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30 Cards in this Set
- Front
- Back
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What is the difference between a seizure and epilepsy?
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Seizure = an episode of inappropriate electrical activity in the brain
Epilepsy = when seizures happen regularly |
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There are FOUR (4) key words used in the ICES classification of seizures. Provide a definition for EACH of these key words a epilepsy.
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Partial = seizures that occur within localised areas of the brain
General = seizures that appear throughout the forbain (at least at the beginning of the seizure activity) Simple = little or no disruption of consciousness or cognitive ability Complex = major or complete disruption of consciousness or cognitive ability |
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A patients epilepsy is described as having simple partial seizures. Provide a brief description of this type of seizure (HINT: duration ? Physical manifestations? state of consciousness?)
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- generally small, rapid muscle movements (might resemble a "tic" if facial muscles involve)
- can have sensory (numbness, tingling in body parts) - preservation of consciousness key feature - lasts 20 - 60 seconds |
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Another patients is described as having complex partial seizures. Provide a brief description of this type of seizure
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- Impaired consciousness - glazed, vague, dream-like state
- duration = 30 sec - 2 min - associated with purposeless movements ie (face washing) - little to no memory of seizure |
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A patient is described as having myoclonic seizures. provide a brief description of this type of seizure.
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- Brief, marked contraction of muscles (shock-like jerk)
- Less than 30 seconds often only a few seconds 1 - 5 secs - may be restricted to a specific muscle group or may involve a number of muscle groups |
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A patient is described as having tonic-clonic seizures. Provide a brief description of this type of seizure.
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- initial rigid extensor spasm (tonic)
- momentary cessation of breathing, loss of control of vowels - repetitive muscle spasming (convulsing) may be quite severe (clonic) - associated with loss of consciousness - last 2 min up to many minutes - followed by post-seizure coma |
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A patient is described as having absence seizures. Provide a brief description of this type of seizure.
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- temporal lobe epilepsy
- activity does not cease, only awareness/memory -"automatic pilot" - individuals appear to interact with others but is not truely voluntary - physical activity may continue provided it is a well-learned pattern (eg walking, driving) |
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A patient has temoral lobe epilepsy. provide THREE (3) examples of the sort of seizures that might occur in a patient with temporal lobe epilepsy.
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- Religiosity - may hallucinate - visitations by religious figures
- Automatic activity - once initiated, automatic activity continues until seizure stops or something prevents ongoing activity - sexually inappropriate behaviour - verbal or physical advances of inappropriate sexual behaviour |
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It is not unusual for certain epilepsies to be missed or misdiagnosed. Provide a brief explanation for why epilepsy might be missed or misdiagnosed.
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- Because some types of epilepsy are so mild that you wouldn't think they are a seizure
- because there are symptoms that could be mistaken for other conditions ie day dreaming |
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Although the anti-epileptic drugs are considered stand-alone agents, you can broadly group their mechanism of action into THREE (3) classes or groups. What are these 3 "groups" for the mechanisms of action of the anti-epileptic drugs and which drugs belong to each "group".
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- Drugs that boost gaba: barbituates, bennzos, Gaba pentin
- drugs that block sodium channels: * phenytoin * carbamazepine * valproic acid sort of - drugs that block calcium channels in the thalamus * ethosuximide * valproic acid |
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A 15 year old girl comes into A & E having had a tonic-clonic seizure. On questioning her, you learn that she abruptly stopped taking her anti-epileptic medication because the side effects were embarrassing. there are 2 drugs that we discussed that have side effects that this girl might find embarrassing enough to prompt her to quit taking her treatment. What are the two drugs and what are the side effects that would create this problem?
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- Phenytoin - hirsutism (excessive hair growth)
- Ethosuximide - alopecia |
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Both benzodiazepines and barbiturates increase the amount of GABA signalling but these two groups of drugs accomplish this in very different ways. Explain how benzodiazepines and barbiturates can augment GABA signalling even though neither drug is an agonist.
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- Benzodiazepines allow GABA to open more channels
- Bartiturates make channels stay open longer causing GABA 'A' channel to produce more inhibition of neuronal firing |
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What is the mechanism of action of all local anaesthetic drugs?
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- block Na+ and neurons can't fire
- prevents transmission of noci-ceptive and mechanical signals to the brain (because neuron action potential uses Na+ to depolarise and K+ to repolarise) |
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Local anaesthetics are weak bases. what is the implication of this information when considering the route of administration of a local anaesthetic?
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If the PH drops (becomes acidic), local anaesthetic compounds become very ionised. Change in charge prevents migration across the cell membrane and prevents binding of drug to ion channel
- During inflammation the drug becomes acidic therefore allows very little anaesthetic to penetrate the nerve and block transmission. |
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Both Bier's block and epidurals are potentially dangerous for the patient. Provide a BRIEF description of each and explain why the method is dangerous.
