Because pulmonary hypertension is a complex condition that can result from a wide variety of factors, it shows up in many different kinds of patients. Pulmonary hypertension -- high blood pressure in the arteries supplying blood to the lungs -- has been diagnosed in newborns and in older people, in men and women, and in people with other serious health problems as well as those who have no other diseases.

Primary pulmonary hypertension (PPH) can strike at any age, although it occurs most often among people 20 to 40 years old, according to the National Institutes of Health. The disease affects people of all racial and ethnic origins equally. During childhood, it affects both males and females equally. After puberty, PPH strikes women almost twice as often as men. Why that gender difference exists is a mystery.

The cause of primary pulmonary hypertension is unknown, but researchers do know that the condition can run in families. About 6 percent of patients diagnosed with primary pulmonary hypertension are found to have at least one other family member with the disease. Because of this inherited risk, experts may recommend that all first-order relatives of a patient (siblings, children, and parents) be screened for the disease. The recommended test is an echocardiogram, which is relatively simple and painless. A device that resembles a microphone is placed against the chest. Using sonic waves, the device creates a moving picture of the heart. By studying the image, doctors can estimate pulmonary artery blood pressure. They can also detect changes characteristic of pulmonary hypertension, such as an enlarged right ventricle in the heart.

Appetite suppressants -- most recently, fenfluramine and dexfenfluramine -- have also been definitely associated with the onset of what the World Health Organization calls "pulmonary arterial hypertension (PAH)." PAH is identical to PPH except for the history of diet pill use.

Experts have speculated that people who develop the disease have blood vessels that are abnormally sensitive to certain factors, including pregnancy, cocaine, HIV/AIDS, and a form of human herpes, HHV-8 (one that targets blood vessels and is unrelated to the herpes that causes cold viruses). In 2003, researchers at the University of Colorado Health Sciences Center in Denver reported that some patients with pulmonary hypertension are infected with HHV-8.

Because it is the result of other medical conditions, including heart and lung diseases, secondary pulmonary hypertension (SPH) tends to occur later in life than primary pulmonary hypertension. A wide range of underlying conditions can lead to SPH.

•Human Immunodeficiency Virus (HIV). There is a direct causal relationship between HIV and secondary pulmonary hypertension. An HIV test is one of several initial tests your doctor may have you take once a diagnosis of pulmonary hypertension is made.

•Collagen vascular diseases. These conditions include CREST syndrome, scleroderma, systemic lupus erythematosus, Sjogren's syndrome, dermatomyositis, polymyositis, and rheumatoid arthritis. Patients with these diseases may show signs of some scarring of lung tissue. They also often suffer from hypoxia, a lack of sufficient oxygen in the blood.

•Sleep apnea. This condition occurs when breathing temporarily stops during sleep, causing a drop in oxygen levels in the blood. Over time, insufficient oxygen can injure the lining and smooth muscle cells in pulmonary arteries, making them stiffer and impairing their ability to open or dilate normally. Only about 20 percent of people with sleep apnea show signs of pulmonary hypertension, however, and the condition is usually very mild. Treatments aimed at alleviating sleep apnea, such as wearing face masks that deliver positive air pressure during sleep, are usually effective in reducing the risk of pulmonary hypertension.

•Blood clots. Blood clots accumulating in pulmonary arteries can force the heart to work harder to push blood through, increasing pulmonary blood pressure. Occasionally, blood clots can cut off blood flow in an artery altogether.

•Congenital heart disease. Defects in the structure of the heart can affect the way blood flows through its chambers, causing elevated pulmonary blood pressure. This is usually diagnosed in childhood, but may go undetected until later in life.

•COPD (chronic obstructive pulmonary disease). COPD includes emphysema and/or chronic bronchitis. This is the most common cause of secondary pulmonary hypertension and is a leading cause of death in the United States.

•Interstitial lung diseases. These diseases, which are many, can be lumped together under the name "pulmonary fibrosis." They can cause scarring in the lungs and low oxygen levels. If the cause of the lung disease is not known, it's known as "idiopathic." Examples of interstitial lung diseases with a known cause include asbestosis, berylliosis, farmer's lung, and pigeon breeder's disease.

•Mitral valve disease. The heart's mitral valve consists of two flaps of tissue that normally open and close rhythmically to allow the blood to flow from the upper chamber of the heart to the lower chamber. In some cases, defects in the mitral valve can cause increased pulmonary blood pressure. The problem can usually be detected by an echocardiogram, which uses sound waves to create a moving picture of the heart as it pumps. Corrective surgery of the heart valve is often performed and may reduce pulmonary artery pressure.

•Left-sided atrial or ventricular heart muscle disease. This is a common cause of pulmonary hypertension that may respond to treatment of the underlying heart condition.

•Liver disease. Pulmonary hypertension is sometimes a complication of advanced liver disease. About 1 percent of patients with chronic liver disease and resulting portal hypertension (high blood pressure in the artery supplying the liver) also develop pulmonary hypertension.

•Sickle cell disease. Pulmonary hypertension may occur in as many as 20 percent of patients with sickle cell disease. The link between pulmonary hypertension and sickle cell disease, which causes abnormalities in red blood cells, isn't well understood. PH probably results from obstruction of the pulmonary arteries by the abnormal, sickle-shaped red blood cells.

•Sarcoidosis. This disease, an inflammation of the lungs of unknown cause, can lead to fibrosis, or the formation of scar tissue, in the lungs. As blood flow is blocked, blood pressure in the pulmonary arteries increases. In some cases, inflammation can directly affect the pulmonary blood vessels.

When pulmonary hypertension is caused by an underlying medical condition, doctors can sometimes treat the primary cause and relieve the hypertension. In the best cases, treatment eliminates the problem altogether. In others, it reduces pulmonary hypertension or slows its progress.

-- Peter Jaret is a contributing editor for Health magazine and a winner of the American Medical Association's award for medical reporting. His work has appeared in National Geographic, Newsweek, Hippocrates, and many other national magazines. He is also the author of In Self-Defense (Harcourt Brace Jovanovich), Active Living Every Day, and Heart Healthy for Life.

References

First published October 27, 2003
Last updated October 30, 2007
Copyright © 2003 Consumer Health Interactive

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