Epilepsy Flashcards
1
Q
What are the common symptoms of abnormal electrical activity in epilepsy?
A
Loss of consciousness, abnormal movements, atypical behavior, and distorted perception.
2
Q
What percentage of individuals are affected by epilepsy by the age of 80?
A
Approximately 3%.
3
Q
What is the rank of epilepsy among neurological disorders?
A
It is the 3rd most common after cardiovascular and Alzheimer diseases.
4
Q
What percentage of epilepsy cases can be completely controlled?
A
70-80%.
5
Q
What percentage of epilepsy cases require more than one drug?
A
10-15%.
6
Q
What percentage of epilepsy patients may not achieve complete seizure control?
A
10%.
7
Q
What is the cause of epilepsy in most cases?
A
In most cases, epilepsy has no identifiable cause.
8
Q
How can epilepsy be classified?
A
Idiopathic (unknown etiology) and symptomatic (secondary to an identifiable condition).
9
Q
What are some conditions that can cause symptomatic epilepsy?
A
Alterations in blood gases, pH, electrolytes, blood glucose level, sleep deprivation, alcohol intake, and stress.
10
Q
What is idiopathic epilepsy also known as?
A
Cryptogenic (primary) epilepsy.
11
Q
What is a key characteristic of idiopathic epilepsy?
A
No specific anatomic cause for the seizure is evident.
12
Q
What is the common cause of idiopathic epilepsy?
A
Inherited abnormality in the central nervous system.
13
Q
What type of epilepsy constitutes most cases?
A
Idiopathic epilepsy.
14
Q
What are some causes of symptomatic epilepsy?
A
Illicit drug use, tumor, head injury, hypoglycemia, meningeal infection, and rapid withdrawal of alcohol.
15
Q
Why is the appropriate classification of seizures important?
A
Because it leads to appropriate treatment.
16
Q
What characterizes a simple partial seizure?
A
Consciousness is preserved.
17
Q
What characterizes a complex partial seizure?
A
Loss of consciousness and possible memory impairment.
18
Q
What characterizes generalized seizures?
A
They involve both hemispheres of the brain and usually result in loss of consciousness.
19
Q
What part of the brain is affected by partial seizures?
A
Only a portion of the brain, typically one lobe of one hemisphere.
20
Q
What do the symptoms of partial seizures depend on?
A
The site of neuronal discharge and the extent to which the electrical activity spreads to other neurons.
21
Q
Is consciousness preserved during partial seizures?
A
Yes, consciousness is usually preserved.
22
Q
Where are the hyperactive neurons confined in a simple partial seizure?
A
To a single locus in the brain.
23
Q
Does the patient lose consciousness during a simple partial seizure?
A
No, the patient does not lose consciousness.
24
Q
What type of abnormal activity occurs in a simple partial seizure?
A
Abnormal activity of a single limb or muscle group.
25
What sensory symptoms are associated with simple partial seizures?
Sensory distortions.
26
What are the sensory and mental symptoms of complex partial seizures?
Complex sensory hallucinations and mental distortion.
27
What types of motor dysfunction can occur during complex partial seizures?
Chewing movements, diarrhea, and/or urination.
28
Is consciousness preserved or altered during complex partial seizures?
Consciousness is altered.
29
What characterizes generalized seizures?
They may begin locally and progress to both hemispheres of the brain, resulting in immediate loss of consciousness.
30
What are the phases of a tonic-clonic seizure?
Loss of consciousness followed by tonic (continuous contraction) and clonic (rapid contraction and relaxation) phases.
31
What are the characteristics of absence seizures?
Brief, abrupt, self-limiting loss of consciousness, onset at 3-5 years, with rapid eye-blinking lasting 3-5 seconds.
32
What characterizes myoclonic seizures?
Short episodes of muscle contractions that may recur for several minutes. These seizures usually occur after waking up, and manifest as brief jerks of the limbs.
33
What age groups are at risk of being affected by myoclonic seizures?
Can occur at any age but usually begins around puberty or early adulthood.
34
Who is most commonly affected by febrile seizures?
