Shortness Of Breath

Shortness of breath is a common symptom of many internal medicine diseases. It is virtually impossible to give a complete list of all factors that can cause shortness of breath and therefore only the most common and most important shall be mentioned. Shortness of breath can best be defined as an unpleasant sensation of strenuous breathing and lack of air. Shortness of breath can appear during, or at rest. Especially resting shortness of breath is a warning sign.


Feeling of breathlessness occurs when tissues of our suffer lack of oxygen, the primary cause most usually lies in lungs, heart and blood circulation or in anemia.

I. Lungs


Chronic obstructive pulmonary disease is common cause of breath problems in our smoking society. Chronic inflammation of airways caused by inhaling cigarette smoke fumes is associated with excess mucus secretion and productive cough.


Asthma is in its symptoms somewhat similar to COPD with some important differences. Asthma occurs on the basis of an allergic reaction, it comes in paroxysms with periods of calm in between. Shortness of breath in asthma is sudden and can be very uncomfortable. In severe cases, affected person may easily suffocate.

Lung cancer

Lung cancer may cause shortness of breath in advanced stages, when the tumor mass has damaged large part o lung tissue by its growth, or when it has grown into one of main bronchi resulting by its obstruction. Multiple lung metastases of other tumors may cause breathing disorders as well.


Severe pneumonia of bacterial or viral origin is often connected to shortness of breath. In addition fever and cough occur. It should be added that so-called atypical pneumonia may cause a considerable extent of lung tissue damage with relatively mild noticeable symptoms.

Inhalation of foreign bodies

Inhalation of rigid bodies or fluid causes cough as a defense mechanism and this situation can be associated with shortness of breath. When respiratory tract is suddenly irritated by a foreign body, it may react by inadequately strong muscle spasms and sudden death by suffocation.


Pneumothorax is a condition when air gets into the pleural cavity (a paired chest cavity located around both lungs). Normally, pleural cavity is filled with vacuum that allows easy dilation of lungs during inspiration. If air is present in pleural cavity, its pressure causes collapse of the affected lung. A pneumothorax occurs either in chest trauma or in rupture of lung tissue.

Fluid in the chest

This condition is also referred to as pleural effusion. Pneumothorax means air in pleural cavity; pleural effusion is fluid presence in the same location. The effect is similar – fluid located around the lungs blocks them from proper inspiration.

Pulmonary fibrosis

This whole group of diseases is associated with progressive transformation of lung tissue into fibrous tissue. Therapy is very challenging and in advanced stages home oxygen therapy may be the only way of (at least symptomatic) treatment.

II. Heart and blood circulation

Heart failure

Failure of heart pumping ability leads to blood stasis. When there is left-side heart failure, blood accumulates in pulmonary vessels. In advanced stages the blood can even filter into pulmonary because of locally elevated blood pressure causing so-called pulmonary edema (“swelling of lungs”). Cardiac failure has many causes and these include: heart valve disorders, heart attack, myocarditis, cardiomyopathy, heart rhythm disorders and others. Details are available in article dedicated to heart failure.

Pulmonary Embolism

Pulmonary embolism is a potentially life-threatening condition when a blood clot (usually having its origin in deep vein thrombosis of lower extremities) obstructs lung blood vessels. This condition can result in sudden death without any previous symptom. Most often, however, it manifests as sudden shortness of breath, chest pain and sometimes even blood expectoration.

III. Anemia

Anemia is a very important cause of breath disorders. It can cause shortness of breath just by itself, or it may be combined with already preset heart and lungs diseases. Why does anemia manifest by dyspnea? It is quite logical. An anemic person has a lack of blood substance known as hemoglobin that carries oxygen to tissues. Even when lungs and heart work normally the tissues receive inadequate amount of oxygen and this condition presents as shortness of breath. In milder forms there is rather exertion-related shortness of breath, in more severe cases of anemia even at rest.

IV. Other causes

In this part I mention shortness of breath triggering factors that can not be included in the preceding three issues.


Goiter (enlarged thyroid gland) may in some cases even compress trachea and thus narrowing the airway. Let just add that goiter presence itself doesn’t determine function of thyroid gland. The function may be completely normal.


Obesity and unhealthy lifestyle can lead to shortness of breath in exertion. It is practically not a disease; it is only a natural result of insufficient physical activity and poor exertion tolerance. If obesity is truly monstrous, then we talk about so-called Pickwickian syndrome. It occurs in a horizontal position when obese abdomen pushes diaphragm upward and compresses the lungs. Shortness of breath eases when in vertical position, i.e. when sitting or standing.

Diagnostic approach

Diagnosis should always start with medical history (known diseases, medication, family history, etc.) followed by physical examination. It is particularly important to listen patient’s breathing using a stethoscope. Obtained findings can give us a great clue for the right diagnosis. Blood test may show changes typical for infectious processes (like elevated CRP by pneumonia), low D-dimers may rule out pulmonary embolism, cardiac enzymes are elevated by heart muscle damage and hemoglobin level informs us about presence of anemia. Obtaining sample of arterial blood is important to measure level of breathing gases that tells us about severity of dyspnea. ECG examination can help us to diagnose heart attack or pulmonary embolism. Imaging methods are necessary for further diagnostics – chest X-ray is a basic method, computed tomography is more accurate, but also much more expensive. When there is a great suspicion of acute embolism, lung scintigraphy or CT angiography are performed. Echocardiography is essential to heart function assessment including its pumping ability and heart valve conditions. Lung functions are diagnosable by special examinations like spirometry.

Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources