EXAM #3: ANTICONVULSANTS Flashcards

1
Q

What causes a seizure?

A

Abnormally excessive, synchronous, and rhythmic firing of populations of hyper-excitable neurons

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2
Q

What is epilepsy?

A

Chronic neurological disorder characterized by recurrent seizures

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3
Q

What is the general feature of partial seizures?

A

Only part of the brain is involved i.e. seizure stars in one region and remain there

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4
Q

What is the general feature of a generalized seizure?

A

Involvement of the entire brain with global EEG changes

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5
Q

What are the three subtypes of partial seizures?

A

1) Simple Partial
2) Complex Partial
3) Partial becoming generalized

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6
Q

What is a Simple Partial Seizure?

A
  • Seizure with no loss of consciousness and only focal involvement
  • Characterized by minimal spread of abnormal neuronal discharge
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7
Q

What is a Complex Partial Seizure?

A
  • Seizure with altered consciousness and potential automatisms
  • Focus originates in a small brain area and quickly spreads to other areas
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8
Q

What is a partial seizure becoming generalized?

A

Partial seizure that spreads throughout the brain and progresses to a generalizes seizure

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9
Q

What is the most common type of partial seizure?

A

Complex partial

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10
Q

What is an automatism?

A

Lip smacking
Fumbling
Swallowing

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11
Q

What is an Absence or Petit Mal seizure?

A
  • Brief LOC with some motor signs/ automatisms

- Typically seen in children

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12
Q

What is a Tonic-Clonic or Grand Mal seizure?

A

Prototypical seizure with tonic spasms and major convulsions with LOC

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13
Q

What are the stages of seizures?

A

1) Aura
2) Tonic phase–rigidity
3) Clonic phase–convulsions
4) Stuporous state/sleep

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14
Q

What is Status Epilepticus?

A
  • Continuous or very rapidly recurring seizures (tonic-clonic)
  • Medical EMERGENCY
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15
Q

What is an atonic seizure?

A

Sudden loss of muscle/ postural tone

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16
Q

What are the three stages of epileptic seizure generation?

A

1) Initiation i.e. lowered threshold of activation
2) Synchronization of surrounding tissue
3) Propagation and recruitment of normal neurons

17
Q

What is an EPSP?

A

Excitatory Postsynaptic Potential

18
Q

What is the molecular basis for EPSPs?

A

Na+ influx
Ca++ currents
Paroxysmal Deplarization

19
Q

What is the goal of antiepileptic medications?

A

Restoration of normal patterns of electrical activity

20
Q

What are the three drugs that are best to treat partial seizures?

A

Carbamazepine
Phenytoin
Valrpoate

21
Q

What are the drugs that are best to treat tonic clonic seizures?

A

Carbamazepine
Phenytoin
Valrpoate

22
Q

What drugs are best for treating absence/petite mal seizures? What ion channel do these drugs block?

A

Ethosiximide
Valproate

Ca++*

23
Q

What drugs are best for treating myoclonic seizures?

A

Clonazepam

Valproate

24
Q

What drugs are best for treating status epilepticus?

A

Diazepam
Lorazepam
Phenytoin
Fosphenytoin

25
Q

What is the general mechanism of action of anticonvulsant drugs?

A

Inhibit firing of hyperexctiable cerebral neurons

26
Q

How do anticonvulsants inhibit firing of hyperexcitable neurons?

A

1) Decrease excitatory effects of glutamate by blocking voltage-gated Na+ channels
2) Increase inhibitory effects of GABA
3) Alter neuronal activation by altering Ca++ currents i.e. block voltage gated Ca++ channels (T-type)

27
Q

What do Na+ blockers do in treating seizures?

A

Bind to the Na+ channel in inactive state and prevent conversion back to resting state

**This decreases sustained, high frequency, and repetitive discharge*

28
Q

What is the effect of reducing Ca++ influx in the pre-synaptic neuron?

A

Decreased NT release

29
Q

What type of seizures are Ca++ blockers best at treating?

A

Petit mal

30
Q

What are the side effects of anticonvulsant drugs?

A
  • Sedation
  • Diplopia
  • Nystagmus
  • Ataxia
  • GI upset
31
Q

What can happen with the abrupt withdrawal of anticonvulsants?

A

Increased potential for seizures

32
Q

What are the special considerations regarding anticonvulsants and women?

A

1) Decreases efficacy of oral contraceptives

2) Teratrogenic

33
Q

What anticonvulsant is considered to be the safest in pregnancy?

A

Phenobarbital