8. OCD Flashcards
Describe an obsession
Intrusive, causes distress, repetitive, pt has insight
Ego-dystonic
- contamination (dirt, virus, germs, bodily fluids)
- fear of harm (door locks not safe)
- excessive concern with order/symmetry
- others: sex, violence, blasphemy, doubt
Describe a compulsion
Obsessional act
May be mediated by an obsessional mental image or fear
Normally a way to reduce the distress of the obsession
- overt = washing, checking, ordering
- covert = praying, counting, repeating words
Outline the diagnosis of obsessional/compulsion disorders
Present on most days for a period of at least 2 weeks
Originate in the mind of the patient
Repetitive and unpleasant
Acknowledged as excessive or unreasonable
Patient tries to resist, but at least one obsession/compulsion is unsuccessfully resisted
When do obsessional/compulsion disorder usually begin?
adolescence or early adulthood
Outline the pathophysiology of OCD
Re-entry circuits in basal ganglia = high activity makes it hard to get rid of excess
Reduced serotonin
Reduced activity in dorsolateral prefrontal cortex, orbitofrontal cortex, cingulate cortex
PANDAS = Paediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infection
What are the basal ganglia re-entry circuits?
Normal = INPUT from sub/cortical areas, PROCESSING by caudate nucleus and putamen, OUTPUT by inhib projection from GP and SN to thalamus
OCD = circuit loop from output back to processing that continues around
What is Paediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infection?
Sudden onset of OCD post infection with group-A beta-haemolytic strep
Antibodies ‘cross-react’ with neurones in basal ganglia, causing symptoms
How is OCD treated?
1st line: Exposure Response Prevention = not allowing you to carry out your compulsion, breaking the cycle, exposure to anxiety
High dose SSRIs - fluoxetine (give 8-12w trial)
Deep brain stimulation – stimulate STN to stim GPi to inhibit thalamus – less stim to the cortex (ONLY if severe depressive Sx)
How should OCD be Ix?
Yale-Brown obsessive-compulsive scale (Y-BOCS) = 10 item questionnaire with each item graded 0-4
Time occupied by obsessive thoughts (0 = none, 4 = extreme, >8h/d)
Give a DDx for OCD
O+C = eating disorder, anankastic PD, body dysmorphic disorder
Primarily O = anxiety disorders, depressive disorder, hypochondriacal disorder, schizophrenia
Primarily C = tourettes syndrome, kleptomania, autistic
Organic = dementia, epilepsy, head injury
