Condition: Chronic Cough

Acute cough is an extremely common symptom which we have all experienced. It often resolves spontaneously and most people don’t feel the need to seek medical attention.

A continuous cough that lasts longer than 4 weeks is concerning and is a criteria for referral to see a specialist to exclude a serious underlying illness such as cancer, vocal fold paralysis or tuberculosis.

Worrying associated symptoms include:

• Difficulty with swallow (dysphagia)
• Blood in the sputum
• Green thick sputum
• Coughing and spluttering after ingestion of food and fluid (aspiration)
• Recurrent episodes of pneumonia
• Noisy breathing with shortness of breath
• Generalised symptoms such as fever and rapid loss of weight

Most causes of chronic cough will be benign and multifactorial in origin. Exacerbating or causal factors include tobacco smoking, laryngopharyngeal reflux, allergy, fungal infection, rhinosinusitis, obstructive sleep apnoea, asthma and other lung pathology. A group of cardiac medications called ACE inhibitors may also cause a chronic dry cough.

As part of the history, you may be asked to fill out validated questionnaires related to voice and chronic cough. This will help us assess the severity of your symptoms and provide us with a baseline against which to compare improvement from therapeutic interventions.

An examination of the larynx via nasal endoscopy is very important to exclude growths on the vocal folds (VFs) that may be triggering the cough. It will also demonstrate stigmata of other conditions like laryngopharyngeal reflux. Examination of vocal fold motion whilst breathing may in some cases demonstrate dys-coordinated vocal fold opening with respiration (normally the vocal folds move apart when you breathe in or out) called paradoxical vocal fold motion. Other more subtle motion defects can only be visualised after performing video stroboscopy which we perform routinely when assessing the larynx.

You may also require allergy testing and certain specific blood tests depending on the potential cause(s).

A high-resolution CT scan of the neck and chest may be requested to aid diagnosis. Occasionally this may demonstrate a narrowing in the airway just below the vocal folds, which may warrant further investigations and specific surgical management.

A CT scan of the paranasal sinuses will help diagnose chronic rhinosinusitis.

If there is concern about aspiration then a video swallow assessment may be useful. This is a dynamic X-ray study which looks at how a swallowed radio-dense dye passes through and around the larynx and upper swallowing apparatus.

As conditions pertinent to gastroenterology and respiratory medicine may contribute to or indeed cause the cough, you may be referred to a gastroenterologist or respiratory physician for further investigations and management. These may include an ambulatory pH study, a gastric endoscopy, and lung function testing.

Reassuringly, a combination of good vocal hygiene strategies and targeted medical treatment will relieve cough in up to 80% of patients. Benign causes are many but your clinician may suggest a combination of one or more of the following groups of medication: antibiotic, antifungal, topical and/ or systemic steroids, anti-allergy and anti-reflux medicines.

A small percentage of patients will have cough refractory to the above treatment with no obvious underlying cause despite exhaustive investigations. Often, innocuous triggers such as a cold atmosphere or talking for a long time may trigger bouts of coughing. There may be some tenderness on neck palpation and this is usually due to compensatory tension in the muscles surrounding the larynx. Such patients have usually developed a hypersensitive larynx that is exacerbated and made ironically worse by repeated coughing.

Further therapy can be effective if you remain motivated.

Speech and language therapy is very useful and has a number of aims. Speech and language therapists (SLTs) are experts in teaching you strategies to obtain voluntary control of the cough and to try and respond in a manner other than coughing; they will also guide physiotherapeutic manoeuvres aimed to reduce the tension in the laryngeal muscles. These strategies will help break the cycle of hypersensitivity-cough-hypersensitivity-cough. Good hydration and lifestyle modification to improve vocal hygiene should counter the effects of ongoing irritants like gastro-oesophageal reflux.

There is also some evidence that certain neuromodulator medications can dampen down the sensitivity of the larynx and help improve chronic cough especially when used in conjunction with speech and language therapy.