Coughing is a reflex action in which successive inspiration, a brief closing of the glottis, and then immediately after the pressurization of the rib cage, a sudden opening of the glottis, which leads to cough shake. This cough jolt in fact corresponds to a fast flowing expiration.
When the cough shakes succeed, they realize the cough.In this reflex action comes one afferent: it is the irritant receptors present in large numbers in the head and neck, trachea and main bronchi, pleura and diaphragm, incidentally the ear canal. The signal is transmitted to the cough center (bulb) and / or to the cerebral cortex, which explains the character often reflex sometimes volunteer this symptom.
The efferent pathway is represented by the phrenic nerve, the intercostal nerve and every nerve branches of accessory respiratory muscles (abdominals, lower back). The important point is the great richness of sensory nerve endings in the airways, upper, bronchi and pleura, which contrasts with the poverty of nociceptive information from the lung tissue itself. A discreet cough is inflammation of pharyngolarynx and a large parenchymal tumor and mediastinal pleura respect is not.
Faced with the symptom, cough, the practitioner must specify the characteristics: chronicity, period and conditions of occurrence, productive or not.
Acute and chronic cough cough:
Faced with a recent cough occurring in clear clinical context (nasopharyngeal infection, bronchitis, fever, exposure to an irritant agent), the etiological is unnecessary and the doctor is allowed to use symptomatic treatment. Faced with a chronic cough, a systematic diagnostic research is required: a cough is considered chronic when it lasts not less than 6 weeks.
This is a common symptom, it is the fifth reason for consultation in medicine practitioner in the United States (Pratter et al., 1993) and its prevalence in non-smoking adults is approximately 15%.
Dry and productive cough:
It is conventional to oppose the cough reflex (spasmodic cough) that authorizes an antitussive treatment and productive cough bringing a mucous or purulent sputum that demands to be met. Administer an antitussive drug in a crowded chronic respiratory insufficient constitutes serious misconduct.
Condition and time of occurrence:
These elements are indicative, but prove faithful in little practice.
A coughing primodécubitus or association evokes heartburn gastroesophageal reflux.
Nocturnal cough is observed in asthma and is a key element in the assessment of good asthma control.
The effort cough occurs in two very different circumstances: it is a variant asthma, especially in children. In hypertensive or coronary adult, it may reflect an underlying heart failure.
The perprandiale cough evokes swallowing disorders or the occurrence of fistula oesotrachéale.
More typical is the whooping coughing.
Evident in young children before the age of vaccination, it is now observed more frequently in adults, but usually loses semeiological purity.
If the cough lasts more than 6 weeks, it is necessary and sufficient to start the etiological investigation request a chest X-ray front and profile. The diagnosis is usually easy if abnormal chest radiograph.
Usually the chest radiograph is normal, which leads to systematically explore four main diagnoses.
Chronic cough associated with a radiological anomaly:
It is the easiest event to the doctor.
If the fault is located, it may be the first symptom of lung cancer: cough occurring after 40 years in a smoker occurs in the context of a bronchial irritation syndrome made cough, mucous expectoration, rarely hémoptoïques sputum (found in 15% of cases at the initial stage). Lung cancer affects about 20,000 patients per year, with a growing percentage of female subjects.
The radiological image is often evocative. Cancer can sometimes hide under the cover of repeated lung diseases affecting the same territory. We can bring the accompanying cough of a compression syndrome of the mediastinum (mediastinal tumors, mediastinal lymphadenopathy).
As cough is associated with poor general condition, low-grade fever, especially as there is a contagion, tuberculosis must always be mentioned, even if it has become rarer nowadays often causing a delay in diagnosis especially in the elderly living in the community.
Among the localized cough-generating anomalies include bronchiectasis where cough is associated with a regular morning sputum, pleural disease whose initial symptoms were ignored or childhood intrabronchially a foreign body.
Cough warrants regular bronchiectasis and respiratory physiotherapy in case of purulent sputum, antibiotics (eg Zithromax in 5-day cure).
The foreign body intrabronchially the child must be removed during the diagnostic endoscopy.
