Fact Sheets.

VASCULAR DEMENTIA

Vascular dementia is the second most common type of dementia in North America and Europe. It is responsible for 10 to 20% of dementia cases. In Asian populations it appears to be more common, being responsible for up to 60% of those with dementia.

Vascular dementia may co-exist with Alzheimer's disease or other dementias.

Its prevalence increases with age.

Both sexes are equally affected, although stokes are more common in men.

Clinical features:

* Onset usually abrupt.

* Progress usually step-wise.

* History of transient ischemic attacks or stokes.

* Presence of atherosclerosis, hypertension, diabetes mellitus, hyperlipidemia, or source of thromboembolism such as carotid artery disease or atrial fibrillation.

* Patchy cognitive impairment.

* Focal neurological signs. Gait abnormalities, asymmetric motor/sensory deficits, rigidity, exaggerated tendon reflexes, extensor plantar responses, aphasia, and agnosia are often detected clinically. Apathy, psychomotor retardation, slow mental process, and emotional lability are suggestive of sub-cortical infarcts.

* Patients with vascular dementias tend to have more difficulties with planning, sequencing and verbal fluency than those with Alzheimer's disease.

Risk factors:

* Hypertension.

* Cardiovascular disease.

* Smoking.

* Atherosclerosis, hyperlipidemia.

* Diabetes mellitus.

* Old age.

* Excessive alcohol consumption.

* History of transient ischemic attacks or previous stokes.

Diagnosis:

* Brain imaging studies.

Treatment:

* Treatment of risk factors predisposing to vascular dementia. In older hypertensive patients, however, too energetic blood pressure reduction may reduce the cerebral blood flow and predispose to cerebral infarcts.

* Antiplatelet medication: aspirin, plavix (clopidogrel bisulfate), ticlid (toclopidine).

* Anticoagulants: The potential risks of anticoagulants in older patients should be weighed against its potential benefits.

* A number of medications are being studied including: propentoxifilline, nimodipine, buflomedil, alpha-glycerylphosphorylcholine, and cystosine diphosphocholine.

Clinical syndromes:

* Multi-infarct dementia (MID):

Due to multiple infarcts, although patients may become demented after the first stoke. Suggestive clinical features include an abrupt onset and localized neurological deficits. Hachinski Ischemic scale is useful to differentiate multi-infarct dementia from other dementias. Some questions have been raised about the validity of this scale.

* Lacunar Dementia:

Due to multiple very small cerebral infarcts (lacunae). Suggestive clinical features include mood lability with outbursts of rage, lack of initiative, psychomotor retardation, presence of primitive reflexes, muscle rigidity, dysarthria, and urinary incontinence.

* Biswanger's disease (diffuse leukoaraiosis): Hypertension and probable episodes of hypotension are the main predisposing factors. Suggestive clinical features include: slowly progressive dementia starting around the age of 50 years, loss of initiative and interest, and slowing of thought process.

DEMENTIA DUE TO PARKINSON'S DISEASE

Dementia affects about 25% of patients with Parkinson's Disease.

Clinical features:

* Signs of Parkinson's disease.

* Depressive symptoms.

* Impaired executive functions: abstract thinking, planning, judgment, and initiative.

* Psychomotor retardation and cognitive slowing.

* Hallucinations, delusions.

* Insomnia, agitation, personality changes.

* Speech disturbances such as dysarthria and hypophonia, no aphasia.

* Impaired visuospatial skills.

Risk factors:

* Age: 70 years and older;

* Female gender;

* Low educational or socio-economic status;

* 'Mask face' as the presenting sign of Parkinson's disease, as opposed to tremors;

* Confusion or psychosis complicating intake of medication containing levo-dopa;

* Depression;

* Hypertension;

* Psychological stress;

* Family history.

Diagnosis:

* Clinical features of Parkinson's disease and dementia.

Treatment:

* No specific therapy for dementia due to Parkinson's disease. Treatment of Parkinson's disease may improve the cognitive functions.

