Pediatric Craniofacial Vascular Malformations
What are they?
They are abnormally formed vessels carrying blood or lymphatic fluid that are present at birth but may not become evident until later in life.
What are the different types of vascular malformations?
They are two different broad categories: high flow and low flow malformations. The high flow malformations are called arterio-venous malformations because they represent abnormal connections between arteries or arterioles and veins or venules which bypass the normal capillary circulation. These can also occur in the brain (brain arteriovenous malformations). In the body, arteriovenous malformations can have life-threatening bleeding or mass effect, local tissue effects, and/or cosmetic disturbance. They are often treated with embolization as described in the brain arteriovenous malformation section. The low-flow malformations are due to abnormal formation of capillaries, veins or lymphatics. Sometimes the malformations are combined such as a veno-lymphatic malformation.
How are they diagnosed?
The lesions are usually identifiable on a physical exam as a vascular lesion. The venous malformations may demonstrate enlargement with various maneuvers that in crease pressure in the veins such as bringing the lesion below the level of the heart. High-flow lesions may be associated with a pulsatile bruit on exam.
How are they evaluated?
The lesions are most commonly evaluated with contrast enhanced MRI. Occasionally US and CT are used.
Coronal CT with contrast demonstrating large left neck macrocystic lymphatic malformation
Coronal MRI STIR images demonstrating large left neck macrocystic lymphatic malformation
What are the symptoms of a vascular malformation?
The lesions are often associated with pain and cosmetic disfigurement. They can also often present with pain at the site of the malformation. They can occasionally present with bleeding, especially if they involve the lining of the nose or mouth. This bleeding can be profound with high-flow vascular malformations. In addition, the lesions involving the aero-digestive tract, such as in the throat can present with difficulty breathing and\or swallowing.
How are they treated?
A team approach is utilized in the treatment of vascular malformations. The following specialists may be involved depending on the location of the lesion: dermatologists, otolaygologists, plastic surgery, ophthalmology and neuro-interventional radiology. Often, minimally invasive image guided percutaneous sclerotherapy is successful for the low flow venous and veno-lymphatic malformations. In this procedure X-ray and\or high resolution ultrasound guidance is used to inject a sclerosant into the malformation to damage the cells lining the lesion so that the fluid in the lesion does not re-accumulate. Sometimes several sclerotherapy sessions may be necessary. Patients typically go home on the day of the procedure.
The high-flow vascular malformations are treated with an endovascular approach from a small puncture in the femoral artery. In this procedure, micro-catheters are used to deliver liquid embolic agents to close the abnormal arteries supplying the malformation.
US guided needle placement into a macrocystic lymphatic malformation
Vein of Galen Malformation
What is a Vein of Galen Malformation?
The vein of Galen malformation (also known as VGAM or VOGM) is a rare congenital blood vessel malformation in the brain that develops prenatally. A vein of Galen malformation is a tangled mass of abnormal connection of the arteries and the median prosencephalic vein of Markowski. However most people refer to this as the vein of Galen. This congenital malformation develops between weeks six and eleven in embryonic and fetal development. It is the most common arteriovenous malformation (a deformity that includes veins and arteries) in fetuses.
The capillaries in this tangled mass, which are supposed to slow down blood flow and allow for oxygen exchange into the surrounding tissues, are missing, so blood flows directly from the arteries to the veins without supplying the surrounding tissues with oxygen and nutrients. This supply of blood travels almost immediately to the heart, which may overwhelm the heart, leading to congestive heart failure. The vein of Galen defect is occasionally seen upon prenatal ultrasound examination, but generally it is not seen until birth.
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Causes of Vein Of Galen Malformation:
Vein of Galen Malformation is a congenital - acquired - birth defect, and there are currently no known causes.
Symptoms of Vein of Galen Malformation:
Often the abnormality is detected on the prenatal ultrasounds. It is usually symptomatic in newborns. Less commonly it may present in early childhood.
In newborns, it typically presents with signs and symptoms of congestive heart failure - the newborn may present with respiratory distress, cyanosis (blue or purple in appearance due to low oxygen), and tachypnea (increased respirations). These newborns often require ventilator support with aggressive management of heart failure.
Early childhood presentation symptoms include: headaches, convulsive seizures, cardiac failure, or hydrocephalus (fluid accumulation in the brain). On exam, large head circumference, prominent scalp veins and drooping eyes may be noted.
Diagnosis of Vein of Galen Malformation:
The following diagnostic tests may be performed in the evaluation:
- Pre-natal Ultrasound - Often the dilated “vein of galen” can be identified on a routine pre-natal screening US done in the 2nd trimester of pregnancy.
- Cranial Ultrasound - A neonatal cranial ultrasound can help identify and localize the lesion. Doppler studies can illustrate the blood flow of the lesion.
- Cranial MRI and/or CT Scan (performed with or without contrast medium) - Cranial imaging can assist in confirming the diagnosis of VGAM and determine whether hydrocephalus is present, as well. Non invasive MR angiography can provide very useful information for treatment planning.
- Cranial Angiography - cranial angiography is usually performed in the setting of endovascular treatment
- Cardiac Ultrasound - may be used to assess the severity of congestive heart failure.
Treatment of Vein of Galen Malformation:
The treatment requires the collaboration of many medical specialties including: neonatology, cardiology, anesthesiology, neurosurgery and neuro-interventional radiology.
In patients diagnosed as neonates, the timing of the treatment is largely determined by the severity of cardiac dysfunction present. In patients who are stable from a cardiac standpoint the treatment can be delayed for a few months allowing the baby to grow and better tolerate the procedure. However, in many cases due to severe cardiac failure the treatment is performed in the first several days of life.
Endovascular embolization is the preferred method of treatment. In an embolization, the abnormal blood vessels are intentionally closed with soft platinum coils or liquid embolic agents, which reduce the abnormal blood flow to the vein of Galen. Sometimes, several procedures are required over a period of several months.
Endovascular embolization with coils
Prognosis for Vein of Galen Malformation:
The prognosis depends upon how much organ (heart and brain) damage has been done prior to the embolization procedure. The earlier treatment is obtained, the better chances the patient has. Most patients who undergo successful embolization go on to lead normal lives.
In untreated patients the prognosis is poor. The disease is almost always fatal if untreated.