Vein of Galen

At Boston Children's Hospital, we know that a diagnosis of a brain abnormality, especially one as rare as vein of Galen malformation (VOGM), can be frightening experience. You probably have many questions and concerns, such as:

• What are the risks and benefits of surgical procedures for VOGM?
• Will my child have normal neurological and cognitive development?
• What is the long-term outlook for my child?

We’ve provided answers to commonly asked questions in the following pages, and our doctors will explain your child’s condition and treatment options to you in more detail during your appointment.

What is a vein of Galen malformation (VOGM)?

• VOGM is a form of an arteriovenous malformation (AVM), which is an abnormal connection between the arteries (blood vessels that carry blood from the heart to the body) and the veins (blood vessels that return blood to the heart).

• All AVMs involve high-pressure, fast-flow blood that travels from the arteries directly into the veins (which are designed to handle low-pressure) and then directly to the heart at the same high-pressure and fast speed.  This rapid blood flow in AVMs is due to the absence of capillaries, small blood vessels located between the arteries and veins that act to slow down the flow of blood, allowing oxygen to enter the tissues.

• VOGM affects the median vein, which is only present in the first 6 – 11 weeks of gestation before it disappears and contributes to the development of the true vein of Galen, one of the main deep veins of the brain. VOGMs are different than most other AVMs because they form so early in pregnancy and are usually diagnosed soon after the baby is born.

• VOGM often presents itself with heart failure in newborns, although other organs can also be affected, leading to potential kidney and liver dysfunction.

• Injury to the brain may or may not be present already at the time of diagnosis, even if the condition is discovered during pregnancy. The extent and severity of injury to the brain is an important factor to weigh in deciding how aggressively to treat VOGM. In order to avoid the development of such brain injury, we aim to treat VOGM by age 6 months whenever possible.

• In a small number of cases, VOGM may be undiagnosed in infancy, and is thus left untreated.  Some of these undiagnosed children present later in childhood or even in early adulthood with new headaches or other neurologic symptoms.

How serious is VOGM?

VOGM is a life-threatening condition. However, survival rates have improved significantly since the 1980s, when more modern techniques used for treating the disorder (in particular, endovascular techniques) were developed.  Most children with VOGM will do very well if their brains have not been permanently injured and their other organs are intact, either developing entirely normally, or else having mild developmental delay.

Unfortunately, if there is already multi-organ damage at the time of diagnosis, the chance that a newborn will recover is very low. If the brain has already been severly injured, there is a very low chance that the child will have normal neurological and cognitive development.

Causes

What caused my child to develop VOGM?

VOGM is a congenital disorder, which means it is present at birth. This malformation develops early on in pregnancy because it forms in the median vein, which is only present during weeks 6-11 of fetal development. After that time window, the median vein disappears and contributes to the development of the true vein of Galen, one of the important deep veins of the brain.

There is no single identifiable reason why a child develops this malformation. However, the majority of cases are sporadic, which means that the condition is not inherited and is not linked to any known problems or environmental exposures during pregnancy. In a minority of cases, there are mutations causing more widespread vascular malformations in the body, and some of these conditions are associated with an increased risk of VOGM.

Symptoms

What are the symptoms of VOGM?

Symptoms of VOGM can show up at different ages and vary depending on the severity of the malformation.

Neonates - newborns

• The most severe forms of VOGM involve the highest and fastest flow of blood between arteries and veins.  

• In these cases, the defect may is most often diagnosed in newbornswho experience rapid onset of heart failure, typically between days 1 and 3 of life. 

• The increased stress on the heart may also lead to an increased workload on other organs, leading potentially to pulmonary hypertension, liver failure and kidney failure.

• Significant brain damage may occur as a result of the brain’s inability to properly drain its venous outflow.

Newborns - children

Less severe symptoms of VOGM, which can show up at a variety of ages, include:

• subacute to chronic cardiac problems that result from the change in circulation that occurs once the baby is born, when the heart struggles to pump enough blood to the entire body.

• hydrocephalus (buildup of fluid in the brain) because the high venous pressures generated by the VOGM interferes with the normal flow and absorption of the cerebrospinal fluid. An early sign of hydrocephalus is increasing head circumference.

• prominent veins on the face

• As the high-pressure blood flows from the arteries directly to the veins in the VOGM, the entire system of veins in the brain becomes pressurized, the brain tissue starts to look for alternative ways to send blood back to the heart for re-oxygenation.

• Normally, there are many very small connections between the veins draining the brain and  the head and neck and scalp veins. As the main venous pathways of the brain become pressurized by the VOGM, these connections with the face and scalp veins grow and the brain can start draining out of facial veins, making them appear prominent.

• failure to meet developmental milestones:

• A fast-flow VOGM that doesn’t cause heart failure might not be detected and treated early on. If this is the case, it is possible that the infant will stop meeting his expected developmental milestones because of the chronically high venous pressure interfering with normal brain perfusion.

• These developmental delays can range from exteremly mild to potentially very severe limitations. They can include gross motor difficulties, fine motor difficulties, language delay, and general cognitive disabilities.

Late childhood - early adulthood

It is also possible that a VOGM will escape detection entirely until late childhood or early adulthood, appearing at that time with symptoms such as:

• seizures
• severe headache
• in rare cases, a bleed in the brain

Does VOGM affect life expectancy?

Children who are treated early and have normal development or only mild delays lead full lives. There is no evidence to suggest that such patients have a shortened lifespan.  Most patients we treat fall into this category. Unfortuntely, newborns with severe multi-organ damage at the outset have a very low chance of recovery. If significant brain damage has already occurred at presentation, there is a very low chance of achieving meaningful neurocognitive development.

Questions to ask your doctor

You will probably have many questions on your mind before meeting with your child’s doctor. At the appointment, it can be easy to become overwhelmed with information and forget the questions you wanted to ask.

Parents often find it helpful to jot down questions beforehand. That way, when you talk to your child’s clinician, you can be sure that all your concerns are addressed. Remember that physicians are open to learning from families too. Attend conferences, read up on updated materials and don’t be afraid to share what you have learned.

Some questions you might ask include:

• What treatment will my child need?
• What are the risks of these procedures?
• What’s in store for my child’s future cognitive development?
• What other resources can you point me to for more information?