Young children.
35
What triggers febrile seizures?
Illness accompanied by high fever, resulting in generalized tonic-clonic convulsions of short duration.
36
What defines status epilepticus?
Two or more seizures occur without full recovery of consciousness between them, requiring emergency treatment.
37
What are the mechanisms of action for antiepileptic drugs?
Blocking voltage-gated channels (Na+ or Ca2+), enhancing inhibitory GABAergic impulses, and interfering with excitatory glutamate transmission.
38
What factors influence the choice of antiepileptic drug?
Classification of the seizures, patient-specific variables, and characteristics of the drug.
39
What is the initial treatment strategy for newly diagnosed epilepsy patients?
Monotherapy with a single agent until seizures are controlled or toxicity occurs.
40
What are the benefits of monotherapy in epilepsy treatment?
Better adherence and fewer side effects.
41
What are some 1st generation antiepileptic drugs?
Phenobarbital, phenytoin, carbamazepine, ethosuximide, divalproex, and valproic acid.
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42
What are some 2nd generation antiepileptic drugs?
Gabapentin, lamotrigine, levetiracetam, oxcarbazepine, topiramate, and zonisamide.
Great Lions Leap Over Tall Zebras
43
What is the mechanism of action for benzodiazepines in epilepsy?
They bind to GABA inhibitory receptors and reduce the firing rate of neurons.
44
For which types of seizures are diazepam and lorazepam used?
Myoclonic, partial, and generalized tonic-clonic seizures.
45
Why is diazepam available for rectal administration?
To avoid prolonged generalized tonic-clonic seizures.
46
What is the first-line treatment for status epilepticus according to FDA guidelines?
Benzodiazepines, specifically diazepam and lorazepam.
47
What is the mechanism of action for carbamazepine?
It blocks sodium channels, inhibiting repetitive action potentials and preventing their spread.
48
For which conditions is carbamazepine effective?
Partial seizures, generalized tonic-clonic seizures, trigeminal neuralgia, and bipolar disorder.
49
Why should carbamazepine not be prescribed for patients with absence seizures?
Because it may cause an increase in seizures, due to the activation of GABA receptors in ventrobasal complex (which aggregates absence seizures).
50
What are some side effects of carbamazepine?
Diplopia, blurred vision, and hyponatremia.
Can't see straight, can't see shit, can't keep the fucking salt.
51
What is a significant metabolic effect of carbamazepine?
It induces its own metabolism and increases the metabolism of other drugs through CYP450 and UGT enzyme induction.
52
What is the active metabolite of carbamazepine?
Epoxide metabolite --> Causes blood dyscrasias.
53
What is oxcarbazepine and how is it activated?
It is a prodrug reduced to the monohydroxy (MHD) metabolite, which is responsible for its anticonvulsant activity.
54
What is the mechanism of action for oxcarbazepine?
It blocks sodium channels, preventing the spread of abnormal discharge.
55
For which type of seizures is oxcarbazepine effective?
Partial onset seizures.
56
How does oxcarbazepine compare to carbamazepine in terms of drug interactions?
It is a less potent inducer of CYP3A4 and UGT, resulting in lower drug-drug interactions.
57
What are some side effects of oxcarbazepine?
Nausea, vomiting, headache, and visual disturbances.
Feel like I am gonna puke, fuck, I am vomiting, shit, my head's fucked up and I can't see shit.
58
What is the mechanism of action for phenytoin and fosphenytoin?
They block voltage-gated sodium channels by binding to the inactive state and slowing recovery. At high concentrations, phenytoin can also block calcium channels and interfere with monoaminergic neurotransmitters.
59
For which conditions is phenytoin effective?
Partial seizures, generalized tonic-clonic seizures, status epilepticus, and trigeminal neuralgia.
60
Why should phenytoin not be used in absence seizures?
Because it can exacerbate absence epilepsy.
61
What are some side effects of phenytoin?
CNS depression causing nystagmus and ataxia, gingival hyperplasia, peripheral neuropathies, osteoporosis, and risk of megaloblastic anemia.
