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Klippel-Trenaunay-Weber Syndrome (KTWS) is a rare congenital disease that affects blood vessels, lymph vessels, bones and soft tissues. The disruption in blood and lymph vessels causes problems with flow through these vessels. This can lead to pooling of fluid in the affected area which can cause pain, swelling, inflammation and infection. The abnormal growth of the bones and soft tissue can lead to enlargement of an affected limb.
KTWS is a sporadic disease which means that it is not inherited. Both boys and girls are affected equally and there is no racial predominance.
The physical findings in KTWS are usually noted at birth or in the early months of infancy and include: 1) port wine stains which are collections of small blood vessels under the skin, 2) swollen veins known as varicose veins, and 3) hypertrophy (overgrowth) of the bones and tissues in one limb, usually a leg. The port wine stains are typically present at birth and often are the first indication of the disease. They can occur anywhere but most commonly occur over the lower half of the body. They have sharp borders and may get larger in the first few years of life. However, about 20% will get smaller or go away over time. The varicose veins are not visible at birth, but become apparent when the child begins walking. The limb hypertrophy generally gets progressively worse during the first few years of life. If only the soft tissue in the limb is affected, the limb will have increased width or girth. However, if the bone is also involved, the affected limb will also be longer. When the legs are involved, this can lead to leg length discrepancy which if significant enough can cause problems with walking. Since the lymph vessels are very similar to the blood vessels, the lymphatic system is often affected in children with KTWS.
The exact cause of KTWS is not known at this time, but it does not seem to be inherited. Researchers have suggested that children with KTWS may have a defect in an angiogenic factor (VG5Q) which is a protein that helps blood vessels grow. The defect would prevent blood vessels from developing normally. This would cause normal blood flow to be disrupted and lead to backup of blood in the veins.
The diagnosis of KTWS is based on the classic physical findings. Currently, there is no laboratory test to diagnose the disease. Imaging studies such as ultrasound or MRI can be performed to evaluate the blood vessels, but they are not required for diagnosis.
There is no cure for KTWS. Therefore, the treatment focuses on symptomatic relief and prevention of complications. Compression garments worn on the affected limb help promote blood flow and protect the limb from injury, infection and bleeding. Heel inserts can be used to treat leg length discrepancy. Port wine stains are generally not dangerous, but laser therapy can be used to lighten the color. Sclerotherapy which involves injection of a chemical into the dilated vein can be used as a treatment for varicose veins. This treatment causes thickening of the vein and subsequent obstruction. If necessary, surgery can be considered. However, surgical methods are used as a last resort because of high recurrence rates. The following are the success rates for various surgical procedures: 1) excision of blood vessel malformation (60%), 2) excision of varicose veins (40%), 3) debulking surgery (65%), and 4) correction of bony deformity and limb length correction (90%). A few medications have been shown to prevent complications from the disease. These include aspirin to prevent complications of blood pooling and prednisolone which is a corticosteroid to decrease inflammation.
Children with KTWS typically have normal life expectancy and intelligence is not affected by the disease. However, since children with KTWS have slowed blood flow through the dilated vessels, they are at increased risk for developing a clot in a deep vein. If this clot moves to the lungs which is called a pulmonary embolus, it can be very dangerous, even fatal. The risk of pulmonary embolus for a child with KTWS is approximately 10%, particularly after surgery. Other potential complications for children with KTWS include infection of the skin or bone due to poor wound healing and possible amputation or an extremity if hypertrophy is severe. Pain associated with the disease can be managed with pain medications.
Klippel-Trenaunay Support Group
A detailed website with information about the syndrome as well as links to support networks and other available resources.
The Vascular Birthmarks Foundation
Website containing general information about congenital birthmarks, support groups and related weblinks.
Morelli J. Chapter 649 (Vascular Disorders), Part XXX (The Skin). In Nelson Text book of Pediatrics, 18th ed, p2669-2670