Cerebral arteriovenous malformation

Disease Description (Causes and Symptoms)

• Definition/Pathophysiology: This is a disease in which the capillary network that should normally exist between the arteries and veins in the brain is absent, resulting in the formation of a cluster of blood vessels (nidus) that directly connects the arteries to the veins. It consists of feeding arteries, a nidus, and draining veins; high-pressure arterial blood is directly transmitted to the veins, increasing the risk of bleeding.
• Cause: It is usually congenital, although changes or onset in adulthood have rarely been reported.
• Main symptoms: Headache, migraine, seizures (epilepsy), focal neurological deficits (such as paralysis and speech impairment), pulsatile tinnitus (vascular bruit), and acute neurological symptoms caused by cerebral hemorrhage. Symptoms vary depending on the size, location, characteristics of the draining veins, and history of hemorrhage.
• Risk of hemorrhage: The annual rupture rate is generally reported to be approximately 2–4%; the risk of rebleeding is higher in people with a history of prior hemorrhage.

Treatment Methods

• General principles: Depending on the lesion’s size, location, anatomy, the patient’s age, and symptoms (such as a history of hemorrhage or seizures), a multidisciplinary team (neurosurgery, endovascular, and radiosurgery teams) develops an individualized treatment plan.
• Main treatment options
  • Microsurgery (complete resection through craniotomy): It produces excellent results as a curative treatment when the lesion is superficial and has a low Spetzler‑Martin grade (small and located in a nonfunctional area).
  • Endovascular embolization: An embolic material is used to occlude the feeding artery or nidus. Cases that can be cured with this alone are limited, and it is often used as an adjunctive treatment before surgery or radiosurgery.
  • Stereotactic radiosurgery (e.g., Gamma Knife, LINAC): Suitable for small niduses (generally 3 cm or less), it gradually induces vascular occlusion over several months to several years. Complete occlusion takes time, and the risk of hemorrhage remains during that period.
  • Conservative management (observation): Considered when the patient is asymptomatic, the risk of rupture is low, or the risks of treatment are high.
• Medication and symptom management
  • Anticonvulsants: Used to control seizures. There is no curative medication for the lesion itself.
  • Blood pressure management: Managing hypertension to control the risk of hemorrhage.
  • Symptomatic treatment, including pain and headache management.
  • Whether to use anticoagulants or antiplatelet agents should be decided carefully by considering the risk of hemorrhage and other underlying diseases—do not start or stop them without medical advice.
• Possible complications: Hemorrhage, neurological deficits, recurrence or subsequent hemorrhage caused by a residual nidus after surgery, embolization, or radiosurgery, and radiation necrosis.
• Precautions (self-care)
  • Follow the designated treatment plan, and consult your attending physician about whether to take anticoagulants or antiplatelet agents.
  • Manage vascular risk factors such as hypertension, smoking, and excessive alcohol consumption.
  • If you have a history of seizures, discuss lifestyle guidelines with your doctor, including restrictions on driving and high-risk work.

Checklist Before an Outpatient Visit (Items to Bring and Sample Questions)

• Items to bring
  • A list of medications currently being taken (including dosage and administration times)
  • Copies of previous test results: CT, MRI, MRA, and cerebral angiography (DSA) image files (USB) or radiology reports
  • A record of recent changes in symptoms (seizure frequency and type, headache characteristics, newly occurring neurological symptoms, etc.)
  • Medical history (history of hemorrhage, surgical and anesthesia history), family history, and allergies (especially to contrast media)
  • For women, whether pregnancy is possible or planned
• Important information to tell the doctor in advance at the outpatient visit
  • Symptoms that have suddenly worsened recently (what the symptoms are and when they began)
  • Whether anticoagulants or antithrombotic agents are being taken
  • Details of seizures (whether loss of consciousness occurred, duration, and aura symptoms)

Examples of General Questions to Ask the Doctor

• "Why does my AVM need to be treated, and what are the expected risks if it is not treated?"
• "What treatment options are available in my situation, and what are the benefits and risks of each (hemorrhage, neurological injury, and recurrence rate)?"
• "What is the expected recovery period after surgery or a procedure, and when can I expect to return to daily activities?"
• "What medication do you recommend for seizure control, and what are its main side effects?"
• "I am planning a pregnancy; how should my AVM be managed if I have one?"

Examples of Disease-Specific Questions

• "What is the Spetzler‑Martin grade of my AVM, and specifically how does that grade affect the treatment decision?"
• "Considering the location, size, and characteristics of the draining veins of my AVM, what is the estimated annual rupture risk, and do you recommend active treatment even if I have no history of hemorrhage?"