Post on 23-Jan-2018
Goals
• Knowing basic points on circuits of addiction
• How alcohol manipulates these circuits
• What are the effects of a single drink
• What are the effects of chronic alcoholism
• Some diseases of the CNS caused by alcohol
the DOLMA principle
• You do something , eating DOLMA as an example
• dolma is a good meal
• Your nucleus accumbens will release dopamine after you eat a good meal or do something pleasant
• Dopamine makes you feel great
• You liked this feeling
• You try to repeat this feeling by begging your mother to make another Dolma next Friday .
The reward circuit
• Nucleus Accumbens is part from the mesolimbic system ( the major dopaminergic pathway of brain)
• Where your most primitive desires are kept
• Food , sex and other gratifying behaviours
• Drugs and alcohol play with the ( dopamine release ) from these circuits
• Alcohol make N. Acc. Release more dopamine
Controltaking
• Your thinking , your higher functions , your sensory perception , your balance and memory , your emotions and your logical judgment
• directly influenced by the reward circuits
Alcohol and neurotransmitters
• Inhibition of acetylcholine release
• Increase release of dopamine (happy)
• Enhancing GABA neurotransmission ( GABA has inhibitory action on neurons)
• Ca-k channel inhibition
• Decreasing glutamate levels ( excitatory)
guess what these changes can cause?
Acute effects of alcohol
• Euphoria
• CNS depression
• Disinhibition
• Poor judgment
• Decreased memory and concentration
• Decreased reflexes
• More prone to falls , RTAs
• Emotional outbursts
Is alcohol healthy ?
Its all related to the amount being consumed
If moderate : healthy
If excessive : unhealthy
Measuring alcohol
Alcohol is measured in units
Each unit contain 8 grams of absolute alcohol
Each unit needs 1 hour to be metabolized in liver
Up to 21 units / week / for men is good
Up to 14 units / week / for women
Excessive is bad
• Definition of Alcoholism : maladaptive alcohol use with clinically significant impairments
Acute alcohol poisoning
Medical ER
High levels of alcohol in blood sufficient to
induce coma , respiratory depression and
death !!
Signs and symptoms :
Severe confusion, stupor , unconsciousness
Vomiting while unconscious , seizures ,
decreased resp. rate , central cyanosis
Acute alcohol poisoning
• Diagnosis : clinical then for alcohol levels in blood .
• Managing : ABC
Important to ensure Airway, tongue, vomitus ..
If unconscious : intubate
Breathing : give O2
Circulation : check O2 sats
Acute alcohol poisoning
• Also :
Treat hypoglycemia if present by 50% glc water
Give thiamine to prevent Wernickes – Korsakoff syndrome
Treat nausea , anxiety , tremor
Hemodialysis if severe intoxication
Chronic alcoholism
• Memory impairment
• Ataxia
• Vision changes
• Depression
• Irritability
• Sleep disorders
• Anxiety
Effects of alcohol depend on
• Frequency of drinking
• Quantity of drinking
• Age onset of drinking
• Duration of drinking
• Gender
• Genetic factors
• Family history of alcoholism
• Diet and general health
Chronic effects of alcohol / diseases
• Withdrawal
• Wernicke's – Korsakoff syndrome
• Alcoholic neuropathy
• Alcoholic cerebellar degeneration
• Alcoholic myopathy
• Fetal alcohol syndrome
• Dementia
• Neurological manifestations of liver disease
Withdrawal
• Sudden cessation of drinking
• Hyper excitability of the nervous system
• Insomnia , agitation , delerium , auditory and visual hallucinations
• Autonomic hyperactivity ( BP , heart rate …)
• Usually 6-8 hours after abstinence
• May lead to seizures (grand mal seizures)
Management of withdrawal
• Treat associated electrolyte abnormalities .
• Correct hyperthermia
• Fluid replacement
• Sedation with tapered dose of BDZ for 5 days
syndromeWernicke - Korsakoff
• Thiamine deficiency in alcoholics ( and others)
• Initial phase is Wernicke which is triad of :
• Mental confusion
• Oculomotor disturbance
• Cerebellar ataxia
• May progress to stupor , coma or even death if undiagnosed or untreated well
• Nystagmus , 6th palsy , Gait ataxia
syndromeWernicke - Korsakoff
• Korsakoff Follow the Wernickes encephalopathy• Retrograde and anterograde amnesia and other
features .
• Rx of w-k syndrome :• Iv thiamine 100 mg for 5 days• Alcohol Detox prophylaxis (BDZ)• (Fluid is N/S) never give GLC water• Daily oral thiamine 1oo mg after discharge
Peripheral neuropathy
• Distal ,sensory or sensory-neural polyneuropathy
• Tingling sensations , burning pain in the extremities
• Sometimes distal muscle weakness and atrophy
• Ankle reflex diminished
• Autonomic disturbances (impotence , sweating abn. ….)
Alcoholic cerebellar degeneration
• Slowly progressive cerebellar degeneration
• Occurs in severe alcoholics
• Anterior and superior vermis is involved
• Ataxic , wide based gait
Alcoholic myopathy
• Chronic painless syndrome of proximal muscle weakness and wasting
• Usually after several days of heavy binge drinking
• maybe severe , leading to rhabdomyolysis and hyperkalemia
Fetal alcohol syndrome
• Happens in infants of alcoholic mothers
• Prenatal ethanol exposure impairs fetal growth and development
• distnictive dysmorphic features :
1. Short palpebral fissures
2. Thin upper lip
3. Flat midface
4. Short stature and microcephaly
5. Mental retardation
Hepatic encephalopathy
• Liver is diseased, cant metabolize ammonia
• High ammonia levels in the brain
• Ammonia enhance release of GABA in the brain
• GABA is inhibitory for neurons
• Change in sleeping pattern , psychological changes , then disturbances in level of consciousness .
Others
• Alcoholics more susceptible to falls ( subdural hematomas and brain cuncussions)
• Injuries to peripheral nerves ( Saturday night palsy)
• Road traffic accidents
• Crimes
In summary
• Reward circuits are crucial for life , and very important in neurobiology of addiction.
• The dolma principle of addiction
• Alcohol plays with neurotransmitters to control the brains
• Effects are either acute or if long-standing : chronic and lead to many diseases