Persistent cough or breathlessness in a child — when could it be a chest mass?

Most viral coughs in children improve within two to three weeks even without treatment. When a cough persists beyond three to four weeks and does not respond to a course of antibiotics or standard asthma inhalers, it no longer fits the typical infection pattern. A cough that started during what seemed like a chest infection — but has not cleared up weeks later — may mean the windpipe or a central airway is being compressed by something inside the chest. This is especially true of a dry, non-productive cough that is not associated with a runny nose, fever, or the usual signs of a chest infection. The persistence of the cough, rather than its severity, is the key signal that a chest X-ray is the right next step.

Children are normally full of energy and can run, climb, and play for extended periods. A child who is suddenly struggling to climb stairs, needs to stop and catch their breath during activities they previously found easy, or who becomes noticeably breathless while sitting or lying flat is showing a change that needs medical attention. Breathlessness when lying flat — a condition called orthopnea — can occur when a chest mass presses on the airways more effectively in the supine position. Equally important is stridor: a high-pitched, musical sound when the child breathes in. Stridor is caused by partial obstruction of the upper airway and in a child without an obvious infection is a reason to seek evaluation on the same day.

Lymph nodes in the neck normally swell and become tender during throat and ear infections — this is the immune system doing its job. What is different in the context of a mediastinal mass is a painless, firm or rubbery lump — particularly in the lower neck, above the collarbone (supraclavicular area), or in the armpits — that does not reduce in size within two to four weeks of an infection clearing. Supraclavicular lymph nodes are anatomically connected to the mediastinum, which is why a lymph node in this location in a child with a chest cough is taken particularly seriously. The combination of a persistent cough, breathlessness, and a painless neck or armpit lump is the classic presentation of mediastinal Hodgkin lymphoma in children and adolescents.

In oncology, the combination of unexplained fever persisting for more than two weeks, drenching night sweats (sweating that soaks the child's pyjamas and bedding, not explained by a warm room), and significant unintended weight loss over one to two months is collectively called "B symptoms." These three together are a recognised hallmark of lymphoma — particularly Hodgkin lymphoma and some forms of non-Hodgkin lymphoma. In the context of a persistent chest cough, B symptoms make the case for prompt investigation considerably stronger. None of these three symptoms alone confirms lymphoma, but two or more alongside a cough that has not resolved in over a month is a combination that paediatric oncologists act on with urgency.

A large mass in the front portion of the mediastinum (the anterior mediastinum) can compress the superior vena cava — the large vein that carries blood from the head, neck, and arms back to the heart. When this vein is compressed, blood backs up and causes swelling of the face, neck, and arms. Parents may notice that their child's face looks puffy in the morning, that the veins on the chest or neck are more visible than usual, or that the child develops a headache when bending forward or lying down. This collection of signs is called superior vena cava (SVC) syndrome and it is a medical emergency that requires urgent specialist evaluation — usually the same day. Any child with a known chest mass who develops these features should be taken to an emergency department immediately.

A mass inside the chest can affect nearby structures in ways that produce less obvious symptoms. Pressure on the nerve that controls the left vocal cord (the recurrent laryngeal nerve) can cause a child's voice to become hoarse — an unusual finding in a child without a sore throat. Pressure on the oesophagus can cause difficulty swallowing solids or a sensation that food is getting stuck. Recurring chest infections — two or more pneumonias in the same area of the lung within six to twelve months — suggest that a section of the airway is being partially blocked and is prone to collecting secretions. Any one of these features alongside a persistent cough in a child who is otherwise well warrants a chest X-ray and paediatric review.