Definition

Pulmonary hypertension [2] occurs when there is elevated blood pressure [3] 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 [4] can eventually fail.

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 [5] (holes between the right and left sides of the heart)
  • Tight (stenotic) or leaky heart [4] valves
• Chronic obstructive pulmonary disease (COPD)—the most common cause of pulmonary hypertension [2], causes destruction of lung tissue which decreases blood vessels, and lowers the amount of oxygen available.
  • COPD is a combination of chronic bronchitis [6] and emphysema [7] , usually due to years of tobacco damage.
• Lung diseases that scar the lungs, making them less flexible.
  • Scleroderma [8] (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 [2].
  • Systemic lupus erythematous [9]
• Obstructive sleep [10] apnea —breathing stops periodically throughout the night. This lowers available oxygen and raises pulmonary blood pressure.
• Muscle weakness—can decrease the ability to breathe well lowering the available oxygen. This weakness is common in neuromuscular disorders such as:
  • Polio [11]
  • ALS [12]
  • Myasthenia gravis [13]
• Altitude–mountain climbers all develop pulmonary hypertension [2], the natural result of breathing thin air. This is one cause of high altitude sickness.
• Pulmonary embolism [14] —cumulative blood clots in the lungs plug up the blood vessels.
• Chest wall deformity—condition 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 [15] positive status
• Liver disease
• Idiopathic pulmonary arterial hypertension—formerly called primary pulmonary hypertenion. Here pulmonary hypertension [2] 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 [2]. If you have any of these risk factors, tell your doctor:

• Smoking
• Asthma [16] or other chronic lung disease
• Recurring pulmonary emboli
• Obstructive sleep [17] apnea
• Obesity [18]
• Low thyroid (myxedema)
• Certain congenital and valvular heart [4] conditions
• Muscle weakness diseases
• Home 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 [2] or many other conditions, all of which require medical [19] attention.

• Progressive shortness of breath
• Chronic cough
• Chronic fatigue
• Fainting spells
• Ankle swelling from fluid retention
• Heart pain [20] ( angina [21] )

Diagnosis

Your doctor will ask about your symptoms and medical [19] history, and perform a physical exam. You may be referred to a specialist in heart [4] diseases (cardiologist) and/or lung diseases (pulmonologist).

Tests may include the following:

• Blood gas determination
• Cardiac catheterization [22]
• Pulmonary function test [23]
• Computerized axial tomography (CAT) scan [24]
• Echocardiogram [25]

Treatment

Most pulmonary hypertension [2] 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:

Prevention

To help reduce your chances of getting pulmonary hypertension [2], take the following steps:

• Do not smoke
• Control asthma [16] effectively
• Maintain proper weight
• Treat conditions that can lead to pulmonary hypertension [2]