Brisbane, June 10 (The Conversation): A persistent cough can be quite embarrassing, especially in the current climate where it might be mistaken for COVID-19.
Frequent coughing can also lead to physical exhaustion, disrupt sleep, and sometimes trigger urinary incontinence. As a general practitioner, I have even encountered patients whose constant and forceful coughing resulted in stress fractures in their ribs.
So, why does a cough sometimes linger? Let's delve into some common causes and recognize when it's important to consult a doctor for potentially more serious issues.
Why do we cough? The cough reflex serves as an essential protective mechanism. By forcefully expelling air, we help clear our lungs, protecting them from irritants, infections, and the risk of choking.
Certain individuals with long-term conditions like chronic bronchitis or bronchiectasis cough frequently because their lung’s cilia—tiny hair-like structures—fail to move mucus, debris, and germs effectively.
Wet or 'productive' coughs occur when there's an expulsion of heavy mucus. In contrast, a dry or 'unproductive' cough occurs when the cough receptors in the airways, throat, and upper esophagus become overly sensitized, prompting a cough even without mucus.
Causes of a chronic cough: Any cough lasting longer than eight weeks in adults, or four weeks in children, is considered chronic.
Three common causes include post-nasal drip, asthma, and acid reflux from the stomach. Often, these conditions coincide. A study noted that 23% of people with chronic cough had two of these conditions, while 3% had all three.
This makes sense because people prone to airway allergies often develop both asthma and hay fever, with hay fever likely being a significant cause of persistent post-nasal drip. Prolonged, vigorous coughing can also lead to reflux, which might in turn trigger further coughing.
Chronic cough is the primary symptom of conditions like cough-variant asthma and eosinophilic bronchitis, both of which inflame the airways yet don't improve rapidly with Ventolin, the standard clinical test for diagnosing asthma.
Coughs following respiratory infections: Coughs may persist long after a respiratory infection subsides. In children with colds, one systematic review revealed that over 90% took 25 days to be cough-free. After an infection, inflamed airways and overly responsive cough receptors might develop cough hypersensitivity, wherein minor irritants provoke the coughing reflex.
The body’s response to infection makes mucus stickier, complicating clearance by recovering cilia. This forms a feedback loop that delays recovery. Excessive coughing exhausts the recovering cilia and aggravates the airway lining.
Could This Be an Infection? When a persistent cough arises, people often fear it may signify a secondary bacterial infection following the original viral one. However, coughing up yellow or green phlegm alone isn't conclusive. Physicians consider broader symptoms such as shortness of breath, worsening fever, or unusual stethoscope sounds for a serious chest infection.
Untreated asthma or allergies should also be contemplated.
Treating a persistent cough: Healthy individuals suffering from a persistent cough sometimes request antibiotics, although these seldom shorten a cough's duration since irritation, rather than infection, is typically the root cause.
The most effective ways to shift sticky mucus involve simple treatments: saline nose sprays and washes, steam inhalation, and medicated sore throat sprays. Honey helps, too, by reducing throat irritation and coughing frequency. Although cough syrup’s effectiveness is uncertain, its potential side effects caution for careful use.
When to suspect something more serious: Sometimes a stubborn cough might indicate grave conditions such as lung cancer or rare infections; however, these instances are uncommon. To exclude these possibilities, Australia’s chronic cough guidelines suggest chest x-rays and spirometry to assess lung volume and flow for anyone presenting with a chronic cough.
Prompt medical attention is warranted if, alongside a cough, you experience symptoms like blood in phlegm, excessive phlegm production, significant shortness of breath—especially when resting or at night, difficulty swallowing, weight loss or fever, recurrent pneumonia, or if you're a smoker over 45 with a new or altered cough.
What if no clear cause is found? Occasionally, even after thorough testing and treatment, a cough persists, termed refractory chronic cough. If no cause surfaces, it's diagnosed as unexplained chronic cough. Formerly considered “psychogenic” or “habit” cough, the focus is now on cough hypersensitivity, where a person coughs out of proportion. Although the relationship between hypersensitivity and chronic cough remains incomplete, both the peripheral and central nervous systems are implicated.
These disabling conditions merit referral to a respiratory clinic or chronic cough specialist. Speech pathology might also prove effective for refractory and unexplained coughs. New medication classes are emerging that block cough receptors, showing promise for persistent, troublesome coughs.
(The Conversation) NSA NSA
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