What are the other Names for this Condition? (Also known as/Synonyms)

• Developmental Venous Anomalies of the Brain
• Venous Angioma of the Brain
• VM of the Brain

What is Venous Malformations of the Brain? (Definition/Background Information)

• Venous Malformations (VM) of the Brain is a collection of abnormally-enlarged veins draining into a large vein in the brain. The pattern of vein development in this condition resembles the snakes on Medusa’s head (Greek mythology) and is often described as “caput medusae”
• In the brain, the network of veins work to drain the organ of deoxygenated blood. The venous malformations (or venous angiomas) are developmental anomalies that grow gradually and are considered benign. Although aberrant in structure, they are still functional and fully-integrated with the venous system
• In most cases, Venous Malformations of the Brain arises sporadically, with spontaneous mutation(s) in the TIE-2 gene. The mutation is not passed on to the next generation and exists only in the affected tissue. The risk factors for these spontaneous mutations are not known
• It is believed that in some cases, the TIE-2 mutations are inherited. Therefore, having a family history of the condition may be a risk factor for being diagnosed with the malformation
• Venous malformations are caused by errors in the formation of veins during fetal development. The vein walls in the brains of affected individuals also have insufficient smooth muscle cells, which may contribute to development of the anomaly
• Since the aberration in veins occurs during fetal development, the condition is present at birth, although it may not be manifested until adolescence or even later, when a rapid growth may be seen
• The signs and symptoms of Venous Malformations of the Brain may include hemorrhage, blood clot formation, ischemic stroke, and epilepsy. In some cases, the condition may remain silent and present no symptoms
• Since the condition develops gradually, it may often go undiagnosed. The diagnosis is made by physical examination, assessment of symptoms (if any), evaluation of personal and family medical history, through imaging studies, such as CT or MRI scans, and cerebral arteriography
• Venous Malformations by itself may not give rise to many complications, if it is solitary (seen in about 75% of the cases). However, in combination with other lesions, such as cavernous malformations (in about 20% the cases), many complications are known to arise, such as bleeding in the brain, numbness, paralysis, and speech and memory problems
• Since Venous Malformations of the Brain are typically benign, the general policy of management is a “wait and watch” approach. However, if there is a possibility of a mixed vascular malformation, such as coexistence with a cavernous malformation, then the treatment options may include surgical removal of the anomaly
• The number and location of Venous Malformations of the Brain, as well as the presence of other vascular malformations, determines its overall prognosis. In many cases, if venous malformations are solitary, the prognosis is typically good

Who gets Venous Malformations of the Brain? (Age and Sex Distribution)

• The exact prevalence of Venous Malformations of the Brain is not known. It accounts for over half of all cerebral vascular malformations. Based on the number of cases diagnosed, the condition is uncommon
• Venous Malformations of the Brain is a developmental disorder that is present at birth. However, manifestation of the signs and symptoms of the condition may never occur in some cases. In others, it may occur during adolescence or even in adulthood
• The disorder can occur in both male and female sexes

What are the Risk Factors for Venous Malformations of the Brain? (Predisposing Factors)

• The risk factors for Venous Malformations of the Brain are not known, since many cases occur sporadically
• In the small percentage of cases where it is known to run in families, a positive family history of the condition may be a risk factor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Venous Malformations of the Brain? (Etiology)

In majority of cases of Venous Malformations of the Brain, the cause is unknown.

• In a few instances, the condition is caused by mutation(s) in the TIE-2 gene, which in turn leads to errors in the development of veins in the brain during gestation
• Under normal circumstances, the TIE-2 gene codes for a receptor. This receptor is regulated by factors known as angiopoietins, which play a role in the development of blood vessels during gestation and after birth
  • The binding of angiopoietin 1 to the receptor sets forth a signaling mechanism that promotes the formation and stabilization of blood vessels
  • The binding of angiopoietin 2 to the TIE-2 receptor has the opposite effect, and results in the destabilization of cell-cell connections and blood vessels
• A mutated or deficient TIE-2 receptor most likely leads to disruption in the formation of blood vessels causing venous malformations. In most cases, the TIE-2 genetic mutation occurs sporadically, and exists only in the affected tissue
• In a few instances, the condition runs in the family and may be inherited. Generally, TIE-2 mutations pertaining to vascular malformations are inherited in an autosomal dominant fashion

Autosomal dominant: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly function gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring.

