Curious causes of cough
published in Reader's Digest,
19 September 2023
Coughing and wheezing isn't always about the lungs. If you're suffering from a persistent cough, it may be tied to one of these ailing body parts.
A cough clears the airways; it’s a natural defence and is encouraged when someone is choking. But when a cough becomes chronic, it can be a sign of something serious. In its ‘Help Us, Help You’ campaign, the NHS urged people to seek medical advice for a cough that lasts 3 weeks or more, in case it’s lung cancer. Sometimes though, doctors need to look beyond the lungs to find the cause of a cough; it doesn’t always originate in the airways.
Your heart
Have you heard of ‘cardiac asthma’? First described by James Hope in 1832, its symptoms (wheezing and coughing) are similar to what we all know as asthma (where the airways are sensitive and inflamed), but in this case the problem is with the heart.
When you’ve got a diagnosis of heart failure, your heart has lost its pumping efficiency and blood can build up in the heart, backing up via veins into the lungs. You might cough up blood or ‘bloody froth’. Worse at night, when you lie down and blood shifts from the legs to the lungs, sleeping with extra pillows is recommended.
Drugs to strengthen the heartbeat don’t always clear the cough; inhalers are mostly ineffective in airways which may have stiffened and thickened. Lifestyle changes such as stopping smoking, eating well and exercising can slow down progression of the condition.
Your nose
It’s normal for mucus to drip from your nose into your throat, but for some people there’s too much mucus and they sense something tickling the throat, and need to constantly clear their airway, in a cough. Known as post-nasal drip, and triggered by allergy, cold weather or the common cold, it is one of the commonest causes of cough. Decongestants and anti-allergy tables may help.
Nowadays, doctors are more likely to call the condition ‘rhinosinusitis’ (from the Greek word ‘rhino’ for nose) – but they still draw on a definition made by Dr Dobell (a throat specialist) in 1866, calling it the best and most complete: “A sense of fullness deeply seated in the back of the nose, with constant stinging and tickling sensation….much aggravated after sleep, so that the patient awakes every morning with a sore throat….there is frequent hawking and spitting of small pellets of mucus….shreds of stringy mucus seen hanging down (in the throat)”.
Your stomach
Stomach acid is strong: it can corrode coins, and would burn the lining of the stomach itself if it were not covered by a protective mucous layer. If acid is pushed up from the stomach into the oesophagus (gullet) in so-called acid reflux, it will burn, causing indigestion, ulcers, bleeding and perhaps cancer.
Rising higher still, reflux can hit the respiratory system, where it will irritate and inflame and cause cough. Your airways will take defensive action, in a reflex (as when you remove your hand from a hot stove), automatically narrowing and making mucus, worsening the cough.
Interestingly, acid reflux can cause cough without triggering heartburn, so it can be a surprise to know you’ve got an acid problem when you’re not in pain. Taking medicines to suppress acid secretion doesn’t always help, and the cough itself can ramp up the reflux. It’s a vicious cycle that’s difficult to break. Dietary and lifestyle changes can help; surgery is a last resort.
Your brain
Aspiration is when something you swallow enters your airway by accident, “going down the wrong way”, making you cough. Swallowing is a complex task in which your brain coordinates some 22 pairs of muscles in a precise order. If your brain is damaged or diseased, you may have difficulty swallowing and be at risk of aspiration. After a stroke almost half of people will have swallowing problems at first, and 50 per cent of those living with Parkinson’s struggle to swallow. Other brain conditions that affect swallow include Alzheimer’s, multiple sclerosis, cerebral palsy, head and neck cancers, and head injury.
If you don’t manage to ‘cough your lungs clear’, because your cough reflex is also impaired, bacteria in the aspirated food or saliva can cause pneumonia, and you may cough up yellow, green, brown or blood-stained phlegm.
Your drugs
Some blood pressure medicines can, surprisingly, cause you to cough. There’s a particular class of drugs prescribed in heart failure, high blood pressure and after a heart attack which halt production of a hormone involved in raising blood pressure, helping to reduce strain on your heart. Known as ‘ACE inhibitors’, common examples include ramipril, lisinopril, captopril and enalapril. The cough can be dry and persistent, and start within hours – or months – of the first dose. What causes the cough is unclear, but it could be build-up of a protein in the blood which sensitises the cough reflex.
The drugs are important for the heart, featuring on the World Health Organization List of Essential Medicines. Switching drugs is possible if the cough is tiresome or troublesome; avoiding a high-salt diet is suggested whilst on the drugs since salt raises blood pressure – and specifically interferes with the action of ACE inhibitors.
Your circulation
An almost invisible rare condition, with no cure, so-called pulmonary hypertension affects some 8,000 people in the UK. Pulmonary Hypertension Association UK describes how arteries in the lungs become stiff, thickened or blocked by blood clots, making it harder for the right side of the heart to pump blood into the lungs to pick up oxygen; heart failure can result.
Symptoms can include severe breathlessness, chest pain and, sometimes, swollen ankles and arms, but symptoms may not be obvious to others. Rarely, the enlarged arteries can compress the airways, causing chronic cough, which is too commonly assumed to be asthma.
In life (and in human biology) it’s said that “all are but parts of one stupendous whole”. Interconnected and interdependent, your body parts help – and occasionally harm - each other, especially when it comes to cough.