When radiographic abnormalities are diffuse cough fact evoke several ailments including five particularly worth keeping:
– Cough, dyspnea and crackles are suggestive of fibrosing interstitial pneumonia;
– Cough and manifestations of left ventricular failure are integrated in the heart lung;
– Some parenchymal infections are readily tussigènes as Pneumocystis carinii infection in immunocompromised but the context is different;
– More recently reappeared pertussis in adults. The delicate diagnosis relies on PCR (sampling nasopharyngeal secretions) and the rise of antitoxin antibodies of pertussis on two blood samples collected at monthly intervals and distance of a recent vaccination (6 months).
Chronic cough in normal chest:
The diagnosis is more difficult when the chest radiograph is normal. The isolated chronic cough is often very old moving for months or years despite multiple treatments, varied, generally poorly monitored by the patient does not tolerate this annoying symptom for himself and his entourage all that disturbs seriously his social and professional life.
The only way to solve the problem is to consider systematically the four predominant etiologies: the original ORL cough, asthma including allergic asthma, gastroesophageal reflux, iatrogenic cough.
This simple intervention scheme for a chronic cough should not ignore the difficulties encountered by the doctor, faced with a disease lasting for several years. Also in the same patient several etiologies coexist complicating the diagnostic investigation and treatment. Furthermore, facing a very long history of cough, it is certain that the cough itself, generating basithoraciques pain, sometimes even rib fractures, eventually the mechanical irritation of the larynx and bronchi and evolves on its own account, explaining some bitter failures even without any identifiable cause.
Original cough ENT:
It may be related to chronic laryngitis, a new formation of the vocal cords benign or malignant, a condition of the outer ear (ear-canal foreign body). The most common cause is postnasal drip called by the Anglo-Saxons the postnasal drip syndrome.
Faced with a chronic cough in non-smoking adults, it is oriented by nature morning cough, the notion of rhinitis and concomitant sinusitis, the notion of a rarely objectified flow of secretions by subsequent examination of the pharynx.
It is useful to ask an ENT opinion and if needed a sinus scanner. If this hypothesis is accepted an empirical treatment of at least 2 months with an antihistamine nasal corticosteroids associated solve the problem in 60% of cases.
Chronic cough and asthma:
This is often an allergic asthma, justifying the search of atopy and conducting a skin allergy tests vis-à-vis the common allergens. Cough “spasmodic” is a variant asthma, especially in children and even more when the child made an effort.The origin of asthmatic cough is often accompanied by non-specific bronchial hyperresponsiveness (HRBN).
There are also cough without asthma but with NSBH whose evidence is furnished by the methacholine challenge.
Treatment is initially to bronchodilators and inhaled corticosteroids, often combined in the same device (for example Symbicort).
Chronic cough and digestive diseases:
The first cause is the refl ux gastroesophageal disease (GERD). The diagnosis is easy when the cough is associated with classic symptoms: heartburn, indigestion, throat or earache pain, but it is often isolated and requires pH monitoring.
An interesting semeiologic element is the presence of an inflammatory area of the rear edge of the larynx evocative of GERD.
Many cough associated with GERD have already received an antacid treatment more or less followed. If in doubt, better to suspend and resume the usual medication digestive explorations.
Beside other causes of GERD are observed: tracheobronchial fistula during the evolution of lung or esophageal cancer, coughing when choking in connection with a neurological disease, paralysis sousphréniques.
Recently have been reported some chronic cough after comments by adjustable band gastroplasty in patients with morbid obesity.
GERD coughing is often relieved by a proton-pump inhibitor (omeprazole for example) twice daily.
They mainly result from the use of angiotensin converting enzyme (ACE). The prevalence is high (10-15% of treatments).
Cough disappears 2 to 15 days after stopping treatment. The IEC will be replaced by the antagonists of the angiotensin receptor
II which only rarely cause such symptoms.
Twelve percent remain unexplained chronic coughs and do not meet any symptomatic treatment. We must patiently continue to monitor these patients. Psychogenic cough too often evoked remains a diagnosis of exclusion not considered with extreme caution.
A review of the patient, achieving a new chest radiograph after 6 months or a year, and ultimately the use of systematic endoscopy help reassure both the patient and physician.
Cough suppressants containing codeine or oxomemazine may be used only after ensuring that oxygen saturation is normal and the patient is not crowded.