PBL Topic 3 Case 8 Flashcards

1
Q

Outline the epidemiology of schizophrenia

A
  • Affects 1% of population
  • More common in makes
  • Onset is usually between 16 and 25
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2
Q

Identify 3 genes implicated in the pathogenesis of schizophrenia

A
  • Neuregulin (synaptic development and plasticity)
  • Dysbindin (NMDA tethering)
  • DISC-1 (Receptor trafficking)
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3
Q

Outline 2 environmental factors implicated in the pathogenesis of schizophrenia

A
  • Maternal virus infections during pregnancy
  • Cannabis consumption in adolescence and early adulthood
  • Childhood sexual abuse
  • Urban living
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4
Q

Which dopaminergic pathway is implicated in positive symptoms?

A
  • Nigrostriatal pathway
  • From substantia nigra pars compacta
  • To association striatum
  • Excess dopamine acting on D2 receptors
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5
Q

Which dopaminergic pathway is implicated in negative symptoms?

A
  • Mesocortical pathway
  • From ventral tegmental area of midbrain
  • To prefrontal cortex
  • Lack of dopamine acting on D1 receptors
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6
Q

Outline the role of glutamate in the pathogenesis of schizophrenia

A
  • NMDA hypofunction reduces activity in mesocortical pathway and increased activity in mesolimbic pathway
  • Reduce dopamine acting on inhibitory D1 receptors and increase dopamine acting on excitatory D2 receptors
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7
Q

What is the cause of neurodegeneration in schizophrenia?

A
  • Glutamate induced excitotoxicity
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8
Q

Outline 5 positive symptoms of schizophrenia

A
  • Paranoid delusions
  • Hallucinations
  • Thought disorder
  • Disorganised behaviour
  • Catatonia (immobility, purposeless motor activity)
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9
Q

Outline 4 negative symptoms of schizophrenia

A
  • Withdrawal from social contact
  • Flattening of emotional responses
  • Anhedonia
  • Reluctance to perform everyday tasks
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10
Q

What percentage of schizophrenia cases lead to suicidal attempts and successful suicide attempts respectively?

A
  • 50%

- 10%

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11
Q

What is selective attention and how is it impaired in schizophrenia?

A
  • Ability to focus on important information

- Schizophrenic patients fail to discriminate between significant and irrelevant stimuli

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12
Q

Outline 4 differential diagnoses of schizophrenia

A
  • Organic mental disorders e.g. partial complex epilepsy
  • Affective disorders e.g. mania
  • Drug psychosis e.g. amphetamine psychosis
  • Personality disorders e.g. schizotypal
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13
Q

Identify two first general antipsychotic drugs

A
  • Chlorpromazine

- Haloperidol

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14
Q

Identify two atypical antipsychotic drugs

A
  • Risperidone

- Clozapine

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15
Q

Explain how antipsychotics act on dopamine receptors and which type of symptom they reduce

A
  • Antagonism of D2 receptors in nigrostriatal pathway, resulting in increased firing in nigrostriatal pathway
  • Reduces positive symptoms
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16
Q

What side effects occur as a result of D2 antagonism and why do they occur?

A
  • Systemic antipsychotics do not discriminate between D2 receptors in distinct brain regions
  • Unwanted motor affects due to block of D2 receptors in nigrostriatal pathway (dorsal striatum)
  • Enhanced prolactin secretion due to block of D2 receptors in tuberohypophyseal pathway
  • Reduced pleasure due to block of D2 receptors in mesolimbic pathway
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17
Q

Why are 5-HT2a receptor antagonists important in the control of extrapyramidal side effects of antipsychotics?

A
  • 5-HT2a receptors cause inhibition of dopaminergic nigrostriatal neurons
  • Antagonism of these receptors enhances dopamine release into striatum
  • So blocks unwanted motor affects of D2 blockage
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18
Q

Why are muscarinic acetylcholine receptor antagonists important in the control of extrapyramidal side effects of antipsychotics?

A
  • D2 blockage in striatum results in enhanced ACh release on muscarinic receptors
  • Which further inhibits D2 receptors??
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19
Q

What is acute dystonia?

