Week 6 Flashcards
What is the mechanism of action of benzodiazepines?
activate more frequently the GABA-A receptor (GABA agonists) - which functions as a Chloride ion channel
What type of epilepsy episode is benzodiazepines used for?
status epilepticus(lorazepam, diazepam, midazolam)
Most benzodiazepines have long half-lives and active metabolites except…? (remember acronym)
ATOM are short acting with higher addictive potential1. alprazolam2. triazolam3. oxazepam4. midazolam
What is the common suffixes for benzodiazepines? (2)
-pam-lam (theres also chlordiazepoxide)
Treat overdose of benzodiazepines with?
Flumazenil (competetive agonist at GABA receptor)## Footnote* But can precipitate seizures by causing acute benzodiazepine withdrawal
How do barbiturates work against seizures?
- MOA: bind to allosteric site on GABA-A receptor → improving the effects of GABA
- The GABA-A receptor is a chloride channel - leads to hyper-polarization which inhibits synaptic transmission
- Barbiturates increase the duration of Chloride ion channel
Phenobarbital
1. what type of drug is this
2. what types of seizures is this used for? (3)
- Barbiturate
- Focal, general tonic clonic, status epilepticus (for stat. ep. -> use other drugs first and then barbiturate is last choice)
Phenobarbital
1. side effects
- sedation -> cardio and respiratory depression, CNS depressoin
Primidone
1. what type of drug is this?
2. What disorders is this used for?
3. side effects
- barbiturate
- used to treat seizures and essential tremor
- sedating effects of barbiturates
Valproate
1. what kind of drug is this
2. MOA
3. what seizure types is this used for?
- Broad spectrum anticonvulsant
- binds VG Na+ channels to prevent high freq. firing of neurons
- focal, generalized, absence
Valproate
1. side effects
VALPPROaTTE
VALPPROaTTE:
1. Vomiting
2. Alopecia
3. Liver damage (hepatotoxic)
4. Pancreatitis
5. P-450 inhibition
6. Rash
7. Obesity (weight gain)
8. Tremor
9. Teratogenesis (neural tube defects)
10. Epigastric pain (GI distress)
Topiramate
1. what kind of drug is this
2. MOA (2)
3. what seizure types is this used for?
- broad spectrum anticonvulsant
- Binds to VG Na+ channel AND binds to GABA-A to potentiate effects of GABA
- focal and generalized tonic clonic
Topiramate
1. side effects
1.Sedation
2.slow cognition
3.kidney stones
4.skinny (weight loss)
5. sight threatened (glaucoma)
6. speech (wordinding) dificulties
Lamotrigine
1. what kind of drug is this
2. MOA
3. what seizure types is this used for? (3)
- broad spectrum anticonvulsant
- Binds to VG Na+ channels
- Focal, generalized tonic clonic, absence (not as effective for absence as other meds)
Lamotrigine
1. side effects
- SJS
- Diplopia
Levetiracetam
1. what kind of drug is this
3. what seizure types is this used for?
4. side effects
- broad spectrum anticonvulsant
- Focal, generalized tonic clonic, absence
- somnolence
Carbamazepine
1. what kind of drug is this
2. MOA
3. what situations is this used for?
- narrow spectrum anticonvulsant
- Increases Na+ channel inactivation duration
- partial/focal seizure BUT it is actually first line med for trigeminal neuralgia
Carbamazepine
1. side effects
- Diplopia
- ataxia
- agranulocytosis
- liver toxicity
- teratogenesis (cleft lip/palate, spina biida)
- induction of cytochrome P-450
- SIADH
- SJS
Phenytoin
1. what kind of drug is this
2. MOA
3. what situations is this used for?
- narrow spectrum anticonvulsant
- increases duration of Na+ channel inactivation
- given as maintenance therapy after status epilepticus + can be used for partial/focal seizures too
Phenytoin
1. side effects
PPHENY TOIN
PPHENY TOIN:
1. cytochrome P-450 induction
2. Pseudolymphoma
3. Hirsutism
4. Enlarged gums
5. Nystagmus
6. Yellow-brown skin
7. Teratogenicity -cleft palate
8. Osteopenia
9. Inhibited folate absorption
10. Neuropathy
Gabapentin
1. what kind of drug is this
2. MOA
3. what situations is this used for?
- narrow spectrum anticonvulsant
- blocks VG Ca2+ channels
- Peripheral neuropathy/pain but also partial/focal seizures
Gabapentin
1. side effects
- sedation and ataxia
Vigabatrin and Tigabine
1. What kind of drug is this
2. MOA
3. what situations is this used for?
- narrow spectrum anticonvulsants
- two methods of increasing GABA
- partial seizures
Ethosuximide
1. What kind of drug is this
2. MOA
3. what situations is this used for?
- anticonvulsant
- Blocks T type Ca2+ channels in the thalamus
- 1st line treatment for absence seizures in children
- What pattern is necessary for epilepsy dx?
- atleast 2 unprovoked seizures occuring >24 hours apart
How do you differentiate post-ictal state vs cardiac syncope?
- After cardiac syncope you are immediately aware of your surroundings but in post-ictal state pt is confused and lacks alertness
Generalized
1. What part of brain is affected?
2. What are the types? (4)
- entire brain
- Absence “petit mal”, tonic clonic “grand mal”, Atonic “drop seizure”, and myoclonic
Generalized Tonic Clonic “grand mal”
1. presentation
- Tonic - pt clenches their muscles
- Clonic - muscles begin jerking
- Involves muscle groups of arms and legs
- It is immediate, brutal loss of consciousness
Absence “petit mal”
1. Common in what type of patient
2. presentation
- common in children
- Child stares off into space and eye rolling may be seen
this needs to be dx
Atonic “drop seizure”
1. presentation
- pt drops to ground with flaccid muscles
Myoclonic seizure
1. presentation
- Myoclonic seizures are characterized by a sudden body “jolts” or increases in muscle tone as if the person had been jolted with electricity.
