Shortness of breath, known as “dyspnoea” in medicine, is a subjective sensation of difficulty in breathing. It is a common symptom experienced by individuals across various age groups, and can be a manifestation of diverse underlying medical conditions. It can arise from heart and lung diseases, as well as from metabolic, neuromuscular, or psychological factors.

The lung causes of shortness of breath:

Chronic Obstructive Pulmonary Disease: encompasses chronic bronchitis and emphysema, which are characterised by increased resistance to airflow in and out of the lungs. Breathlessness is a hallmark symptom of COPD, particularly during physical exertion. It progressively worsens as the disease advances.

Asthma: is a chronic inflammation of the airways, leading to recurrent episodes of wheezing, breathlessness, chest tightness, and coughing. During an asthma attack, the airways become acutely narrowed due to contraction of airway muscles and increased mucus production. Dyspnoea in asthma can vary in severity, ranging from mild to life-threatening respiratory distress.

Pulmonary embolism: occurs when a clot obstructs the lung arteries, preventing adequate oxygenation of the blood and leading to a sudden-onset of shortness of breath, chest pain, and sometimes coughing up blood. PE is a medical emergency requiring immediate attention.

Interstitial lung diseases: refers to a group of chronic disorders characterised by progressive inflammation and scarring of the lung tissue. An example is sarcoidosis. ILD can cause gradual breathlessness as lung function deteriorates. It is often exertional initially, but could progress to occurring at rest in advanced stages.

Covid-19 and “long Covid”: in acute Covid-19 infection, shortness of breath is commonly associated with pneumonia and/or acute respiratory distress syndrome. It resolves as the lungs heal. However, some individuals may continue to experience persistent breathlessness as a part of long Covid syndrome, even after the infection has resolved. The exact mechanisms underlying long Covid-related dyspnoea are still under investigation.

Other respiratory sources of breathing difficulty may include a high pressure inside the lungs, pneumonia, lung cancer, and so forth. They can all result in varying degrees of breathlessness.

Diagnosing the lung cause of shortness of breath often involves a combination of medical history, physical examination, pulmonary function tests, imaging studies (such as chest X-ray or CT scan), blood work and gas analysis, and specific tests targeting suspected underlying conditions, such as Covid-19 testing in individuals with relevant symptoms or exposure history.

The cardiac causes of shortness of breath:

Heart failure: occurs when the heart is unable to pump blood effectively, in order to meet the body's demands. With that, fluid backs up in the lungs, leading to congestion. This fluid build-up impairs oxygen exchange, resulting in shortness of breath, especially during exertion or when lying flat.

Coronary disease: reduced blood flow to the heart muscle due to coronary artery disease can lead to angina or myocardial infarction (“heart attack”, a medical emergency).

Shortness of breath, known as “dyspnoea” in medicine, is a subjective sensation of difficulty in breathing.

It is a common symptom experienced by individuals across various age groups, and can be a manifestation of diverse underlying medical conditions. It can arise from heart and lung diseases, as well as from metabolic, neuromuscular, or psychological factors.

Sometimes as the sole symptom of CAD especially in patients with diabetes or kidney failure, shortness of breath can ensue, either at rest or with effort.

Atrial fibrillation: which is characterised by irregular and rapid heartbeats, can result in inadequate blood supply to different body systems and contribute to shortness of breath.

Heart valve disease: involves abnormalities in the valves that regulate blood flow within the heart. Valve abnormalities, such as aortic stenosis (narrowing of the aortic valve) or mitral regurgitation (leakage of blood backward through the mitral valve), can impose an increased workload on the heart, leading to inefficient performance and consequent breathlessness.

Tamponade: occurs when fluid accumulates in the pericardial sac surrounding the heart, compressing the cardiac chambers and impairing both heart filling and pumping ability. This condition can arise from various causes, such as infection, trauma, or malignancy. It is another medical emergency, and severe shortness of breath is a common symptom of this condition.

In cases of suspected cardiac causes of dyspnoea, diagnostic tests such as electrocardiography, echocardiography, rhythm monitors, and blood markers analysis may be performed to evaluate the structure and function of the heart, assess for tamponade, and/or detect abnormal rhythms.

Other causes of shortness of breath:

Anaemia: is characterised by a decrease in red blood cells count. Red cells carry the oxygen between the lung, heart and body organs. Reduced oxygen-carrying capacity of the blood due to anaemia can result in breathing difficulty, especially during physical activity.

Metabolic conditions: such as acidosis, for example, seen in diabetes decompensation [DKA] or renal failure, can cause shortness of breath.

Neuromuscular disorders: such as muscular dystrophy or Lou Gehrig's disease can weaken the respiratory muscles, leading to breathlessness.

Psychological factors: can contribute to “air hunger”, particularly in individuals with anxiety or panic disorders.

Difficulty breathing is a complex symptom with various potential causes. An accurate diagnosis of the underlying source is needed for a swift and effective treatment.

• Joe Yammine is a cardiologist at the Bermuda Hospitals Board. He trained at the State University of New York, Brown University and Brigham and Women’s Hospital. He holds five American Board certifications. He was in academic practice between 2007 and 2014, when he joined the BHB. During his career in the US, he was awarded multiple teaching and patients care recognition awards. The information herein is not intended as medical advice nor as a substitute for professional medical opinion. Always seek the advice of your physician. You should never delay seeking medical advice, disregard medical advice or discontinue treatment because of any information in this article