Pulmonary Hypertension Causes, Symptoms and Treatments

Pediatric pulmonary hypertension (PH) is high blood pressure in the arteries of the lungs (the pulmonary arteries). PH is a progressive disease where the pulmonary arteries continue to shrink, making the right side of the heart work harder as it makes the higher pressure needed to force blood through the narrowed arteries.

In severe cases of pediatric PH, the small blood vessels in the lungs are damaged to the point they are lost. This happens because the muscle in the arteries contracts (vasoconstriction) and the artery muscle cells divide and plug up the arteries (muscle cell proliferation). The vessels can also become blocked with blood clots or the lungs can become damaged by illness. This causes the loss of air spaces and blood vessels in the lungs. PH may cause the right side of your child's heart to become enlarged and eventually can cause right heart failure.

Your child may develop PH for many reasons. Sometimes, PH will have more than one cause.

Pulmonary hypertension is classified into five major groups:

Group 1

True pulmonary arteriolar hypertension can result from some, but not all, forms of congenital heart disease, connective tissue disease, or sometimes PH has a genetic cause, which may also be seen in family members.

Cardiac problems that can lead to Group 1 PH include:

• Patent ductus arteriosus (PDA)
• Ventricular septal defects (VSDs)
• Atrial septal defects (ASDs)
• Transposition of the great arteries

These defects can cause damage to the blood vessels by allowing too high a pressure or too much blood to flow through the lungs that can overtime lead to a condition called Eisenmenger syndrome.

In adults, PH is seen in connective tissue diseases, but in children this is rare. We work closely with the Division of Rheumatology to screen children who might have an increased risk of this complication.

PH with a genetic cause is very rare and thought to be in the range of 2 to 3 in 1 million people. However, this is seemingly even rarer in children and extremely rare in infants. We are consulted to screen children from families where PH has been found in adults, and we are able to screen for the seven common PH genes. However, we are also actively researching other genetic causes for PH since these seven genes do not seem to be involved in the majority of children with PH.

Group 2

PH that is caused by failure of the left side of the heart that causes the pressure to back up into the lungs. This group of children have very difficult PH to control and treat. We have become committed to finding safe and effective ways to improve the lives and activity tolerance of these children. Heart problems that can lead to Group 2 PH include:

• Mitral stenosis (when one of the heart valves narrows)
• Pulmonary vein stenosis (narrowing or loss of the vessels coming from the lungs)
• Dilated cardiomyopathy (abnormal function of the left heart muscle)

Group 3

PH that is caused by any disease that primarily affects the air spaces and air tubes in the lungs. The Cardiac Center’s Pulmonary Hypertension Program treats hundreds of infants and children who have Group 3 PH as a result of chronic lung disease of prematurity (bronchopulmonary dysplasia or BPD), lung hypoplasia (small lungs), after repair of congenital diaphragmatic hernia (CDH), or other lung lesions that make the lung small or hypoplastic. We are actively working with the Division of Neonatology, the Division of Pulmonary Medicine and the Wyss/Campbell Center for Thoracic Insufficiency Syndrome to find new ways to evaluate and improve the growth and development of these small lungs.

Group 4

PH that is caused by blood clots (or thrombosis) in the blood vessels in the lung, often called pulmonary embolism. This is a rare cause of PH in adults and children, but it is also often missed. We have been working on advanced imaging modalities to safely evaluate the effect of a clot on the lungs of infants and children. There are new treatment modalities that are specifically utilized in adults with this disease but the effectiveness in children is still in question.

Group 5

A combination of many rare diseases that infrequently cause PH are still seen in children. Children with sickle cell disease are at increased risk for PH as are some children who have undergone treatment for cancer, liver and kidney diseases.

Symptoms of pulmonary hypertension are often similar to other less severe childhood conditions. Because they are so common, the evaluation for childhood pulmonary hypertension is often delayed by several months.

• Fatigue (usually with activity is the first symptom to develop)
• Difficulty breathing or shortness of breath with activity
• Dizziness
• Fainting, especially with activity as in running up the stairs
• Swelling and/or discoloration in the lower legs or ankles
• Chest pain
• A bluish discoloration of the lips

Although PH is rare in children, it is being diagnosed more frequently. Since 1995, our program has evaluated and treated more than 1,800 children and adolescents with signs or symptoms of pulmonary hypertension.