A
  • Reversible extrapyramidal motor side-effect of antipsychotics
  • Beginning within the first few weeks
  • Characterised by fixed upward gaze, torticollis (involuntary spasm of neck muscles) and restlessness
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20
Q

What is tardive dyskinesia?

A
  • Irreversible extrapyramidal motor side-effect of antipsychotics
  • Beginning after months or years in a fifth of patients
  • Characterised by athetosis (writhing movements of the face, neck and limbs), chorea
  • Resembles effects of levodopa in Parkinson’s
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21
Q

What are the effects of enhanced prolactin concentration?

A
  • Dopamine acts on D2 receptors in tuberohypophyseal pathway to inhibit prolactin secretion
  • Blockage of receptors results in breast swelling, and lactation
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22
Q

What are the effects of blockage of histamine receptors by antipsychotics?

A
  • Drowsiness

- Sedation

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23
Q

What are the effects of blockage of muscarinic receptors by antipsychotics?

A
  • Blurred vision
  • Increased intraocular pressure
  • Dry mouth
  • Dry eyes
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24
Q

What are the effects of blockage of alpha adrenoreceptors receptors by antipsychotics?

A
  • Orthostatic hypotension
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25
What are the effects of blockage of 5-HT receptors by antipsychotics?
- Weight gain | - Increased risk of diabetes and cardiovascular disease
26
What is antipsychotic malignant syndrome?
- Muscle rigidity and rapid rise in body temperature
27
What does psychological treatment of schizophrenia involve?
- Reassurance and support - CBT to reduce intensity of delusions - Psychotherapy is contraindicated
28
What does social treatment of schizophrenia involve?
- Attention paid to patient's environment and social functioning - Family education on optimal amount of emotional and social stimulation - Sheltered employment - Assertive outreach mental health teams for poor adherence to medication
29
Outline the prognosis for schizophrenia
- 25% have good outcome - 33% develop chronic schizophrenia - Most will not work or live independently - 1 in 10 take their own lives
30
What is the role of the early intervention service?
- Address needs of patients during period of untreated psychosis (between first episode and receiving of effective treatment) - To improve symptom severity, admission rates, relapse rates and prognosis
31
What is the role of the care-coordinator in the EIS and who typically carries out this role?
- Ensure everyone is working together to identify patients needs - Community psychiatric nurse/occupational therapist/social worker
32
What is the role of Approved Mental Health Practitioners in the EIS?
- Make decisions about whether a person should be admitted to hospital for assessment or treatment
33
What is the role of the psychiatrists in the EIS?
- Specialise in diagnosis and treatment
34
What is the active principle of cannabis?
- Cannabinoids | - The most abundent of which is delta 9 tetrahydrocannabinol (THC)
35
What is cannabidiol?
- Precursor of THC
36
What is cannabinol?
- Breakdown product from THC
37
What is meant by a psychotomimetic effect?
- Produces hallucinations and delusions
38
How do the effects of cannabis differ to ethanol?
- Cannabis does not produce reckless and aggressive behaviour
39
Outline subjective effects of cannabis
- Relaxation - Wellbeing - Sharpened sensory awareness - Time passes extremely slowly
40
Outline six adverse central effects of cannabis
- Impairment of short-term memory and simple learning tasks - Impairment of motor co-ordination - Catalepsy - Hypothermia - Analgesia - Increased appetite
41
Outline five peripheral adverse effects of cannabis
- Tachycardia - Vasodilation (scleral and conjunctival vessels producing bloodshot eyes) - Reduction in intraocular pressure - Bronchodilation
42
What is the time frame of the effects of cannabis?
- Takes 1 hour to develop | - Lasts between 2 and 3 hours
43
Outline the distribution of CB1 receptors and how these relate to their central effects
- Hippocampus (impaired memory) - Cerebellum (impaired co-ordination) - Hypothalamus (increased appetite and hypothermia) - Substantia nigra (impaired motor control)
44
Where are CB2 receptors located?
- Lymphoid tissue including - Spleen, tonsils, thymus, - Lymphocytes, monocytes, mast cells, microglia
45
Describe CB1 receptors
- G protein coupled receptors located presynaptically - Activation of inward-rectifying potassium channels causing hyperpolarisation - Also influences gene expression by acting on mitogen activating protein kinase
