Cough is a very common clinical symptom that internal medicine clinicians encounter almost every day. For some coughs, especially acute coughs, a clear diagnosis can be made and effective treatment can be obtained by taking a medical history, physical examination, laboratory tests with chest radiographs and other relevant tests. However, a significant proportion of coughs, especially chronic coughs, cannot be diagnosed after a series of tests to find a positive result, and the treatment is naturally less effective. The treatment of cough in TCM is mainly based on the clinical symptoms and signs of the patient, combined with climate, environment, diet and emotions, to determine the type of symptoms and give the corresponding treatment. The treatment of cough in TCM is based on the symptoms rather than the specific “disease” and does not depend on equipment examination, which is especially suitable for primary care physicians.
I. New advances in cough
The new developments in cough are fully reflected in the first “Draft Guidelines for the Diagnosis and Treatment of Cough”, which was officially published in China in November 2005. Cough is classified into acute cough (less than 3 weeks), subacute cough (3 weeks-8 weeks) and chronic cough (more than 8 weeks). The etiologic diagnosis is the basis for successful cough treatment and is therefore the focus and center of the guidelines. While the etiologic diagnosis of acute cough is relatively simple and easily confirmed, chronic cough is often misdiagnosed and missed in clinical practice due to few diagnostic clues and insufficient attention by physicians. Therefore, the diagnosis of chronic cough is again a top priority in this guideline. In other words, new advances in cough are also focused on the recognition of chronic cough.
The guidelines define chronic cough (without abnormalities on chest X-ray) as cough as the main or only symptom, with a duration of cough greater than or equal to 8 weeks and no significant abnormalities on chest X-ray. This definition includes the three major elements of clinical symptoms, duration of illness, and examination, all of which are missing. If the patient has symptoms such as significant shortness of breath, dyspnea, coughing up blood, or fever, or if the chest X-ray reveals significant shadows, cavities, volume changes, or other lesions, these cases do not fall into the category of chronic cough as defined by the guidelines.
The main reason why the guidelines focus on the diagnosis and management of chronic cough as defined above is due to the following reasons: First, patients with this type of cough have few concomitant symptoms, no obvious abnormalities on X-ray, and few diagnostic clues, which, combined with insufficient attention by physicians, are often misdiagnosed and missed in clinical practice. Second, these patients have special etiological distribution characteristics. A large number of chronic patients are misdiagnosed as “bronchitis” or “chronic bronchitis”, and many of them have a disease duration of several years, which seriously interferes with the patients’ daily life, study and work. Due to unclear diagnosis, these patients are either treated with various antibiotics repeatedly or undergo various meaningless tests repeatedly, resulting in a great waste of medical resources.
The following is a brief discussion of some issues related to the etiologic diagnosis of chronic cough and the common types of chronic cough in conjunction with the guidelines.
The diagnosis of the etiology of chronic cough includes both history taking and examination selection.
First, the history of chronic cough: when cough is mentioned, many physicians naturally associate it with respiratory diseases and often ignore diseases of other systems. Cough receptors are not only found in the respiratory system such as the pharynx, trachea and bronchi, but also in the esophagus, paranasal sinuses, external auditory canal, pleura and pericardium, etc. Lesions in these systems or areas may produce cough symptoms. Therefore, when taking a medical history, in addition to the respiratory system, attention should also be paid to the digestive, otorhinolaryngological, and cardiovascular systems. Cough is also associated with a history of specific occupational exposures, such as warehouse dust, dust mites, pollen, silk, and mushroom spores, etc. Occupational exposure to chemicals or chemical products, such as latex gloves and acrylic salts, has also been reported. Cough is a common side effect of taking ACEI-type antihypertensive drugs, with an incidence of about 10%-30%, accounting for 1%-3% of the causes of chronic cough. Attention to the above mentioned medical history can sometimes provide direct diagnostic clues from these histories.
The characteristics of the cough are also helpful in the diagnosis, such as the nature, timbre, rhythm and duration of the cough, and triggering or aggravating factors. Most chronic coughs present as a dry cough, and if the patient has a high sputum level attention should be paid to the presence of bronchiectasis or chronic bronchitis. If the cough is predominantly nocturnal, cough variant asthma (CVA) should be highly suspected. Coughing after meals or worsening cough suggests gastroesophageal reflux cough (GERC).
