I. Coughing, a protective respiratory reflex action of the body. The cough reflex arc consists of four links.
1. respiratory nerve endings receptors, including mechanoreceptors, chemoreceptors and pulmonary traction receptors.
2. afferent nerves, which are vagal nerve fibers.
The medullary cough center, located in the dorsal part of the medulla oblongata, adjacent to the respiratory center.
4. efferent nerves, including the vagal efferent fibers, the supraglottic nerve and the cerebral nerve.
Chronic cough is defined as a cough lasting more than 8 weeks, with cough being the only symptom present, not accompanied by hemoptysis, denying cough-related respiratory disease, and difficult to confirm the diagnosis on recent X-ray examination. The etiology of this type of disease is unknown, the symptoms are atypical, and many factors need to be excluded. Zhang Weilu, Department of Pulmonary Diseases, Affiliated Hospital of Shandong University of Traditional Chinese Medicine
II. In summary, the diseases that cause chronic cough include
1. cough variant asthma (CVA).
2. postnasal drip syndrome (PNDs).
3. gastroesophageal reflux cough (GERC).
4. Eosinophilic bronchitis (EB). The above account for 70% to 95% of chronic cough in respiratory medicine outpatient clinics.
III. CVA is characterized by.
1. Cough that occurs continuously or repeatedly for more than one month, often occurring at night or in the early morning with episodes of coughing, aggravated by exercise and little sputum;
2. Laboratory tests or other examinations show no obvious signs of infection or long-term antibiotic treatment is ineffective;
3. The attack can be reduced with bronchodilators;
4, there is a personal history of allergy, i.e., with a history of eczema, urticaria, allergic rhinitis, etc., and family history of allergy can also be found;
5, Exercise, cold air, allergens or viral infections trigger asthma attacks;
6, Asthma is seasonal, mostly seen in spring and autumn and recurrent;
7. Chest X-ray shows normal or increased lung texture but no other organic changes;
IV. Diagnostic criteria for PNDs (recommended in China’s Guidelines for the Diagnosis and Treatment of Cough).
1. Episodic or persistent cough, predominantly during the daytime, with less coughing after sleep;
2, postnasal drip and/or a sense of mucus adhesion to the posterior pharyngeal wall;
3, history of rhinitis, sinusitis, nasal polyps or chronic pharyngitis;
4, examination found that the posterior pharyngeal wall mucus adhesion, cobblestone-like view
5. The cough is relieved after targeted treatment.
V. The diagnostic criteria for GERC are
1. Chronic cough for more than 8 weeks, with daytime cough predominantly and aggravated after meals.
2, 24-hour esophageal pH monitoring Demeester’s score ≥ 12.70, and/or the probability of correlation between reflux and cough symptoms (SAP) I>75%. (Postprandial pH measurement is the gold standard for diagnosis)
3, No obvious lesions on imaging, and diseases such as cough variant asthma (CVA), eosinophilic bronchitis (EB), and postnasal drip syndrome (PNDs) can be excluded.
4. The cough is ineffective after anti-inflammatory and cough suppressant treatment, and is significantly reduced or disappears after anti-reflux treatment.
VI. Diagnostic criteria for EB.
1.Chronic cough, mostly irritating dry cough, or with a small amount of mucous sputum;
2. Normal X-ray chest film;
3, normal pulmonary ventilation function, negative airway hyperresponsiveness, normal peak expiratory flow rate variability;
4, sputum cytology eosinophil ratio ≥ 2.5%;
5.Exclude other eosinophilic diseases;
6.Oral or inhaled glucocorticoid therapy is effective.