Abstract
Introduction Isolated bilateral thalamic congestion due to an arteriovenous malformation (AVM)
is a rare entity. Few case reports of dural arteriovenous fistula associated with
it have been reported in the literature. The association of pial arteriovenous fistula
(pial AVF) with thalamic hyperintensities has never been described before. The pial
AVF is a recently recognized lesion in which the multiple pial arterial feeders drain
into a single venous channel without a nidus like in conventional AVM. In spite of
being congenital in origin, these lesions may have expression in adulthood due to
abrupt change in the venous drainage system. Successful management of pial AVF associated
with bilateral thalamic hyperintensities is described here with review of the literature.
Case Presentation A 60-year-old man presented with rapidly progressive gait disturbance and cognitive
decline. Magnetic resonance imaging (MRI) showed hyperintensities in the thalami on
T2-weighted and fluid attenuated inversion recovery image. Digital subtraction angiography
revealed a pial AVF near the splenium of corpus callosum. It had feeders from posterior
choroidal arteries and drained into the vein of Galen through an abnormal mesencephalic
vein. The stagnation and increase of pressure in the deep venous system led to congestion
in the thalami. He was treated by partial transarterial embolization of the feeders
followed by gamma knife therapy (GKT). The clinical symptoms and MRI improved rapidly
after embolization and further reduction in shunt flow was observed after GKT.
Conclusion Strong suspicion of vascular malformation as a cause of bilateral thalamic hyperintensities
helps in early detection. Such lesions like pial AVF presented here require active
intervention by surgery or endovascular therapy. GKT is an important adjuvant in lesions
refractory to either of them.
Keywords
bilateral thalamic hyperintensities - embolization - gamma knife - pial arterio-venous
fistula - venous congestion
