arisen in the region of the already damaged respiratory epithelium. Commonly it is one of the ‘healthy’ bacteria, which usually reside harmlessly in the lining of the upper respiratory tract, that causes these complications. Therefore, these sorts of deeper bacterial infections are not usually contagious. This complication of bacterial infection is recognised to be more likely in people who are susceptible due to some form of chronic ill-health. As long as upper respiratory conditions last for less than 5 days there is usually no need for medical referral, except in the case of infants or frail individuals.
The treatment for all minor viral upper respiratory conditions needs be supportive only, as the antiviral drugs currently available are expensive, carry risks and only shorten rather than eliminate the symptoms of illness in healthy individuals. For this reason, the use of these drugs in the NHS is restricted according to the UK National Institute of Health and Clinical Excellence (NICE) guidance (2009), being given only in cases of influenza in vulnerable individuals. Common treatment approaches recommended by doctors include aspirin and paracetamol to reduce pain and fever, plenty of fluids to counteract fluid loss through fever, keeping warm and letting the body rest.
There is no doubt that smokers are more prone to severe forms of upper respiratory tract infections. It is also recognised that atmospheric pollution results in increased rates of severe respiratory infections. Both these factors reduce the health of the respiratory epithelium so that it is less well equipped to deal with minor infections. Smoking, in particular, is known to damage the action of the cilia in the respiratory epithelium and also to cause a change in the production of the mucus so that it becomes much thicker and thus resistant to clearance from the air passages.
The accumulation of thick and sticky mucus that results when a smoker develops a viral respiratory infection is much more likely to become further infected by bacteria and to result in a persistent phlegmy infection.
The cough and profuse phlegm familiar to people who have recently stopped smoking is a healthy sign. It is a result of the recovery of the cilia, which then are able to clear accumulated toxins and mucus from the lower parts of the respiratory tract.
The common cold virus affects the nose and pharynx (throat), leading to sore throat, stuffy and runny nose, and watery eyes. The secretions are usually clear. Fever is slight or absent. Simple treatments for the common cold include vitamin C and zinc preparations and steam inhalations to loosen secretions. Eucalyptus and menthol oils can be a helpful addition to a steam inhalation, and these aromatic compounds are also commonly found in proprietary cough sweets and medicines. Aspirin or paracetamol may be taken to relieve the discomfort of sore throat and to reduce fever.
Decongestant preparations that act by constriction of the blood vessels of the nose are not generally considered to be of great benefit. However, they are freely available as proprietary medications in the form of tablets or nasal sprays containing drugs similar in action to the chemical ephedrine. Decongestants reduce the swelling of the nasal lining and reduce the secretions. However, these are conventionally recognised to be suppressive, and it is recognised that the symptoms may recur in a more pronounced form when the drug wears off. Examples of decongestant medication include Vicks Sinex nasal spray and Sudafed nasal spray.
Sinusitis is the result of infection of the respiratory epithelium that lines the sinus cavities situated in the facial bones. Although it is commonly triggered by a virus infection, sinusitis can readily become more persistent due to subsequent bacterial infection. This is because the narrow opening of the inflamed sinuses into the nasal cavity easily becomes blocked, and the stagnation of the secretions within predispose to further infection, often by the ‘healthy’ bacteria that usually reside harmlessly in the nose.
Prolonged sinusitis is more likely to occur in certain susceptible people. Susceptibility can be the result of a congenital structural abnormality sinuses (and so could run in families), a tendency to produce excessive phlegmy secretions, and of smoking.
The symptoms of sinusitis include painful and tender sinuses, with foci of pain over the inner aspect of the eyebrows and in the centre of the cheekbones. In a persistent infection the patient may feel very unwell and feverish, and may have a headache over the forehead. Thick green secretions, indicating bacterial infection, may be produced.
Supportive measures include inhalation of aromatic oils, such as Olbas oil, in steam. Doctors will frequently prescribe antibiotics (most commonly amoxicillin) in a severe case of sinusitis, although increasingly other antibiotics such as doxycycline or erythromycin may have to be chosen because of increasing bacterial resistance to amoxicillin.