Mnemonic: "Phenytoin: Can't See Straight, Can't Walk, Gums Gone Wild, Numb as Hell, Bones Like Glass, Blood's a Mess"
Can't See Straight - Nystagmus (eye movement disorder)
Can't Walk - Ataxia (lack of muscle coordination)
Gums Gone Wild - Gingival hyperplasia (overgrown gums)
Numb as Hell - Peripheral neuropathies (nerve damage)
Bones Like Glass - Osteoporosis (weak bones)
Blood's a Mess - Risk of megaloblastic anemia (impaired blood cell production)
62
What is fosphenytoin and how is it activated?
Fosphenytoin is a prodrug rapidly converted to phenytoin in the blood.
63
What metabolic characteristics does phenytoin have?
It induces drug-metabolizing enzymes, has saturable metabolism at low serum concentrations, and small dose increases can lead to large plasma concentration increases, causing toxicity.
64
What is gabapentin and how does it function?
It is an analog of GABA but does not bind to GABA receptors or activate them; its mechanism is unknown.
65
For which conditions is gabapentin used as an adjunct therapy?
Partial seizures and postherpetic neuralgia (nerve pain due to damage caused by the varicella zoster virus).
66
What is a notable pharmacokinetic property of gabapentin?
It has nonlinear pharmacokinetics due to uptake by a saturable transporter in the gut.
67
How is gabapentin excreted, and what is its significance regarding drug interactions?
It is excreted unchanged through the kidneys and does not bind to plasma proteins, resulting in low drug-drug interaction.
68
Why is gabapentin considered a good choice for older patients?
It is well-tolerated due to its mild side effects.
69
What is the mechanism of action for tiagabine?
It blocks GABA uptake into presynaptic neurons, allowing more GABA to be available for receptor binding and enhancing inhibitory activity.
70
For which type of epilepsy is tiagabine effective?
Partial onset epilepsy.
71
Is tiagabine approved for use in absence seizures?
No, it is not used for absence seizures.
72
What is the mechanism of action for lamotrigine?
It blocks sodium channels and high voltage-dependent calcium channels.
73
For which types of seizures is lamotrigine effective?
Partial seizures, generalized seizures, and typical absence seizures.
74
What is another condition for which lamotrigine is used?
Bipolar disorder.
75
How is lamotrigine's half-life affected by other drugs?
Reduced by enzyme-inducing drugs (carbamazepine) and increased by enzyme-inhibitor drugs (valproate).
76
What is a potential side effect of rapid titration of lamotrigine?
It can cause a rash, potentially progressing to a serious, life-threatening reaction.
77
Why is lamotrigine well tolerated by the elderly?
Due to its minor side effects.
78
For which types of seizures is levetiracetam effective?
Partial onset seizures, myoclonic seizures, and primary generalized tonic-clonic seizures in adults and children.
79
What is the proposed mechanism of action for levetiracetam?
It is unknown, but most probably acts on synaptic vesicle protein SV2A.
80
How does levetiracetam interact with metabolic systems?
It does not interact with CYP or UGT metabolism systems, resulting in low drug-drug interactions.
81
What is the mechanism of action for phenobarbital?
Enhancing the inhibitory effects of GABA-mediated neurons.
82
For what condition is phenobarbital primarily used?
Treatment of status epilepticus.
83
Why is phenobarbital considered for chronic therapy only in refractory patients?
Due to its high side effects, including sedation, enzyme induction, and osteoporosis.
84
Which antiepileptic drugs are associated with decreased bone cell proliferation and decreased Vitamin D levels?
Phenytoin, carbamazepine, and phenobarbital.
85
What is the spectrum of action for felbamate?
Broad spectrum of anticonvulsant action.
86
What are the proposed mechanisms of action for felbamate?
Blocking voltage-dependent sodium channels, competing with the glycine binding site on the NMDA glutamate receptor, blocking calcium channels, and potentiating the action of GABA.
87
Why does felbamate have high drug-drug interactions?
It inhibits drugs metabolized by CYP2C19 and ß-oxidation and induces drugs metabolized by CYP3A4.
