Presentation
Sudden onset vertigo, nausea and grogginess.
Patient Data
Extensive intraventricular blood is demonstrated, filling the fourth ventricle, third ventricle refluxing into the frontal horns of the lateral ventricles. Only a tiny amount is seen pooling dependently within the occipital horns. No convincing subarachnoid blood is identified. Hydrocephalus is present. The brain is otherwise unremarkable in appearance.
A globular region of arterial enhancement is demonstrated just to the left of midline, within the vermian sulci which presumably represents a distal PICA aneurysm measuring 3mm. No definite vascular intracranial abnormality identified.
A dominant left vertebral artery supplies a large left PICA. A 3.0 x 2.5mm aneurysm arises from the distal left PICA, pointing posteriorly. A branch of the PICA then goes on to supply a tangle of abnormal vessels measuring approximately 1cm diameter, located adjacent to the medial left transverse sinus. This results in early venous shunting into the transverse sinus, with some reflux into the contralateral sinus. Branches from the left posterior cerebral, superior cerebellar and posterior meningeal arteries also appear to supply the vascular malformation. The right vertebral artery is hypoplastic, predominantly terminating in the right PICA with only minor supply to the basilar artery. There is no significant left AICA demonstrated. No supply from the anterior circulation is vident.
Comment: Probable left posterior fossa pial AVM with supply from left PICA, PCA and SCA, and 3mm flow related left PICA aneurysm representing the likely source of IVH.
Blood is seen in the fourth ventricle (V4), ascending via the aqueduct of Sylvius (AS) into the third ventricle (V3) and into the frontal horns of the lateral ventricles (FH). The ventricles are distended, consistent with hydrocephalus, best seen as dilatation of the temporal horns (TH).
On CTA a 3mm 'blob' of contrast is seen near the midline on the left (red arrow), which on angiography is seen to arise from an enlarged PICA (red dotted line), which is contributing to a superficial arteriovenous malformation (yellow dotted line) posteriorly.
The patient went on to have attempted endovascular treatment, however this was technically not possible. They proceeded to surgery and had the vascular malformation removed and the aneurysm clipped.
Case Discussion
Intraventricular hemorrhage should be investigated for an underlying vascular lesion, especially in younger patients. Occasionally no source can be found, and in older individuals it is attributed to a hypertensive bleed with essentially no parenchymal component, the blood having decompressed into the ventricles.