* Medications containing levo-dopa, however, or its precursor may trigger an acute confusional state or even a psychotic event.

* Neuroleptics such as phenothiazine, haloperidol, or risperidone may worsen the patient's motor impairment. Clozaril (clozapine) is less likely to induce such changes.

* Anticholinergic agents should be used cautiously as they may induce cognitive dysfunction.

DEMENTIA WITH LEWY BODIES

Dementia with Lewy Bodies (DLB) is becoming increasingly recognized and may be more common than vascular dementia.

Clinical features:

* Progressive dementia.

* Fluctuating course, with marked variations in attention and level of consciousness, including transient clouding of consciousness and syncope.

* Hallucinations, predominantly visual, occasionally auditory. Visual hallucinations are often detailed of people and animals.

* Psychosis, delusional or paranoid ideation.

* Mild extrapyramidal signs such as flexed posture, bradykinesia, rigidity, and shuffling gait. Tremors are not common.

* Cortical deficits such as anomia, aphasia, apraxia, and agnosia.

* Prominent subcortical deficits such as decreased attention, verbal fluency deficits.

* Repeated falls are common.

* Visuo-spatial impairment.

* Difficulty writing from dictation.

Risk factors:

* Age 60 years and older.

Treatment:

* Cholinesterase inhibitors.

* Neuroleptics should be avoided.

Points of interest:

* The administration of neuroleptics to these patients may lead to severe and irreversible extrapyramidal signs and in some cases the neuroleptic malignant syndrome. There is evidence to suggest that the survival of patients receiving neuroleptic medication is reduced.

* Visual hallucinations appear to be due to an imbalance between the decreased cholinergic and preserved serotonergic activity in the temporal neocortex.

* Lewy bodies are rounded, cosinophilic intracytoplasmic neuronal inclusions composed of altered neurofilaments. In Lewy Body Dementia they are widely distributed in the cortex, basal ganglia and brain stem.

* The presence of a protein 'ubiquitin' in the hippocampus is diagnostic of Lewy Body Dementia and differentiates it from Alzheimer's disease.

HIV/AIDS DEMENTIA

Dementia may affect one third of patients with AIDS.

Mean survival after onset of dementia is about 6 months.

Clinical features:

* Progressive cognitive decline, especially impaired attention and concentration, forgetfulness, excessive preoccupation with other topics, and difficulties understanding written material. Thought process is slow. Executive functions are impaired.

* Depression and anxiety are common. Agitation and psychosis may be seen.

* Motor dysfunction including tremors, ataxia, and frequent falls. Handwriting is difficult and gait is impaired. Myoclonus and seizures may develop in late stages.

* Behavioral abnormalities, especially apathy, resulting in decreased work production and withdrawal from society.

* Speech is preserved until late stages when it becomes monotonous, with word-finding difficulty, eventually amounting to mutism.

* Bladder and bowel incontinence occurs in late stages.

Risk factors:

* Low hemoglobin level.

* Low body mass index.

* More constitutional symptoms.

* Low CD4+ cell counts.

* Older age at onset of AIDS.

* Female gender.

* Intravenous drug users.

* Homosexual men.

Diagnosis:

* Laboratory studies to confirm the diagnosis of AIDS.

Treatment/Management:

There is evidence to suggest that present antiviral agents may prevent, postpone or even treat the dementia associated with AIDS.

Zidovudine.

Methylphenidate.

Haloperidol or chlorpromazine.

Points of interest:

* HIV-associated dementia may be due to the production of substances such as HIV proteins, cellular metabolites, and cytokines that may be toxic to neurons, oligodendrocytes or myelin.

* Infection of astrocytes may lead to neuronal dysfunction directly or through loss of supporting growth factors, impairment of neurotransmitter reuptake, or impairment of blood-brain barrier that may permit further infection of neurons.

* Large numbers of macrophages and microglia cells have been seen in the nervous system of patients with AIDS dementia. Their number may correlate with the severity of the dementia.

