Cavernomas are clusters of abnormal blood vessels mainly found in the brain and spinal cord.
They are sometimes known as cavernous angiomas, cavernous hemangiomas or cerebral cavernous malformations.
A typical cavernoma looks a bit like a blackberry. It is filled with blood that flows slowly through vessels that are like "caverns". Cavernomas vary in size, from a few millimetres to several centimetres across.
In the UK, many people diagnosed with a cavernoma won't have any symptoms, and the condition is only diagnosed after a magnetic resonance imaging (MRI) scan has been carried out for another reason.
However, even if you haven't had any noticeable problems by the time you are diagnosed, you may still develop symptoms at a later stage.
Who is affected
Cavernomas that haven't or won't cause symptoms are estimated to occur in about 1 in every 600 people in the UK.
Every year, roughly 1 person in every 400,000 in the UK is diagnosed with a cavernoma that has caused symptoms.
On average, most people who will develop symptoms will do so by the time they reach their 30s.
What causes cavernomas?
In most cases, there is no clear reason why a person develops a cavernoma.
Cavernomas can sometimes run in families, with every child of someone with inherited cavernomas having a 50% chance of inheriting the condition. However, for the majority of people, cavernomas occur as a one-off without affecting other family members.
Some cases have also been linked to radiation exposure, such as previously having radiotherapy to the brain (usually as a child).
What problems can they cause?
Problems that cavernomas can cause include:
slurred speech (dysarthria)
a type of stroke called a haemorrhagic stroke
These problems can occur because of the cavernoma pressing on certain areas of the brain, or as a result of the cavernoma bleeding.
The cells that line a cavernoma are often thinner than those lining normal blood vessels, which means cavernomas are prone to leaking blood. When a cavernoma does bleed, it is known as a haemorrhage.
In most cases, the bleeding is very small (half a teaspoonful, on average) and may not cause any symptoms. However, severe haemorrhages can be life-threatening and may lead to long-lasting problems.
You should seek medical help as soon as possible if you experience any of these symptoms for the first time.
Monitoring your symptoms
Any symptoms you have may come and go as the cavernoma bleeds and then reabsorbs blood. Monitoring your symptoms is important, because any new symptoms might be a sign of a haemorrhage.
Your doctor can advise you about what to do if you experience any new or worsening symptoms. They may also recommend having a further brain scan.
MRI and computerised tomography (CT) scans can be used to detect bleeding on the brain, although they cannot necessarily identify cavernomas that are at an increased risk of bleeding. This is because the features of a cavernoma that can be seen on a brain scan, such as an increase in size, don’t appear to be directly linked to the likelihood of bleeding.
Although cavernomas can get bigger, it's not thought that large cavernomas are any more likely to bleed than smaller ones.
What are the chances of a cavernoma bleeding?
The risk of having a haemorrhage varies from person to person, depending on whether you have experienced any bleeding before.
If you have not had any bleeding before, it's estimated that you have a less than 1% chance of experiencing a haemorrhage each year.
If your cavernoma has bled previously, your risk of having another haemorrhage is somewhere between 4% and 25% each year, although this risk decreases progressively over time if you don't experience any further bleeds, and eventually returns to the same level as that of people who have not had any bleeding before.
Your level of risk will be one of the main factors taken into consideration when deciding if you would benefit from treatment.
Some symptoms of cavernomas, such as seizures and headaches, can be controlled with medication.
However, more invasive treatment may sometimes be offered to reduce the risk of future haemorrhages. The decision to have such treatment is made on a case-by case-basis in discussion with your doctor.
Types of treatment that are used in the UK to reduce the risk of haemorrhages include:
neurosurgery – carried out under general anaesthetic to open up the skull and remove the cavernoma
stereotactic radiosurgery – where beams of radiation are aimed directly at the cavernoma to cause it to become thickened and scarred
Neurosurgery is preferred to radiosurgery in most cases, because it is not yet known exactly how effective stereotactic radiosurgery is at preventing haemorrhages. Stereotactic radiosurgery is usually only considered if the position of the cavernoma makes neurosurgery too difficult or dangerous.
Risks of invasive treatment include stroke and death, although the exact risks depend on the location of the cavernoma. Discuss the possible risks of treatment with your doctor beforehand.
International research programmes are trying to find the cause of this condition and how these defective blood vessels are formed. The long-term outlook for people with cavernomas is also being investigated.
For more information on cavernomas, visit the Cavernoma Alliance UK website.
MRI scan showing a cavernoma in the brain (highlighted in yellow)
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