Cerebral arteriovenous malformation rarely causes symptoms unless the blood vessels rupture. Sudden onset of a severe headache is the most common initial symptom; usually, it is the worst headache one has ever experienced.

Other symptoms of cerebral arteriovenous malformation may include:

• Numbness in one arm or leg:
• Arm numbness (unilateral)
• Leg numbness (unilateral)
• Arm and leg numbness (unilateral)
• Weakness in one arm or leg:
• Arm weakness (unilateral)
• Leg weakness (unilateral)
• Arm and leg weakness (unilateral)
• Difficulty speaking
• Difficulty swallowing
• Difficulty walking
• Facial numbness (unilateral)
• Facial weakness
• Vertigo

Additional symptoms of a leaking or ruptured cerebral arteriovenous malformation include:

• Loss of consciousness
• Nausea
• Vomiting
• Neck stiffness
• Vision loss
• Confusion
• Lethargy:
• Excessive sleepiness
• Seizure