Focal (partial) seizures
1. involves what part of brain
2. What are the two types
- discrete part of brain - various parts
- Simple partial (discrete part of brain with no alteration of consciousness) ;;; Complex partial (discrete part of brain with altered consciousness)
- What is the most common part of the brain that is affected in focal seizures?
- what changes are seen in the brain?
- Temporal lobe (Mesial temporal sclerosis)
- neuronal loss in hippocampus
What is secondary generalized seizures?
- begins as focal seizures then becomes generalized
What sx are seen from a temporal lobe epilepsy disorder?
- loss of consciousness
- motor automatisms (chewing, lip smacking, etc)
- langugae disturbances
Juvenile Myoclonic Epilepsy
1. common patient
2. presentation
3. Hallmark sx
- common in children
- Can include absence (around 5 years old), myoclonic jerks: bilateral, predominate in upper limbs and occurs WITHOUT LOC (around 15 years old), and grand mal seizures soon after
- Myoclonic jerks on awakening from sleep
Childhood Absence Epilepsy
1. presentation
2. Classic EEG finding
3. First line treatment
- sudden impairment of consciousness - no change in body/motor tone and lasts few seconds
- 2.5-5Hz spike wave activity
- Ethosuximide
Childhood absence epilepsy
1. How long do episodes last?
2. When does disorder remit?
- a few seconds
- remits by puberty
History, clinical exam, blood test, EEG, then MRI brain scan -> an example of evaluation of first time what? (BLANK A)
- First seizure
Nodopathy (type of neuropathy)
- Any peripheral neuropathy caused by changes restricted to the nodes of Ranvier and paranodal regions → via direct injury
Axonal neuropathy
- lack of effective axonal transport. Disruption to this can cause distal axonal degeneration
- Most axonal neuropathies start with injury of small fibers followed by arge fibers
Diabetes related neuropathies
1. Which nerve fibers are damaged? small or large?
2. Positive sx
3. Negative sx
- Gradual loss of integrity of both
- excessive sensation like prickling and tingling
- numbness, sensory loss w/ severe pain, limitation of activities
How is diabetic neuropathy dx?
- Via a nerve conduction study which can detect large nerve fiber injury only
What are some sx of peripheral neuropathy?
- Altered distal symmetric sensory sx
- Distal symmetric sensory loss
- Diminished reflexes
What type of neuropathy do toxins like amiodarone, n-hexane, arsenic cause?
- demyelinating neuropathy
injury of schwann cells which leads to negative effects on myelin
Guillen bare syndrome
1. presentation
2. sx
3. When do sx end?
- ascending muscle weakness over days and weaks leading to quadriparesis (starts in legs)
- Decreased/absent reflexes
- respiratory failure
- facial muscle weakness
- mild sensory deficits
- dysautonomia
sx resolves over weeks to months
Guillen Barre
1. When or why does it occur?
2. pathophysiology
- often begins after URI or gastroenteritis
- acute inflammatory demyelination due to schwann cells being destroyed by immune system
Chronic inflammatory demylinating polyneuropathy (CIDP)
1. time course
2. Affects proximal or distal limbs? (in what way?)
3. sx
- over 8 weeks
- progressive symmetric proximal and distal weakness and sensory deficit
- distal limb pains, fatigue, autonomic dysfunction, CN dysfunction, decreased/absent reflexes
Wernicke Encephalopathy is due to a deficiency in what vitamin?
Thiamine deficiency
Wernicke Encephalopathy (part of wernicke korsakoff syndrome)
1. what symptoms present
2. changes to brain
3. Is this an acute or chronic presentation?
- confusion, paralysis of eye movements with nystagmus, gait ataxia, can progress to coma or death
- punctate hemorrhages and necross adjacent to third ventricle, aqueduct, and fourth ventricle
- Acute - neurologic emergency
Korsakoff Psychosis (part of wernicke korsakoff syndrome)
1. what symptoms present
2. changes to brain
3. Is this an acute or chronic presentation?
- amnesia with confabulation
- Remote hemorrhagic lesions with atrophy, cystic degeneration, and hemosiderin deposition -> especially mamillary bodies and thalamus
- Chronic
Thiamine deficiency is most commonly seen in what type of patient?
alcoholics
What changes to CNS can happen with vitamin B12 deficiency
- degeneration of spinal cord (dorsal and corticospinal tracts) - image shows less dark blue areas in these tracts
Chronic alcoholism can cause degeneration in what part of the brain
- cerebellar vermis - loss of granule and purkinje cells
Carbon monoxide toxicity
1. what happens to brain?
- Bilateral necrosis of globus pallidus
+ other changes similar to global hypoxia
Hepatic encephalopathy
1. presentation/sx
2. caused by?
- alteration in consiousness such as confusion or coma, asterixis, elevated blood ammonia levels cause these sx
- hepatic disorder
Neurulation
1. when does it occur
2. explain the process
- ## Begins in the 3rd week
- Notochord induces overlying ectodermal cells to differentiate into a thick plate of pseudostratified columnar neuroepithelial cells/neuroectoderm → this is forming of neural plate (neural induction)
—> Cells of notochord block BMP4 signaling pathway to inhibit the overlying ectoderm cells from becoming skin and instead allow them to become neuroectoderm