Chronic cough: XY symptoms … unsolved

23. November 2015
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In five to ten percent of patients who suffer from a chronic cough, no organic cause can be found. New guidelines for American pulmonologists now provide evidence-based recommendations for treatment.

A cough is described as chronic when it lasts for longer than eight weeks. Frequent coughing for a long period of time may have a number of causes – from serious diseases such as lung cancer or heart failure to minor illnesses such as chronic inflammation of the paranasal sinuses or allergies. Though even drugs or irritation from vapours or dust can cause a chronic cough.

However, there are patients for whom no cause can be found even after careful clarification: according to American data, this applies to five to ten percent of patients who seek medical attention due to a chronic cough. Women seem to be affected twice as often as men.

A chronic cough, which can last for months and even years, may be very distressing for those affected and can impair their quality of life significantly. The high level of pressure which occurs during coughing often leads to a headache or chest pain. Hoarseness is also a frequent consequence. Moreover, increased nervousness and depressive symptoms may be observed in many patients.

Corticosteroids and gastric acid inhibitors can only be used appropriately as indicated.

Now, a committee of experts from the American College of Chest Physicians have analyzed existing studies on the subject in a review and have used these as a basis to form new guidelines on chronic coughing with unknown causes. “The evidence for these recommendations may not be particularly high,” says Heinrich Worth, Deputy Chairman of Deutsche Atemwegsliga [the German Respiratory Tract League]. “But they correspond to the current state of research on the chronic cough of unknown origin.”

In the guidelines, the experts recommend a systematic approach, in which, following careful diagnosis and unsuccessful attempts at treatment, tests for bronchial hyperreactivity and sputum eosinophilia are performed. A sputum eosinophilia can be detected by an increased number of eosinophils in the cough sputum or increased levels of nitric oxide (NO) in the exhaled air. This indicates an allergy or increased sensitivity of the airways towards certain substances. If the results are positive, the researchers recommend treatment with inhalative corticosteroids – however, no corticosteroids should be prescribed if the results of both tests are negative. Moreover, the unexplained cough should not be treated speculatively with proton pump inhibitors if no gastroesophageal reflux can be detected.

Treatment at the level of the nervous system

Another recommendation of the lung specialists is a treatment trial with the antiepileptic drug gabapentin. The possible side effects of this treatment should be discussed with the patient in advance, and the effects and side effects should be monitored over a period of six months. “Gabapentin is a neuromodulatory substance and can help reduce the hypersensitivity of the cough reflex on the level of the brain nervous system,” explained Worth. The new results suggest that middle-aged women in particular often develop a chronic cough of unknown cause, of which the underlying cause is hypersensitivity of the cough reflex [paywall].

However, when taking drugs which suppress a cough, it must be ensured that the cough does not fulfill a useful function, emphasized Gerhard W. Sybrecht, Chairman of the Board of the German Lung Foundation. “A cough is a vital reflex which helps to remove harmful particles from the lungs and bronchi”, stated the lung expert. “Cough suppressants should therefore be given only for dry coughs without expectoration.”

Non-drug treatment approaches

The American team of experts further recommends trying a multimodal speech therapy treatment. In the analyzed studies, this consisted of techniques for suppressing cough, breathing exercises, sharing information and advice. In all or most of the studies, the frequency and severity of the cough decreased – and in general led to a better quality of life. However, further studies are necessary in order to verify the effectiveness systematically, according to the authors. “Speech therapy does not yet carry much weight in the German guidelines or in treatment practice speech therapy” explained Heinrich Worth. “But this approach should be thoroughly considered.”

In speech therapy or physiotherapy approaches, the patients learn, for example, how to exhale in a slow and controlled manner, so that the cough reflex no longer occurs. “In addition, the cough reflex is often triggered more easily by stress and excitement – a typical example of this is the nervous cough in television broadcasters,” explained Sybrecht. “In this case, it may be helpful for the patient to speak slowly, calmly and consciously to calm themselves or to apply relaxation techniques.” Psychotherapeutic methods, suggestion or hypnosis can also help to reduce a mentally (co-)induced cough in some cases.

Detecting rare causes

It is also important in chronic cough cases to carefully clarify and rule out any possible causes, so as not to overlook a rare disease. “A chronic cough for which no cause can be initially be found, should not be classified as ‘psychogenic’ or ‘unexplained’ too hastily,” emphasized Sybrecht. “Instead, the diagnostic process should take place systematically and step by step. Improbable causes should be considered – for example, irritants in the environment, or an allergy to substances which are not yet known to be allergens “. In addition, bronchial lesions caused by radiotherapy for breast cancer can cause a severe cough in women. “It is therefore important to find a specialist who is able to clarify the problems with competence and commitment,” said Sybrecht.

Moreover, it could be useful to improve cooperation between physicians of different disciplines in the treatment of the chronic cough, as shown by an American study [paywall]. Communication between doctors of various disciplines were promoted here and treatment decisions were made based on shared decision trees in a model project. These measures have helped to shorten the course of treatment for patients and to reduce health care costs.

Perhaps a simple trick can also help

Finally, there may still be a fairly simple way to alleviate an irritating chronic cough: use herbal substances such as eucalyptus, thyme or Myrtol – or high-dose capsaicin, the “spicy source” of chillies. “These substances have not yet been adequately tested in studies,” said Worth. “But there is evidence to suggest, for example, that high-dose capsaicin can effectively alleviate the need to cough.” By taking the substance in capsule form, the sensitivity and frequency of the cough is significantly reduced. Eucalyptus or Myrtol is contained in many cough drops or capsules, while capsaicin can be found in some “extra strong” cough drops.

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1 comment:

lies huizink
lies huizink

What about a retreat in the mountains?

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