Our involvement starts at the first phone call or Hospital visit, when we evaluate the history and symptoms to determine how urgently your child needs to be seen or treated. During your child's evaluation for PH:

• We will perform a thorough physical exam and may order testing. If you have reports and images from previous studies, we will ask to review them and we may perform our own, including a very complete echocardiogram (ultrasound of the heart).
• We will determine if exercise testing is possible, safe and appropriate, even if it is just a short monitored hall walk.
• We may order blood tests. Simple blood tests can confirm our assessment of the severity of heart failure and can be extremely important in determining the cause and planning treatment.
• We may perform a cardiac catheterization, which is the gold standard to provide a definitive diagnosis of PH, to determine the severity of PH and guide our treatment. Because cardiac catheterization is an invasive procedure we require the assistance of our cardiac anesthesiologists and often a night’s stay in our Evelyn and Daniel M. Tabas Cardiac Intensive Care Unit. Because we perform hundreds of catheterizations in children with PH, we can identify and minimize the risks of this procedure. During the procedure, a catheter is threaded through blood vessels into the right side of the heart to the pulmonary artery. With this catheter, we measure the pressures in the pulmonary vessels and the blood flow into the lungs to help us determine the severity of the condition and confirm the diagnosis. We may give your child medications during the catheterization so that we can see how treatment will affect the pressure in the pulmonary artery. Catheterization can help us predict disease progression.

Because PH is a rare and complex disease and is difficult to diagnose, your child's treatment team should have special expertise in the disease. At Children's Hospital of Philadelphia, we provide in-hospital treatment to more than 20 children with PH every day, so PH is understood by every member of your CHOP team, from the emergency room to the intensive care.

Whenever possible, we start by identifying and treating the underlying problem before your child develops permanent and life threatening pulmonary hypertension. For example, if your child has a heart valve problem that is causing the PH, repairing the valve can improve the PH. If heart disease is found during testing, we may be able to treat it or even repair the problem with surgery. 

If lung disease is identified as a cause of the PH, we work closely with our world-renowned colleagues in the Division of Pulmonary Medicine as well as other specialties, such as the Pulmonary Hypoplasia Program and the Neonatal and Infant Chronic Lung Disease Program. With over 20 years of experience and hundreds of infants with PH and lung disease, our protocols have been extremely successful; however, the earlier we can start treatment, the better our outcomes are going to be.

Treatment of pulmonary hypertension may include:

• Therapies to eliminate the cause of the vessel damage
• Oxygen to relax the blood vessels in the lung
• Medications that relax and promote growth of the blood vessels in the lungs
• Anticoagulants that reduce clotting and help blood flow
• Diuretics to reduce the heart failure and the amount of fluid in the body
• Medications so that the heart doesn't have to work as hard

There are currently no FDA-approved therapies for pediatric pulmonary hypertension; however, our program has more than 20 years of experience with the careful use of all therapies that are FDA-approved for adult PH. We are also working with new medications that stop the muscle cells from plugging up the vessels of the lung. All therapies, including newer and more experimental treatments for pediatric PH, are available in our dedicated PH clinic.

Although there is no cure for PH, our treatments have become very sophisticated. Also, the earlier the condition is diagnosed and treated, the better we're able to control it. At CHOP, we have been very successful in providing children with a good quality of life.

Some children with pulmonary hypertension eventually require lung or heart-lung transplantation, but we first use aggressive medical treatments that may improve your child's health and quality of life. Our transplant team has an extensive experience with children with PH, and CHOP’s Pulmonary Hypertension Program is well integrated into both pre- and post-operative transplantation care.

In addition to providing the finest clinical care, we are actively engaged in research and advocacy to advance the understanding and treatment of pediatric PH. We are a founding institution of the Pediatric Pulmonary Hypertension Network, we participate in multi-centered research trials, and we lecture on pediatric PH both nationally and internationally. We pride ourselves in the partnership with families and children that ensures the best outcomes for all children with PH.