* Patients with AIDS are more susceptible to extrapyramidal symptoms than psychotic patients without AIDS. High potency neuroleptics may induce the neuroleptic malignant syndrome.

PICK'S DISEASE--FRONTOTEMPORAL DEMENTIA

Circumscribed frontal and/or temporal atrophy. The most common dementia after Alzheimer's disease and Multi-infarct Dementia. It is responsible for about 10% of the cases.

Clinical features:

* Disinhibition and sexually inappropriate, childlike or aggressive behavior. Often precedes cognitive deficit by several years. Early manifestations include inattention to personal hygiene and misdemeanors such as shop-lifting.

* Personality changes such as apathy, laxity, indecisiveness, mental rigidity, perseverative behavior, easy distractibility and impulsivity.

* Emotional lability, anxiety, depression and occasional hypochondriasis.

* Speech impairment: anomia, dysarthria, perseveration, echololia, and decreased verbal output progressing to mutism.

* Hyperorality such as placing various objects in mouth or attempting to eating inedible material.

* Physical signs: primitive reflexes, akinesia, rigidity, tremors, labile or low blood pressure.

Diagnosis:

* Brain imaging.

Treatment:

* No specific therapy.

NORMAL PRESSURE HYDROCEPHALUS 

Clinical features:

* Characteristic triad:

Dementia;

Urinary incontinence;

Gait disturbances due to excessive rigidity: wide-based, slow shuffling and ataxic.

* Characteristic cognitive disturbance: slow mental process, impaired recall, difficulties planning complex actions.

* No evidence of cortical dysfunction until late in the disease.

Diagnosis:

* Brain imaging.

Treatment:

* Shunt surgery. Prognosis is better if the gait disturbance precedes cognitive impairment. It is worse if the dementia, urinary or fecal incontinence have been long-standing. The patient's age per se does not significantly affect the outcome of surgery.

* The cerebrospinal fluid tap test may identify those patients who are likely to respond favorably to surgery.

CREUTZFELD-JAKOB DISEASE

Transmissible encephalopathy that may occur sporadically (about 1 case per million population), be inherited (5 to 10% of all cases) or transmitted through the intake of contaminated material as may occur during medical procedures such as the administration of pituitary derived hormones, and corneal transplants. A variant of Creuztfeld-Jakob disease transmitted to humans through the ingestion of infected beef has been described in Europe (Spongiform Bovine Encephalopathy or mad cow disease).

Rapidly progressive. Most patients die within 4 to 6 months of diagnosis.

Diagnosis:

* EEG: periodic sharp wave complexes.

* Brain imaging.

DEMENTIA DUE TO HUNTINGTON'S DISEASE

Inherited disease.

Subcortical dementia.

Clinical features:

* Dementia.

* Depression.

* Movement disorder.

* Grossly impaired visuo-spatial processing capacity.

* Mood disorders, personality changes, irritable and explosive behavior.

Diagnosis:

* Genetic testing.

* Brain imaging.

Treatment:

* Nonspecific.

DEMENTIAS COMPLICATING MEDICAL DISEASES

Alcohol-Induced Dementia

Alcohol and its metabolite acetyldehyde are neurotoxic.

Cognitive dysfunction;

Wernicke-Korsakoff Syndrome;

Alcoholic cerebellar degeneration; Alcohol dementia.

SUBDURAL HEMATOMA:

Most common form of intracranial hemorrhage in older people.

Usually due to a fall or head trauma, symptoms may not manifest themselves for a few days after the trauma.

Clinical features:

* Wide range of symptoms including confusion, disorientation, memory deficits, personality changes, hallucinations, hemiparesis and headaches.

* Physical examination may not reveal any evidence of head trauma. Signs of increased intracranial pressure may be evident such as papilledema, cranial nerve impairment especially the third and sixth.

* Aphasia, hemiparesis, and gait disturbances may be evident.

Diagnosis:

* Brain imaging.

Risk factors:

* Accidental falls.

* Older age group.

* Anticoagulant therapy.