DR MARTIN SCURR: Why do I always have to cough after eating? 

After every meal, regardless of the time of day or what I ate, I have to cough to clear food and drink from my throat. I endured this for years but now believe it to be a medical problem rather than normal. Can you give me advice to help?

David Stone, lecture.

From what you describe it sounds like you have some form of dysphagia, in other words, difficulty swallowing.

Normally, when we swallow, a series of automatic muscle movements kick in, contracting in a coordinated way to move food and drink from the esophagus (or esophagus) to the intestines.

Sometimes, though — often due to pressure on the valve between the esophagus and stomach — food or drink spills back up, causing acid reflux: This can irritate the esophagus and even travel down the throat, causing the cough.

Dr. Martin Scurr: ‘Acid reflux is more common in older men – we don’t know why’

You mention in your longer letter that you have not experienced acid reflux.

In fact, sometimes coughing is the only sign of acid regurgitation (also known as silent regurgitation), although this seems unlikely in your case because your symptoms occur while food and drink are still in your throat.

One possibility is a Zenker diverticulum, essentially a bulge in the wall of the esophagus.

This is more common in older men — we don’t know why: it can be ‘silent’ (ie, without symptoms) or can cause a variety of symptoms, including difficulty swallowing, coughing, or backflow of food into the mouth. It can be repaired with surgery.

In any case, I suggest that you be referred to a gastroenterologist or an ear, nose and throat doctor, who can check for these and other possible causes.

The standard investigations for such problems are a barium swallow X-ray (where you are X-rayed while swallowing a thick fluid that appears on the screen to reveal any abnormalities such as a Zenker diverticulum) and an endoscopy (where a camera is placed on a flexible tube is used to inspect the throat and upper esophagus).

Both are simple outpatient procedures – the barium swallow X-ray is the best early stage investigation.

After a nine-hour flight in 2015, I suffered a pulmonary embolism and ended up in hospital in Barbados for a week. I am about to take the same flight and am afraid it will happen again. Is there anything I can do to calm my mind?

Liz Milner, address provided.

For those readers unfamiliar with the term, a pulmonary embolus is a clot that blocks blood flow in the arteries in the lungs.

These clots usually start in a deep vein in the leg and pose a risk to any long-distance traveler because standing still for that long can cause blood to pool in the veins, leading to the formation of a clot. The clot can then travel to the heart and from there reach the lungs.

Given your history, I think it is advisable to receive a preventive injection with the blood-thinning agent heparin or enoxaparin (file image)

As you point out in your longer letter, once you’ve had a pulmonary embolism you are statistically at a higher risk of having another pulmonary embolism (we don’t really know why this is).

The first clot occurred despite the sensible precautions you took – wearing compression socks and walking up and down the aisle regularly during the 2015 flight.

In addition, your mobility is now reduced, you say, after a few falls in recent years.

Given your history, I think it’s advisable to get a preventative shot of the blood-thinning drug heparin or enoxaparin (brand name Clexane), a newer type of anticoagulant.

Clexane is prescribed in a pre-filled syringe for you to inject yourself.

I would recommend an injection the day before you travel and the second dose on the day of travel. You will also need a stock that you can use at the time of return. (This may seem daunting, but practice nurses and general practitioners are well-versed in teaching patients how to administer the injection.)

Personally, I would not allow any of my patients who have had a previous pulmonary embolism to make a journey of more than four hours, whether by car, bus, train or plane, without this highly effective protective measure.

I recommend that you seek advice from your GP well in advance of your flight so that you are fully prepared.

• Write to dr. Scurr at Good Health, Daily Mail, 9 Derry Street, London, W8 5HY or email: drmartin@dailymail.co.uk. Dr. Scurr cannot respond to personal correspondence. Answers should be taken in a general context. In case of health problems, consult your own doctor.

In my opinion… We need roadside checks on all drugs

Many road accidents are caused by excessive fatigue, new research from Australia shows, so I welcome plans to test drivers to see if fatigue affects their ability to drive safely.

This can be done when police stop a driver to check, as breathalyzers are now. A blood test that measures sleep deprivation is in the works, and it is predicted that we will have such tests within five years.

But my bigger concern right now is those driving under the influence of drugs, either illegal or prescription drugs.

In 2015, UK legislation set limits on blood levels for 16 drugs, eight of which are prescription drugs. But roadside testing – via a saliva sample – is only used for cocaine and cannabis.

Testing for the other potentially dangerous drugs is urgently needed.