Case 3 - alcohol Flashcards
how is alcohol absorbed
absorbed form the upper small intestine via the portal vein and is then transported to the liver
what is some alcohol in the stomach metabolised by
alcohol dehydrogenase
why is womens safe limit less than men
they have a lack of alcohol dehydrogenase
where is the rest of alcohol metabolised
the liver
what happens in the liver to this alcohol
converted to acetaldehyde and excreted by conversion to carbon dioxide in citric acid cycle
what enzyme is involved in the metabolism of alcohol in the liver
cytochrome p4502E1
what is alcohol at low levels
a stimulant
what happens if there is chronic use of alcohol
it has depressant effects on the CNS , mainly depression of cardiovascular and repsiratory centres in the brainstem
at low doses, what does alcohol protect against
atheromas
what is Wernicke’s encephalopathy
decreased thiamine effects mammiliary bodies in the brain
what is induced in alcohol related disease mechanisms
induction of enzyme systems, especially cytochrome p450
what is the biggest nutrient deficiency
vitamin B
what is the early change in alcohol liver disease
acute fatty change
which area does this acute fatty change usually affect
predominantly acinar zone 3 - this area is furthest away from a blood supply
features of acute fatty change
Mainly large droplet
May cause acute hepatic failure
Reversible on withdrawal of alcohol
what is alcoholic hepatitis
alcoholic steatohepatitis
what is alcoholic steatohepatitis
fatty change, mainly large droplet
what is there an accumulation of in alcoholic hepatitifs
Intracytoplasmic accumulation of cytoskeletal components (keratin)
what is associated with alcoholic steatohepatitis
associated neutrophil polymorph infiltration
what is non-alcoholic steatophepatitis
Identical features to alcoholic hepatitis
Associated with obesity, diabetes mellitus, hyperlipidemia, drug use (corticosteroids)
May progress to fibrosis and cirrhosis
Reversible on correction of underlying factor
what is hepatic fibrosis, where does it start and what is it caused by
Starts in acinar zone 3
Initially pericellular fibrosis
Caused by activation of hepatic stellate (ito) cell = facultative myofibroblast
Reversible by TIMPs on withdrawal of alcohol
is cirrhosis reversible
no
what happens when there is liver failure as a result of cirrhosis
Protein synthesis: low albumin
Coagulation factors: bleeding
Hyperoestrogenism: gynacomastia, gonadal atrophy, Dupuytren’s contracture, liver palms, spider naevi
Jaundice
Encephalopathy: confusion
what are the blood tests that can be done to identify heavy drinkers
gamma glutamyl transferase (GGT)
Mean corpuscular volume (MCV)
Screening tools:
CAGE or AUDIT can help
what score on the CAGE test is clinically significant
2 or greater
what is an addict
someone who has no control over their behaviour, lacks moral fibre, uses a maladaptive coping mechanism and has an addictive behaviour
what is addiction
: a need for a drug, the use of a substance that is psychologically and physiological addictive, showing tolerance and withdrawal
what is dependency
showing psychological and physiological withdrawal
what are the three theories of addiction
Moral model; addiction as a result of weakness and a lack of moral fibre
Biomedical model; addiction as a disease
Social learning theories; behaviours that are learned according to the rules of the learning theory
what is the moral model of addiction
addicts are weak, and can overcome a compulsion to use with willpower
Drug abusers choose to use drugs
Drug abusers are anti-social and should be punished
Drugs are evil
what is the biomedical model of addiction
addiction is a brain disease
Neurotransmitter imbalance
Disease model:
Agent: drug
Vector: dealers
Host: addict
need to stamp out the disease by eliminating drugs
Drug antagonist medicine e.g Wellbutrin, naltrexone, Antabuse
what is the social model of addiction
drug use is a learned behaviour
Classical conditioning: associative behaviour
Operant conditioning: probability of behaviour occurring Is increased if it is either positively reinforced by the presence of a positive event, or negatively reinforced by the absence or removal of a negative agent
Observational learning/modelling: behaviours are learnt by observing significant others carrying them out
Cognitive factors: factors such as self image, problem solving behaviour, coping mechanisms
what does alcohol do to GABA interneurones
alcohol inhibits the inhibition of GABA interneurones have on dopamine neurones
what happens when dopamine interneurones are dis inhibited
increase in dopamine
what happens when there is extra dopamine in the brain
the dopamine receptors up regulate
what happens then, when you are presented with the stimulus of alcohol
your response is dampened, therefore you have to drink more to maintain the state of reward sensation and so you become addicted
