Arteriovenous Malformation

Arteriovenous Malformation
SYMPTOMS Headaches | seizures | mental impairment | reduced vision due to retinal ischemic events | orbital pain | orbital pressure | diplopia | ocular redness
SIGNS Pulsatile proptosis | EOM restriction | Dilated conjunctival and episcleral vessels in a corkscrew configuration | Conjunctival chemosis | Elevated IOP | Tortuous retinal veins | Retinal hemorrhages
WORK-UP Thorough history | Pupils | EOMs | Slit lamp examination | Dilated retinal examination | Exophthalmometry | Check for orbital bruit (Ocular auscultation)
TREATMENT Refer to a neuro-ophthalmologist STAT for additional testing and treatment. Treatment is usually conservative but surgery is an option: surgical resection, radiation therapy, or embolization.
FOLLOW-UP After seeing neuro-ophthalmogist, patients should be followed every 6-12 months
ADDITIONAL LAB | TESTS Testing will typically be ordered through the neuro-ophthalmologist: MRI of the brain and orbits with and without contrast | MRA | Selective orbital angiography
ETIOLOGY Typically congenital. AV malformations tend to form due to high flow communications between enlarged arteries and veins that bypass normal capillary beds. A characteristic nidus is typically noted.
DIFFERENTIAL DX Sturge-Weber syndrome | von Hippel-Lindau disease | hereditary hemorrhagic telangiectasias | capillary retinal hemangioma | thyroid eye disease | idiopathic orbital inflammation | scleritis
NOTES Often associated with Wyburn-Mason syndrome. Signs and symptoms are typically not experienced in childhood but experienced later on in life as the orbital AVM grows. Orbital AVMs expand slowly but factors such as trauma and pregnancy can speed up growth.