The vessel responsible to bilateral cerebellar infarction
Case 107
【Progress】He continued to receive rehabilitation in our hospital. However, unfortunately, he passed away one month later. He had suffered from vertigo when he awakened at bed since he was admitted in our hospital.
【Discussion】
Of the three arteries supplying the cerebellum, posterior inferior cerebellar artery (PICA) is the largest in size and most crucial in clinical medicine. PICA irrigate not only the posterior inferior part of the cerebellum hemisphere (neo-mammalian brain) but also vermis (paleo-mammalian brain), and nodulus and flocculus (reptilian brain) (1). According to different input-information routes of neurological information, cerebellum hemisphere is called pons-cerebellum, vermis is called spinal cerebellum and nodulus and flocculus are called vestibular cerebellum (1). Cerebellum hemisphere has developed greatly for human erection and walking with two legs. It gets neurological (command) information from cerebral cortex via pons through middle cerebellar peduncle and gives it to cerebrum cortex and spinal cord through superior cerebellar peduncle to thalamus and red nucleus, respectively. Vermis functions coordination of muscle tonus against gravitation strength. Vermis compares the intended command from cerebral cortex with the sensations from spinal cord, leading to motor coordination. Vermis gets neurological information from spinal cord through inferior cerebellar peduncle and give it to spinal cord through superior spinal cord. Nodulus and flocculus get neurological information from vestibular nerve through inferior cerebellar peduncle and vestibular nucleus and give it to vestibular nerve nucleus (vestibular-cerebellum circuit) through inferior cerebellar peduncle (1). As a result, occlusion of PICA causes the damages of pons cerebellum, spine cerebellum and vestibular cerebellum, inducing ataxia and vertigo.
PICA has two main branches: lateral branch and medial branch. The lateral branch irrigates posterior inferior part of cerebellar hemisphere and can communicate with branches from superior cerebellar artery (SCA) and anterior inferior cerebellar artery (AICA). Meanwhile, the medial branch of PICA irrigates vestibular cerebellum and spinal cerebellum and a part of pons cerebellum and least communication with branches of SCA and AICA (1). Bilateral cerebellar infarction irrigated the medial branches of PICA has getting often encountered through MRI prevalence (2-8). The infarction of bilateral territory of the medial branch of PICA can be occurred in two situations: one, occlusion of one single vertebral artery with two medial branches: another one, occlusion of two medial branches from one dominant vertebral artery (2-8). The etiology of the occlusion is atherosclerotic thrombus or embolus.
In our case, bilateral cerebellum infarction including vermis, nodulus and flocculus were found in CT and MRI corresponded to territory of bilateral medial branch of PICA. Compared between BPAS and MR angiography (MRA), BPAS showed the existence of right vertebral artery and right PICA (Fig. 6C) and no visualization of the left PICA but MRA showed severe stenosis of the right vertebral artery and occlusion of the right PICA (Fig. 6A and 6B), implying that one PICA which divides two medical branches is occluded, leading to bilateral cerebellar infarction.
【Summary】
We present a seventy nine-year-old male suffering from vertigo, headache, vomiting and disturbance of standing up and walking. CT and MRI showed bilateral cerebellar infarction corresponded to the irrigation area of the medial branch of PICA. BPAS showed the existence of the right vertebral artery and the right PICA but MRA showed the occlusive stenosis of the right vertebral artery and no visualization of one single (right) PICA, which probably irrigate bilateral medial branch territory. It is borne in mind that bilateral cerebellar infarction occur in case of occlusion of one single vertebral artery or occlusion of a dominant PICA which irrigate the territories of the medial branches of both PICAs. Further, PICA irrigate the pons cerebellum, spinal cerebellum and vestibular cerebellum.
【References】
1.Peter Duus. Neuroloigisch-topische Diagnostik: Anatomie Physiologie Klinik, second edition translated in Japanese by Hajime Handa and Junya Hanakita. Bunkodo, Tokyo
2.Tada YMizutani TNishimura TTamura MMori N Acute bilateral cerebellar infarction in the territory of the medial branches of posterior interior cerebellar arteries. Stroke.1994;25:686-688.PubMedGoogle Scholar
3.Han SW, et al. Bilateral cerebellar infarction caused by dominant medial posterior inferior cerebellar artery. Neurology 2006;66:1125–1126
4.Brusa L et al. Bilateral simultaneous cerebellar infarction in the medial branches of the posterior interior cerebellar artery territories. Ital J Neurol Sci.1996;17:433-466.PubMedGoogle Scholar
5.Sorenson EJ et al. Acute bilateral infarcts of the posterior inferior cerebellar artery. J Neuroimaging.1997;7:250-251.PubMedGoogle Scholar
6.Kang DW, et al. Acute bilateral cerebellar infarcts in the territory of posterior inferior cerebellar artery. Neurology.2000;55:582-584.PubMedGoogle Scholar
7.Gaida-Hommernick B et al. Bilateral cerebellar infarctions caused by a stenosis of congenitally unpaired posterior inferior cerebellar artery. J Neuroimaging.2001;11:435-437.PubMedGoogle Scholar
8.Gurer G et al. Acute bilateral cerebral infarction in the territory of medial branches of posterior inferior cerebellar arteries. Clin Neurol Neurosurg.2001;103:194-196.PubMedGoogle Scholar
2018.6.6