Then there is the choice of tests related to chronic cough: for patients with chronic cough, the guidelines recommend X-ray chest radiographs as a routine examination because of the popularity and low cost of X-ray examinations, and because if significant lesions are found, further tests can be selected according to the morphology and nature of the lesions to avoid delaying the diagnosis. However, many patients with chronic cough have already undergone several out-of-hospital chest radiographs and even CT examinations without finding any abnormalities, so if there is no significant change in the patient’s condition, there is no need for further X-ray examinations.
Eosinophilic bronchitis (EB) and cough variant asthma (CVA) are the two most common causes of chronic cough. Induced sputum cytology, pulmonary ventilation function and airway hyperresponsiveness examination are the key methods to diagnose EB and CVA, so pulmonary ventilation function + bronchial excitation test and induced sputum examination are listed as the first-line tests for chronic cough.
Sinus film/nasopharyngoscopy, fibrinoscopy, esophageal pH monitoring, and chest CT are classified as second-line tests, mainly because of their diagnostic value in chronic cough, test cost, or patient compliance. Postnasal drip syndrome (PNDS) is a common cause of chronic cough, but the initial diagnosis can be obtained in many patients by history taking. Fibronectomy is mainly used for the diagnosis of rare causes such as endobronchial tuberculosis and early bronchopulmonary cancer. High-resolution chest CT is the best method to diagnose bronchiectasis, but the cost of the examination is high and bronchiectasis accounts for a very low proportion of the causes of chronic cough, so it is not used as a routine examination for chronic cough. Esophageal pH monitoring is currently the most specific and sensitive method for the diagnosis of gastroesophageal reflux cough (GERC), a common cause of chronic cough. At this level, esophageal pH monitoring should be included as a first-line test. However, due to the high cost of the test, the long monitoring time, the patient’s pain and the fact that not many units are currently performing it, it was finally classified as a second-line test. Of course, the distinction between first-line and second-line tests is not absolute. If there is a high suspicion from the medical history that a second-line test is needed to confirm the diagnosis, a second-line test can be performed directly when available.
The following is a description of several common types of chronic cough.
Postnasal drip syndrome (PNDs), cough variant asthma (CVA), eosinophilic bronchitis (EB), gastroesophageal reflux disease (GERC), chronic bronchitis, and drug effects are the six major causes of chronic cough, with the first three accounting for 90% of the causes of chronic cough. They are described separately below.
(1) Postnasal drip syndrome (PNDs): This is a syndrome, not a specific disease, and the diagnosis needs to be determined by symptoms, signs, imaging and response to treatment. When inflammatory secretions from the nose and sinuses post-drip into the throat or respiratory tract, coughing can occur due to irritation. The diagnostic criteria are: (i) episodic or persistent cough, predominantly during the day and less frequently after sleep; (ii) postnasal drip and/or a sense of mucus adhesion to the posterior pharyngeal wall; (iii) a history of rhinitis, rhinitis], nasal polyps or chronic pharyngitis; (iv) examination reveals a mucus adhesion, cobblestone-like view of the posterior pharyngeal wall; and (v) relief of the cough with targeted treatment. Treatment for this is preferred to first-generation antihistamines or mucosal congestion-reducing agents.
(2) Cough variant asthma (CVA): a special type of asthma, also known medically as “cough asthma”, whose main manifestation is a persistent cough, mostly at night or in the early morning, sensitive to irritating odors, often with an irritating cough, and mostly without croup on lung examination. These patients are often misdiagnosed as having chronic bronchitis or chronic laryngitis, and their quality of life is seriously affected by the long-term use of antibiotics without relief. This cough has the following four characteristics: (1) the cough is mainly at night or in the early morning; (2) there is a prolonged dry cough with little sputum; (3) the cough is aggravated by cold air or irritating odors; and (4) the effect of prolonged antibiotic treatment is unsatisfactory. The diagnosis can be confirmed by bronchial excitation test or bronchodilatation test (or peak expiratory flow rate (PEF) with a day-to-day variability of >20%). Treatment with inhaled hormones and bronchodilators provides complete relief of cough symptoms.
