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Author: Vladimir Popa-Nimigean, Medical Student, School of Clinical Medicine, University of Cambridge, Cambridge, UK. DermNet NZ Editor in Chief: Adjunct A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. Copy edited by Gus Mitchell/Maria McGivern. October 2018.
Klippel–Trénaunay syndrome (KTS) is a rare congenital vascular bone syndrome that is characterised by a triad of symptoms and features; these being:
The syndrome is also called Klippel–Trénaunay–Weber syndrome, angio-osteohypertrophy syndrome, and haemangiectactic hypertrophy.
Klippel–Trénaunay syndrome is a rare disease, affecting one in 20,000–40,000 children. It affects both sexes equally and it occurs in all races . While it mostly occurs sporadically, some inherited cases have been reported .
While the exact cause of Klippel–Trénaunay syndrome is not clear, several genes and pathways have been identified in its pathogenesis. Notably, PIK3CA gene mutations have been detected in some cases of Klippel–Trénaunay syndrome. PIK3CA encodes for a subunit of the phosphoinositide 3-kinase enzyme, which is involved in cell proliferation and migration. Gain-of-function mutations can lead to tissue hypertrophy in the bone, soft tissue, and blood vessels [2,4].
The angiogenic gene VG5Q has also been implicated in Klippel–Trénaunay syndrome .
One or more capillary vascular malformations (port-wine stains) are present in the overwhelming majority of patients with Klippel-Trénaunay syndrome and this is usually the first noticeable feature [1,2,6]. Commonly, the capillary malformation occurs over the affected hypertrophic limb, but it can also be present at other sites. Rarely, the affected area can blister and bleed .
Varicose veins are a common feature of Klippel–Trénaunay syndrome. They tend to be larger than normal varicose veins and they can be painful. Varicose veins may not be present initially. They usually become noticeable in later infancy, childhood, or adolescence. Deep veins can also be affected, increasing the risk of developing deep vein thrombosis (DVT) [1–3,6].
Additionally, the formation of veins may be atypical, resulting in lateral veins or persistent sciatic veins (inflammation in the veins leading from the spine down to the legs), for example. Bleeding can also occur, which may result in bleeding from the rectum or blood in the urine [6–9].
Malformations in Klippel-Trénaunay syndrome are of slow-flow vessels, and fast-flow arteriovenous malformations (clumps of blood vessels that link between arteries and veins) are not present. Bruits (murmurs caused by the narrowing of arteries) tend to be absent on examination .
Limb hypertrophy affects the lower limb in most cases (about 95%), with the remainder affecting the upper limb. Limb enlargement is disproportionate, with the width of the leg enlarging more than length, as the skin and muscles tend to become thicker than other sites. The average difference in limb length is around 2 cm. The length discrepancy can cause uneven walking, unstable gait, or pain. The child might appear to have scoliosis [1–3,6,9].
Less commonly, syndactyly or polydactyly (extra fingers or toes) may occur.
The possible complications of Klippel-Trénaunay syndrome include [1,2]:
The diagnosis of Klippel–Trénaunay syndrome is made clinically when the classical triad of port-wine stain, varicose veins, and limb hypertrophy are present. While a diagnosis of Klippel-Trénaunay syndrome can be suspected in a newborn when a port-wine stain is present, the confirmation comes later when other symptoms become more apparent [1–3].
Possible diagnostic tests include:
Conditions that can be mistaken for Klippel–Trénaunay syndrome include:
There is no specific cure for Klippel–Trénaunay syndrome, and generally, most patients can be managed conservatively. Specific treatments and procedures can also be used to reduce symptoms and prevent complications [1,6,10].
Compression stockings are often used to control the symptoms of varicose veins, alleviate pain and swelling, and prevent complications such as bleeding (in which case dressings, leg elevation, and rest are recommended [1,10].
If the difference in leg lengths is small (< 2 cm), shoe raisers might be recommended to allow the child to walk more easily and prevent compensatory scoliosis. Physiotherapy can also help reduce swelling in the affected limb [1,10].
Ligation of the veins (the surgical tying off of veins) can be used to treat varicose veins in conjunction with vein stripping. (See DermNet NZ's page of Leg vein therapies). This treatment is not advised in children [1,7,10].
Sclerotherapy refers to the injection of a sclerosing agent into the veins in order to collapse them. It is used to treat complications arising from varicose veins so they are no longer noticeable on the surface of the skin. It can be used in children after detailed scans of the veins in the leg have been made. Several sclerotherapy sessions months apart are usually required [1,7,10].
A variation of this procedure is foam sclerotherapy, which involves injecting a foaming agent (in addition to the sclerosing one) into the veins .
Laser therapy can be used to treat or manage the port-wine stains, although to a limited extent. It is also used to treat small varicose veins and as an adjuvant for sclerotherapy or endovascular ablation (see below) [7,10].
Problematic varicose veins can be closed off by using high-frequency radio waves to create local heat in the affected vein. This is generally associated with fewer risks and faster recovery compared to ligation and stripping .
If the asymmetry between the affected and unaffected legs is larger than 2 cm, epiphysiodesis can be performed to slow down the growth in the affected leg. This procedure involves prematurely fusing the growth plate of a bone and needs to be timed correctly in order to match the lengths of the legs by the end of the growth phase [6,7].
Alternatively, the normal leg can also be lengthened surgically to achieve matching size .
Patients with Klippel–Trénaunay syndrome tend to do very well. While it is not a life-threatening condition and most patients end up having normal lives, ongoing care is required. This is best provided by a multidisciplinary team of dermatologists, vascular and orthopaedic surgeons, and general surgeons [1,10]. Some people may require counselling to adjust to the cosmetic aspects of the disease .
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