Parkes Weber's Syndrome

Nomenclature

The terms Klippel-Trénaunay-Weber syndrome and Klippel-Trénaunay-Parkes Weber syndrome have sometimes been used synonymously with Parkes Weber's syndrome (PWS). However, current usage favours the term Parkes Weber's syndrome. Note that Klippel-Trénaunay syndrome (without the 'Parkes' or 'Weber') is a separate condition (limb overgrowth and a slow-flowing vascular malformation without significant AVFs - clinically different from PWS).^{[1, 2]}

Definition^{[3, 4]}

Parkes Weber's syndrome (PWS) is vascular malformation comprising:

• A capillary arteriovenous malformation, manifest as a visible red skin lesion.
• Arteriovenous fistulae (AVFs).
• Lymphoedema.
• Overgrowth of a limb.

PWS is classified as a complex combined vascular malformation.

Epidemiology and aetiology

• Parkes Weber's syndrome (PWS) is rare.^[5]
• Most cases are sporadic, although familial cases have been reported.^{[3, 6]}
• A recent study suggests that PWS (and other capillary malformation-arteriovenous malformations) may be linked to mutations of the RASA1 gene.^{[7, 8]}

Presentation^{[3, 4, 9]}

Onset:

• May present antenatally (on ultrasound), at birth, or may develop during childhood.

Clinical features in the affected limb:

• A congenital, red or pink skin lesion (a 'geographical' red stain), which is a high-flow lesion.^[11]
• Limb enlargement - including muscle and bone hypertrophy, with an increase in limb length and girth. One case involving a shortened limb is reported.^[12]
• Signs of a vascular shunt in the affected limb, eg warmth; dilated veins; a thrill, bruit or pulsation.
• Lymphoedema - localised or diffuse. Lymphatic vesicles may be visible in the skin.
• May have limb pain, due to vessel enlargement.
• In some cases, the skin lesions may bleed easily, eg on minor trauma.^[11]
• Distal skin changes in the limb (due to distal vascular steal), eg ischaemic ulcers, pigmentation and fibrosis.

Diagnosis and investigations^[3]

The diagnosis can usually be made clinically, without the need for imaging. A bedside audible Doppler ultrasound can confirm vascular shunting.

Various imaging methods can be used to assess the extent of lesions:

• Plain X-rays - show lytic bone lesions and limb-length discrepancy.
• MRI scans - can show enlarged limb muscles and bones, the extent of the vascular lesion, and the high-flow nature of the vascular malformations.^{[9, 13, 14]}
• Catheter angiography is used in some cases.^[15]

Differential diagnosis

• Klippel-Trénaunay syndrome (slow-flow capillary lesions without significant arteriovenous fistulae (AVFs)).
• Other vascular malformations, eg port-wine stains^[16] (tend to be purplish in colour rather than the pink-red stain found in Parkes Weber's syndrome (PWS)).
• Other causes of lymphoedema.

Management^[3]

Conservative management is preferred, if possible, since invasive treatment may worsen the arteriovenous fistulae (AVFs). Multidisciplinary care is often appropriate.

Conservative treatments:

• Prevention of trauma (lifestyle modification, eg care with sporting activity) - since trauma may worsen the AVFs.
• First aid advice for patients if they have lesions prone to bleeding - apply firm pressure and seek medical help.
• Elastic hosiery to reduce lymphoedema and vascular steal.
• Avoid laser treatment of the skin lesions - this can worsen the shunting through AVFs.

Orthopaedic care for the limb-length discrepancy:^[4]

• Monitor limb growth.
• Treatment is conservative if possible.
• Stapling epiphysiodesis (eg of the knee cartilages) may be performed to limit leg length, but the procedure may worsen the arterial venous malformation in the limb.

Vascular treatment:^[17] This may be required if there are troublesome complications such as pain, ulceration or cardiac failure. Possible treatments are:

• Arterial embolisation (but this procedure often fails to control the shunting in Parkes Weber's syndrome (PWS)).^{[3, 18, 19]}
• Surgical resection of the lesion may be possible in some cases.
• Limb amputation may be required in some cases.^[20]

Complications^[3]

• Skin:
  • Cosmetic problems with the appearance of the lesions.
  • Some skin lesions may bleed easily, eg on minor trauma - patients need advice about first aid.
  • Ischaemic ulcers distal to the lesion.
  • Recurrent skin infections due to lymphoedema.
• Cardiovascular:
  • Limb pain resulting from vessel dilatation.
  • High-output cardiac failure - due to the high-flow shunting lesions.^{[5, 15]}
  • One case report describes disseminated intravascular coagulation following a leg fracture in a patient with Parkes Weber's syndrome (PWS).^[21]
• Orthopaedic:
  • Pelvic tilt and scoliosis due to leg-length discrepancy.
  • Pathological fractures due to lytic bony lesions.

Prognosis^[1]

The deformity tends to progress with time; the affected limb continues to show increased growth until epiphyseal closure.