(3) Eosinophilic bronchiectasis (EB): clinically manifested by irritant dry cough or cough with little mucus sputum, normal pulmonary ventilation, no airway hyperresponsiveness (AHR), normal peak expiratory flow rate (PEF) variability, increased induced sputum eosinophils (Eos) (≥ peal 5%), and good effect of glucocorticoid therapy. The clinical manifestations of the disease are not characteristic and some patients have a similar presentation to cough variant asthma, which can occur at any age, but is mostly seen in young adults, with no abnormal findings on physical examination.Whether EB is an independent disease or an early stage of asthma remains to be clarified. (4) Gastroesophageal reflux
(4) Gastroesophageal reflux disease (GERC): The fact that gastroesophageal reflux can cause chronic cough is something that many people do not readily think about. According to the literature, chronic cough caused by gastroesophageal reflux disease accounts for about 20% of cases. This is due to irritation of the lower esophagus by the reflux entering the esophagus, causing abnormal nerve reflexes and resulting in respiratory spasms that produce cough. Esophageal pH monitoring is currently the most specific and sensitive method for diagnosing gastroesophageal reflux cough (GERC). Once the diagnosis is established, doctors treat the cough with appropriate medications or anti-reflux surgery, which can result in significant relief. However, esophageal pH monitoring is not performed in any primary care hospital. Diagnostic treatment can be performed if the following pointers are present, and the diagnosis can be established if it is effective (1) there is obvious feeding-related cough, such as postprandial cough and feeding cough; (2) it is often accompanied by gastroesophageal reflux symptoms, such as acid reflux, belching, and retrosternal burning sensation; (3) except for diseases such as CVA, EB, allergic rhinitis, and rhinitis], or if treatment according to these diseases is ineffective.
(5) Chronic bronchitis (ChB): chronic bronchitis cough is characterized by a cough with a large amount of sputum coughed up, predominantly in the morning, with increased and purulent sputum and yellow color in the presence of acute infection. Chronic bronchitis often has a history of more than two years, and the cough lasts for more than three months each year. Its treatment, first of all, is to quit smoking, strengthen exercise, enhance physical fitness, and reduce the number of episodes of respiratory infection.
(6) Drug effects: Many drugs can cause coughing, for example, commonly used drugs for hypertension, i.e. angiotensin-converting enzyme inhibitors, such as Kepone, Yuetinin and Lodinin; amiodarone and diuretics can also cause coughing. The cough can be relieved by immediate discontinuation of the medication. Therefore, patients should be reminded to read the instructions carefully before using the medication to have a good idea of what to expect.
Chinese medical evidence and treatment of cough
More than 2,000 years ago, Chinese medicine had a profound understanding of coughing, and in the Yellow Emperor’s Classic of Internal Medicine, there is a treatise on coughing called “On Coughing”. This treatise provides a more comprehensive discussion of the etiology, clinical symptoms and treatment of cough. These understandings have been continuously enriched in the clinical practice of successive generations of medical practitioners, and a wealth of clinical experience has been accumulated. The following is a brief description of the etiology and treatment of cough in Chinese medicine.
(I) Causes
According to TCM, cough is located in the lung and is caused by a loss of the lung’s declarative and descending functions and the upward rebellion of lung qi. The causes of malfunctioning of the lung qi can be summarized as internal and external.
1. External causes: This refers to the various factors in the external environment that can cause the onset of disease in the human body, but in most cases it refers to seasonal and climatic factors, which are summarized in Chinese medicine as the six pathogenic factors of wind, cold, summer, humidity, dryness and fire, referred to as the “Six Phenomena”, which are the main causes of external cough. They are the main causes of external coughs. Cough Theory” says: “The six gases of cold, heat, dryness, dampness, wind and fire all cause cough.”
How to determine the cause of external cough in clinical practice? It can be considered from the following aspects.