In susceptible people, sinusitis, even when treated with antibiotics, can become recurrent. Occasionally it can become chronic, with symptoms that never totally go away. In such cases the patient may be referred to an ear, nose and throat specialist for consideration of endoscopic sinus surgery, which is a means of widening and draining the sinus passages.
Information Box 3.3c-I The common cold: comments from a Chinese medicine perspective
In Chinese medicine, the symptoms of the common cold are described as an invasion of Wind Heat or Wind Cold (and occasionally Wind Damp Heat or Wind Dry Heat) on the Exterior. They are believed to occur because of the relative weakness of Wei Qi compared to the strength of the Pathogenic Factor. As such, if treated in its early stages by releasing the Exterior and Clearing Wind, the development of a common cold is believed to be preventable.
According to the Six Stages theory, a common cold due to Wind Cold is at the most superficial Greater Yang (Tai Yang) level. According to the Four Levels theory, a common cold due to Wind Heat is at the most superficial Defensive (Wei) Qi Level.
In contrast to conventional medicine, an Invasion of Wind Heat or Wind Cold is taken very seriously, as there is a risk it may descend to deeper energetic levels and change into Heat unless appropriate care and treatment is given.
From the integrated perspective of infectious disease introduced in Chapter 2.4d, the infectious viruses might be seen as the source of a Pathogenic Factor of external origin, whereas many bacterial complications of these infections would be seen as the result of additional Pathogenic Factors of internal origin. This is comparable to the concept in Chinese medicine that superficial invasions of Wind Heat or Wind Cold can progress to deeper levels in people with depleted Qi, and so fits in with the idea that in these cases the Pathogenic Factor is of internal origin.
For example, the development of a phlegmy bacterial bronchial infection following a minor viral illness, as is common in heavy smokers, could be interpreted in Chinese medicine as the accumulation of Heat and Phlegm at a deeper level than the Exterior. These pathogenic factors are consequences of long-term damage from smoking, and so would be recognised as Internal in origin.
Aspirin may be an appropriate energetic remedy for an invasion of Wind Cold or Wind Heat, in that it is believed to release the exterior and promote sweating. Aspirin is also anti-inflammatory and will temporarily relieve discomfort due to fever, sore throat and aching joints. This suggests a clearing of Heat from the Exterior level and a moving of stagnant Qi. However, the tablet preparation of aspirin is also Heating at a deep level, as evidenced by its causing inflammation of the stomach and increasing the tendency to bleed. This may not be desirable in a patient with Wind Heat invasion. Although aspirin clears Heat at a superficial level, the appearance of Heat at a deeper level suggests this could be, in part, the result of suppression.
Paracetamol also temporarily reduces fever, inflammation and pain. Like aspirin, this represents the clearing of Heat from the Exterior level and moving of stagnant Qi. Although it does not have the Heating properties of aspirin, in overdose it is known to be toxic, to the liver in particular. The temporary effects suggest the mechanism is also suppressive.
Decongestant drugs reduce secretions from the nose and stuffiness. This would correspond to the clearing of Wind Cold. Interestingly, these drugs have a very close relation in Chinese medicine known as ma huang (ephedra), which as a pungent warm herb is recognised to Clear Wind Cold. However, conventionally, decongestants are recognised to be suppressive in action. This suggests that if used without simultaneous attention to the root deficiency, the action of ma huang can also be suppressive.
Information Box 3.3c-II Sinusitis: comments from a Chinese medicine perspective
In Chinese medicine, sinusitis may simply be a manifestation of Wind Heat or Wind Cold invasion, but more severe cases may indicate other full conditions such as Lung Heat, Liver and Gallbladder Fire or Stomach and Spleen Damp Heat. These conditions occur on a pre-existing deficiency, commonly of the Spleen, which predisposes to accumulation of Damp, Phlegm and Heat.
If, as in most cases, the problem is a result of an internal imbalance, antibiotic treatment will not be treating the root cause, and due to its Cold and Damp nature may be compounding the problem with additional drug-induced disease. Therefore, the main action of antibiotics in this sort of case is suppressive. This explains why sinusitis can often recur after treatment.
