Pulmonary arterial hypertension is an abnormally high blood pressure occurring in the arteries of the lungs. It is a rare condition and research to determine the cause of this condition has been difficult.
Due to the low incidence of its occurrence it has made it even more difficult to determine its cause. Animal models are generally studied to help determine causes of disease, but with PAH an acceptable animal model has not been available to study. There are theories as to the cause and it has been shown that people with certain conditions or exposure to some substances have a higher tendency for development of the condition.
Researchers believe that persons who have blood vessels that are particularly sensitive to certain external or internal factors which cause constriction of the vessels have an increased tendency for PAH. People with Raynaud’s disease, a condition in which the toes and fingers of the individual turn blue when they are exposed to cold because of the extreme sensitivity of the blood vessels seem more likely to develop PAH than those without the condition.
The diet drug Fen-Phen has shown to have a significant association with the development of PAH. Scientific studies have shown that the effect of the medication and development of the disease may not be apparent for several years after stopping the medication.
Other factors thought to influence the development of pulmonary arterial hypertension include the use of cocaine, pregnancy and HIV. These factors can trigger constriction of the pulmonary artery which can result in PAH. There has been some indications that the condition is inherited or that if you have a family history of PAH you may be at an increased risk for its development. These causes are theories and observations, the exact cause or causes of PAH continue to be unknown.
Symptoms and Diagnosis
Symptoms of PAH are generally related to breathing. They may happen suddenly or slow progress over time.
- Progressive shortness of breath, this is especially noticeable with activity
- Breathing rapidly and hard, hyperventilation
- Increased and progressive weakness of the muscles
- Dizziness or lightheadedness
- Cough up blood
- Cyanosis, this may begin gradually but progresses.
Diagnosis of PAH is not an easy task. It is rare that it is noticed on routine medical examinations because the symptoms can be easily attributed to other conditions of the heart and lungs. To make a diagnosis involves ruling out all other reasons for the symptoms. The diagnosis can only be confirmed when other reasons for the high blood pressure in the lungs arteries such as blood clots in the lungs, chronic obstructive pulmonary disease, heart disease and other possible causes have been tested and eliminated as the source.
A physical examination by the physician may reveal a distention of the veins in the neck, water retention and swelling of the hands and feet or legs and an enlargement of the liver. These findings are due to the difficulty of the right ventricle of the heart has trying to pump blood into the lungs blood vessels.
Other tests for the diagnosis and to determine the progress of the disease include:
- Electrocardiogram – This should show an enlargement of the right side of the heart.
- Chest X-Ray – This will also show enlargement of the heart and is a good way to monitor the condition as it progresses.
- Echocardiogram – This is an ultrasound of the heart. This can measure the size of the heart and is also a good way to follow the diseases progression. Sometimes the echocardiogram can estimate the pressure of the right ventricle of the heart and of the pulmonary arteries.
- Cardiac catheterization – This is an invasive procedure, but it is the best way to diagnose PAH. With this procedure the physician is able to measure the pressures on the right ventricle and calculate the resistance of the lungs arteries.
There are only two different options for treating pulmonary arterial hypertension. These two options are medications and a lung transplant.
Multiple medications are used in the treatment of PAH.
- Prostacyclin analogues – medications which enable the blood vessels in the lungs to expand allowing the blood to move through them without as much resistance.
- Endothelin receptor antagonists – medications to help reverse the effects of a substance in the blood known as endothelin. Endothelin causes the blood vessels to constrict.
- Anticoagulants – medications used to prevent blood clotting.
- High dose calcium channel blockers – medication which promotes vasodilation by helping the muscles in the blood vessels to relax.
- Diuretics – medications which help to remove excess fluids from the body. Excess fluid may accumulate due to the high pressures in the vessels.
Lung transplantation is also done to treat PAH. The most common method is a single lung transplant where only one lung is transplanted. Double lung transplants are done, but are less common. There are fewer complications with a single lung transplant but some complications include rejection of the organ by the body and infection. When you have an organ transplanted you will take anti rejection medications for the rest of your lift to reduce the chance that your body’s immune system will reject the organ.