Cavernous Malformations – Symptoms and Causes
Overview
Cerebral cavernous malformations (CCMs) are abnormal clusters of blood vessels that appear in the brain or spinal cord.
These malformations resemble small mulberries and contain slow-moving, often clotted blood within their thin-walled vessels. CCMs typically measure less than 1 centimeter in diameter.
Most CCMs occur sporadically as single malformations without family history. However, about 20% of cases are familial, meaning they run in families due to genetic mutations.
People with the familial form often develop multiple CCMs throughout their brain or spinal cord.
CCMs represent one type of vascular malformation affecting the brain. Other types include:
- Arteriovenous malformations (AVMs)
- Dural arteriovenous fistulas
- Developmental venous anomalies (DVAs)
- Capillary telangiectasias
Individuals with sporadic CCMs commonly have both a CCM and a DVA present simultaneously.
The primary concern with CCMs is their potential to leak blood, causing hemorrhage in brain or spinal tissue. These bleeds can trigger various symptoms depending on their location and severity. Seizures are a common result of CCM-related hemorrhages.
When CCMs form in certain areas, they may produce stroke-like symptoms, including:
- Movement difficulties
- Sensory problems in the legs and sometimes arms
- Bowel and bladder dysfunction
The symptoms and potential complications vary based on the CCM’s size, location, and whether bleeding has occurred. Medical imaging is typically needed to confirm the presence of these vascular malformations and determine appropriate management.
Signs and Symptoms
People with cerebral cavernous malformations (CCMs) may not always have symptoms. When CCMs form on the brain’s outer surface, they can trigger seizures.
CCMs in different brain areas cause various symptoms. For example, if they occur in the spinal cord, brainstem, or basal ganglia (inner brain), symptoms will differ.
Bleeding in the spinal cord might affect bowel and bladder control or cause movement or sensation problems in the arms or legs.
Common symptoms of CCMs include:
- Seizures
- Severe headaches
- Arm or leg weakness
- Numbness
- Speech difficulties
- Memory and attention problems
- Balance and walking difficulties
- Vision changes, including double vision
Symptoms can worsen over time if bleeding happens repeatedly. A second bleed might occur shortly after the first one or much later. Some people never experience another bleeding episode.
When To Get Medical Help
If you have any seizure symptoms, seek immediate medical attention. Also get emergency care if you experience any signs that might indicate a cerebral cavernous malformation or bleeding in the brain.
Causes
Cerebral cavernous malformations (CCMs) typically occur in two main forms. The more common type is the sporadic form, which appears as a single malformation without any family connection.
These sporadic CCMs often develop alongside a developmental venous anomaly (DVA), which looks like an irregular vein with a distinctive “witch’s broom” pattern.
About 20% of CCM cases are genetic and run in families. This is called familial cavernous malformation syndrome. People with this inherited form usually have multiple malformations rather than just one. Blood or saliva tests can confirm this genetic condition.
Genetic testing is particularly important for people who show:
- Multiple CCMs on an MRI without a DVA
- Family members who also have CCMs
CCMs can sometimes develop 2-20 years after radiation treatment to the brain or spinal cord. In rare cases, CCMs may appear as part of other uncommon syndromes.
Risk Factors
Cerebral cavernous malformations (CCMs) often occur without a clear cause. However, the familial form can lead to multiple CCMs initially and over time.
Research has identified three genetic changes linked to inherited CCMs. Most familial cases can be traced to these specific genetic changes:
- KRIT1 (also known as CCM1)
- CCM2
- PDCD10 (also known as CCM3)
These genes play important roles in blood vessel function. They affect:
- How leaky blood vessels become
- The proteins that hold blood vessel cells together
When a person inherits a change in one of these genes, they have a higher risk of developing multiple CCMs throughout their lifetime.
Complications
Repeated bleeding, or hemorrhages, from cerebral cavernous malformations (CCMs) can lead to serious health problems. These recurring bleeds may cause hemorrhagic stroke and result in nervous system damage.
People who have experienced previous hemorrhages face a higher risk of future bleeding events. The location of the CCM also matters significantly. CCMs found in the brainstem area have a greater likelihood of bleeding again compared to those in other brain regions.