It is very common for a virus infection to affect the back of the throat and/or the tonsils without also affecting the nasal lining. The inflammation that results from this sort of infection is termed ‘pharyngitis’ (sore throat) or ‘tonsillitis’, depending on the site of the worst symptoms.
Like the common cold, this sort of viral infection, although uncomfortable, should be mild and short lived. In more severe cases the tonsils can become very inflamed and enlarged, and this can be accompanied by high fever, headache, joint pains and malaise.
Infection with the bacterium Streptococcus pyogenes used to be a very common cause of tonsillitis and pharyngitis, although it is now less common. The bacterial tonsillitis is characteristically more severe than that resulting from a viral infection, and yellow areas of pus can often be seen on the tonsil. However, there is no absolute distinction, as some viral tonsillitis can be very severe, and may also generate pus on the tonsil. Bacterial tonsillitis and pharyngitis can be diagnosed by means of a throat swab, although this takes a few days to process.
The treatment for bacterial tonsillitis is penicillin(phenoxymethyl) rather than amoxicillin. Often, a doctor might choose to prescribe penicillin in a severe case of tonsillitis, even when it is uncertain that the cause is bacterial. The delays involved in processing a throat swab and the discomfort for the patient deter many doctors from performing this test. This is an example of ‘treating blind’ (see Chapter 2.4d). In many cases it may never be known whether the antibiotic helped because the tonsillitis naturally gets better in most people by 3–7 days of onset.
There are two reasons to prescribe antibiotics in tonsillitis. The first is that the symptoms of bacterial infection may be reduced in severity by penicillin. The second, more important, reason is that in some people the Streptococcus infection can have more serious complications. These are scarlet fever, rheumatic fever and glomerulonephritis (also known as acute nephritis). However, for reasons that are unclear, these complications are becoming increasingly uncommon, even when the use of antibiotics is accounted for. For this reason current medical guidelines (NICE 2008) recommend that antibiotics are not prescribed in uncomplicated cases of pharyngitis and tonsillitis.
In rare cases, one tonsil can become very inflamed and full of pus. This condition, known as ‘quinsy’ (peritonsillar abscess), is very debilitating, and is associated with fever. The treatment is with antibiotics and may require urgent surgical drainage of the pus from the tonsil. In some cases the enlarged tonsil may compromise breathing, in which case it becomes a surgical emergency.
In some people, and children in particular, tonsillitis can become recurrent. It used to be common practice to remove the tonsils surgically in such cases. However, surgery is now performed only relatively rarely, as it is recognised to be a risky and traumatic experience for a child, and does not necessarily reduce recurrent attacks of pharyngitis. Tonsillectomy would only currently be considered if attacks of tonsillitis exceeded five a year for at least 2 years.
Information Box 3.3c-III Tonsillitis: comments from a Chinese medicine perspective
In Chinese medicine, the signs and symptoms of tonsillitis and pharyngitis are usually attributed to Wind Heat invasion. In children in particular, Stomach Heat may be an additional internal source of the Pathogenic Factor. The symptoms of severe tonsillitis correspond to the Chinese medicine condition of Fire Poison, especially with the accumulation of pus and high fever that can occur in such cases. There may be underlying Kidney or Spleen deficiency in cases of Fire poison.
Quinsy is a severe example of Fire Poison, and develops because of underlying deficiency. Antibiotics, although necessary in many cases because of the severity of the condition, are suppressive in action. Surgical drainage is energetically appropriate, as it is simply speeds up the body’s tendency to discharge pus, and probably acts by enabling clearance of the Fire Poison (extreme Damp Heat).
Interestingly, Fire Poison has been described in Chinese medicine as one of the causes of acute nephritis. This fits with the conventionally recognised association between streptococcal tonsillitis and acute nephritis.
