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Pulmonary Hypertension -- Adult

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by Polsdorfer R

(Hypertension, Pulmonary—Adult)

 

Causes

The blood vessels in the lungs are very sensitive to oxygen. The lower the level of oxygen, the narrower the vessels become. Higher pressure will be needed to push blood through the narrow blood vessels. Pressure will also increase when there is more blood in the lungs than normal.
These situations may be caused by:
  • Chronic obstructive pulmonary disease (COPD) is the most common cause. This condition causes destruction of lung tissue. This decreases the number of blood vessels. It also lowers the amount of oxygen available.
  • Heart abnormalities can result in extra blood in the lungs. Some are conditions people are born with. Others may develop over time. Some of these conditions are:
    • Septal defects (holes between the right and left sides of the heart, present at birth)
    • Tight (stenotic) or leaky heart valves
  • Some lung diseases scar the lungs. This makes them less flexible.
    • Scleroderma (systemic sclerosis)—stiffen blood vessels, effectively preventing them from opening which raises the pressure
    • Patients who have large sections of lung removed surgically
    • Systemic lupus erythematous
  • In obstructive sleep apnea breathing stops at times through the night. This lowers available oxygen. As a result, pulmonary blood pressure will also increase.
  • Muscle weakness can make it difficult to breathe. This will lower the available oxygen. This weakness is common in neuromuscular disorders such as:
  • Mountain climbers all develop the condition. It is the natural result of breathing thin air. This is one cause of high altitude sickness.
  • Pulmonary embolism is a build up of blood clots in the lungs. These clots plug up the blood vessels.
  • A type of chest wall deformity is known as pectus excavatum. Rarely, severe scarring of the chest wall, can prevent chest expansion. It has the same effect as scarring of the lungs themselves.
  • Idiopathic pulmonary arterial hypertension is due to defects in the arteries of the lungs. There is no known cause. It is likely due to genetic factors.
Other factors and conditions that can create pulmonary hypertension include:
  • Exposure to certain substances, such as cocaine and amphetamines
  • HIV positive status
  • Liver disease
 

Risk Factors

The following factors increase your chance of developing this condition:
  • Smoking
  • Asthma or other chronic lung disease
  • Recurring pulmonary emboli
  • Obstructive sleep apnea
  • Obesity
  • Low thyroid (myxedema)
  • Certain congenital and valvular heart conditions
  • Muscle weakness diseases
  • Home at high altitude (over 10,000 feet)
  • Pectus excavatum or other severe chest deformity (eg, kyphoscoliosis)
 

Prevention

To help reduce your chances of getting pulmonary hypertension, take the following steps:
  • Do not smoke
  • Control asthma effectively
  • Maintain proper weight
  • Treat conditions that can lead to pulmonary hypertension
 

RESOURCES

American Heart Association
http://www.americanheart.org/

National Library of Medicine
http://www.nlm.nih.gov/

 

CANADIAN RESOURCES

Health Canada
http://www.hc-sc.gc.ca/index%5Fe.html/

Heart and Stroke Foundation of Canada
http://ww2.heartandstroke.ca/

 

References


Kasper DL et al., eds. Harrison's Principles of Internal Medicine . 16th ed. New York: McGraw-Hill; 2005.


Libby P, Braunwald E. Braunwald’s Heart Disease . 6th ed. Philadelphia, PA: Saunders/Elsevier; 2005.


Physicians’ Desk Reference . 59th ed. Oradell, NJ: Thomson PDR; 2005.


Rubin LJ, Badesch DB. Evaluation and management of the patient with pulmonary arterial hypertension. Annals of Internal Medicine . 2005;143(4):282-292.


Weinberger SE, Drazen JM. Disturbances of respiratory function. In: Braunwald E. Harrison's Principles of Internal Medicine . 15th ed. New York, NY: McGraw-Hill; 2001.

 

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