Addiction Psychiatry 1.2 Flashcards
What models explain the relationship between substance misuse and other psychiatric disorders?
Common factor model
Secondary use model
Supersensitivity model
Secondary illness model
What is the common factor model?
Proposes a common factor such as genetic vulnerability which predisposes to both illnesses.
Evidence for common factor model
Patients with a dual diagnosis often have more relatives with a substance use disorder.
What is the secondary use model?
Patients use substances to self-medicate and reduce social isolation.
What is the supersensitivity model?
Mentally ill patients are unusually sensitive to negative social and health consequences os substance exposure leading to diagnosis of substance misuse.
What is the secondary illness model?
Substance misuse leads to mental illness by a mechanism similar to kindling or behavioural sensitisation.
Which model of substance misuse and psychiatric disorders is popular with the lay public?
Secondary illness model
What is another name for pathological intoxication?
Idiosyncratic alcohol intoxication
What is pathological intoxication?
Severe behavioural reaction developing rapidly after consumption of small amount of alcohol.
Sx of pathological intoxication?
Confusion
Hallucinations
Psychomotor agitation
Impulsive/aggressive behaviour with risk to self or others
How long do sx of pathological intoxication last?
Few hours
How do sx of pathological intoxication terminate?
In a prolonged sleep
What factors have been proposed to be linked to pathological intoxication?
High levels of anxiety
Brain damage
Age
Sedative-hypnotic drugs
Feeling fatigued
What treatment may need to be considered for pathological intoxication?
Physical restraint
IM Haloperidol
Which classification has a diagnostic criterion for alcohol-induced psychotic disorders?
DSM
Most common hallucinations in alcoholic hallucinosis
Unstructured sounds or voices that may be threatenng
How long do hallucinations last in alcoholic hallucinosis
Less than a week
When do hallucinations in alcoholic hallucinosis tend to occur?
In patients with a chronic hx of alcohol abuse
Difference between alcoholic hallucinosis and delirium tremens?
In alcoholic hallucinosis there is clear sensorium.
At what point should hallucinations in alcoholic hallucinosis lead to suspicion of an underlying psychosis?
> 6 months
Differentiating factors of alcoholic hallucinosis compared to schizophrenia
Atypical or late age of onset of psychotic sx
Onset of alcohol drinking preceding onset
Remission of psychotic episodes during abstinence
Lack of thought disorder and affect incongruence
What are alcoholic blackouts?
Discrete episodes of anterograde amnesia that occur in association with alcohol intoxication
How does alcohol affect memory?
Blocks consolidation of new memories into old memories at the hippocampus
What happens to memory during alcoholic blackout?
Remote memory is intact but patients experience specific short-term episodic memory deficit
How long does memory gap tend to last in alcoholic blackouts?
Hours
What types of alcoholic dementia are there?
Primary alcoholic dementia
Wernickes/Korsakoffs
Marchiafava-Bignami
Hepato-cerebral degeneration
Vitamin deficiency
What is primary alcoholic dementia?
Direct toxic effects of alcohol on the brain
What brain findings can be reversed on abstinence of alcohol?
Atrophy
Other alcohol-related brain changes
What are the sx of Wernickes?
Ohthalmoplegia
Ataxia
Global confusion
How many patients with Wernickes present with the triad of sx?
10%
What causes Wernickes?
Thiamine deficiency
What leads to thiamine deficiency?
Inadequate dietary intake
Reduced GI absorption
Decreased hepatic storage
Impaired utilization
What factor increases risk of Wernickes?
Anormal thiamine-dependent transketolase
Brain findings in Wernickes
Gliosis and small haemorrhages in periventricular and periaqueductal structures - especially in mammillary bodies, hypothalamus, mediodorsal thalamic nucleus, colliculi and midbrain tegmentum
How many chronic alcoholics exhibit signs of Wernickes?
12.%
What is the most valuable diagnostic tool for Wernickes?
MRI
MRI sensitivity for Wernickes
53%
MRI specificity for Wernickes
93%
How many untreated patients with Wernickes go on to develop Korsakoffs?
84%
Mortality rate of untreated Wernickes?
20%
Why should Thiamine be given before glucose?
Glucose infusion exacerbates thiamine deficiency
How much PO thiamine should be given in low risk drinkers
300mg/day
How much thiamine should be given in high risk drinkers
250mg IM/IV OD for 3-5 days.
What does Pabrinex contain?
Thiamine
Nicotinamide
Vitamin B2 and B6
Vitamin C
How much thiamine should be given if Wernickes is suspected?
IM/IV of >500mg for 3-5 days
Which sx of Wernickes resolves with hours?
Ophthalmoplegia
Whatt characterises Korsakoffs?