Antibiotic treatment in tonsillitis may often have either no effect or a simple placebo effect if prescribed in viral infections. However, it may also damage Stomach and Spleen Qi because of its Cold and Damp nature, and so may be less than helpful in the patient with viral tonsillitis. It may be the appropriate energetic remedy in streptococcal infections if the Pathogen is of external origin, however. This is most likely if the case is one of many ‘going round’. Often, tonsillitis has an internal component, and is an external manifestation of internal Stomach Heat. If this is the case, antibiotics will be suppressive, and recurrence of the ‘infection’ is a possibility.
Glandular fever is one of the more severe forms of viral tonsillitis, and is caused by a virus known as the Epstein–Barr virus (EBV). However, most cases of EBV infection are mild. The evidence for this comes from studies of healthy students, in which blood tests showed that up to 90% of the students had contracted the infection at some point in their lives. Most of these infections had occurred without the students knowing that they had contracted glandular fever.
However, severe cases can be prolonged and draining. The patient can suffer from severe tonsillitis, with fever and joint aches. The lymph nodes in the neck are enlarged. There may be abdominal pain as other lymph tissue in the body, including the spleen, can become enlarged, and the liver may become inflamed. Occasionally, a red, measles-like rash can develop, particularly in patients who have been mistakenly prescribed amoxicillin because a bacterial tonsillitis was suspected. In very rare cases the virus can affect the lining of the brain and cause meningitis.
EBV infection can be diagnosed by a blood test that detects antibodies to the virus in or after the second week of symptoms. Treatment is supportive only. In severe cases, when there is enlargement of the spleen, corticosteroid tablets may be prescribed.
Information Box 3.3c-IV Glandular fever: comments from a Chinese medicine perspective
In severe cases, the swelling of glands, muscle and joint aches, and disturbance of the liver and spleen suggest that the Pathogenic Factor has penetrated to deeper levels. This suggests either Residual Pathogenic Factor with Damp Heat in the muscles, or the Lesser Yang (Shao Yang) pattern of the Six Stages, or a combination of both.
Some of the other viral infections primarily affect the larynx and the trachea. The result is inflammation of these tissues, leading to one or more of hoarseness, cough and pain felt beneath the sternum. The pain is related to coughing and deep breathing.
Again, these infections may only be short lived except in those who are susceptible, particularly young children and smokers. In susceptible people there is a risk that tracheitis can descend to involve the bronchi and cause a much more severe and prolonged infection.
In children under the age of 3 years the swelling of the vocal cords can be so severe as to lead to difficulty in breathing. The affected child will be hoarse, have a rapid respiratory rate and may have a barking cough. If severe, a rasping noise, known as ‘stridor’, is heard as the child breathes in. In very severe cases the child needs to be nursed in a steam-filled tent in an intensive care unit to allow for safe recovery. The barking cough in such cases is called ‘croup’, and may persist in a child for weeks.
In some cases laryngitis may persist to give a syndrome of persistently hoarse voice and thick stringy mucus that is difficult to clear. This is known as ‘chronic laryngitis’. The patient is otherwise well. This is more common in people who smoke or in those who overuse their voices, such as singers.
The treatment of chronic laryngitis is to rest the voice and avoid smoking. Steam inhalations can soothe the vocal cords and loosen the mucus. However, if the hoarseness persists for more than 3 weeks it is considered good practice for the patient to be referred to an ear, nose and throat specialist. The vocal cords can then be examined by laryngoscopy to exclude the unlikely possibility of a tumour of the vocal cords.
Information Box 3.3c-V Laryngotracheitis: comments from a Chinese medicine perspective
In Chinese medicine, the symptom of a hoarse voice is usually associated with Wind Heat or Wind Cold invasion. However, the pain and depth of tracheitis suggests that the Pathogen has penetrated to a deeper level than the Exterior. The cough and breathlessness that accompany tracheitis in children in particular is suggestive of Lung Heat (Qi Level according to the Four Levels categorisation). Chronic laryngitis is also consistent with a diagnosis of Lung Heat, although in these cases the likely origin of the Heat is internal, as the condition affects smokers in particular. The dryness resulting from Lung Heat explains why inhalation of steam can be of relief.