Involved artery
Case 87
【Progress】
She was inhibited to take biaspirin and the following day, she started to get rehabilitation.
【Discussion】
Thalamus is a wall-nut-sized and egg-shaped nucleus composed of grey matter. In the thalamus, there is Y-shaped internal meddulary lamina which devides the thalamus largely into lateral, medial and anterior portions. Lateral portion includes pulvinar situated at the most dorsal site. Each portion is blood supplied mainly by branches of posterior cerebral artery. In short, anterior portion is supplied by polar artery (= tuberothalamic artery), medial portion, supplied by paramedian artery (= thalamic perforating artery), lateral portion, supplied by inferolateral artery (= thalamogeniculate artery) and pulvinar, supplied by posterior chroidal artery (1-3). Posterior chroidal artery and inferolateral artey branch from posterior cerebral artery, paramedian artery branches from posterior cerebral artery prior to bifurcation of posterior communicating artery and polar artery branches from posterior communicating artery (4).
Each portion has its own function. Largery, the nucleus in the lateral portion function relay of all sensory nerves except olfactory nerve and relay of motion via cerebellum tract. For example, lateral portion include spino-thalamic tract related to pain and temperature, and cellebellar-thalamic tract related to mortion.
Medial portion includes median nucleus and medial nucleus. Median nucleus includes reticular component related to consciousness and connects reticular in the brain stem. This portion functions alertness and wakeness to whole cerebrum. Medial nucleus connects to frontal lobe and olfactory nucleus.
Anterior portion is one of Papez circuit or limbic system related to emotion and memory.
Pulvinar accept the reverse information from cerebral cortex and functions selection and coordination of information of sensation and mortion. Lateral geniculate nucleus relates to visual pathway and medial geniculate nucleus relates to auditory pathway.
Therefore, infarction of anterior portion (nucleus) due to occlusion of polar artery causes memory deficit, infarction of medial portion due to ovcclusion of paramedian artery causes coma, infarction of lateral portion due to occlusion of inferior lateral artery causes sensory and/or motor defict and infarction of pulvinar due to posterior choroidal artery cause visual or auditory deficit.
In our case, she experienced sudden left-sided hemiparesis, hemineglect and anisocoria. Brain CT revealed hemorrhage at bilateral thalamus (lateral portion), corresponded to blood supply area of thalamus geniculate artery (=inferolateral artery).
【Summary】
We present a seventy seven-year-old female suffering from sudden weakness and sensory-neglect of left-sided hemisphere. Brain CT and MRI showed bilateral hemorrhage in both thalamus, namely lateral portions of the thalamus blood-supplied from inferior lateral (thalamo-geniculate) artery.
We should keep in mind that lateral portion of thalamus functions sensation and mortion associated from spimo-thalamic tract and thalamo-cerebellum tract, respectively. Anterior portion blood-supplied from polar artery (branching from posterior communicating artery) connects to Papez circuit and functions memory and emotion. Medial portion blood-supplied from paramedian artery branching from posterior cerebral artery functions consciousness and connects to olfactory nerve and frontal lobe. Posterior portion called pulvinar blood supplied from posterior choroidal artery branching from posterior cerebral artery funcions selection and coordination by obtaining reverse information from cerebral cortex. In addition, lateral geniculate nucleus is related to visual pathway and medial geniculate nucleus is related to auditory pathway.
【References】
1.Amici S, et al. Thalamic infarcts and hemorrhages. Front Neurol Neurosci. 2012;30:132-6. doi: 10.1159/000333611. Epub 2012 Feb 14.
2.Krause T, et al. Thalamic sensory strokes with and without pain: differences in lesion patterns in the ventral posterior thalamus. J Neurol Neurosurg Psychiatry. 2012 Aug;83(8):776-84. doi: 10.1136/jnnp-2011-301936. Epub 2012 Jun 13.
3.Roitberg BZ, et al. Bilateral paramedian thalamic infarct in the presence of an unpaired thalamic perforating artery. Acta Neurochir (Wien). 2002 Mar;144(3):301-4; discussion 304.
4.Neau JP, et al. The syndrome of posterior choroidal artery territory infarction. Ann Neurol. 1996 Jun;39(6):779-88
2018.1.10