Dementia and Delirium: Characteristics and Causes

Dementia

Characteristics

• Impairments in short- and long-term memory, abstract thinking, and judgment
• Aphasia (language disorder)
• Apraxia (inability to carry out motor activities despite intact comprehension and motor function)
• Agnosia (inability to recognize or identify items despite intact sensory function)
• Constructional difficulty (inability to copy three-dimensional figures, assemble blocks, or arrange sticks in specific designs)
• Personality change or alteration and accentuation of premorbid traits
• Mood disturbances
• Loss of self-care abilities

Causes

Most Common Causes

• Alzheimer's disease
• Vascular dementia
• Alcohol-related dementia

Common Metabolic/Toxic Causes

• Chronic drug-alcohol-nutritional abuse (e.g., Wernicke-Korsakoff syndrome)
• Organ system failure
• Anoxia
• Folic acid deficiency
• Hypothyroidism
• Bromide intoxication
• Hypoglycemia

Common Infectious Causes

• Neurosyphilis paresis (a syphilitic infection manifested as dementia, seizures, and problems walking and standing)
• AIDS/HIV-related disorders
• Meningitis
• Encephalitis

Other Common Causes

• Huntington's chorea
• Parkinson's disease
• Creutzfeldt-Jakob disease
• Lewy body dementia

Delirium

Characteristics

• Inability to appreciate and respond normally to the environment, often with altered awareness, disorientation, inability to process visual and auditory stimuli, and other signs of cognitive dysfunction
• Potentially life threatening
• Acute onset
• Clouding of consciousness
• Reduced wakefulness
• Disorientation to time and space
• Increased motor activity (e.g., restlessness, plucking, picking)
• Impaired attention and concentration
• Impaired memory
• Anxiety, suspicion, and agitation
• Variability of symptoms over time
• Misinterpretation, illusions, or hallucinations
• Disrupted thinking, delusions, speech abnormalities

Causes

Common Intracranial Causes

• Infections (e.g., meningitis, encephalitis)
• Seizures
• Stroke
• Subdural hematomas
• Tumors

Common Extracranial Causes

• Anesthesia
• Drug-drug or alcohol-drug interactions
• Intoxication and/or withdrawal from alcohol or drugs (particularly psychoactive drugs)
• Toxic effects of prescribed or over-the-counter drugs
• Giant cell arteritis (a chronic inflammatory process involving the extracranial arteries)
• Hip fracture
• Hydrocephalus (increased fluid in the brain)
• Hypercapnia (reduced ventilation often associated with chronic obstructive pulmonary disease)
• Infections
• Dehydration
• Malnutrition
• Metabolic disturbances (e.g., liver or kidney failure, electrolyte disturbances, hyper- or hypoglycemia, diabetes, thyroid disorders)
• Myocardial infarction (heart attack)
• Sudden environmental changes
• Depression