A chronic cough can severely impair quality of life and raise a number of questions. Pneumologist Prof. Dr Rainald Fischer talks about the possible causes, diagnostic procedures and what can help get a grip on a persistent cough.
Prof. Dr Fischer: A chronic cough is one that is persistent. According to German guidelines, a cough is considered persistent or chronic if it lasts for eight weeks. This distinguishes it from an acute cough, which can last up to three weeks.
Prof. Dr Fischer: An important point when assessing a cough is whether it is present at night. If you cough at night, it is an unconscious and therefore real cough – unlike a psychogenic cough which has no physical causes. Psychogenic coughs are triggered by mental factors such as stress, anxiety or unconscious behavioural patterns, but are rare.
In terms of how often someone coughs, in studies on chronic coughs it has been classified as relevant if someone coughs more than 20 times an hour. However, even less frequent coughing fits can be perceived as stressful.
Prof. Dr Fischer: All chronic lung diseases such as COPD, bronchitis, cystic fibrosis or asthma can present with a chronic cough. But there are also chronic coughs for which there is no obvious discernible reason. As soon as a cough lasts longer than eight weeks, the search for the cause begins.
We use a range of diagnostic procedures to ascertain what could be going on: smoking or other environmental irritants, asthma, bronchial hyperreactivity, psychogenic cough, reflux, a tumour or causes related to the ears, nose and throat. We cast a wide net.
Sometimes you find the most bizarre causes. For instance, I had a patient who years ago accidentally inhaled a dental crown which was evident on his X-ray. Once the crown was removed by bronchoscopy, the persistent cough disappeared. But there are also cases where the cause is not clear.
It is also not always possible to successfully treat a chronic cough. Unfortunately, there are patients whose chronic cough persists despite everyone’s best efforts.
Prof. Dr Fischer: Three organ systems have to be investigated: the ENT region, the lungs and the stomach. In the ENT region we also look for changes to the paranasal sinuses. We check if secretions are trickling down the throat towards the lungs and triggering the cough receptors.
In the lungs, we need to rule out diseases like asthma, COPD or structural changes such as bronchiectasis and also a tumour. Asthma and bronchial hyperreactivity tend to be tested in a lung function test with provocation. Structural changes can be identified in X-ray examinations.
In the stomach – usually with a gastroscopy – we check if the patient may have reflux that is causing the cough. Reflux, be it silent or with noticeable heartburn can cause gastric acids or gastric fluids to enter the lungs where they then trigger a cough.
Prof. Dr Fischer: Coughs are often caused by viral infections. After these kinds of infection, the patient may be left with bronchial hypersensitivity, i.e. hyperreactivity, which can be heading towards asthma. These patients can often be successfully treated with asthma sprays.
Prof. Dr Fischer: It’s possible. This brings us to asthma, or more specifically allergic asthma.
Prof. Dr Fischer: Typically, a chronic cough is an unproductive dry cough, which means there is no sputum. A productive cough that persists indicates there is an underlying disease – such as chronic bronchitis or other lung diseases.
Prof. Dr Fischer: Any cough lasting longer than eight weeks should be checked out by a doctor. Other symptoms such as coughing up blood, severe pain or shortness of breath are warning signs requiring immediate medical attention – even if the cough has not lasted eight weeks at that point.
Prof. Dr Fischer: Whether or not a chronic cough is dangerous depends on the cause. The cause of the cough should always be investigated. Even if it is not possible to find the exact cause – and that isn’t rare in patients with a chronic cough – therapies must be attempted to stop or limit the cough.
This is because a persistent cough can cause tiny injuries to the mucous membranes in the trachea and the bronchial tubes. These microinjuries can heal, but they can also trigger a cough again because they make the bronchial tubes more sensitive to the smallest irritations – such as dry air, air pollution or the like. These microinjuries then keep triggering new coughing fits, which starts off a vicious circle of microinjuries and irritations. It is important to break through this vicious circle or to make sure it doesn’t develop in the first place.
Prof. Dr Fischer: The therapy is based on the cause. Inhalative steroids, or in other words sprays that dilate the airways, stomach acid blockers, physiotherapy or logotherapy can help. You can also inhale saline solution – with an inhalation device with a nebuliser. Some people find that this helps, especially if they have a dry cough. Inhalation therapy with saline solution can make you feel like you can cough something up, which can reduce the urge to cough.
For a cough with a mucus build-up, inhalation therapy with hypertonic saline solution can help liquify the secretions and cough them up so that the lungs are clear and the cough reflex is reduced. For unclear cases, medications that suppress the cough are used to avoid the cough getting worse because of microinjuries and eventually becoming a force of its own. As well as medications, breathing exercises with breathing therapy aids can be helpful.
Prof. Dr Fischer: Especially in children whose cough after a viral infection is sustained and sounds like barking, the following applies: If the child is not coughing at night and can sleep peacefully this is more likely to indicate a reflex pathway. During the day, the child remembers the urge to cough either consciously or subconsciously, and this then triggers a cough.
However, night-time coughing fits that last longer than eight weeks are a clear warning signal that really must be investigated. Occasional coughing during the day or at night, up to two to four times, is harmless, as long as it does not wake up the child.
Prof. Dr Rainald Fischer is a specialist for internal medicine in private practice, with a subspecialty in lung and bronchial medicine, specialty of emergency medicine, sleep medicine and allergy medicine in Munich-Pasing. Before that he worked as an internist and lung specialist, most recently as a senior physician at the Munich university hospital. Prof Dr Rainald Fischer is a founding member and president of the Deutschen Gesellschaft für Berg- und Expeditionsmedizin (German Society for Mountain and Expedition Medicine), and also a member of the Cystic Fibrosis Medical Association.
If the cough lasts longer than eight weeks, it is classified as a chronic cough. Then you can and should do the following:
Note: The information in this blog post is not a treatment recommendation. The needs of patients vary greatly from person to person. The treatment approaches presented should be viewed only as examples. PARI recommends that patients always consult with their physician or physiotherapist first.
An article written by the PARI BLOG editorial team.
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