| Popis: |
The vein of Galen malformations (VGAM) are rare form of embryonic arteriovenous shunt located in the midline in the choroidal fissure. They are complex arteriovenous (AV) fistulas that occur infrequently. Their incidence is about one in 3 million population, and they represent less than 1% of the cerebral AV malformation. It consists of multiple feeding arteries, principally the anterior and posterior choroidal arteries and the anterior cerebral artery, draining directly into an enlarged venous pouch. VGAMs are occasionally detected on antenatal ultrasound scans (from about 25 week’s gestation) as apparently cystic midline brain lesions, colour flow Doppler then suggesting a VGAM. Antenatal magnetic resonance imaging will confirm the diagnosis and allow assessment of any pre-existing damage to the brain. It will also allow treatment planning with delivery at a centre with the appropriate facilities and expertise, principally fetal medicine, neonatology, paediatric cardiology and intensive care, and interventional neuroradiology. More commonly VGAMs are diagnosed after birth. Often delivery and the first 24 hours are unremarkable. Larger shunts may then show rapid deterioration with progressively worsening cardiac failure leading on to multiorgan failure. A smaller shunt may present later with mild cardiac failure and failure to thrive. Commonly, initial investigations seek a cardiac cause for the high output failure. When cardiac examination is normal, transfontanelle ultrasound will detect the VGAM. |
