Arteriovenous malformation treatment

Arteriovenous malformation treatment

Arteriovenous malformation treatment

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🧠 Tangled Vessels 101

An Arteriovenous Malformation (AVM) is a congenital tangle of vessels where arteries connect directly to veins, bypassing the capillary bed. This creates a high-flow, high-pressure central nidus, prone to rupture and cause intracranial hemorrhage (ICH).

Cerebral AVM angiogram with nidus and draining vein

Spetzler-Martin Grading Scale (predicts surgical risk):

  • Size of Nidus:
    • <3 cm: 1 pt
    • 3-6 cm: 2 pts
    • 6 cm: 3 pts

  • Eloquence of Brain Area:
    • Non-eloquent: 0 pts
    • Eloquent: 1 pt
  • Venous Drainage Pattern:
    • Superficial only: 0 pts
    • Deep: 1 pt

⭐ The annual hemorrhage risk for an unruptured AVM is 2-4%. Risk is higher if previously ruptured or associated with an aneurysm.

💣 Diagnosis - Finding the Ticking Bomb

  • Clinical Presentation:

    • Intracranial Hemorrhage (ICH): Most common (~50%), often a sudden, severe "worst headache of life."
    • Seizures: New-onset, particularly in a young adult.
    • Focal Neurological Deficits (FNDs): Weakness, sensory loss, aphasia.
    • Headaches: Chronic, often pulsatile or migraine-like.
  • Imaging Pathway:

    • Acute: Non-contrast CT to rapidly detect hemorrhage.
    • Non-invasive: CT Angiography (CTA) or MR Angiography (MRA) to visualize the vascular tangle.
    • Gold Standard: Digital Subtraction Angiography (DSA) provides definitive diagnosis and is essential for treatment planning.

DSA of cerebral AVM showing nidus and draining veins

⭐ AVM is the most common cause of spontaneous intracerebral hemorrhage in children and young adults.

🧠 Management - Untangling the Knot

  • Goal: Obliterate the nidus to prevent hemorrhage while preserving function. Decision balances treatment risk vs. natural history, guided by the Spetzler-Martin (SM) Grade (Size, Venous Drainage, Eloquence). Multimodality therapy is common.
ModalityMechanismBest ForProsCons
MicrosurgeryDirect excision of nidusSmall, superficial, non-eloquent AVMs (SM Grade I-II)Immediate & high rate of cureInvasive; risk of intra-op bleed, neuro deficit
EmbolizationEndovascular glue/coils to block feeding arteriesAdjunct to surgery/SRS; palliative for high-grade AVMsMinimally invasive; reduces nidus size/flowRarely curative alone; risk of stroke, vessel perforation
SRSFocused radiation induces thrombosisSmall (<3 cm), deep, eloquent AVMsNon-invasiveDelayed effect (1-3 yrs); hemorrhage risk during latency; radiation necrosis

Treatment Algorithm:

AVM treatment modalities by patient and AVM type

⚠️ Complications - When Things Go Wrong

  • Untreated AVMs:
    • Re-hemorrhage (highest risk in 1st year)
    • Seizures, hydrocephalus, vasospasm
  • Treatment-Related:
    • Microsurgery: Infection, new neurological deficits
    • Embolization: Embolic stroke, vessel perforation
    • SRS: Radiation necrosis (delayed), hemorrhage before obliteration

Normal Perfusion Pressure Breakthrough (NPPB): Post-resection, chronically hypo-perfused brain tissue is suddenly exposed to normal arterial pressure. Loss of autoregulation leads to vasogenic edema, hemorrhage, and seizures.

⚡ Biggest Takeaways

  • The primary goal of AVM treatment is preventing hemorrhage, the most feared complication, especially in young adults.
  • Microsurgical resection is the gold standard for accessible AVMs, providing an immediate and definitive cure.
  • Stereotactic radiosurgery (SRS) is ideal for small (<3 cm), deep, or eloquent-area AVMs; obliteration takes 1-3 years.
  • Endovascular embolization is typically an adjunctive therapy to reduce AVM size and blood flow before surgery or SRS.
  • Treatment choice is guided by the Spetzler-Martin grade.

Practice Questions: Arteriovenous malformation treatment

Test your understanding with these related questions

A 72-year-old woman comes to the physician for follow-up care. One year ago, she was diagnosed with a 3.8-cm infrarenal aortic aneurysm found incidentally on abdominal ultrasound. She has no complaints. She has hypertension, type 2 diabetes mellitus, and COPD. Current medications include hydrochlorothiazide, lisinopril, glyburide, and an albuterol inhaler. She has smoked a pack of cigarettes daily for 45 years. Her temperature is 37°C (98.6°F), pulse is 90/min, respirations are 12/min, and blood pressure is 145/85 mm Hg. Examination shows a faint abdominal bruit on auscultation. Ultrasonography of the abdomen shows a 4.9-cm saccular dilation of the infrarenal aorta. Which of the following is the most appropriate next step in management?

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Flashcards: Arteriovenous malformation treatment

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Schwannomas are treated with _____ and/or stereotactic radiosurgery

TAP TO REVEAL ANSWER

Schwannomas are treated with _____ and/or stereotactic radiosurgery

resection

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