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- Biers Block. requires diminished blood supply to the target region via elastic bandage, then tourniquet or BP Cuff to further reduce blood flow. Bandage is removed and local anaesthetic injected via line or canula
- risk of ischaemia due to tourniquet - anaesthesia is injected into the epidural space target is spinal cord roots - risk of neurological damage if sub arachnoid space hit instead |
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Which route of administration of a local anaesthetic is recommended for tissues that are necrotic, ischaemic or have encapsulation? why is this methoc recommended (i.e. what advantage does it have over other methods?)
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Nerve block is good as it allows you to inject distally and anaesthetise the whole leg
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What is the primary difference between a nerve block and infiltration anaesthesia?
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Infiltration you inject directly into target tissue whereas nerve block you inject around peripheral nerves
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Briefly outline the TWO (2) theories for the mechanism of action of inhaled general anaesthetic gases.
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- Lipid Theory: This theory proposes alterations to membrane stability if you increase the volume of the membrane by adding anaesthetic to it, you'll compress ion channels and receptors, making them unable to function
- Protein (GABA) Theory: inhaled anaesthetics inhibit the action of glutamate and augment the action of GABA * GABA inhibits brain activity therefore inhaled anaesthetics would increase depression of brain signalling * Glutamate excites brain activity therefore inhaled anaesthetics would prevent brain excitation |
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A scale was created to provide an index of the dose of an inhaled general anaesthetic gas call MAC. what does MAC stand for?
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Minimum Alveolar Concentration
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MAC is said to be independent of height and weight, whereas many drugs are delivered as a certain amount per kg body weight. Why do height and weight have no bearing on MAC?
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MAC is only about the brain and everybody's brains are the same size. Although MAC is dependent on Age and Temperature as these will influence metabolic rate, sensitivity of tissue to the drugs.
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By contrast, the induction and recovery times do depend on height and weight. What do we mean by induction and recovery times and what are the FOUR (4) factors that primarily influence uptake and distribution of the inhaled general anaesthetic gases?
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Distribution = the movement of agent throughout the body. This will effect the time it takes for the person to become anaesthetised - rate of induction. Time it takes for the person to come out of anaesthetic state = recovery time. 4 factors responsible for partial pressure:
* Concentration of drug in the inspired gas * Pulmonary ventilation during drug delivery * Gas exchange in the lungs * loss of drug to tissues other than the brain |
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what does the anaesthetist mean when they say that MAC values are additive?
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You can mix drugs for example 0.5MAC + 0.5 MAC = 1 MAC
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Briefly explain the THREE (3) components of general anaesthesia?
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- Analgesia =
* pre-emptive blockade of pain * decrease anxiety / stress - Loss of consciousness with amnesia * May not be necessary in every case * allows intervention of a more controlled nature - Muscle relaxation * ease of access to surgical site * decrease amount of inhaled anaesthetic required * Minimise cardiovascular depression |
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What is the role of drugs such as thiopentone and ketamine in creating a surgical anaesthetic state?
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Thipentone:
* is a barbiturate that acts on GABA receptor ion channels like a "chemcial stent" * Propofol is also used but does not appear to have a specific target Ketamine: * Is a glutamate NMDA receptor antagonist * prevents brain excitation |
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What is meant medically by the words sedation, hypnotic and anxiolytic?
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- Sedative = any compound which reduces the overall activity and diminishes the level of excitation of an organ or tissue
- Anxiolytic = any compound which reduces anxiety to manageable proportions - Hypnotic - any compound which induces drowsiness |
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The diagnosis of anxiety and anxiety disorders relies heavily on patient self-report. what are the manifestations of so-called pathological anxiety?
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- Verbal complaint
- Somatic and/or autonomic alterations ie restlessness, agitation, tachycardia, increased sweating, inappropriate weeping, gastrointestinal distress - interference with normal productivity |
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Two types of anxiety are "phobic" anxiety and "panic disorder". Briefly describe these two conditions.
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- Phobic anxiety - associated with recognisable trigger (eg open spaces, speaking in public)
- In certain circumstances pt can be "desensitised" to the trigger. Panic disorder - no apparent trigger - patient is overwhelmed, a reaction is "stereotyped". |
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What are the 2 types of partial seizures. Provide a brief description of each.
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Simple:
* little of no disstruption of consciousness or dognitive ability * duration: 20 - 60 secs * numbness, tingling, blushing, nausea, hallucination Complex: * Major or complete disruption of consciousness or cognitive ability * duration: 30 secs - 2mins * hand washing, pill rolling, face washing, fidgeting, walking around, mumbling |
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What is the mechanism of action of carbamazepine and what is ONE (1) side effect of this drug?
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- Slow rate of recovery of voltage-gated Na+ channel > decrease recover > decreases repetitive firing
- reduces firing rate of neurons & excitability - Side effects: Nausea, headache, live/kidney disruption, vomiting, sedation, sleepyness. |
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Why does the doctor need to be careful about the route of administration of a local anaesthetic for a patient with a broken arm that is very swollen?
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Local anaesthetic is a weak base. The oedema is acidic. Therefore the drug will be in a charged environment.
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