Interstitial lung diseases represent many different conditions; some have a known cause like asbestos, while others have an unknown cause like progressive systemic sclerosis, or scleroderma. ILD occurs in approximately 75 percent of patients with scleroderma, according to "Harrison's Principles of Internal Medicine." Interstitial means the small, narrow spaces between tissues. ILD causes thickening of the air spaces, pleura, as well as pulmonary arteries and arterioles. Pulmonary artery hypertension means high blood pressure in the vessels that carry blood from the right side of the heart to the lungs. Pulmonary artery hypertension progressively restricts breathing. This disease has a high mortality and is challenging to treat.
Shortness of Breath
Normal pulmonary artery pressure is twelve to sixteen mm mercury, while pulmonary artery hypertension occurs at greater than thirty mm mercury, according to the American Academy of Family Physicians.
According to Virginia Commonwealth University, the most common symptom of pulmonary artery hypertension and the one that causes patients go to a physician is shortness of breath, or dyspnea on exertion. Other symptoms include fatigue, fainting, or syncope, peripheral edema and chest tightness and pain on exertion. The mechanism for this latter symptom appears related to stretching of the pulmonary artery, or ischemia of the right ventricle. The early symptoms of pulmonary artery hypertension, such as breathlessness, chest tightness and fatigue, can be mild and confused with other diseases. These symptoms can progressively increase in severity and may limit activities. Some patients develop intractable shortness of breath and fatigue; consequently, activities of daily living such as dressing and walking become difficult.
Fatigue
Fatigue is a non-specific symptom that may involve anemia or other disorders.
Subtle and non-specific signs and symptoms of pulmonary artery hypertension require a high index of suspicion, a careful history and a meticulous physical exam to diagnose pulmonary artery hypertension. In addition to routine laboratory tests, all patients who have an electrocardiogram showing signs of right heart strain should have two-dimensional echocardiography and Doppler flow studies to confirm pulmonary artery hypertension.
Fainting
As pulmonary artery pressure increases, the heart works harder to pump blood. The heart enlarges and cannot pump blood through the lungs as efficiently as normal. Many pulmonary hypertension symptoms, including fainting occur due an inability of the heart to increase cardiac output during activity.
References
- "Harrison's Principles of Internal Medicine"; Dennis Kasper, M.D.; 2005
- Pulmonary Arterial Hypertension
- NY Times; Patient Voices: Scleroderma; Aug 17, 2010
- American Family Physician: Diagnosis and Treatment of Pulmonary Hypertension; Trenton D. Nauser, M.D.; May 1, 2001
- Pulmonary and Critical Care Medicine: Virginia Commonwealth University: Pulmonary Hypertension