(1) “Examining the symptoms to find the cause”: Based on the clinical manifestations of the disease, the symptoms and signs of the disease are comprehensively analyzed to deduce the cause of the disease and provide a basis for treatment and medication. It is worth noting that the principle of examining the symptoms and seeking the cause is the inverse method, which is to deduce the cause from the effect. The symptoms of a disease are the result of the joint action of the causative factors and the individual’s constitution. The “symptoms” in our examination include not only the causative factors but also the physical factors. The same disease-causing environment, due to the different physique of the individual, the occurrence of the disease will be different, Chinese medicine called this phenomenon “from the chemical”. That is, after the disease-causing factors enter the body, they are transformed with different constitutions. For example, if a Yang deficiency person feels wind-cold, he will have wind-cold symptoms, and if a Yin deficiency person feels wind-cold, he will have wind-heat symptoms.
(2) “Seeking the cause according to the time of the year”: to explore the cause of the disease according to the season and climate where the disease is. In clinical practice, we find that a significant number of patients with cough have no other symptoms or signs other than cough. In this case, “examining the symptoms to find the cause” does not work, but we can consider the cause according to the characteristics of the climate at that time. Two points should be noted when using the “seasonal approach”: (1) there is no evidence other than the cough; (2) the cough is of short duration or in the exacerbation phase of a chronic cough.
(3) The “artificial environment” should not be ignored: the emergence of greenhouses has led to counter-seasonal vegetables; the application of air conditioning has also led to counter-seasonal diseases. Excessive heating and hot pot in winter can lead to a wind-heat cough; excessive craving for cold and eating cold food in summer can lead to a wind-cold cough.
(4) “All six gases cause coughing, and wind-cold is the main cause”: This is the view of Zhang Jinyue, a doctor of the Ming Dynasty, who believed that coughs are mostly caused by wind and cold. The modern famous doctor Tang Buqi also shares the same experience, “Although the six coughs are closely related to the seasons, such as winter with more cold, spring with more wind, summer with more heat, summer heat and humidity, and autumn with more dryness, they should not be confined to all of them, especially typhoid cough, which is the most common and occurs in all four seasons, and is not confined to the winter season, it is still appropriate to seek the cause and examine the cause for treatment.” Here we should grasp two points: first, when diagnosing a cough with external sensation, we should first think about whether it is caused by wind-cold; second, when treating a cough with external sensation, we should not use cold medicines prematurely, for fear that they will block the lung qi and cause the cough to be prolonged and difficult to cure.
(5) “The six molestations also cause a prolonged cough”: Most books take the length of the illness as a key point in the differentiation between external coughs and internal coughs. In fact, if the cough is not treated correctly, the evil that has visited the lung and lingered can also cause a prolonged cough. In this case, the key to identifying the cause is to “examine the symptoms”. I recently treated a case of recurrent coughing for more than two years, with small and sticky sputum, which was untreated for a long time, accompanied by sweating and bad wind, especially at night. The pulse was found to be floating and soft. The dialectical analysis was that the wind had been visiting the lung and guard, staying there for a long time, and the lung surface and camp and guard were not in harmony. He started to use Gui Zhi plus Hou Pu Apricot Soup from the Treatise on Typhoid Fever, and took the medicine for one week with slight reduction of symptoms. Reviewing the reason, the dialectical evidence is good, but the prescription is not appropriate. Gui Zhi Tang focuses on harmonizing Ying and Wei, and is weak in dispelling wind. Since the evidence is that the wind visits the lung health, the main focus should be on dispelling the wind, and Tang Buqi’s formula should be used instead (Jing Wei Wei Wei Poisoning San (Jing Wei, Fang Feng, Almond, Burdock, Radix Platycodon grandiflorus, Licorice, Radix Panax, Poria, Mouton, Bamboo Roo). After taking two doses, the coughing and sweating was significantly reduced, and was cured after taking three more doses.
2. Internal causes: Generally speaking, they refer to the internal pathogenic factors in the body. The internal causes of coughing are roughly the dysfunction of the internal organs, the influence of pathological products, and the deficiency of qi, blood, yin and yang in three aspects.
