Syndrome pure motor

While physicians may not recognize up to 80% of lacunes (Tuszynski et al. 1989), several clinical syndromes have been correlated with relevant lacunes detected at subsequent autopsy. Five of these are regarded as the classic lacunar syndromes pure motor hemiparesis, sensorimotor stroke, pure sensory hemiparesis, dysarthria clumsy hand syndrome, and ataxic hemiparesis (Donnan et al. 2002 Fisher 1982 Bamford 2001). Pure motor stroke is the commonest lacunar syndrome in clinical practice, while pure sensory stroke is encountered less frequently. The involvement of the face, arm and leg of one side is the characteristic feature of the first three syndromes while reductions of consciousness, cognitive or visual field defects are absent. Even though lacunar infarcts have been linked to lacunar syndromes, the latter are of course not specific for this stroke subtype and mimicked by cortical infarcts, intracerebral hematomas, and non-vascular causes (Bogousslavsky et al. 1988 Bamford 2001). 

Subcortical white matter infarcts may mimic a superficial MCA infarct causing a partial anterior circulation syndrome or present as a lacunar syndrome (pure motor, ataxic hemiparesis or sensori motor stroke). Superficial perforating artery infarcts (medullary branches) are often accompanied by cortical spotty lesions. Borderzone and white matter medullary branches infarctions are usually caused by hypoperfusion due lo large vessel occlusion or stenosis (Bogousslavsky 1993 Donnan and Yasaka 1998), but white matter medullary branches infarction can also be caused by cardioembolism (Lee et al. 2003). 

Aphasia and neglect can be found following respectively dominant and non-dominant anterior choroidal artery infarcts. Anterior choroidal artery infarcts usually cause the classical 3H syndrome hemiparesis, hemihypesthesia, hemianopia. Pure motor hemiparesis and isolated hemianopia can also occur (Han et al. 2000). Anterior choroidal artery territory infarcts are rarely caused by small vessel occlusion. In general they are caused by cardioembolism or large artery disease with occlusion or artery-to-artery embolism (Leys et al. 1994). 

Pure motor stroke constitutes about 50% of lacunar cases. It consists of a unilateral motor deficit involving two or three areas, the face, upper arm and/or leg, including the whole of each area that is affected. There are often sensory symptoms but no sensory signs. The lesion occurs at locations where the motor pathways are closely packed together and separate from other pathways usually in the internal capsule or pons, sometimes the corona radiata or cerebral peduncle, and rarely in the medullary pyramid. There may be a flurry of immediately preceding TIAs, the so-called capsular warning syndrome (Donnan et al. 1996). 

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