In traditional thinking, coughs are mostly caused by respiratory diseases, and coughs that remain untreated are often treated as bronchitis or pharyngitis, and many patients have been misdiagnosed as “chronic bronchitis, bronchitis” or “pharyngitis,” etc. According to some statistics, the average time of misdiagnosis is 5 years, with the longest being over 20 years.
Many patients suffer from chronic cough for years, repeatedly using various tests and antibiotics, but still the treatment is ineffective, causing a great waste of medical resources and bringing physical pain and financial pressure to the patient. The large number of patients with incurable coughs has also long puzzled clinicians.
In fact, cough involves different parts of the respiratory system: nose, pharyngeal trachea, lungs, stomach, etc.; it also involves different systems, such as respiratory, digestive, and cardiovascular, etc. Therefore, all clinical departments encounter problems in the diagnosis and treatment of cough, and the causes of cough are very complex. Because of these complexities, treatment should be multidimensional and multifaceted, and it is difficult to achieve good results with the use of antibiotics alone.
The complex etiology of chronic cough requires comprehensive and accurate collection of medical history and physical examination, as well as necessary ancillary examinations, such as fiberoptic bronchoscopy, sputum examination, CT and HRCT, spirometry, diffusion function examination and radionuclide examination. However, the reasonableness of the indications and the appropriateness of the timing need to be mastered.
The etiological diagnosis is the key to the diagnosis and treatment of chronic cough, and the main ideas that can be followed in the diagnosis are:
(1) Pay attention to the medical history, including ear, nose and throat and gastrointestinal examination. Rhinitis/sinusitis should be considered in those with nasal symptoms such as nasal itching, nasal discharge, sneezing or postnasal drip flu. In particular, patients with hypertension who take some anti-hypertensive drugs that cause coughing should take a detailed history;
(2) Select the relevant tests according to the medical history, from simple to complex tests, common diseases first, then rare diseases, to reduce the cost of diagnosis for patients.
Both diagnosis and treatment should be carried out simultaneously or sequentially. Since eosinophilic bronchitis is the primary cause of chronic cough, induced sputum examination is an important method to diagnose EB without expensive instruments and complicated techniques, and BHR is an important criterion to diagnose CVA and the main criterion to differentiate it from EB, we list induced sputum, pulmonary ventilation function and airway excitation test as the primary examination items.
CT, fibrinoscopy, nasopharyngoscopy and other tests are not easily accepted by patients, are more expensive, and have relatively little value for the diagnosis of common causes, so these tests are listed as second-line tests.
(3) If the patient has limited economic conditions or hospital equipment, diagnostic treatment can be based on clinical features. If there is a significant nocturnal cough, cough variant asthma (CVA) is highly suspected. Those with food-induced cough or cough that worsens after eating with reflux-related symptoms may be treated as GERC.
Common causes of cough are:
Acute cough :
The common cold is the most common cause of acute cough. Other causes include acute bronchitis, acute sinusitis, allergic rhinitis, acute attacks of chronic bronchitis, and bronchial asthma (referred to as asthma).
Subacute cough:
The most common causes are post-cold cough, bacterial sinusitis, asthma, etc.
Chronic cough:
Gastro-oesophageal reflux cough (GERC) Post-nasal drip syndrome (PNDs),.
Other chronic cough causes: chronic bronchitis (ChB), bronchiectasis, allergic cough, endobronchial tuberculosis, angiotensin-converting enzyme inhibitor (ACEI)-induced cough, psychogenic cough, and
The specific diagnostic steps for cough are:
(1) Take a medical history and physical examination. In particular, ask about the environment, whether the patient is taking angiotensin-converting enzyme inhibitors (anti-hypertensives) and whether there is a history of colds or upper respiratory tract infections before the cough.
(2) Chest X-ray examination. X-ray chest examinations should be routinely performed for chronic cough to exclude other lung pathologies.
