Organic mental disorders Flashcards
What are ‘organic mental disorders’?
An underlying “physical” disorder as the cause of the mental disturbance.
They can be primary or secondary:
- Primary – neurological disorder having direct effect on the brain
- Secondary – systemic diseases that affect the brain in addition to other systems/organs i.e endocrine disorders or substance induced problems (alcohol/drug)
Common features seen in organic disorders?
- Cognitive - memory, intellect, learning (but not learning disabilities)
- Sensorium - consciousness, attention
- Mood - depression, elation, anxiety
- Psychotic - hallucinations, delusions
- Personality and behavioural disturbances - phineas gage
- Onset - any age but most primary organic disorders tend to start in adult or later life
- Some irreversible and progressive whilst some are transient/respond to treatments
Give 3 examples of acute / sub-acute organic brain disorders
- Delirium
- Organic mood disorder
- Organic psychotic disorder
Give 3 examples of chronic organic mental disorders
- Dementia
- Amnesic syndrome
- Organic personality change
Chronic organic mental disorders
Chronic organic brain syndrome is long-term.
- For example, some forms of chronic drug or alcohol dependence can cause organic brain syndrome due to their long-lasting or permanent toxic effects on brain function.
- Other common causes sometimes listed are the various types of dementia which result from permanent brain damage due to strokes, Alzheimer’s disease, or other damaging causes which are not reversible.
Acute organic mental disorders
Acute organic brain syndrome is (by definition) a recently appearing state of mental impairment, as a result of intoxication, drug overdose, infection, pain, and many other physical problems affecting mental status.
In medical contexts, “acute” means “of recent onset”. As is the case with most acute disease problems, acute organic brain syndrome is often temporary–however this is not guaranteed (a recent-onset problem may continue to be chronic or long term).
Name some of the psychiatric symptoms of Delirium tremens
- Fluctuating confusion
- Disorientation in time and place
- Memory impairment
- Psychotic phenomena e.g hallucinations or dellusional thinking
- Tremor
- Agitation
- Sleeplessness
- Autonomic over-activity - sweating etc
What causes Wernicke-Korsakoff syndrome?
Acute deficiency of Thiamine (Vitamin B1)
Symptoms associated with Wernicke’s Encephalopathy
- Acute confsuional state
- Ataxia
- Opthalmoplegia
- Nystagmus
With treatment confusional state and opthalmoplegia can resolve within days. However, nystagmus, neuropathy and ataxia may be prolonged or permanent.
Symptoms of Alcohol Amnesic Syndrome (Korsakoff’s psychosis)
- Marked impairment of anterograde memory (ability to learn new information) and retrograde memory
- Preservation of immediate recall
- Disturbance of time sense
- Variable degrees of cognitive impairment
- Personality changes, apathy, loss of initiative
- Confabulation in the early stage - they confuse things they have imagined with real memories (not lying).
- No general cognitive impairment
Psychiatric symptoms in Hepatic Encephalopathy
General psychomotor retardation
Drowsiness
Fluctuating levels of confusion
Disorientation
What causes the psychiatric symptoms in Hepatic Encephalopathy?
A build up of toxic products (e.g. ammonia) - the liver can no longer process it.
How can alcohol related brain damage come about? (7)
- Neurotoxic effects of alcohol
- Head injury
- Vitamin deficiencies
- Cerebrovascular disease
- Hypoxia
- Hypoglycaemia
- Seizures
50-80% heavy drinkers display cognitive impairment when sober
Define dementia
A syndrome which is characterised by global cognitive impairment which is chronic in nature.
Types of dementia
- Alzheimer
- Vascular
- (Mixed - alzheimer’s and vascular)
- Lewy body
- Frontotemporal
Due to other brain disorders:
- Huntington’s chorea
- Head injury
- Parkinson’s disease
How do you differentiate between dementia and depressive pseudodementia (severe depression)?