(1) Dysfunction of internal organs: Cough is not only a result of dysfunction of the lungs, but also a result of dysfunction of other internal organs. This was recognized by Chinese physicians more than 2,000 years ago in the Su Wen? It is written in the “Treatise on Coughing” that “all five organs and six internal organs cause coughing, not just the lungs.” For example, the cough of gastroesophageal reflux disease, which is now spoken of, is caused by the upward rebellion of stomach qi; the cough of cardiac origin is related to liver depression in Chinese medicine.
(2) Influence of pathological products: Dysfunction of the internal organs, if it leads to impaired metabolism of substances in the body and obstruction of the flow of qi, blood and fluids, will form pathological products, which will become a new cause of disease and lead to its onset. The pathological products that cause cough are mainly phlegm and beverages. Phlegm and beverages are mainly due to the impaired metabolism of water and moisture in the body, of which thick ones are called phlegm and clear ones are beverages. This article will only discuss two types of coughs: phlegm-damp cough and cold-drink cough.
(3) Insufficient qi, blood, yin and yang: The normal activity of the internal organs cannot be separated from the warmth of yang and the nourishment of yin and blood. When the deficiency of Qi, Blood, Yin and Yang in the body reaches a certain level, it will lead to dysfunction of the internal organs. If the lung qi is affected, and the lung qi is reversed, then coughing will occur. It is important to note that a deficiency of positive qi often leads to a susceptibility to certain kinds of evil qi, which manifests itself as a situation where the deficiency is mixed with the real. For example, Yang deficiency is susceptible to cold evil, Wei Qi deficiency is susceptible to wind evil, etc.
The above brief description of the causes of cough is intended to provide ideas for the treatment of cough. The following is an introduction to the treatment of common types of cough.
(II) Treatment of evidence
Tang Buqi wrote a monograph on cough in more than 160,000 words – “Discriminatory Treatment of Cough”. Therefore, what I discuss here is only a little bit of the evidence and treatment of cough, which is of course more commonly used in clinical practice.
I would like to introduce a few common types of coughs.
1. Typhoid cough
Symptoms: heavy cough, thin white sputum, clear nasal congestion, no sweating, and a neutral mouth, often accompanied by wind-cold superficial evidence, with a light red tongue, thin white moist coating, and a floating tight pulse. It can develop in all seasons, but is mostly seen in winter.
Treatment: Pungent, warm, dispersing cold, promoting the lung and relieving cough.
Recipe: Su Chen Jiu Bao Tang.
Drugs: Ephedra, cinnamon stick, almond, licorice, perilla, Chen Pi, mulberry bark, big belly skin, peppermint.
2.Cough with wind
Symptoms: cough with itchy throat, or throat discomfort, sneezing and runny nose, slightly red tongue, floating and soft pulse. It can be seen in all seasons, with spring being the most common.
Treatment: Drain wind and promote lung circulation, resolve phlegm and stop cough.
Direction: Drain the wind and promote the lung, resolve phlegm and relieve cough.
Effects: Thorny mustard, windbreak, orris, licorice, burdock, almonds, half summer, poria, mucuna pruriens, bamboo rhizome.
3. Wind-heat cough
Symptoms: unpleasant cough, thick or yellow sputum, poor vomiting, and wind-heat symptoms, with red and red throat, red and red tongue with thin yellow fur, and floating pulse. Most often seen in spring and summer, but can also be seen in other seasons.
Treatment: Drain wind and clear heat, promote the lung and stop cough.
Recipe: Mulberry-Chrysanthemum Drink plus or minus.
Drug: Mulberry leaf, chrysanthemum, orris, raw licorice, forsythia, almond, peppermint, Zhi Mu, Zhe Bei.
4.Cough due to heatstroke
Symptoms: uncontrolled cough, sticky phlegm, excessive sweating, disturbed heart, dullness with little food, yellow urine, loose stools, thirst for drinks, red tongue with thick and greasy coating. Seen in summer.
Treatment: Clearing heat and penetrating summer heat, promoting lung and resolving dampness.
Formulation: Lei’s method of clearing and promoting the golden organs.
Effects: Stir-fried burdock seeds, zhebei, loquat leaves (hair removed), horsetail, guavashell, orris, mulberry leaves, almonds, slippery stones, raw licorice.