(3) Pulmonary function tests. Ventilation function, bronchodilatation test and bronchial excitation test can be done optionally according to the condition.
(4) Induced sputum examination to diagnose eosinophilic bronchitis (EB), etc.
(5) Sinus X-ray or CT examination and nasopharyngoscopy or fiberoptic nasolaryngoscopy. The main diagnosis is rhinitis, sinusitis, and throat diseases.
(6) 24h esophageal pH monitoring. This test can be done for the proposed diagnosis of gastroesophageal reflux cough.
(7) For suspected allergic cough, allergen skin test, serum IgE determination and cough provocation test are feasible.
(8) If the diagnosis is still not confirmed by the above tests or if the cough is not relieved by diagnostic treatment, high-resolution CT and fiberoptic bronchoscopy should be performed to exclude intra-airway lesions (e.g. foreign bodies that have been misdiagnosed for a long time) and other lesions in the lungs, etc.
(9) If all tests are normal, the diagnosis of psychogenic cough should be considered only after the above-mentioned organic lesion-induced cough has been excluded.
Principles of cough treatment.
(1) First, the diagnosis should be clarified and the cause treated;
(2) If the causal treatment is not immediately effective, symptomatic treatment is needed to control cough symptoms in order to improve the patient’s quality of life;
(3) When diagnostic conditions are inadequate, diagnostic treatment is performed to clarify the diagnosis.
Specific treatment of cough: In the treatment of cough, especially chronic cough, a clear etiology is a key factor for successful treatment. Specific treatment needs to be given for different causes of chronic cough.
Non-specific treatment of cough: ACCP recommends the choice of non-addictive cough suppressants, such as dextromethorphan, for reference.
Commonly used cough suppressant drugs :
1. Dependent cough suppressants
(1) Codeine: Directly inhibits the medulla oblongata, which has a strong and rapid cough suppressant effect, and also has analgesic and sedative effects. It can be used for severe dry cough and irritating cough due to various reasons, especially dry cough with chest pain. It can be given orally or by subcutaneous injection, 15-30mg each time, 30-90mg per day.
(2) Forcodine (pholcodine): similar to codeine, but less addictive. Take 5-10mg orally each time.
2.Non-dependent cough suppressants
(1) Dextromethorphan is one of the most used non-dependent central cough suppressants, which acts on the central and peripheral Sigma receptors, with similar or stronger cough suppressant effects than codeine, but no analgesic or hypnotic effects, and no inhibitory effect on the respiratory center in the therapeutic amount, without dependence and tolerance. ) considered dextromethorphan to be a safer alternative to codeine as a cough suppressant.
In 1998, the American College of Chest Physicians (ACCP) issued guidelines for coughs stating that dextromethorphan is an effective cough suppressant with Class I evidence. It is primarily used for dry cough in the setting of colds, acute or chronic bronchitis, bronchial asthma, pharyngitis, tuberculosis, and other upper respiratory tract infections. A variety of over-the-counter compounded cough suppressants contain this product. Take 15-30 mg orally 3-4 times a day. It is well absorbed orally and takes effect within 10-30 minutes of administration.
(2) pentoxyverine: a long-used cough suppressant in China, with 1/3 of the strength of codeine and anticonvulsant and antispasmodic effects. It should be used with caution in patients with glaucoma and cardiac insufficiency. Take 25mg orally 3 times a day.
(3) Dextrophane (dextrophan): a metabolite of dextromethorphan, which is well tolerated by patients.
3.Peripheral cough suppressants
(1) benproperine: non-narcotic cough suppressant, the effect is 2 to 4 times that of codeine. It can inhibit the peripheral afferent nerves and also inhibit the cough center. Take 20-40mg orally 3 times a day.
(2) Moguistenine: non-narcotic cough suppressant with strong effects. Take 100mg orally 3 times a day.
(3) Narcodine (narcodine): an isoline alkaloid contained in opioids, with effects comparable to codeine. Take orally 15-30mg each time, 3-4 times a day.