Not All Patients with a Headache need a CT Scan, but they should be Listened to, and also with a Stethoscope: A Report of a Large Arteriovenous Malformation with a Loud Cranial Bruit

Abstract

Background: Arteriovenous malformations (AVMs) are abnormal direct connections between arterial and venous systems, without an interposed capillary bed. This permits high-flow arteriovenous shunting, which precipitates structural changes in the afferent and efferent vessels, namely arterial smooth muscle hyperplasia and thinning of venous walls. Patients with intracranial AVMs typically present with a haemorrhage, headache or seizure. Treatment is either via medical management aimed at control of seizures, headache and blood pressure, or interventional via surgical, radiation or radiologically guided embolisation.

Case description: We report the case of a woman in her early 40s presenting with a tonic-clonic seizure against a background of a 31-year history of migraine and an 18-month history of tremors in her right arm. The clinical examination was remarkable for an extremely loud cranial bruit and a right homonymous hemianopia. Imaging diagnosed an 8 cm Martin-Spetzler grade V intracranial arteriovenous malformation in her left parietal lobe, which was deemed unsuitable for operative or radiotherapy-based intervention.

Conclusion: The patient was managed through observation and relatively good control of her breakthrough seizures was achieved through the addition of brivaracetam to her lamotrigine and carbamazepine-based therapy, six years after her initial presentation.

Learning points: Arteriovenous malformations may go undetected for decades.The presence of a cranial bruit is an important sign and tool in diagnosing an intracranial arteriovenous malformation. The presence of a homonymous hemianopia, of which a patient may be unaware, helps to localise an intracranial lesion.The risks of operative or radiological intervention must be balanced with the risks of haemorrhage or refractory seizure when adopting a strategy for the treatment of an intracranial arteriovenous malformation. Good control of epileptic symptoms in those deemed not suitable for operative or radiological intervention can be achieved by careful titration of anti-seizure medications.

Keywords: Arteriovenous malformation; Martin-Spetzler; cranial bruit; epilepsy; homonymous hemianopia.

Figure and Video 1

Axial CT brain with contrast showing a large intracranial arteriovenous malformation (8×6×5 cm) in the posterior left parietal lobe. It extends from the vertex almost to the tentorium cerebelli and is associated with large, calcified draining veins. The associated transverse sinuses are shown to be markedly enlarged. No significant mass effect or midline shift is shown. There is additionally some marked vascular indentation shown at the inner diploe of the skull consistent with a large chronic arterial supply and venous drainage. https://youtu.be/cifohV4NUAY

Figure and Video 2

Coronal MRI brain showing a large intracranial arteriovenous malformation in the left parietal lobe of Spetzler-Martin Grade V. The vascular nidus is shown to extend into the left temporal and occipital lobes and to be of 8 cm in anteroposterior diameter, 4 cm in transverse diameter and 5 cm in depth. Extensive gliosis of the adjacent parenchyma is shown in addition to evidence of venous hypertension and congestion in the cortical draining veins. https://youtu.be/xZUuHgdcGDQ

Figure and Video 3

Left internal carotid angiogram showing a large intracranial arteriovenous malformation in the left parietal lobe of Spetzler-Martin grade V. It shows arterial supply from the left anterior cerebral artery, right cavernous carotid artery, left middle cerebral artery, left external carotid artery, left posterior cerebral artery and left anterior inferior cerebellar artery. It additionally shows both superficial and deep venous drainage and aneurysmal pedicles from both the left anterior cerebral artery and left posterior cerebral artery. https://youtu.be/56Zpc6NNqe0

Figure 4

MRI brain and MRI cerebral angiography 3-D axial performed six years after Figure 2 and Video 2, showing a large intracranial arteriovenous malformation in the left parietal lobe with no significant change in size, gliosis of adjacent neural parenchyma or evidence of venous hypertension.