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Pulmonary Arterial Hypertension

Pulmonary Arterial Hypertension (PAH)

What is PAH?

Pulmonary Arterial Hypertension (PAH) is the medical term for a unique disease process which takes place in the small vessels which carry blood from the heart to the lungs (the "pulmonary arteries and or arterioles"). Although it is uncommon, it is a disease that can affect males and females of all ages and ethnic backgrounds. Rarely, it can occur in childhood. The disease process in the pulmonary arteries which leads to PAH occurs over several years. The signs and symptoms of this disease are often hard to distinguish from other diseases or conditions, particularly in the early stages. This frequently delays the formal diagnosis of PAH.

This disease process severely restricts the flow of blood from the heart to the lungs, which increases the pressure in the pulmonary arteries. The heart must pump against this increased pressure to maintain blood flow to the lungs and then to the rest of the body. The heart eventually fails to pump efficiently and as a result eventually may fail completely.

During this time, symptoms such as tiredness and breathlessness are experienced. Understandably, these can impact greatly on daily life. Eventually fluid can build up in the legs and patients may experience dizziness or light headedness on walking.

Types of PAH

PAH can be associated with several different diseases, including:

Scleroderma (also known as systemic sclerosis)
Lupus
HIV/AIDS
Congenital heart defects
Some liver disorders
Certain drugs or toxins

Pulmonary Hypertension can also occur following blood clots in the lung or in association with chronic lung diseases. Although there are many similarities between these conditions and with PAH, there are important differences also.

Pulmonary Arterial Hypertension can also occur without obvious association and sometimes there is a familial predisposition (ie it may be seen in several members of the same extended family). These forms of PAH are known as idiopathic PAH and familial PAH. These terms have replaced the previous term of primary pulmonary hypertension (PPH).

Some of the early symptoms of PAH include:

Shortness of breath during exertion or normal daily activities
Fatigue (feeling tired all the time)
Dizziness, especially when climbing stairs or upon standing up
Fluid build up in the limbs
In babies, the first signs may be difficulty with feeding, breathlessness, going blue and failure to gain weight

Often, people do not take much notice of these early signs of PAH. They may think they are just over-tired or lacking in fitness.

As the disease progresses, the symptoms become more noticeable. Breathlessness and tiredness become more a part of daily life, so that even simple tasks, such as getting dressed and walking short distances, become increasingly difficult. Fluids can build up in the legs and chest pain may also be experienced. These are all signs of the increased stress being placed on the heart as it attempts to adjust to the disease's effects on the body's heart-lung blood flow functioning.

It is usually when these symptoms severely affect normal activities of daily life, that people go to their doctor to identify the cause.

PAH is an uncommon disease with early symptoms that are easily confused with those of other conditions, such as asthma, and may be incorrectly treated on this basis. Further, as the symptoms may be dismissed as due to stress or a lack of fitness, there is often a delay before a doctor is even consulted. As a result, the path to a confirmed diagnosis of PAH can take several years from the time of the first symptoms, while other possibilities are eliminated.

To assist in the diagnosis of PAH, the doctor asks questions to gain a clear and detailed history of all prior and current medical conditions, and those of close relatives. Additionally, the doctor needs to know of any drugs (be they prescription, over-the-counter or illegal) that have been taken in the past, or are currently being taken.

Blood tests and a physical examination are conducted. Additionally, further tests are required to help diagnose PAH. Diagnosis usually results from ruling out the presence of other diseases which may have similar symptoms to PAH.

Your doctor will have more information on each of these tests, such as how they are performed and what they are looking for. Other tests, which are not listed here, may also be used to help diagnose PAH.

An echocardiogram (ultrasound of the heart) is required and if there is a suggestion of PAH, then other tests including breathing tests and walking tests, CT scans and a right heart catheter is also required.

Doctors have devised a grading system to help understand to what extent the PAH symptoms are affecting lifestyle and well-being. This is referred to as a PAH "functional class", and helps the doctor know what type of treatment can be given. This functional class system classifies how severe the PAH is, based on the symptoms. It is graded from class I through to class IV, where class I is very early stage PAH and a functional class of IV is very severe PAH.

Treatment

Without treatment, the outlook for patients with PAH is extremely guarded. However, there are now several good treatments available. These can vary from tablets to nebulisers and in the very severe end of the spectrum, continuous intravenous infusion.

Most patients do very well with this treatment but occasionally and only if these treatments are ineffective, more involved treatments including lung transplantation may need to be considered.

As PAH is uncommon and its treatment complex, all patients with PAH should be managed by an experienced centre of which there is at least one in each state in Australia.

Your doctor should be able to advise you where the centres are in your state and further information is available from the following websites.