Pathophysiology Flashcards
What is Delirium Tremens (DT)?
DT is the most serious withdrawl state in Alcohol withdrawl (effects 5% of patients undergoing alcohol withdrawl.
It is characterised by disorientation, agitation, marked tremor and visual hallucinations.
Signs include sweating, tachycardia, tachypnoea and pyrexia.
Complications include: dehydration, infection, hepatic diseae, Wernicke-Korsakoff’s syndrome.
What is the symptom triad of Wernicke’s encephalopathy?
Wernicke’s encephalopathy is characterised by:
1. Confusion
2. Ataxia
3. Nastigmus (apparent in controlateral eye in abduction
What is Korskoff’s syndrome
If untreated Wernicke’s encephalopathy progresses to (irreversible) Korskoff’s syndrome. Korskoff’s syndrome involves significant memory loss (unable to form new memories (anterograde amnesia) or call up exising memories (retrograde amnesia). This characteristically presents with confabulation.
Diagnostically, clinical impression of above; bloods show thiamine defficency; MRI shows degeneration of the mamillary bodies.
Is Wernickie’s encephalopathy reversible?
Yes - thiamine, thiamine, thiamine!
Is Korskoff’s syndrom reversible?
NO - permenant and severe anterograde and retrograde amnesia; confabulation characteristic to fill in memory ‘gaps’, MRI mamillary body degeneration.
Wernicke’s is a medical emergency. How do you treat Wernicke’s?
- Thiamine IV
- Correct electrolyte imbalance & rehydrate.
- Provide dextrose when thiamine levels improve (not prior or metabolic acidosis a risk).
Why is metabolic acidosis a risk when dextrose (glucose solution) is given to a patient with Wernicke’s encephalopathy prematurely?
What areas of the brain are relevant to substance dependence?
The most prominant area of the brain relevant to substance dependence is the ‘reward pathway’ otherwise known as the mesolimbic system / pathway.
The mesolimbic pathway begins in the VTA (vental tegmental area (of the midbrain) which houses a relative high density of dopaminergic neurons. When stimulated these neurons send dopamine (released from their terminal buttons) to areas including the amygdala and the nucleus accumbens of the striatum.
This increase in dopamine is believed to be responsible for the positive reinforcers (euphoria, relaxation, sleepiness) in susbstance abuse.
Other areas of the brain activated by the reward pathway include cortical regions such as the prefrontal cortex, cingulate and the occipital cortex; all to a lesser extent than the amygdala and nucleaus accumbens.
What does alcohol do to the nerve cell membranes and link this to behavioural change in users?
Alcohol allosterically binds to receptors on the GABBA A receptor proteins causing hyperpolarisation of the post synaptic neuron. This is achieved by causing a conformational change to the GABBA A receptor which increases the receptors affinity to the GABBA neurotransmitter. Increase affinty results in increased opening of the GABBA A receptor channel and thus and increased influx of Cl-.
GABBA normally functions to inhibit other neruons int he CNS. When alcohol causes reduced GABBA activity the net effect is increased excitation within the CNS.
Behaviour changes such as slower processing time, response time and slurred speech are in part a reflection of the depressive effects on the CNS that alcohol induces.
What does benzodiazapines do to the nerve cell membranes and link this to behavioural change observed in users?
Benzodiazapines allosterically binds to Benzo receptors on the GABBA A receptor proteins causing hyperpolarisation of the post synaptic neuron. This is achieved by causing a conformational change to the GABBA A receptor which increases the receptors affinity to the GABBA neurotransmitter. Increase affinty results in increased opening of the GABBA A receptor channel and thus and increased influx of Cl-.
GABBA normally functions to inhibit other neruons int he CNS. When benzodiazapines causes reduced GABBA activity the net effect is increased excitation within the CNS.
Behaviour changes sleepiness, slow processing time and respiratory depression are examples of the depressive effects on the CNS that alcohol induces.
What does opoids do to nerve cell membranes and link this to behavioural change observed in users?
Opioids function by increasing the levels of dopamine present within the sypnaptic cleft of dopaminergic neurons in 4 main ways.
