Cavernoma of the brain and spinal cord

A cavernoma is a small tangle of abnormally built blood vessels sitting inside nervous tissue. Their walls are thin, blood moves through slowly, and on a scan the tangle looks like a blackberry: many tightly packed blood-filled spaces, anything from a couple of millimetres to several centimetres across. The same thing goes by other names — cavernous angioma, cavernous haemangioma, cerebral cavernous malformation. It is not a tumour: it does not invade neighbouring tissue and does not spread. What matters is a different property: because the walls are thin, it leaks blood from time to time, and where it sits decides whether that goes unnoticed or shows up as neurological problems.

How common a finding it is

Cavernomas are commoner than people assume: in population imaging studies they turn up in roughly one person in two hundred. Almost all of them feel nothing and would never have known, were it not for a scan done for some other reason — after a bump on the head, or for migraine or dizziness. Only a minority develop symptoms, most often between the ages of twenty and forty. So news of a cavernoma almost never means trouble here and now: usually it is a cue to work calmly through the risk figures.

How it makes itself known

What shows up depends less on size than on place. In the brainstem the pathways to the whole body run through a tiny patch of tissue, so even a drop of blood there causes clear problems, while a similar bleed in a hemisphere may pass off almost unnoticed.

• epileptic seizures, the commonest first sign when the tangle lies in the hemispheres; these may be convulsive or take the form of brief blanks, strange smells or a sense of the already-seen;
• headaches that have changed their usual pattern;
• weakness or numbness in the arm and leg on one side, a drooping face;
• slurred speech, difficulty finding words, choking on food;
• double vision, unsteadiness, dizziness, trembling hands — typical of the brainstem and cerebellum;
• fatigue and trouble with memory and concentration;
• with a cavernoma in the spinal cord, weakness and numbness in the legs, band-like pain and difficulty passing urine.

Symptoms often come in waves: a small leak makes things worse, the blood is reabsorbed and things improve. That takes weeks or months, and recovery can be nearly complete.

When the clock counts in hours

A large bleed is rare, but it is the dangerous one. Call the emergency services at once if there is:

• a sudden severe headache unlike any before, especially with vomiting and dislike of light;
• weakness, numbness or clumsiness in the arm and leg on one side, a drooping face, disturbed speech — the same as in a stroke, and it must be treated the same way;
• sudden double vision, loss of sight, inability to stand or walk;
• a first-ever convulsive seizure, a seizure lasting more than five minutes, or seizures one after another;
• increasing drowsiness, confusion or loss of consciousness;
• rapidly worsening leg weakness and retention of urine with a known spinal cavernoma.

Waiting for a booked appointment is not an option here: a bleed from a cavernoma can only be told apart from a stroke of another kind on a scan, and the time limits for treatment are tight either way.

Where it comes from

In most people the cause is unknown and the tangle is a single one: such cavernomas simply arise, with no family history. In about one case in five the form is inherited. It passes on in an autosomal dominant way, meaning a one-in-two chance of passing it to a child; the person usually has several lesions and new ones may appear over the years. Faults in three known genes are responsible, and genetic testing separates the inherited form from the sporadic one where that matters for family planning. The first hint comes from the scan itself: several lesions in a young person.

There is also an acquired cause that few people know about: cavernomas can appear in an area that received radiotherapy to the head, sometimes ten years or more after treatment, and most often in those irradiated as children. If that is in your history, say so plainly to the doctor even if it was a long time ago.

Injury, stress, physical exertion and high blood pressure do not create a cavernoma — that belief is a stubborn myth.

How it is found

There is essentially one reliable method: magnetic resonance imaging using sequences sensitive to traces of blood, on which old micro-bleeds show as dark dots and which often reveal small additional lesions. A computed tomography scan will show a fresh bleed but misses small cavernomas. Angiography usually comes back normal: the flow through the tangle is too slow for contrast to outline it.

Alongside a cavernoma there is often a developmental venous anomaly, a vein with an unusual layout. It is harmless in itself, but the surgeon must know about it in advance: that vein drains healthy brain and must not be touched. If a cavernoma was found by chance and causes nothing, routine repeat scans are usually unnecessary, since neither the size of the lesion nor its growth predicts bleeding well. Imaging is repeated when new symptoms appear.

How great the risk of bleeding is

This is the main question, and the answer turns above all on one circumstance: whether there has been a bleed before.

• if the cavernoma was found by chance and has never bled, the chance of haemorrhage is put at under one per cent a year;
• if it has bled, the risk of another bleed over the next few years is much higher — by various estimates from a few per cent up to around a quarter a year, and that spread honestly reflects how differently cavernomas behave;
• the raised risk does not stay for good: it peaks in the first year or two after a bleed and then falls away;
• a brainstem location worsens the outlook, not because it bleeds more often but because every episode costs more.

Risk depends hardly at all on the size of the tangle: a large cavernoma bleeds no more often than a small one. Decisions about intervening rest on these figures, not on the impression the scan makes.

What can be offered

For most people the sensible approach is observation and treatment of symptoms rather than surgery. Seizures are kept in check with antiepileptic medicines, and for many that is enough; ordinary painkillers are chosen for headache, avoiding daily use; after a bleed, rehabilitation and work with a physiotherapist and a speech therapist help.

Surgical removal is discussed when a cavernoma has bled more than once, when seizures do not respond to medicines, or when the lesion can be reached without much damage. Surgery is the only way to remove the risk entirely, but its own risk is real, up to a lasting neurological deficit, and grows the deeper the tangle lies. Stereotactic radiosurgery — targeted irradiation without an incision — remains contested: the evidence that it reduces bleeding is weak, and it is mainly considered where conventional surgery would be too dangerous.

Questions that come up almost every time. Blood-thinning medicines are not automatically forbidden with a cavernoma: the observations gathered so far show no rise in bleeding, and the decision is made individually, weighing why those medicines are needed. Exertion, flying and altitude do not trigger bleeds. Pregnancy and delivery are discussed with a neurologist and an obstetrician; a cavernoma by itself is not a reason for a caesarean. Fitness to drive depends not on the finding but on seizures and neurological problems, and the rules are local ones — check them with your own doctor.

Online consultation

A remote appointment suits this subject unusually well, because what people need is most often an explanation rather than a procedure. The doctor will go through the scan report in plain words, judge from your symptoms and the images which risk group you fall into, and explain when an operation is even on the table and what to ask a neurosurgeon. Separately you can draw up a plan in case of a seizure and discuss testing of relatives and how the finding fits with your medicines and your work. For the acute symptoms listed in the urgent section an online appointment will not do: immediate in-person care and a scan are needed.

This material is for information only and does not replace medical advice.