Lacunar syndromes, Aspects on risk factors, pathophysiology, diagnosis and prognosis

Sammanfattning: The aims of the studies in the thesis were; 1.to investigate incidence, risk factors in comparison to non lacunar stroke patients, initial course and long term prognosis in pure motor stroke (PMS) 2.to determine topography and most probable pathogenetic mechanism of lesions in sensorimotor stroke (SMS). 3.to study if diffusion weighted magnetic resonance tomography(DWI) contribute to a more precise and earlier diagnosis in the acute phase of stroke patients presenting as lacunar syndromes 4.to study location and characteristics of focal abnormalities on DWI in patients with capsular warning syndromes(CWS) and to explore potential underlying mechanisms of the transient symptoms. Results and conclusions; patients with PMS had significantly higher frequency of hypertension than non lacunar strokes and the frequency was related to age. Short term prognosis was favourable. Long term follow-up showed an annual rate of mortality of 6% and for risk of recurrence 2.4%. Patients had an increased mortality after five years compared to sex and age matched population. In 69% of the patients with SMS, small vessel disease (lacunar infarcts) from presumed single perforant artery occlusion was considered the most probable underlying mechanism. Early examination with DWI, demonstrated in patients with lacunar syndromes, in 90% a lesion compatible with in situ small vessel disease. In patients with CWS and TIAs only DWI demonstrated lesions confined to the thalamus or globus pallidus without oinvolvement of the classical motor pathways whereas patients with permanent deficits had lesions involving the corticospinal pathway in putamen/corona radiata or the brainstem. Pathophysiology of CWS is complex. We hypothesise a transient involvement of peri-infarct depolarisation affecting more remote motor pathways or hemodynamic mechanism in perforating arterial territories.