Aneurysm of Vein of Galen - Pathophysiology, Clinical Presentation, Diagnosis, and Treatment

What Is Aneurysm of Vein of Galen?

Aneurysm of the vein of Galen is a congenital anomaly. It is an arteriovenous malformation where the drainage is in the already-formed dilated vein of Galen. It drains the front and middle portions of the brain into the posterior cerebral fossa sinus. Aneurysm of the vein of Galen (VGAM) is seen in children, resulting in congestive heart failure, seizures, developmental delays, and hydrocephalus.

What Is the Pathophysiology of the Aneurysm of the Vein of Galen?

Aneurysm of the vein of Galen is an arteriovenous malformation. It is an autosomal dominant disorder, and the RASA1 gene causes the mutation. It causes arteriovenous shunting (abnormal connection of artery and veins in which blood flows directly from the artery into the vein) of the blood. It is a congenital (present at the time of birth) malformation that develops during 6 to 11 weeks of fetal life. The malformation occurs in the prosencephalic vein of Markowski, which is the precursor for the development of the vein of Galen. The anterior portion of the vein shrinks as the internal cerebral vein develops, and the posterior part persists as the vein of Galen.

Aneurysm of the vein of Galen results in ischemic changes in the brain, causing stroke or progressive hemiparesis (weakness or inability of the body to move on one side). Aneurysm of the vein of Galen also causes many other neurological disabilities or impairments. It also obstructs the cerebrospinal fluid, causing hydrocephalus. In addition, cardiac failure in children is often seen due to high blood flow in the intracranial lesion. Bleeding can occur though it is an unusual finding.

What Is the Epidemiology of the Aneurysm of the Vein of Galen?

This intracranial vascular malformation is mainly seen in the pediatric population. The age group ranges from 1 to 3 years. Aneurysm of the vein of Galen is the most common intracranial vascular malformation diagnosed by doctors in babies before birth. It has an equal preference for males and females.

What Is the Classification of the Aneurysm of the Vein of Galen?

The most commonly seen classification system is mentioned below:

• Yasargil Classification - Classified as type 1, type 2, type 3, and type 4.

• Lasjaunias Classification - Classified as choroidal and mural types.

What Is the Clinical Presentation of the Aneurysm of the Vein of Galen?

The symptoms of the disease may appear during pregnancy, before birth, or after delivery. With the help of antenatal ultrasound, the condition can now be diagnosed antenatally (before birth) during the third trimester of pregnancy. The clinical symptoms differ according to the type of malformation and the age at which it is present.

• Neonate - Choroidal type of aneurysm of the vein of Galen is primarily seen in neonates. Congestive heart failure, bluish discoloration of the skin (cyanosis), respiratory disturbances, and rapid breathing (tachypnea) are commonly seen. Ventilator support is required after birth, and the doctor should quickly manage cardiac failure in these patients.

• Infant - The mural type of aneurysm of the vein of Galen is primarily seen in infants. Due to venous insufficiency, hydrocephalus may occur in infants. Since hydrocephalus is a common finding in infants, sunset eyes (eyes are focused down, and the upward view is blocked) and prominent scalp veins may be present.

• Child - The mural type of aneurysm of the vein of Galen is mainly seen in children. Hydrocephalus and developmental delay are common findings. Headaches and seizures are also noted in the patients.

What Are the Diagnostic Tests for an Aneurysm of the Vein of Galen?

Imaging Tests

• Antenatal Ultrasound - Antenatal ultrasound is done before delivery, majorly during the third trimester. The vein is dilated and hence appears black in the ultrasound.

• Cranial Ultrasound - The cranial ultrasound helps in the identification and localization of the lesion. It also helps to understand the lesion's hemodynamics (blood flow pattern in the arteries and veins).

• Cranial MRI (Magnetic Resonance Imaging) - The cranial MRI helps to confirm the diagnosis and the extent of lesion involvement with the brain. It also ensures the presence of hydrocephalus in infants.

• CT (Computed Tomography) With or Without Contrast Administration - The computed tomography scan also confirms the presence of an aneurysm of the vein of Galen and its extension as a lesion.

• Magnetic Resonance Angiography (MRA) - It is an imaging technique that provides images of the brain's blood vessels and helps diagnose aneurysms or any other blood vessel defects.

• Cranial Angiography - Cranial angiography provides the area of extension of aneurysmal dilatation.

• Cardiac Ultrasound - It is done to check the functions of the heart.

• Other Tests - ECG (electrocardiogram) is done to prevent congestive cardiac failure.

What Is the Treatment for an Aneurysm of the Vein of Galen?

• Medical Care - Cardiac management is vital as heart failure is often seen. Patients are intubated, and seizures, if present, are managed with antiepileptic medicines. Drug of choice for seizure management is Phenytoin and Phenobarbitol. Infants should be checked for the presence of hydrocephalus and any developmental abnormalities.

• Surgical Care - Endovascular embolization is the treatment of choice as it avoids the need for open surgeries with more complications. In this technique, a catheter (tiny and flexible tube) is placed through the skin into the artery. A dye is injected into the catheter so the blood vessels can be easily seen in the images. Once the doctors identify the surgery site, they seal it with glue, coils, and balloons. Embolic glue, N-butyl-cyanoacrylate, is the material of choice. It is called coil embolization if detachable coils are used to seal the blood vessels. Pressure is exerted on the brain due to hydrocephalus, and the ventriculoperitoneal shunt technique is performed to relieve that pressure. It helps in the drainage of the excess cerebrospinal fluid from the brain.

• Follow-Up - Reimaging should be done for patients who have undergone surgeries to check the results of surgical intervention. Head circumference measures should be taken periodically to check for hydrocephalus.

What Is the Differential Diagnosis of an Aneurysm of the Vein of Galen?

• Neonatal Seizures.

• Vascular Intracranial Tumor.

• Cavernous Sinus Syndromes.

• Cerebral Venous Thrombosis.

• Cerebral Palsy.

• Intracranial Hemorrhage.

• Intellectual Disability.

Conclusion

The aneurysm of the vein of Galen is a congenital condition seen in infants and neonates with high mortality rates. It is the most common arteriovenous malformation seen in neonates. The disease outcome or prognosis is poor due to cardiac and cerebral anomalies.