Occlusion and stenosis of unspecified middle cerebral artery

This code signifies a blockage or narrowing within an unspecified segment of the middle cerebral artery. This condition restricts blood flow to parts of the brain, potentially leading to ischemic stroke or transient ischemic attack (TIA).

Apply this code when documentation clearly indicates occlusion or stenosis of the middle cerebral artery, but the specific segment (e.g., M1, M2) is not identified. This diagnosis is typically supported by imaging studies such as MRI, CT angiography, or cerebral angiography, along with neurological examination findings.

• Avoid using this code if the specific segment of the middle cerebral artery is documented; instead, use a more precise code from the I66.0- series.
• Always code the sequelae (e.g., stroke, TIA) if present, linking it to this underlying cause.
• Ensure documentation specifies "unspecified" or lacks detail regarding the segment to justify this code.