# Cerebral Arteriovenous Malformation > Cerebral arteriovenous malformation for NEET-PG Medicine covers haemorrhage or seizure presentation, Spetzler-Martin grading and the choice of treatment. - Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/cerebral-arteriovenous-malformation - Exam / course: NEET-PG · Subject: Medicine - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-15 - Last updated: 2026-10-15 - Reference basis: Adams and Victor's Principles of Neurology; Greenberg's Handbook of Neurosurgery - How to cite: "Cerebral Arteriovenous Malformation", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/cerebral-arteriovenous-malformation ## Direct answer A cerebral arteriovenous malformation is a congenital tangle of abnormal arteries and veins joined directly through a nidus, without an intervening capillary bed. It most often presents with intracranial haemorrhage or seizures, and the bleeding risk is the main reason for treatment. Spetzler-Martin grading, based on size, eloquence and deep venous drainage, predicts surgical risk and guides the choice between surgery, embolisation and radiosurgery. ## What you must remember - **Architecture:** a nidus of abnormal vessels with direct arteriovenous shunting, so the high-pressure arterial flow enters the venous system without a capillary bed. - **Presentation:** haemorrhage is the commonest presentation in adults, with seizures, headache and focal deficits as the other common modes. - **Bleeding risk:** unruptured lesions carry a lower but continuing annual risk of haemorrhage, which is the main long-term concern. - **Spetzler-Martin grade:** a sum of three scores, size (under 3 cm scores 1, 3 to 6 cm scores 2, over 6 cm scores 3), eloquent location (1) and deep venous drainage (1), giving grades I to V. - **Surgical risk:** grades I and II carry low surgical risk, grade III moderate risk, and grades IV and V high risk, so they are often managed without immediate surgery. - **Embolisation:** endovascular embolisation is usually adjunctive before surgery or radiosurgery and rarely cures the lesion alone. - **Radiosurgery:** stereotactic radiosurgery suits small or deep lesions, with obliteration taking two to three years. - **Imaging:** MRI with contrast shows the nidus and prior bleeds, while digital subtraction angiography defines the feeding arteries and venous drainage. ## Grading a lesion before choosing treatment A 26-year-old man presents with a lobar haemorrhage, and angiography shows a 4 cm nidus in the non-dominant temporal cortex with superficial venous drainage. Grading the lesion is the step that decides the treatment pathway. 1. **Confirm the angioarchitecture:** Digital subtraction angiography defines the nidus, the feeding arteries and the venous drainage before any treatment is chosen. 2. **Score the size:** A 4 cm lesion is medium and scores 2, since small lesions score 1 and large lesions over 6 cm score 3. 3. **Score the location and drainage:** A non-dominant temporal nidus is non-eloquent and has superficial drainage, so each scores 0. 4. **Assign the grade:** The total of 2 gives grade II, which carries low surgical risk. 5. **Choose the treatment:** Microsurgical resection is the usual option for a low-grade lesion, with embolisation as an adjunct, and radiosurgery is kept for high-risk or deep lesions. In this patient the grade is II, so surgical resection is usually preferred. The same scoring applied to a deep, eloquent lesion would move the grade up and change the answer. ## Where the exam tries to catch you Most lost marks come from treating the grade as a fixed prognosis or misreading the role of embolisation. - **Trap:** Operating on every unruptured AVM because it might bleed. — **Correct:** The ARUBA trial suggested that medical management alone can outperform intervention in selected unruptured lesions, so risk must be weighed. - **Trap:** Taking a grade V lesion to mean immediate surgery is needed. — **Correct:** High-grade lesions are usually managed without immediate surgery, often with radiosurgery or observation. - **Trap:** Calling embolisation a cure. — **Correct:** Embolisation alone rarely obliterates an AVM, so it is usually an adjunct before resection or radiosurgery. - **Trap:** Confusing a vein of Galen malformation with an ordinary AVM. — **Correct:** Vein of Galen malformation is a neonatal high-flow shunt presenting with heart failure, not adult haemorrhage. ## Frequently asked questions ### What is the Spetzler-Martin grade of a cerebral AVM? The Spetzler-Martin grade is the sum of three scores: size (1 for under 3 cm, 2 for 3 to 6 cm, 3 for over 6 cm), eloquent location (1 if present) and deep venous drainage (1 if present). Grades run from I to V, and higher grades carry greater surgical risk. ### What is the commonest presentation of a cerebral arteriovenous malformation? Intracranial haemorrhage is the commonest presentation of a cerebral arteriovenous malformation in adults. Seizures, headache and focal deficits are the other common presentations, and haemorrhage is also the main reason for treatment. ### Which investigation defines the angioarchitecture of a cerebral AVM? Digital subtraction angiography defines the angioarchitecture of a cerebral AVM, showing the nidus, feeding arteries and venous drainage. MRI with contrast shows the lesion and any prior haemorrhage but gives less detail of flow. ### When is stereotactic radiosurgery used for cerebral AVM? Stereotactic radiosurgery is used for small or deep cerebral AVMs where open surgery carries high risk. Obliteration is slow, with a latency period of two to three years, so follow-up imaging is needed while the lesion remains active. ### How does a vein of Galen malformation differ from a cerebral AVM? A vein of Galen malformation is a neonatal high-flow arteriovenous malformation that presents with heart failure rather than adult haemorrhage. A typical cerebral AVM is a parenchymal nidus that most often presents in adults with haemorrhage or seizures.