Mohammed T. Abou-Saleh

254 PRINCIPLES AND PRACTICE OF GERIATRIC PSYCHIATRYblood flow and metabolism has become increasingly moresophisticated with the advent of positron emission tomography(PET) which uses radioactive tracers to measure metabolism andblood flow. Frackowiak et al. showed that cerebral blood flow(CBF) and metabolism fell with increasing dementia in both MIDand degenerative dementia 38 . Normal CBF is 50–70 ml/100 g/min:ischaemia only occurs once the CBF falls below 10–20 ml/100 g/min.Focal abnormalities are found in both MID and degenerativedementia, although in the vascular group the individual focallyderanged areas are patchy and match the unique patterns ofischaemic damage, whereas in AD the focal abnormalities aremainly temporoparietal. PET largely remains a research tool.Single photon emission CT (SPECT) is becoming a more widelyavailable tool, as most X-ray departments have the necessaryequipment. Radioactive tracers are used to measure blood flow.Similar temporoparietal abnormalities in AD and patchy irregularitiesin MD have been reported 39 . However, all these studieshave used a clinical scoring system with/without CT todifferentiate MID and AD. None have had pathological confirmation.Because only 10–20% of dementias are multi-infarct,and because an approximate equal percentage have mixed disease(stroke with coincidental AD), it will not be possible to know thetrue value of PET and SPECT until serial studies are performedwith pathological confirmation.TreatmentAs with all vascular disease treatment initially involves dealingwith the risk factors—hypertension, hyperlipidaemia, diabetesmellitus and smoking. The Syst-Eur Hypertension trial hasdemonstrated that treating hypertension prevents dementia 40 .This is combined with specific treatment for the underlying diseaseprocess. Aspirin is of proven value in preventing stroke 41 .Whether adding dipyridamole to aspirin confers any greaterbenefit than aspirin alone remains debatable 42,43 . There is nodoubt that clopidogrel is a new effective antiplatelet agent at leastas good as aspirin; it should be considered in those intolerant ofaspirin 44 .Warfarin is the treatment of choice in those with atrialfibrillation, but the risk of haemorrhage secondary to warfarinis higher in those with leukoaraiosis 45,46 . It must be used withcaution if poor compliance and falls are a problem. Anticoagulationshould also be considered in the antiphospholipidsyndrome 16 .In spite of the many claims, no vasodilator, calcium antagonistor neuroprotective agent has been shown to help vasculardementia. Steroids and immunosuppression may be indicated ifan arteritis is proven.Tatemichi 37 has published a case of dementia with bilateralinternal carotid occlusions which improved after extracranial–intracranial bypass surgery to improve the blood flow to thebrain.This section has dealt with the specific treatments for vasculardisease: it is crucial, of course, to provide symptomatic treatmentand a full care package for the many other problems theunfortunate patient with vascular dementia may experience.REFERENCES1. Brust JCM. Vascular dementia—still overdiagnosed. Stroke, 1983; 14:298–300.2. Snowdon DA, Greiner LH, Mortimer JA et al. Brain infarction andthe clinical expression of Alzheimer disease. The nun study. JAmMed Assoc 1997; 277: 813–17.3. Skoog I, Nilsson L, Palmertz B. A population-based study ofdementia in 85 year-olds. N Eng J Med 1993; 328: 153–8.4. Wade JPH, Mirsen TR, Hachinski VC et al. The clinical diagnosis ofAlzheimer’s disease. Arch Neurol 1987; 44: 24–9.5. 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