Stroke in young adults in northern Sweden

Abstract: Objectives. To study different aspects of cerebral venous and arterial occlusive disease including cerebrospinalfluid hydrodynamics, epidemiology, aetiology, genetics, metabolic and haemostatic disorders, andcognitive function in young adults in Northern Sweden.Methods. Cerebrospinal fluid hydrodynamics were investigated with a constant pressure infusion methodin patients with superior sagittal sinus thrombosis. Ten patients were studied with serial examinations, upto 15 years after the onset of the disease.Epidemiological data on ischaemic stroke in young adults aged 18 to 44 years were collected to calculateincidence and mortality based on the WHO Northern Sweden MONICA register of acute strokeevents. One hundred and seven consecutive patients aged 18-44 years with ischaemic stroke referred toUmeå university hospital were studied prospectively during a five-year period and were extensively evaluatedaccording to a standardized protocol. During follow-up at least three months after onset 102 and 80patients, respectively, were evaluated for disturbances in the fibrinolytic system and in the metabolism ofhomocysteine. A comprehensive neuropsychological battery was performed in a subset of 20 patients withinfratentorial infarcts.Results and conclusions. All patients with superior sagittal sinus thrombosis demonstrated a marked increasein intracranial pressure due to raised pressure in the sagittal sinus. A striking feature was the persistentintracranial pressure increase with only a slow decline over time.The incidence rate for ischaemic stroke was higher than previously reported from most countries inWestern Europe. The higher incidence was not explained by a higher prevalence of atherosclerotic vasculopathy. In spite of extensive evaluation, including advanced cardiac imaging, the cause of ischaemic strokein young adults still remains uncertain or unknown in most cases.Patients had lowered tissue plasminogen activator activity and increased plasminogen activator inhibitortype 1 activity. Increased fibrinogen levels and tissue plasminogen activator mass concentration wereindependently associated with ischaemic stroke. Metabolic perturbations were closely interrelated with tissueplasminogen activator and plasminogen activator inhibitor type 1 activity. Elevated plasma fibrinogenlevels and abnormalities in the fibrinolytic system in conjunction with metabolic perturbations may be importantcontributors to an increased stroke risk among young adults.Stroke patients had an exaggerated increase in total homocysteine levels after methionine loading.Abnormal responsivity to methionine loading was associated with higher tissue plasminogen activatormass concentration, plasminogen activator inhibitor 1 levels and lower tissue plasminogen activator activity. Abnormal homocysteine metabolism may provide an additional thrombogenetic risk, partly mediatedby interactions with the fibrinolytic system.Circumscribed infratentorial lesions (mainly cerebellar) impaired central aspects of attention andworking memory, and inflicted damage upon visuospatial skills. In contrast, these patients may not sufferfrom global intellectual impairment and difficulties with respect to memory for previous events. The prognosisis favorable in terms of neurological deficits and handicap, but cognitive disability may be the mostsignificant problem in adapting to their former occupations.Key w ords. Cerebral venous thrombosis, cerebrospinal fluid dynamics, ischaemic stroke, young adults, epidemiology,fibrinolysis, homocysteine, cerebellar infarct, neuropsychology.