5.Damp-heat cough
Symptoms: uncontrolled cough, head heaviness and body pain, fullness in the chest and diaphragm, pale or greasy mouth, yellow face without thirst, unfavorable urination, red tongue, white greasy coating, thin and moist pulse. Most often seen in long summer.
Treatment: Open and promote lung qi, clear heat and dampness.
Formulation: San Ren Tang.
Effects: Almond, cardamom, coix seed, thick park, tongcao, slippery stone, bamboo leaf, and half summer.
6. Dry-heat cough
Symptoms: cough with little phlegm, dry nose and throat, dry mouth without drinking much, dry lips and tongue with little fluid, dry stools. Most often seen in autumn.
Treatment: Clear the dryness and moisten the lungs to stop the cough.
Recipe: Sang-almond soup.
Effects: Mulberry leaf, almonds, pointed shell, southern sage, northern sage, fried gardenia, pear skin, orris, raw licorice.
7.Phlegm-heat cough
Symptoms: Mostly seen after a few days of coughing from wind-heat, wind, dry heat and summer heat, with cough, yellow sputum in large amount, red tongue with yellow coating and slippery pulse.
Treatment: Clearing the lung and resolving phlegm to stop cough.
Formulation: Clearing gold and resolving phlegm.
Effects: Mulberry white peel, Qian Hu, Radix et Rhizoma, Scutellaria baicalensis, Gardenia jasminoides, Fishy grass, Radix Platycodon grandiflorus, Zhe Bei, Orange red, Mai Dong, Licorice.
8.Cold-damp cough
Symptoms: cough with cloudy sound, white sputum, cold and no sweat, nausea and vomiting, poor appetite, white and greasy tongue coating and slippery pulse.
Treatment: Promote the lung to disperse cold, dry dampness and resolve phlegm.
Formulation: Almond and Su San.
Effects: Almonds, Su leaves, Phlegmia, Chen Pi, Bai Qian, Citrus Aurantium, Radix Platycodon, Ginger, Roasted Licorice, Poria, Jujube.
9.Cough with wind and phlegm
Symptoms: Episodic cough, mostly at night, with white foamy sputum, red tongue, smooth coating and slippery pulse.
Treatment: Expelling wind and resolving phlegm, relieving spasm and cough.
Recipe: Sagan Ephedra Tang.
Drug: Radix Eucommiae, Ephedra, Zingiber officinale, Radix et Rhizoma, Ginger, Radix et Rhizoma, Fructus Semen, Fructus Schisandrae, Jujube.
10. Deficiency of Wei and wind attacking cough
Symptoms: recurrent cough, excessive sweating and vicious wind, sneezing and clearing of snot, white face and tongue, and deficient pulse.
Treatment: Benefit the Wei to dispel wind and promote the lung to stop cough.
Recipe: Gui Zhi plus Hou Pu and Apricot Soup combined with Yu Ping Feng San.
Effects: Gui Zhi, Bai Shao, ginger, jujube, roasted licorice, Hou Pu, almond, Huang Qi, Atractylodes macrocephala, and Fang Feng.
11.Yin deficiency cough
Symptoms: cough with little phlegm, dry mouth and throat, red tongue with little coating and fine pulse.
Treatment: Nourishing Yin and moistening the lung to stop cough.
Recipe: Sha Shen Mai Dong Tang.
Effects: Salvia miltiorrhiza, maitake, pollen, yucca, lentil, licorice, mulberry leaf, mother of pearl, almond.
12.Pregnancy cough
Symptoms: Women with post-pregnancy cough, with red tongue and little coating and slippery pulse.
Treatment: Nourishing Yin, nourishing Chong, moistening the lung and relieving cough.
Recipe: Baihe Gujin Tang.
Drug: Lily, Radix Rehmanniae, Radix et Rhizoma, Radix et Rhizoma Ginseng, Radix Bupleurum, Radix Platycodon, Almond, Radix Paeoniae Alba, Radix Glycyrrhizae.
The above briefly describes some common clinical types of cough. For the treatment of cough, in addition to medicine, attention should be paid to a light diet, avoiding spicy, fried, cold and other foods; avoiding exposure to cold and cold, etc.