Dementia:
- Progressive onset
- Lon-term symptomatology
- Mood variations
- Patient tries to answer questions
- Patient concealing amnesia
- Constant cognitive decline
Severe depression
- Rapid onset
- Short-term symptomatology
- Consistently depressed mood
- Short answers, negativism
- Highlighting amnesia
- Fluctuating cognitive impairment
Steroid-induced psychosis: how common?
Around 1/3 of patients treated with steroids suffer mild-moderate psychiatric symptoms
Approximately 6% severe reaction
Endocrine and metabolic disorders causing psychiatric symptoms
- Can have a wide variety of clinical presentations
- CNS requires everything to be working for proper functioning
- Psychiatric presentations may be reversible if detected
- Likely to first present to GP but some conditions (i.e. Hypothyroidism, Addison’s disease) may present first to psychiatry and there is risk of mistaken diagnosis
What is Anti-NMDA receptor encephalitis?
Autoimmune disease that targets NMDA receptors - ionotropic glutamate receptor involved in synaptic plasticity and memory function
- Often presents initially with psychiatric symptoms
- Around half associated with malignancy i.e ovarian teratoma
How is anti-NMDA receptor encephalitis treated?
- Immunotherapy
- Tumour resection if there is a tumour present
- Benzodiazepines and anti-psychotics if required
- Rituximab - monoclonal antibody used to treat autoimmune disease and cancers
Define delirium
An aetiologically non-specific syndrome characterised by concurrent disturbances of consciousness and attention, perception, thinking, memory, psychomotor behaviour, emotion, and the sleep-wake cycle
Presenting Features of Delirium
- Impairment of consciousness (ranges from clouding to coma) and attention
- Global disturbance of cognition (delusions, hallucinations)
- Psychomotor disturbances - hypoactive, hyperactive delirium
- Disturbance of sleep-wake cycle
- Emotional disturbance
- Rapid onset, diurnally fluctuating and lasts < 6 months
Physical signs of delirium
- Are due to underlying cause
- Toxic/metabolic disturbance - prone to listlessness and apathy
- Infective processes / alcohol withdrawal - prone to fearfulness, hyperactivtiy and hallucinations
- Autonomic activation: tachycardia, hypertension, diaphoresis (picking at something i.e sheets that aren’t there), dilated pupils, fever
- Dysgraphia often evident
Name some causes of delirium.
N.B there tends to be a mixture of causes
- Medicines
- Infections - any systemic infection in elderly, meningitis, encephalitis and brain abscess. AIDS.
- Drug abuse - Amphetamines and cocaine; phencylidine (PCP); hallucinogens; inhaled drugs (glue, NO)
- Withdrawal syndromes - alcohol, benzodiazepines, barbiturates and other sedative-hypnotics
- Metabolic - hepatic encephalopathy, uraemia, hypoglycaemia, hypoxia
- Vitamin deficiencies - thiamine, Vit B12, nicotinic acid
- Endocrinopathies - hypo and hyperthyroidism / hyper-parathyroidism, cushing’s + addison’s
- Neurological causes - head injury, stroke, hypertensive encephalopathy
- Toxins and industrial exposures - CO, Organic solvents
Delirium vs. Dementia
Delirium vs functional/primary psychosis
Delirium
- Almost always accompanied by clouding of consciousness
- Thinking is more concrete than abstract
- Generally more transient
- Impairment of cognitive functions
- Predominantly visual hallucinations
Functional psychosis
- No clouding of consciousness
- Thinking is more abstract
- Delusions often systematised
- No impairment of cognitive functions
- Predominantly auditory hallucinations
Management of delirium
Correct factors contributing to delirium: i.e give them their glasses, hearing aids, get them up and mobile, food/drink, O2, stop toxic drugs. Turn on clock in room, remind them where they are.
Medications:
- Avoid sedation unless required to maintain safety
- Medication not helpful in delirium - only if necessary
- Anti-psychotics
- Benzodiazepines - can prolong delirium
- Promethazine - anticholinergic; sedative but can worsen delirium, caution in elderly
