Organic Mental Disorders Flashcards
What is the ICD 10 definition of an organic mental disorder?
-A mental disorder that is due to common, demonstrable aetiology in cerebral disease, brain injury or other insult leading to cerebral dysfunction
What is the difference between primary and secondary organic mental disorders?
-Primary: due to a direct effect on the brain
Secondary: systemic diseases that affect the brain in addition to other systems/organs
What are the common features of psychiatric disorders?
- Cognition: memory, intellect and learning
- Sensorium: consciousness and attention
- Mood: depression, elation and anxiety
- Psychotic: hallucinations and delusions
- Personality and behavioural disturbance
- Onset
Give three examples of acute/subacute organic mental disorders
- Delirium
- Organic mood disorder
- Organic psychotic disorder
Give three examples of chronic organic mental disorders
- Dementia
- Amnesic syndrome
- Organic personality change
What is the definition of delirium?
-An aetiologically nonspecific syndrome characterised by concurrent disturbances of consciousness and attention, perception, thinking, memory, psychomotor behaviour, emotion and the sleep wake cycle
What are the presenting features of delirium?
- Rapid onset
- Impairment of consciousness and attention
- Global disturbance of cognition
- Psychomotor disturbances
- Disturbance of sleep-wake cycle
- Emotional disturbance
- Diurnally fluctuating
- < 6 months
- Autonomic activation: tachycardia, hypertension, diaphoresis, dilated pupils and fever
- Dysgraphia (changes in handwriting)
What are the potential causes of delirium?
- Medications: anti-cholinergics (TCAs etc.), sedative hypnotics etc.
- Drug abuse: amphetamines, cocaine etc.
- Withdrawal syndromes: alcohol, BZDs etc.
- Metabolic: hepatic encephalopathy, anaemia, hypogylcaemia etc.
- Vitamin deficiencies: thiamine, B12 etc.
- Endocrine: hypo and hyperthyroidism, cushings etc.
- Neuro: head injury, bleeds, stroke, status epilepticus etc.
- Toxins and industrial exposures: carbon monoxide, heavy metals etc.
- SLE, cerebral vasculitis etc.
How can delirium be managed?
- Treat underlying causes
- Environment and supportive measures: education of relatives and staff, make environment safe, optimise stimulation and orientation
- Avoid sedation unless required to maintain safety
- Antipsychotics, BZDs and promethazine
Which factors that contribute to delirium are able to be corrected?
- Disorientation
- Dehydration
- Constipation
- Hypoxia
- Immobility/limited mobility
- Infection
- Multiple medications
- Pain
- Poor nutrition
- Sensory impairment
- Sleep disturbance
Describe the presentation of hepatic encephalopathy
- Seen in advanced liver disease
- Psychomotor retardation
- Drowsiness
- Fluctuating confusion
- Asterixis
Describe the features of amnesic syndrome
- Impairment of recent and remote memory
- Immediate recall preserved
- New learning reduced
- Anterograde amnesia
- Disorientation in time
- Retrograde amnesia
- Confabulation
- Preservation of perception and other cognitive functions
- Lesion typically affects hypothalamic-diencephalic system or hippocampal region
- Prognosis depends on the underlying lesion
What are the causes of amnesic syndrome?
- Diencephalic: Korsakoff’s syndrome, 3rd ventricle tumours/cysts, bilateral thalamic infarction and post subarachnoid haemorrhage
- Hippocampal: herpes simplex encephalitis, anoxia, surgical removal of temporal lobes, bilateral posterior cerebral artery occlusion, closed head injury and early AD
How can alcohol amnesic syndrome be prevented?
- High risk groups should receive parental vitamin B1
- Abstinence from alcohol
- Slow MDT rehab
