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Vertebrobasilar Insufficiency

Vertebrobasilar Insufficiency is a topic covered in the 5-Minute Emergency Consult.

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  • Vertebrobasilar (VB) vascular system feeds the posterior region ofthe brain, which includes the brainstem, cerebellum, and inner ear
  • 2 vertebral arteries (VA) derive from subclavian arteries and give rise to the anterior spinal artery and then join to form the basilar artery
  • Arteries supplying the brainstem and cerebellum originate from the VB system before it branches into the 2 posterior cerebral arteries (PCA), such that a wide variety of focal neurological deficits arise from VB circulatory dysfunction
  • Vertebrobasilar insufficiency (VBI) results in inadequate perfusion of VB arterial circulation from thrombotic, embolic, or low-flow states


  • Mechanism:
    • Thrombosis:
      • VB ischemia due to underlying VB atherosclerosis and clot formation
    • Embolus:
      • VB ischemia due to embolization of clot from proximal location
    • Low-flow states:
      • Hypoperfusion of VB system from systemic (e.g., cardiogenic shock) or localized (e.g., subclavian steal) reduction in blood flow
    • Less common etiologies:
      • Fibromuscular dysplasia
      • Hypercoagulable states
  • Ischemic mechanisms causing VB insufficiency can herald and lead to VB territory infarcts
  • Severe episodes of VB hypoperfusion or loss of circulation can lead to:
    • “Locked-in” syndrome:
      • Quadriplegia (eyelid or eye movement only) with intact consciousness
    • “Top-of-basilar” syndrome:
      • Pontine and cerebellar dysfunction with diminished level of consciousness

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Rosen, Peter, et al., editors. "Vertebrobasilar Insufficiency." 5-Minute Emergency Consult, 5th ed., Lippincott Williams & Wilkins, 2016. Emergency Central, emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307061/all/Vertebrobasilar_Insufficiency.
Vertebrobasilar Insufficiency. In: Rosen P, Shayne P, Barkin AZ, et al, eds. 5-Minute Emergency Consult. 5th ed. Lippincott Williams & Wilkins; 2016. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307061/all/Vertebrobasilar_Insufficiency. Accessed April 25, 2019.
Vertebrobasilar Insufficiency. (2016). In Rosen, P., Shayne, P., Barkin, A. Z., Wolfe, R. E., Hayden, S. R., Barkin, R. M., & Schaider, J. J. (Eds.), 5-Minute Emergency Consult. Available from https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307061/all/Vertebrobasilar_Insufficiency
Vertebrobasilar Insufficiency [Internet]. In: Rosen P, Shayne P, Barkin AZ, Wolfe RE, Hayden SR, Barkin RM, Schaider JJ, editors. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2016. [cited 2019 April 25]. Available from: https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307061/all/Vertebrobasilar_Insufficiency.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Vertebrobasilar Insufficiency ID - 307061 ED - Rosen,Peter, ED - Shayne,Philip, ED - Barkin,Adam Z, ED - Wolfe,Richard E, ED - Hayden,Stephen R, ED - Barkin,Roger M, ED - Schaider,Jeffrey J, BT - 5-Minute Emergency Consult UR - https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307061/all/Vertebrobasilar_Insufficiency PB - Lippincott Williams & Wilkins ET - 5 DB - Emergency Central DP - Unbound Medicine ER -