Organic Mental Disorders Flashcards

1
Q

Definition of Organic Mental Disorder

A
  • Mental disorders due to common and demonstrable causes in cerebral disease, brain injury or other insult leading to neurological dysfunction → the cross between neurology and psychiatry
  • Acquired → (differentiation from intellectual disability)
  • Alternative to the more common ‘functional’ mental illnesses
  • Primary → direct effect on the brain
  • Secondary → systemic disorder with secondary effects on the brain
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2
Q

Problems in defining functional and organic mental disorders

A
  • Most mental disorders have an ‘organic’ component → schizophrenia, bipolar affective disorder, melancholia
  • Many present with a mixture of both mental and physical features
  • Physical disorders can also have psychological and functional elements
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3
Q

Common presentation of organic mental disorders

A
  • Cognitive
    • Memory
    • Intellect
    • Learning
  • Sensorium?
    • Consciousness
    • Attention
  • Mood
    • Depression
    • Mania
    • Anxiety
  • Psychosis
    • Hallucinations
    • Delusions
  • Personality and behavioural disturbances
  • Onset
    • Any age
    • Most commonly later in life
  • Some irreversible and progressive → neurodegenerative
  • Some transient/ respond to treatment
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4
Q

Classification of organic mental disorder

A
  • Acute/ sub-acute
    • Delirium
    • Organic mood disorder
    • Organic psychotic disorder
  • Chronic
    • Dementia
    • Amnesic syndrome
    • Organic personality changes
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5
Q

Management of Organic Mental Disorder

A
  • Varies according to cause
  • Correct diagnosis
  • Medications ineffective unless for acute situations
  • MDT approach
  • Consider management of patient environment
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6
Q

Delirium tremens

A
  • Acute alcohol withdrawal
  • Fluctuating confusion
  • Disorientation to time and place
  • Memory impairment
  • Psychotic features → hallucination and delusional thinking
  • Mainstay treatment → benzodiazepines (prevents alcohol-related seizure)
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7
Q

Wernicke-Korsakoff Syndrome

A
  • Acute deficiency of thiamine (vitamin B1)
  • Difficult to distinguish from delirium tremens
  • Presentation
    • Acute confusional state
    • Ataxia
    • Opthalmoplegia
    • Nystagmus
  • Untreated acute phase lasts 2 weeks → majority develop Korsakoff psychosis
  • Prognosis
    • Confusional state and opthalmoplegia can resolve in days
    • Nystagmus, neuropathy and ataxia prolonged or permanent
  • Treatment
    • High potency parenteral B1 replacement → oral thiamine
    • Avoid carbohydrate until thiamine fully replaced
    • Concurrent alcohol withdrawal treatment → benzodiazepines
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8
Q

Alcohol amnesic Syndrome (Korsakoff psychosis)

A
  • Marked impairment of anterograde memory → ability to learn new memories
  • Disturbed time sense
  • No clouded consciousness, no defect in immediate recall or global impairment
  • Variable cognitive impairment
  • Personality changes, apathy, loss of initiative
  • Early stages → confabulations
  • Can improve with prolonged abstinence
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9
Q

Hepatic encephalopathy

A
  • Psychomotor retardation, drowsiness, confusion caused by build up of toxic products (ammonia) in the blood stream
  • Often seen in advanced alcoholic liver disease
  • Improves as liver function recovers
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10
Q

Alcohol related brain damage

A
  • Due to neurotoxic effects, head injury, vitamin deficiencies, cerebrovascular disease, hypoxia, hypoglycaemia, seizures
  • Evidence of increasing prevalence
  • Trend of people presenting earlier than in the past
  • Impairment in short-term memory, long-term recall, new skill acquisition
  • Greatest decline in visuospatial ability
  • Can cover spontaneously with absence or reduced drinking
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11
Q

Difference between dementia and depressive pseudo dementia

A
  • Dementia
    • Progressive onset
    • Long-term symptomology
    • Mood variations
    • Patient concealing absnesia
    • Patient willing to answer questions
    • Constant cognitive decline
  • Depressive pseuodementia
    • Rapid onset
    • Short-term symptomology
    • Consistent depressed mood
    • Answers are short and with negativism
    • Highlighting amnesia
    • Fluctuating cognitive decline
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12
Q

Steroid-induced psychosis

A
  • Mild-moderat psychiatric symptoms → 28% of steroid-treated patients
  • 6% with severe reaction
  • Dose-dependent, not timing, duration or severity
  • Always taper steroids
  • Consider antipsychotic or mood stabiliser
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13
Q