Marked deficits in anterograde and retrograde episodic memory
Apathy
Intact sensorium
Preservation of other intellectual abilities: attention, procedural memory, working memory
Physiological process of Korsakoffs
Storage of information in more permanent form (consolidation by transfer of information from primary to secondary memory) are affected
What does diagnosis of Korsakoffs correlate with?
Presence of lesions in dorsomedial thalamus
What correlates with memory dysfunction in Korsakoffs?
Lesions in mammillary bodies, mammilothalamic tract and anterior thalamus
What leads to confabulation in Korsakoffs?
Double lesion - frontal and diencephalic deficits
What leads to cerebellar degeneration in alcohol use?
Degeneration of Purkinje cells in cerebellar cortex due to alcohol-induced damage
How many chronic alcoholics have cerebellar degeneration?
40%
What characterises hepatic encephalopathy?
Altered sensorium
Frontal release signs
Metabolic flapping tremor
Hyperreflexia
Extensor plantar responses
What sx are noted in those who make a partial recovery from hepatic encephalopathy?
Tremor
Choreoathetosis
Dysarthria
Gait ataxia
Dementia
What is the name of the sx that occur in patients who make partial recovery from hepatic encephalopathy?
Hepatocerebral degenaration
Brain changes in hepatic encephalopathy?
Enlargement and proliferation of protoplasmic astrocytes in basal ganglia, thalamus, red nucleus, pons and cerebellum
Who first described Marchiafava-Bignami syndrome?
Carducci in 1898 in Italian red wine drinkers
Who expanded the description of Marchiafava-Bignami syndrome?
Marchiafava and Bignami in 1903
Who does Marchiafava-Bignami syndrome commonly occur in?
Malnourished alcoholics
M:F ratio of Marchiafava-Bignami syndrome
More in males
Pathology of Marchiafava-Bignami syndrome?
Demyelination of corpus callosum and adjacent subcortical white matter - extra-pontine myelinolysis
Sx of Marchiafava-Bignami syndrome
Dementia
Spasticity
Dysarthria
Gait changes
Who described 2 clinical types of Marchiafava-Bignami syndrome
Heinrich, 2004
What is Type A of Marchiafava-Bignami syndrome
Predominant features of coma and stupor
What is Type A Marchiafava-Bignami syndrome associated with?
High prevalence of pyramidal rtact sx
Radiologic features of Type A Marchiafava-Bignami syndrome
Involvement of entire corpus callosum
What characterises Type B Marchiafava-Bignami syndrome?
Normal or mildly impaired mental status
Radiologic features of Type B Marchiafava-Bignami syndrome?
Partial or focal callosal lesions
Who first described central pontine myelinolysis?
Adams et al in 1959
What happens in central pontine myelinolysis?
Demyelination of central portion of base of pons
Sx of central pontine myelinolysis?
Pain sensation in limbs
Bulbar palsy
Quadriplegia
Disordered eye movements
VOmiting
Confusion
COma/locked-in syndrome
Which non-alcoholic diseases can result in central pontine myelinolysis?
Wilsons
Malnutrition
Anorexia
Burns
Cancer
Addisons
Severe hyponatraemia
What is alcoholic pancreatitis associated with?
Hypocalcaemia
Physiology underlying alcoholic pancreatitis?
Damaged pancreas leads to free fatty acids generated by pancreatic lipase.
Free fatty acids chelate the insoluble calcium salts resulting in calcium deposition in retroperitoneum leading to back pain.
How can low Mg result in alcoholic pancreatitis?
Low albumin leads to reduced total serum calcium
If there is emesis or poor nutritional status, low Magnesium can make things worse
PTH levels in pancreatitis-induced hypocalcaemia?
Normal
Elevated if severe hypocalcaemia
Treatment of alcoholic pancreatitis?
Parenteral ca and Mg replacement
Vitamin D levels checked
What type of pancreatitis is associated with depression?
Chronic
Hallmark of amphetamine-induced psychosis?
Paranoia
What is the biological mechanism behind stimulant-induced psychosis?
Sensitisation
Features of stimulant-induced psychosis compared to schizophrenia?
Absence of negative sx
Visual hallucinatinos
Appropriate affect
Hyperactivity
Disinhibited sexual behaviour
Confusion/incoherence
No formal thought disorder
How can one diagnose stimulant-induced psychosis?
Positive finding in urine drug screen
Rapid resolution of sx in a few days
Treatment of stimulant-induced psychosis
Short-term use of antipsychotic such as Haloperidol
What is hemp insanity?
Florid psychosis after high doses of high potency cannabis use
Impact of cannabis on cognition
Long term use can cause impairment in memory, attention and integration of complex information