What are the Signs and Symptoms of Venous Malformations of the Brain?

In some individuals, Venous Malformations of the Brain can exist without presenting any symptoms. When symptoms do occur, they may include:

• Headaches
• Bleeding in the brain
• Weakness in arms or legs or both
• Vision problems, such as double vision
• Problems with balance
• Impaired memory
• Speech impediment
• Seizures
• Ischemic stroke (owing to a blood clot)

How is Venous Malformations of the Brain Diagnosed?

In many cases, the diagnosis of Venous Malformations of the Brain is made incidentally, as the condition can exist asymptomatically in an affected individual. However, when the manifestation does occur, the condition is diagnosed by the following tools:

• A thorough physical examination and an assessment of symptoms
• An evaluation of the affected individual’s personal and family medical history
• Cerebral arteriography:
  • This test provides information on the location and characteristics of the feeding arteries and draining veins, as well as blockages
  • A thin tube is threaded up towards the brain and inserted into an artery in the groin; a dye is injected through this thin tube. The dye provides a contrast for X-ray analysis of the affected organ/area
• Computerized tomography (CT) scans of the brain; it may include CT angiogram that may be performed with a dye injection
• Magnetic resonance imaging (MRI) of the brain; it may include MRI angiogram with an injected dye
• Digital subtraction angiography (DSA), which allows the medical professional to view the blood vessels against bones or soft tissues of the brain
• Since venous malformations can coexist with cavernous malformations (or cavernomas), it should be ruled out with specific imaging tests for cavernomas

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Venous Malformations of the Brain?

Venous Malformation of the Brain is a benign condition and by itself, it does not cause many complications. However, in combination with other vascular malformations, such as cavernomas, the following complications can ensue:

• Venous thrombosis and hemorrhage
• Hydrocephalus (fluid buildup around the brain)
• Brain damage

A damage to the brain may result in the following:

• Stroke
• Seizures
• Difficulty in speaking
• Weakness, numbness
• Loss of vision
• Unsteadiness that may be very severe
• Paralysis on one side of the body
• Scoliosis
• Benign brain tumors
• Lesions on the skin
• Intellectual impairment and problems with memory

How is Venous Malformations of the Brain Treated?

The treatment of Venous Malformations of the Brain depends on each individual’s specific condition. 

• In some, treatment may not be necessary; it can be limited to just monitoring the malformation, since bleeding is rarely observed
• If venous malformations coexist with cavernous malformations of the brain, the treatment usually does not involve excision or radiation, since it can cause venous thrombosis and death
• In such cases, the treatment shall be planned by the healthcare provider on assessment of the overall condition

How can Venous Malformations of the Brain be Prevented?

The occurrence of Venous Malformations of the Brain cannot be prevented, as it occurs sporadically in most cases, with no known risk factors. 

• In cases where a family history exists, genetic testing of prospective parents followed by genetic counseling may help them understand the risks better
• Once diagnosed, a careful and regular monitoring of the condition by a healthcare professional is highly recommended

What is the Prognosis of Venous Malformations of the Brain? (Outcomes/Resolutions)

• Venous Malformations of the Brain may not cause any symptoms in some cases. Also, complications are only rarely noted. According to some studies, the rate of complication is around 0.15% per year (i.e., approximately 1 in 670 cases per year develop complications)
• In general, the prognosis is good, if the condition occurs by itself and is not seen to be associated with other tumors or lesions in the brain
• However, in cases where venous malformations are part of a combination of conditions, such as cavernous malformations of the brain, severe complications can lead to reduced quality of life; it can also be fatal

Additional and Relevant Useful Information for Venous Malformations of the Brain:

• Dandy-Walker malformation (DWM) is a rare, congenital malformation of the brain that includes the cerebellum and the fluid filled spaces around it

The following link may help you find useful additional information on Dandy-Walker malformation:

http://www.dovemed.com/diseases-conditions/dandy-walker-malformation/