The vein of Galen malformation is a rare blood vessel malformation in the brain that develops before birth and is sometimes diagnosed in the womb or soon after birth. The vein itself is a large deep vein at the base of the brain that takes away oxygen-depleted blood. However, in this malformation, capillaries that normally slow blood flow and permit oxygen exchange with the surrounding tissues are missing, and so blood rushes directly from arteries into veins.
The vein of Galen malformation can be detected by brain scans via magnetic resonance imaging (MRI) and computer tomography (CT). Digital subtraction angiography, a test that uses x-rays and a special dye to see inside the arteries, is another diagnostic method a doctor can use.
In the more severe cases, the blood overload goes almost directly to the heart and rapidly overwhelms it, leading to congestive heart failure. Depending on the severity of the condition, it may show up in several ways:
- In newborns with congestive heart failure (sometimes the condition is noted in ultrasound before birth)
- Infants with abnormally enlarging head and developmental delay (the enlarged head occurs because the malformation blocks the normal flow or absorption of cerebrospinal fluid)
- Older children with a large head and possibly seizures and/or strokes; sometimes learning difficulties are noted
The best treatment for the malformation seems to be embolization rather than surgery. In embolization, the surgeons thread a small catheter, or tube, into an artery (femoral) up to the site of the malformation. With the catheter in place, the doctors insert a substance that blocks the blood flow through the malformation and forms a clot that closes it off. The embolization treatment may require several procedures to gradually close off the blood flow. However, when it is completed successfully, patients usually do very well.