Arteriovenous malformation of precerebral vessels

This code represents an abnormal, tangled connection between arteries and veins in the vessels supplying the brain, specifically before they enter the brain itself. This congenital vascular anomaly bypasses the normal capillary bed, leading to direct shunting of blood.

Use this code when documentation confirms an arteriovenous malformation (AVM) affecting the precerebral arteries and veins, such as those in the neck (e.g., carotid or vertebral arteries). This diagnosis is typically made through imaging studies like angiography, MRI, or CT scans.

• Distinguish carefully between precerebral (extracranial) and cerebral (intracranial) AVMs; intracranial AVMs are coded elsewhere.
• Ensure documentation specifies "precerebral" or provides anatomical detail confirming an extracranial location.
• Consider sequencing this code as the primary diagnosis if the AVM is the reason for the encounter, or as a secondary diagnosis if it's a comorbidity.