Definition
Pulmonary hypertension occurs when there is elevated blood pressure in the blood circulation of the lungs.
Blood flows through the lungs normally at one-sixth of the pressure required for the rest of the body. When, for any number of reasons, pressure rises, a potentially serious condition occurs that requires care from your doctor. If left untreated the right side of the heart can eventually fail.
Pulmonary Circulation
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Causes
The blood vessels in the lungs are very sensitive to oxygen. The lower the level of oxygen, the narrower the vessels become. Narrow blood vessels require higher pressure to push blood through. Pressure will also increase when there is more blood in the lungs than normal.
Pressure in the lungs can be raised by:
- Heart abnormalities can result either 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)
- Tight (stenotic) or leaky heart valves
- Chronic obstructive pulmonary disease (COPD)the most common cause of pulmonary hypertension, causes destruction of lung tissue which decreases blood vessels, and lowers the amount of oxygen available.
- COPD is a combination of chronic bronchitis and emphysema , usually due to years of tobacco damage.
- Lung diseases that scar the lungs, making them less flexible.
- Scleroderma (systemic sclerosis) stiffen blood vessels, effectively preventing them from dilating, and thereby raising the pressure within.
- Patients who have large sections of lung removed surgically may also develop pulmonary hypertension.
- Systemic lupus erythematous
- Obstructive sleep apnea breathing stops periodically throughout the night. This lowers available oxygen and raises pulmonary blood pressure.
- Muscle weaknesscan decrease the ability to breathe well lowering the available oxygen. This weakness is common in neuromuscular disorders such as:
- Altitudemountain climbers all develop pulmonary hypertension, the natural result of breathing thin air. This is one cause of high altitude sickness.
- Pulmonary embolism cumulative blood clots in the lungs plug up the blood vessels.
- Chest wall deformitycondition known as pectus excavatum and, rarely, severe scarring of the chest wall, can prevent chest expansion, the same effect as scarring of the lungs themselves.
- Exposure to certain substances, such as cocaine and amphetamines
- HIV positive status
- Liver disease
- Idiopathic pulmonary arterial hypertensionformerly called primary pulmonary hypertenion. Here pulmonary hypertension is due to primary abnormalities of the arteries within the lungs without an underlying cause. This is likely due to genetic abnormalities and may be inheritable.
Risk Factors
The following factors increase your chance of developing pulmonary hypertension. If you have any of these risk factors, tell your doctor:
SmokingAsthma or other chronic lung disease Recurring pulmonary emboliObstructive sleep apneaObesityLow thyroid (myxedema)Certain congenital and valvular heart conditionsMuscle weakness diseasesHome at high altitude (over 10,000 feet)Pectus excavatum or other severe chest deformity (eg, kyphoscoliosis) Symptoms If you experience any of these symptoms, see your physician. They might represent pulmonary hypertension or many other conditions, all of which require medical attention. Progressive shortness of breathChronic coughChronic fatigueFainting spellsAnkle swelling from fluid retention Heart pain ( angina ) DiagnosisYour doctor will ask about your symptoms and medical history, and perform a physical exam. You may be referred to a specialist in heart diseases (cardiologist) and/or lung diseases (pulmonologist). Tests may include the following: Blood gas determinationCardiac catheterizationPulmonary function testComputerized axial tomography (CAT) scanEchocardiogram TreatmentMost pulmonary hypertension is due to preceding disease. If no treatable cause is found, there are several medications that might be of benefit. Talk with your doctor about the best treatment plan for you. Treatment options include the following:
MedicationsCalcium channel blockersAnticoagulantsDiureticsOxygenPhosphodiesterase inhibitors (sildenafil)Prostacyclin (epoprostenol, iloprost). These must be administered by continuous infusion either intravenously, subcutaneously, or by inhalation.Endothelin receptor blockers (bosentan) Lung TransplantationThis is a drastic treatment recommended only for life-threatening disease. Prevention To help reduce your chances of getting pulmonary hypertension, take the following steps: Do not smoke Control asthma effectively Maintain proper weightTreat conditions that can lead to pulmonary hypertension RESOURCES: American Heart Associationhttp://www.americanheart.org The Merck Manual, Second Home Editionhttp://www.merck.com CANADIAN RESOURCES: Heart and Stroke Foundation of Canadahttp://ww2.heartandstroke.ca Pulmonary Hypertension Suppport Grouphttp://www.phassociation.org References: Kasper DL et al., eds. Harrison's Principles of Internal Medicine . 16th ed. New York: McGraw-Hill; 2005. Physicians Desk Reference . 59th ed. Thomson PDR: New Jersey; 2005 Rubin LJ, Badesch DB. Evaluation and management of the patient with pulmonary arterial hypertension. Annals of Internal Medicine . 2005;143(4):282-92.
Braunwalds Heart Disease . 6th ed. 2005. Weinberger SE, Drazen JM. Disturbances of respiratory function. In Kurt Isselbacher et al. Eds. Last reviewed February 2008 by Michael J. Fucci, DOPlease be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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