Endocrine and metabolic disorder in psychiatric symptomology

A
  • Manifests a variety of presentation → psychiatric
  • CNS requires homeostatic biochemical and metabolic conditions
  • Psychiatric disorders reversible if cause is detected
  • I.e correcting hypothyroidism, Addison’s disease
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14
Q

Anti-NMDA receptor encephalitis

A
  • Autoimmune disease targeting NDMA receptor
  • NMDA receptor → ionotropic glutamate receptor in synaptic plasticity and memory
  • ½ associated with malignancy
  • Presents most commonly with psychiatric symptoms
  • Treatment
    • Immunotherapy → IVIg, plasmapheresis, rituximab
    • Tumour resection (when indicated)
    • Benzodiazepines → symptomatic
  • Prognosis → generally good
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15
Q

Delirium

A
  • Non-specific neurological syndrome characterised by disturbances in consciousness, attention, perception, thinking, memory, psychomotor behaviour, emotion and circadian rhythm
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16
Q

Presentation of delirium

A
  • Impaired consciousness and attention
  • Generalised cognitive disturbances
  • Psychomotor dysfunction
  • Disturbed sleep-wake cycle
  • Emotion disturbances
  • Rapid onset
  • Diurnal fluctuating
  • Duration less than 6 months
  • Physical symptoms
    • Autonomic activation → tachycardia, hypertension, dilated pupils, sweating, fever
    • Dysgraphia
17
Q

Causes of delirium (exhaustive list)

A
  • Medications → anticholinergics, sedative-hypnotics, decongestants, glucocorticoids
  • Drug abuse → amphetamines and cocaine
  • Withdrawal syndromes → alcohol, benzodiazepines,
  • Metabolic → hepatic encephalopathy, uraemia, hypoglycaemia, hypoxia, hypo/hypercalcaemia,
  • Vitamin deficiencies → thiamine, vitamin B12, nicotinic acid
  • Endocrinopathies → hypo/hyperthyroidism, bushings, Addison’s disease, hypopituitarism
  • Infections → systemic infection, AIDS, meningitis encephalitis, brain abcess
  • Neurological → head injury, stroke, hypertensive encephalopathy, intracranial neoplasm, status epileptics,
  • Toxins → Carbon monoxide, carbon disulphide, organic solvents, heavy metals
  • Others → SLE, cerebral vasculitis, paraneoplastic syndrome
18
Q

Mechanisms of delirium

A
  • Unclear pathogensis
    • GABAergic and cholinergic neurotransmitter pathways
    • Increased dopaminergic activity
    • Direct neurotoxic effects of cytokines
19
Q

Delirium vs dementia

A
  • Delirium
    • Acute and often at nighy
    • Fluctuating course
    • Hours to weeks
    • Impaired attention
    • Disorganised and delusion thinking
    • Disrupted sleep-wake cycle
    • Generalised slowing on EEG
    • No atrophy on CT, MRI
  • Dementia
    • Insidious onset
    • Stable course in day
    • Months to years
    • Attention unaffected
    • Impoverished thinking
    • Normal sleep-wake cycle
    • No slowing in EEG
    • Atrophic finding on CT, MRI
20
Q

Delirium vs functional psychosis

A
  • Delirium
    • Almost always clouded consciousness
    • Concrete > abstract thinking
    • Transient and changing delusions
    • Impaired cognitive function
    • Visual hallucination predominate
  • Functional psychosis
    • No clouding of consciousness
    • Abstract > concrete thinking
    • Systemised delusions
    • No impairment to cognitive function
    • Auditory hallucinations predominate
21
Q

Prognosis of delirium

A
  • Fluctuating course
  • Gradual resolution with effective treatment
  • Slower resolution in elderly
  • 20% mortality during admission
  • 50% within one year
  • Marker for dementia
22
Q

Management of delirium

A
  • Correct factors
    • Disorientation
    • Dehydration
    • Constipation
    • Hypoxia
    • Immobility/ limited mobility
    • Infection
    • Polypharmacy
    • Pain
    • Poor nutrition
    • Sensory impairment
    • Sleep disturbances
  • Environmental and supportive measures
    • Education of relatives, staff
    • Safe environment
  • Medication
    • Avoid sedation unless necessary
    • Antipsychotic
    • Benzodiazepines
    • Promethazine