A newborn has been brought with seizures refractory to treatment and a continuous bruit through the anterior fontanelle. CT shows midline lesion with hypoechogenesity and dilated lateral ventricles. Most probable diagnosis is?
ANSWER: (B) Vein of Galen malformationREF: Nelson Textbook of Pediatrics 17th edition page 1974, 2037, Wolfgang Dahnert Braindisorders. In: Radiology review manual 5th edition. Lippincott Williams and Wilkins, Phoenix,AZ 2002; 326-327.Vein of Galen aneurysmal malformationsVein of Galen aneurysmal malformations (VGAM) and Vein of Galen aneurysmal dilations (VGAD), which are the most frequent arteriovenous malformations in infants and fetusesVGAM consisted of a tangled mass of dilated vessels supplied by an enlarged artery. The malformation increases greatly in size with age, although the mechanism of the increase is unknown. Dilation of the great cerebral vein of Galen is a secondary result of the force of arterial blood either directly from an artery via an arteriovenous fistula or by w^ay of a tributary vein that receives the blood directly from an artery.Malformations often lead to cardiac failure, cranial bruits (pattern 1), hydrocephaly, and subarachnoid hemorrhage in neonatesPatients with smaller communications may not have cardiovascular manifestations but may later be disposed to hydrocephalus or seizure disordersArteriovenous malformations of the middle cerebral artery or vein of Galen may produce a loud bruit most prominent over the anterior fontanel, temporal region, or the orbits and are best heard through the diaphragm of the stethoscope.Testing for a malformed vein of Galen is indicated when a patient has heart failure which has no obvious cause. Diagnosis is generally achieved by signs such as cranial bruits and symptoms such as expanded facial veins. The vein of Galen can be visualized using ultrasound or Doppler.Contrast enhanced axial CT scan or MRI of the brain usually demonstrates a well-defined, multilobulated, intensely enhancing lesion, located within the cistern of velum interpositum. Dilatation of the ventricular system, periventricular white matter hypodensities as well as diffuse cerebral atrophy is the commonly associated findings.Treatment depends on the anatomy of the malformation as determined by angiography or Magnetic Resonance Imaging (MRI)Neurosurgical procedures to relieve hydrocephalus are important. A ventriculoperitoneal shunt may be required in some infants. Recent advances over the past few decades have made endovascular embolization the preferred method of treatment.A pediatric cardiologist should be consulted to manage high-output failure, if present.Seizures usually are managed with antiepileptic medicationsVein of Galen malformations are difficult to treat and are associated with a poor prognosis.
Teratoma
Vein of Galen malformation
Arachnoid cyst
Encephalocele
Seizures in Childhood and Conditions that Mimic Seizures