LATERAL THALAMIC INFARCTS - 22 CASES

Isolated lateral thalamic infarcts (LThl) are rare. They often produce lacunar syndromes, and their main cause is thought to be an hypertens ive arteriolopathy. To verify these data, we reviewed 639 cerebral inf arcts demonstrated by CT and/or MRI and included in a hospital stroke registry over a 4-year period. We identified 22 cases (3.5 p. 100) of isolated LThl (right LThl: 15; left LThl: 7). Nineteen had MRI study. There were 13 men and 9 women of mean age 65 years. None had the compl ete Dejerine-Roussy syndrome : sensory disturbances 21 cases, hemipare sis 7, hemiataxia 5, involuntary movements 4. They were divided in gro up 1 (14 cases) with prominent sensory symptomatology and group 2 (8 c ases) with prominent motor symptomatology. The pulvinar and the ventra l posterior thalamic nucleus were affected in both groups while adjace nt nuclei such as ventral lateral or lateral posterior were more often affected in group 2. All patients but one had good recovery but 13 de veloped thalamic pain severely interfering with social activities in 5 cases. Several findings suggested That rather an arteriolopathy than large vessels disease or cardiogenic embolism had been a major cause i n this series: 1) all patients but one (including 2 with a potential c ardiac source of embolism) were hypertensive or diabetic, 2) lesions w ere small infarcts in the territory of perforators, 3) patients did no t experience premonitory as well as subsequent cerebral events suggest ive of vertebrobasilar atherosclerosis while 2 experienced deep cerebr al hypertensive hemorrhage, and 4) neuro-imaging found additional asym ptomatic lacunes in numerous patients. However, in the absence of angi ography in most patients, these results donnot preclude a potential ro le of artery-to-artery microembolism.