Klippel-Trenaunay syndrome

It can be hard to find accurate information about Klippel-Trenaunay syndrome (KTS) because it’s such a rare condition. Here at Children’s Hospital Boston, we understand the condition — and we know when and how to treat it.

What causes KTS?

No one knows the precise cause. Some doctors believe it’s caused by a mutation — in the embryonic stage of life — in the cells that form the lymphatic system, veins and other tissues.  No known food, medication or activity during pregnancy can cause KTS.

How common is it?

It’s exceedingly rare.

When does it appear?

Doctors can sometimes see evidence of KTS in a prenatal ultrasound and the capillary malformation (“port-wine stain”) is almost always apparent when your child is born.

Who has KTS?

It’s equally common in boys and girls.

Signs and symptoms

Often, KTS can be misdiagnosed by your child’s primary physician, simply because the condition is so rare.

KTS often has three characteristic signs:

• capillary malformation covering one or more limbs (arm or leg)
• hypertrophy — or excessive growth — of a limb (usually a leg)
• abnormal blood vessels, including veins, capillaries and lymphatic vessels

What symptoms will my child have?

KTS affects different kids in different ways. One child may have a mild form of the syndrome with a small capillary malformation and one hand or foot slightly larger than the other. Another child may have a capillary malformation that runs from her chest down her leg, lots of swelling and one limb that is much larger than the other.

Here are some of the more common symptoms of KTS:

• blood clots
• cellulitis (infections in the skin) — your child may be more prone to infection because he is more likely to bleed easily as a result of the abnormal capillaries near the surface of his skin
• anemia — due to blood loss because of easy bleeding
• pain and heaviness of the affected limb — the pain can often be severe
• difference in size between the affected and non-affected limb

Are there any other signs of KTS?

Based on your child’s symptoms, a doctor may do further tests. Some other signs of KTS include:

• lymphatic abnormalities such as cysts and swelling
• swollen veins

Long-term outlook

What is the long-term outlook for my child?

Because there’s no cure for KTS, we focus on managing your child’s symptoms. The long-term outlook for your child depends on a few factors:

• the extent of the disease
• the amount of hypertrophy in your child’s limb or limbs
• the abnormal blood vessels’ response to therapy
• the overall health of your child
• your child's tolerance of specific medications, procedures, or therapies
• new developments in treatment

Every child is unique and your care team will work with you to develop a treatment plan that works for your family.

Does KTS get better?

No. KTS is a progressive condition, which means that it will grow as your child grows. That said, many kids — especially those with mild cases of KTS — go on to live normal, healthy lives.

What do we do after treatment is over?

Depending on the severity of your child’s condition, your doctor may recommend a series of follow-up visits to check for complications and make sure that we’re managing the KTS effectively. A typical follow-up visit may include some or all of the following:

• a physical exam
• laboratory testing
• imaging scans

FAQ

Q: What are the signs that my child has KTS?
A: KTS often has three characteristic signs:

• Capillary malformation covering one or more limbs (arm or leg)
• Hypertrophy — or excessive growth — of a limb (usually a leg)
• Abnormal blood vessels, including veins, capillaries and lymphatic vessels

Q: What symptoms will my child have?
A: Some of the more common symptoms of KTS include:

• blood clots
• cellulitis (infections in the skin) — your child may be more prone to infection because he is more likely to bleed easily as a result of the abnormal capillaries near the surface of his skin
• anemia — due to blood loss because of easy bleeding
• pain and heaviness of the affected limb — the pain can often be severe
• difference in size between the affected and non-affected limb

Q: How is KTS diagnosed?
A: Doctors can sometimes see evidence of KTS in a prenatal ultrasound and the capillary malformation (sometimes called a port wine stain) is almost always apparent when your child is born.

If your child is older, we’ll start with a complete medical history and a thorough physical exam. In many cases, that initial exam gives us enough information to diagnose KTS. If there’s any doubt, your doctor may recommend MRI, ultrasound or a CT scan, which can help determine the correct diagnosis and the appropriate next steps in treatment.

Q: How is KTS treated?
A: It’s a complicated condition, and it affects different kids in different ways. The first step is to have your child evaluated by members of an experienced interdisciplinary vascular anomalies team. No single specialist can manage KTS and its associated problems, as different interventional techniques and surgical procedures are often needed.

For more information, see the Treatment & Care section.

Q: What kind of support will we get from Children’s?
A: At Children’s, we consider you and your child integral parts of the care team and not simply recipients of care. Your care team will be with you every step of the way to ensure that you and your child are getting the support you need.

Q: What is the long-term outlook for my child?
A: The long-term outlook for your child depends on a few factors:

• the extent of the disease
• the amount of hypertrophy in your child’s limb or limbs
• the abnormal blood vessels’ response to therapy
• the overall health of your child
• your child's tolerance of specific medications, procedures, or therapies
• new developments in treatment

Every child is unique and your care team will work with you to develop a treatment plan that works for your family.

Q: What makes Children’s different?
A: We’re home to the first and largest vascular anomalies center in the world.

When doctors in other states or other countries need help diagnosing or treating children with vascular anomalies such as KTS, they often come to us.

Questions to ask your child’s doctor

After your child is diagnosed with KTS, you may feel overwhelmed with information. It can be easy to lose track of the questions that occur to you.

Lots of parents find it helpful to jot down questions as they arise – that way, when you talk to your child’s doctors, you can be sure that all of your concerns are addressed.

If your child is old enough, you may want to suggest that she write down what she wants to ask her health care provider, too. Some of the questions you may want to ask include:

• How will my child’s KTS be treated?
• What side effects or complications might my child experience due to treatment?
• What kind of follow-up care should my child receive? How often will she need to come in?
• How much experience does this center and my child’s doctor have with treating KTS?