Last reviewed: March 2019
Last updated: January  2018



History and exam

Key diagnostic factors

  • sudden-onset focal neurologic deficit
  • seizures
  • reduced conscious level

Other diagnostic factors

  • sudden-onset headache
  • nausea
  • vomiting
  • confusion
  • gradual-onset headaches
  • hypertension
  • coma
  • gradual-onset focal neurologic deficit
  • cognitive dysfunction

Risk factors

  • familial (malformation)
  • previous hemorrhages (risk of hemorrhage)
  • drug abuse (risk of hemorrhage)
  • abnormal venous drainage (risk of hemorrhage)
  • small AVMs (risk of hemorrhage)
  • posterior fossa and deep AVMs (risk of hemorrhage)
  • coexisting aneurysms (risk of hemorrhage)
  • seizures (risk of hemorrhage)
  • pregnancy (risk of hemorrhage)
  • hypertension (risk of hemorrhage)

Diagnostic investigations

Investigations to consider

  • brain digital subtraction angiogram
  • brain CT angiogram
  • brain MR angiogram
  • CBC
  • clotting screen and group
  • electrolyte panel
  • drug toxicology screen
  • functional imaging
  • superselective Wada
  • neuropsychology
  • perfusion studies
  • EEG
  • visual fields
Full details

Emerging tests

  • 4D CT angiography (CTA)/MR angiography (MRA)
Full details

Treatment algorithm


Authors VIEW ALL

Director of Medical Studies (Neurosurgey)

Assistant Professor

Section of Neurovascular Surgery

Departments of Neurosurgery & Diagnostic Radiology

Yale University, School of Medicine

Yale University HHT Center

Brain Aneurysm & AVM Program and Stroke Program

Yale-New Haven Hospital

New Haven



CM declares that he has no competing interests.

Dr Charles Matouk would like to gratefully acknowledge Dr Catherine E. Gilkes and Dr Richard J. Edwards, the previous contributors to this monograph, and the additional contribution of Dr Branden Cord and Dr Ryan Hebert. CEG and RJE declare that they have no competing interests.

Peer reviewers VIEW ALL


Professor of Neurosurgery

Department of Neurosurgery

Technical University of Munich




BM declares that he has no competing interests.

Assistant Professor of Neurology

Neurosurgery and Radiology

Rush University Medical Center




MC declares that he has no competing interests.

Research Director

Stroke Center/The Neurological Institute

Columbia-Presbyterian Medical Center

New York



JHC declares that he has no competing interests.

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