Ruptured Arteriovenous Malformation Anterior to the Brainstem to a Child with Subsequent Spontaneous Thrombosis: Case Report and Literature Review

Abstract

BACKGROUND Cerebral arteriovenous malformations (AVMs) are considered to be abnormalities of congenital origin, presumably arising due to a disorder in the process of embryogenesis, in the phase of differentiation of premature vascular domes into mature arteries, capillaries, and veins. The end result of that process is the formation of direct arteriovenous communications, without intervening capillary beds. CASE REPORT We report the case of a 6-year-old female who suffered an abrupt deterioration of her level of consciousness due to a subarachnoid hemorrhage located in the basal cisterns. Radiological investigation with magnetic resonance arteriography-magnetic resonance venography (MRA-MRV) was negative, but digital subtraction angiography (DSA) revealed a micro-AVM in the vicinity of the brainstem. The patient subsequently developed communicating hydrocephalus and the repeat DSA, performed 1 month later, failed to re-imagine the lesion. Further workup with DSA 1 year after the ictus was negative for pathological findings. CONCLUSIONS There are a lot of controversies regarding the optimal imaging modality for surveillance of pediatric AVMs, the time period needed to follow-up a given lesion, even if it is considered treated, and the underlying mechanism of spontaneous thrombosis of untreated, yet ruptured, AVMs. All these issues, along with the unusual mode of evolution of the clinical picture of this lesion are discussed in detail, along with a review of the available literature.

Figure 1.

Initial CT scan, showing the thrombus within the fourth ventricle, as well as blood accumulated within the basal cisterns anterior to the brainstem. CT – computed tomography.

Figure 2.

Same CT scan as Figure 1 visualizing a blood clot of adequate dimensions and longitudinally shaped, within the third ventricle. CT – computed tomography.

Figure 3.

CT scan performed the following day depicting the persistence of the blood clot within the fourth ventricle and the incipient dilation of the temporal horns. CT – computed tomography.

Figure 4.

Same CT scan as Figure 3 depicting blood clot within the third ventricle and the dilation-rounding of the frontal horns, indicative of ongoing hydrocephalus. CT – computed tomography.

Figure 5.

Sagittal MRI scan, CUBE FLAIR sequence, depicting blood within the fourth ventricle and in the basal cisterns anterior to the brain stem. MRI – magnetic resonance imaging; FLAIR – fluid-attenuated inversion recovery; CUBE FLAIR – the General Electric (GE) name of their sequence and not an acronym.

Figure 6.

Axial MRI scan, axial T2* GRE, revealing hemosiderin deposition within the third magnetic resonance imaging ventricle. MRI – magnetic resonance imaging; GRE – gradient echo.

Figure 7.

Sagittal view, 3D MRV depicting no abnormal findings. 3D MRV – 3-dimensional magnetic resonance venography.

Figure 8.

Axial MRI, FSPGR sequence, depicting no abnormalities. MRI – magnetic resonance imaging; FSPGR – fast spoiled gradient echo.

Figure 9.

MRA, 3D TOF, failed to visualize any area of abnormality. MRA – magnetic resonance arteriography; 3D TOF – 3-dimensional time-of flight.

Figure 10.

Early arterial phase of the initial DSA, visualizing an AVM (black arrow) in the territory supplied by branches of the vertebro-basilar system. We mention the dominance of the right-left-vertebral artery. DSA – digital subtraction angiography; AVM – arteriovenous malformation.

Figure 11.

Late arterial phase of the same DSA, depicting again the AVM (black arrow). DSA – digital subtraction angiography; AVM – arteriovenous malformation.

Figure 12.

DSA of the right vertebral artery, depicting no abnormal imaging findings. DSA – digital subtraction angiography.

Figure 13.

Repeat, after 1 month, DSA, early arterial phase. No AVM is imagined. DSA – digital subtraction angiography; AVM – arteriovenous malformation.

Figure 14.

Same DSA, as previously, at late arterial phase. Again, the AVM is not depicted. DSA – digital subtraction angiography; AVM – arteriovenous malformation.