88
Why is felbamate used only in refractory epilepsies?
Due to the risk of aplastic anemia and heart failure.
89
What is divalproex sodium and why is it used?
It is a combination of sodium valproate and valproic acid converted to valproate in the gastrointestinal tract to improve GIT tolerance of valproic acid.
90
What are the mechanisms of action for valproic acid and divalproex?
Sodium channel blockade, blockade of GABA transaminase, and blockade action at T-type calcium channels.
91
For which types of epilepsies are valproic acid and divalproex effective?
Partial and primary generalized epilepsies.
92
How do valproic acid and divalproex interact with metabolic systems?
They inhibit the metabolism of CYP2C9, UGT, and epoxide hydrolase systems, resulting in high drug-drug interactions.
93
What are some rare and serious side effects of valproic acid and divalproex?
Hepatic toxicity and teratogenic effects causing neural tube defects, contraindicating use in pregnancy.
94
What are the mechanisms of action for topiramate?
Blocks voltage-dependent sodium channels, increases chloride channel opening by binding to the GABA receptor, inhibits high-voltage calcium currents, acts as a carbonic anhydrase inhibitor, and may act at NMDA sites.
95
For which conditions is topiramate used?
Partial and primary generalized epilepsy, migraine, and absence seizures.
96
How does topiramate interact with metabolic systems?
It inhibits CYP2C19 and is sensitive to induction by phenytoin and carbamazepine. It also reduces ethinyl estradiol levels, requiring additional birth control methods for women.
97
What are some adverse effects of topiramate?
Somnolence, weight loss, paresthesias, renal stones, glaucoma, and oligohidrosis leading to hyperthermia.
Mnemonic: "Topiramate: Sleepy as Hell, Skinny as F*ck, Tingling Toes, Pissing Rocks, Eyes Gone Bad, Sweating Like Crazy"
Sleepy as Hell - Somnolence
Skinny as F*ck - Weight loss
Tingling Toes - Paresthesias (tingling sensation)
Pissing Rocks - Renal stones (kidney stones)
Eyes Gone Bad - Glaucoma
Sweating Like Crazy - Oligohidrosis (reduced sweating leading to hyperthermia)
98
What is the mechanism of action for zonisamide?
Blockade of both voltage-gated sodium channels and T-type calcium currents with limited carbonic anhydrase activity.
99
For which type of epilepsy is zonisamide used?
Partial epilepsy.
100
What are some side effects of zonisamide?
CNS toxicity, kidney stones, increased temperature, and oligohidrosis.
Mnemonic: "Zonisamide: Brain’s F*cked, Pissing Rocks, Hot as Hell, Dry as a Desert"
Brain’s F*cked - CNS toxicity
Pissing Rocks - Kidney stones
Hot as Hell - Increased temperature
Dry as a Desert - Oligohidrosis (reduced sweating)
101
What is the mechanism of action for ethosuximide?
It inhibits T-type calcium channels, reducing the propagation of abnormal electrical activity in the brain.
102
For which type of seizures is ethosuximide the first-line treatment?
Primary generalized absence seizures.
103
Why is the use of ethosuximide limited?
Because of its very narrow spectrum of activity.
104
What does vagal nerve stimulation require?
A surgical implant of a small pulse generator with a battery and a lead wire for stimulus.
105
How does vagal nerve stimulation help seizure patients?
It prevents abnormal electrical activity in seizure patients through electrical vagus stimulation.
106
When do patients activate the vagal nerve stimulator?
When they anticipate a seizure.
107
For which type of seizures is vagal nerve stimulation effective?
Partial onset seizures.
108
What benefit does vagal nerve stimulation provide besides seizure control?
It enables the reduction of drug therapy and is used for refractory patients.
109
What is recommended for women with epilepsy before conception?
High doses of folic acid.
110
Which medications should be avoided during pregnancy for women with epilepsy?
Divalproex and barbiturates.
111
What should be done with seizure medication during pregnancy once seizures are controlled?
The maintenance medication should be reduced to the lowest dose that provides control.
