A cough that continues for weeks is usually blamed on an infection, an allergy or asthma. Sometimes, however, the reason is something quite unexpected. A small piece of food, a seed or even a bone fragment may have accidentally entered the airway and become lodged there.
This is known as foreign body aspiration. While it is more commonly associated with children, adults can experience it too. What makes it difficult to identify is that the person may not remember choking or even realise that anything has entered the airway. The object can remain there for days, weeks or, in some cases, much longer.
Here are a few things worth knowing about this unusual cause of persistent cough.
1. It can happen without a dramatic choking episode
Choking is usually the first thing that comes to mind when something enters the wrong passage. But not every instance of foreign body aspiration causes a prolonged bout of coughing or an obvious breathing difficulty.
A small fragment of food may pass beyond the throat and settle in one of the smaller airways. The initial irritation may be brief, particularly if the object does not completely block the passage of air. Once it gets lodged, the person may simply continue with a cough that does not seem to settle.
This is one reason why the possibility is sometimes overlooked in adults. They may not recall a specific incident while eating, and the symptoms may appear only after some time.
2. The symptoms can look like an ordinary respiratory infection
A persistent cough is the most common complaint, but it is not the only one. Some people develop wheezing, breathlessness or repeated episodes of chest infection. There may also be blood-streaked sputum in certain cases.
The symptoms depend largely on where the object is lodged and how much of the airway it blocks. A partial obstruction may allow air to pass through but interfere with the normal clearance of mucus. Secretions can then collect behind the obstruction, creating conditions for infection.
Sometimes, a patient is treated for pneumonia, gets better and then comes back with another infection in the same part of the lung. That pattern shouldn't be ignored. It raises the question of whether something is sitting in that airway and causing a blockage. Until that is identified and dealt with, the infections may keep coming back.
3. Some people may be more vulnerable
Foreign body aspiration can happen to anyone, but some circumstances increase the likelihood.
In some older patients, particularly those with Parkinson's or a history of stroke, swallowing itself can become a problem. Food may not go down the right passage every time, and a little of it can enter the windpipe. The same can happen when a person is very drowsy or under sedation and is unable to swallow normally.
Sometimes, it happens during an ordinary meal. A person may be talking, laughing or eating in a hurry when a small piece of food goes down the wrong way. In other cases, there is no such incident that the person can recall. They may not have choked or even realised that they had inhaled something.
4. A normal chest X-ray does not always rule it out
One of the difficulties in diagnosing foreign body aspiration is that food particles, seeds and other organic material may not show up on a routine chest X-ray.
Sometimes the scan shows only indirect signs, such as a small area of lung collapse, air trapping or an infection that has not resolved. In other cases, the X-ray may appear normal.
If the cough continues or there are other signs pointing to a blockage, a CT scan may be advised. It can help locate the object and show whether it has caused any changes in the surrounding lung. The scan, however, is only one part of the assessment. What the patient has been experiencing and how long the symptoms have been present matter just as much.
5. Bronchoscopy can help find and remove the object
A bronchoscopy helps the doctor see what is happening inside the airways. A thin, flexible tube with a camera is taken through the nose or mouth and guided into the lungs. If a food particle or any other object has remained lodged there, it can usually be seen during the procedure.
If an object is found, it can often be removed during the same procedure using specialised instruments. The choice between flexible and rigid bronchoscopy depends on the size, shape and location of the object, the extent to which it is stuck and the patient's condition.
Removing the object is only part of the treatment. If the object has been sitting there for some time, it may have already caused a fair amount of irritation in the airway. There may also be an infection or damage to the lung tissue around it. So even after removing the object, the patient may need treatment for these problems as well.
6. When should a persistent cough be investigated further?
If someone keeps coming back with a cough that isn't settling, it is worth looking beyond another course of antibiotics or cough syrup. There could be a more obvious reason for the cough, but if the symptoms don't add up or keep returning despite treatment, it is important to check whether something is blocking the airway.
A history of sudden coughing while eating, unexplained wheezing, repeated pneumonia in the same part of the lung or symptoms that continue despite appropriate treatment should prompt further evaluation.
Sudden choking, difficulty breathing or an inability to speak or cough effectively requires immediate medical attention. These are not symptoms to watch at home.
Foreign body aspiration in adults is uncommon, but it is an important diagnosis to keep in mind. Sometimes, the reason behind a cough that refuses to go away is not another infection or an allergy. It may be something that should never have entered the airway in the first place.
(The author is a consultant, interventional pulmonology, KIMS-Arete Hospital)
The opinions expressed in this article are those of the author and do not purport to reflect the opinions or views of THE WEEK.