1. Blocking reuptake protiens,
2. Binding regulatory protiens,
3. Blocking enzymes from mitochondira that degrade reabsorbed dopamine not yet packaged into vesicles.
4. Altering affinity / agonising post synaptic receptors (Mu, Kappa & Delta).
Over stimulation of dopaminergic pathways such as the mesolimbic results in euphoria, reduced pain perception and behaviour inhibition reduction observed in users.
Dependency is defined as an individual exhibiting 2 or more of the following 11 criteria. Name as many as you can….
Dependency is defined as an individual having two or more of the following:
1. Uses a substance for longer or in quantities greater than intended,
2. Has developed tolerance to the substance,
3. Experiences withdrawal symptoms when not using the substance,
4. Spends much of their time using or obtaining the substance,
5. Gives up activities (work, school, home) to use or obtain the substance,
6. Experiences social / interpersonal problems associated with use,
7. Exhibits hazardous use,
8. *Neglects major roles *(work, school, home) to use,
9. Previously *failed attempts to quit *using the substance,
10. Has experienced problems with the law associated with their substance use,
11. Experiences physical / psychological problems associated with their substance use.
What are the chronic effects of alcohol use?
- Tollerence > withdrawl +/- addition
- Reduced liver function (steatosis > cirrhosis)
- Increased risk of cancer (oesophegeal, stomach, liver breast).
- Increased risk of psychological disorders (ie depression).
- Reduced cognition, memory (retrograde and anterograde) ie as seen in Korskoff’s syndrome).
Psychosocial effects can include:
* relationship deterioration,
* difficulty maintaining employment, etc
What are the chronic effects of benzodiazapine use?
- Dependence, withdrawal & addiction,
- Impaired cognition, memory loss,
- Anxiety and depression,
- Headaches,
- Nausea,
- Weight gain,
- Skin rashes,
- Personality change,
- Weakness lethargy and lack of motivation,
- Irritability, paranoia and aggression.
What does tollerence mean in the context of substance abuse?
Tollerence is when an individual requires greater amounts of a substance to achieve the desired effect.
List some psychosocial managment strategies for the treatment of substance abuse.
- Motivational interviewing.
- Brief interventions
- CBT (learn about withdrawal, discuss drivers for individuals alcohol use, create plan for navigating triggers for use.
- Peer support groups ie AA.
There are 9 types of anxiety disorders listed in the DSMV. List as many as you can.
- Generalised anxiety disorder
- Social phobia (including performance anxiety)
- Specific phobia
- Agoraphobia
- Selective mutism
- Panic disorder
- Medication induced anxiety disorder
- Anxiety disorder due to another medical condition
- Separation disorder.
What is unique about each of the following anxiety disorder subtypes when compared with generalised anxiety disorder?
- Social phobia (including performance anxiety)
- Specific phobia
- Agoraphobia
- Selective mutism
- Panic disorder
- Medication induced anxiety disorder
- Anxiety disorder due to another medical condition
- Separation disorder.
- Social: the anxiety centres around situations where individuals feel like others may be judging them.
- Specific: anxiety is linked to a very specific trigger ie heights, spiders etc.
- Agoraphobia: anxiety is associated with 2 of the following specific situations:
* standing in a line or crowd,
* leaving the individuals home alone,
* being in open spaces (park)
* being in enclosed spaces (lift),
* Using public transport. - Selective mutism: being unable to speak when expected to do so ie. when doing a speech.?
- Panic disorder: anxiety mainfests with at least one episode (usually no longer than 20mins) that involves 4 or more of the following: palpitations, sweating, dyspnoea, trembling, paresthesias (pins & needles), throat tightening, chest pain, nausea, dizziness, chills / hot flushes, fear of dying, fear of losing control, feelings of detachment / loss of reality.
- Medication induced anxiety: anxiety develops in direct link to onset of medication commencement or dosage increase.
- Anxiety due to another medical condition ie: hyper / hypothyroidism.
- Spearation disorder: anxiety occurs when separating from or thinking about separating from a person of significance to the affected individual.
