Cough and shortness of breath are common symptoms and sometimes indicate the presence of a serious underlying disease. These symptoms usually result from problems in your heart or lungs, but they can occur with other disorders as well. The presence of other symptoms that may accompany a cough and shortness of breath and the findings of your physical exam help your doctor narrow the list of possible causes. Several warning signs associated with cough and shortness of breath should prompt you to seek immediate medical attention.
Congestive Heart Failure
Your heart pumps blood from your lungs, where it picks up oxygen, to the rest of your body, which needs oxygen to survive. When your heart isn't working properly, fluid from your blood can back up into your lungs. This fluid reduces the oxygenation of blood that normally occurs in the lungs, causing shortness of breath and cough. One common heart condition that can cause these symptoms is congestive heart failure. This can result from a lifetime of high blood pressure or from damage to the small arteries supplying the heart as a result of high cholesterol.
Other Heart Conditions
Other heart-related conditions may also cause cough and shortness of breath, along with other symptoms. For example, a heart attack may cause cough and shortness of breath, usually accompanied by central chest pain, nausea or sweating. Inflammation of the heart muscle or the sack surrounding the heart -- called myocarditis and pericarditis, respectively -- can also cause cough and shortness of breath if they are severe enough to impair the heart's normal pumping ability. Myocarditis and pericarditis are usually the result of a viral infection.
Acute Lung Infections
Lung infections commonly cause cough and shortness of breath. Pneumonia is an acute infection of the lung that can be caused by bacteria, viruses or fungi. Pneumonia produces shortness of breath because the infection impairs the normal process of oxygen exchange that happens in a healthy lung. Cough is a normal reaction to something foreign finding its way into your lung -- your lung's way of saying "Get this out of me!" Pneumonia usually also produces fever. Pertussis, or whooping cough, is another type of lung infection that can cause intense coughing with accompanying shortness of breath. With whooping cough, coughing fits may last minutes at a time, followed by a characteristic "whoop" that's generated as the ill individual inhales quickly and deeply.
Chronic Lung Diseases
Chronic obstructive pulmonary disease, or COPD, is characterized by slowly worsening shortness of breath on exertion and a cough productive of phlegm. COPD typically develops after years of exposure to cigarette smoke. COPD may also cause acutely worsening cough and shortness of breath during a flare-up. This often occurs in response to an infection. Asthma can also cause cough and shortness of breath. Like COPD, an acute asthma attack is characterized by shortness of breath, coughing and wheezing. Asthma may be worsened by smoking, but unlike COPD, it is not caused by smoking.
Cancerous and noncancerous tumors in the lungs can block and irritate the airways, leading to cough and shortness of breath. Cancerous lung tumors can arise from the lungs themselves or spread to the lungs from cancer in other organs, like the prostate or breast. Other symptoms of cancer in the lungs include unintended weight loss, fatigue and coughing up blood.
Pulmonary embolism, or PE, deserves special mention as a cause of cough and shortness of breath. A PE is a blood clot that has found its way to your lungs. In addition to cough and shortness of breath, a PE may cause your heart to race and pain with deep inspiration. If the blood clot is large, a PE can be fatal if not diagnosed and treated right away.
Less commonly, diseases outside the heart and lungs can also cause cough and shortness of breath. Liver and kidney diseases are two examples. Sepsis -- an overwhelming system-wide infection -- can also cause shortness of breath and cough if it degenerates into acute respiratory distress syndrome, or ARDS.
Red flags -- symptoms that should prompt immediate evaluation by a medical professional -- include shortness of breath at rest, increasing shortness of breath with exertion, high fever, coughing up blood and dizziness or fainting. Any sudden difficulty breathing requires emergency medical evaluation.