46
What are endocannabinoids?
- Endogenous ligands for CB receptors - Made on demand (eicosanoid) - Their role is retrograde mediations passing information from postsynaptic neurons
47
Identify two endocannabinoids
- Anandamide | - 2-AG
48
What is the role of fatty acid amide hydrolase (FAAH)?
- Inactivated anandamide | - Converting it to arachidonic acid and ethanolamine
49
Identify a stimuli that causes release of endocannabinoids
- Increased intracellular Ca2+
50
What is meant by depolarisation induced suppression of inhibition (DSI)?
- Depolarisation of hippocampal pyramidal cells - Causing suppression of GABA mediated inhibition input to these cells - Implying a retrograde flow of information by activation of CB receptors - Inhibited by CB1 antagonists e.g. rimonabant
51
How does NMDA hypofunction cause positive symptoms?
- NMDA hypofunction on GABAergic neurons - Resulting in disinhibition of glutamatergic neurons in the PcSN - Increased dopamine release from PcSN acting on D2 receptors in associative striatum
52
How does NMDA hypofunction cause negative symptoms?
- NMDA hypofunction on GABAergic neurons - Resulting in disinhibition of glutamatergic neurons on GABA neurons - Inhibiting ventral tegmental area - Reduce D1 in mesocortical pathway
53
Outline the diagnostic criteria for schizophrenia
- At least 1 symptom for at least 1 month: - Hallucination - Delusions - Withdrawal
54
How long should antipsychotics be taken to be maximally effective?
- 2-4 weeks
55
In patients with a first psychotic episode, how long should antipsychotic treatment be continued for in order to prevent relapse
- 1-2 years
56
What is the dose of risperidone?
- Orally up to 4 mg
57
Explain the relationship between FAAH and pain threshold?
- Endocannabinoids have analgesic and anxiolytic properties - Capable of reducing anxiety and increased pain threshold - FAAH inhibition increases endocannabinoids concentration
58
What is rimonabant and what are its clinical effects?
- CB1 receptor antagonist - Increased weight loss - Reduced tobacco dependence and drug addiction
59
What percentage block of D2 receptors is required for therapeutic effects of antipsychotics?
-65% to 80%
60
What is meant by sectioning?
- Person is kept in hospital under Mental Health Act 1983
61
Identify three criteria for sectioning
- Patients needs assessment and treatment - Patients health would otherwise deteriorate - Their own safety or safety of others is impaired
62
Outline Section 2 of the MHA
- Patient can be detained if they have a mental disorder that poses risks to their own safety or safety of others - And they need to be detained for a short time for assessment (up to 28 days)
63
Outline Section 3 of the MHA
- Patient can be detained if they have a mental disorder that poses risks to their own safety or safety of others - Treatment can only be given in hospital - Can be detained for up to 6 months
64
Who is able to extent or renew sectioning under Section 3?
- Responsible clinician
65
For how many months can Section 3 be extended: [A] The first time [B] The second time [C] The third time
- [A] 6 months - [B] 6 months - [C] 12 months
66
Who is responsible for discharging the patient?
- Responsible clinician
67
What is the role of the Approved Mental Health Professional?
- Co-ordination of assessment and admission to hospital
68
Aside from the AMHP, identify two other roles involved in assessment and admission
- Registered GP, ideally one who knows the patient | - Section 12 approved doctor e.g. psychiatrist
69
What right's does the nearest relative have?
- They can tell the AMHP their concerns which may lead to sectioning - They should be consulted if the AMHP wants to section the patient - They have the right to object to sectioning
70
What is the role of the independent mental health advocate?
- Help patient express patients views if they refuse sectioning
71
What is escorted leave and who grants permission?
- Patient can leave ward for good reason - Permission clinician - Hospital is not under legal obligation to do this
72
Can patients be given treatment against their will?
- Yes
73
What happens when a patient refuses sectioning?
- AMHP can use reasonable force or can involve the police
74
What is meant by recovery?
- A way of living a satisfying, hopeful and contributing life even with the limitations caused by illness
75
What is a Wood Shedding Model or recovery?
- Following an initial improvement, the individual's condition may ‘plateau’ for long periods - And then suddenly improve in a discontinuous manner.
76
Identify internal and external conditions of recovery
- Internal: Hope | - External: Human rights