Epilepsy Flashcards
What is receptor is responsible for excitatory?
Glutamate
What receptor is responsible for inhibitory?
GABA
How is a seizure defined?
The clinical manifestation resulting from an abnormal or excessive discharge of a set of neurons in the brain.
How is epilepsy defined?
A chronic condition characterized by recurrent (>2) epileptic seizures, unprovoked by any immediate identifiable cause
What are alterations of consciousness, motor, sensory, automatic or psychic events?
Clinical manifestations
What can cause a seizure?
Fever Withdrawal from CNS depressants Metabolic abnormalities Uremia Encephalitis/meningitis Head trauma Brain tumor Stroke Lead poisoning Sleep deprivation Medications
What drugs are known to cause seizures?
Antimicrobials Anesthetics and analgesics Immunosuppressants Psychotropics Radiographic contrast agents Theophylline Sedative hypnotic drug withdrawal Drugs of abuse Flumazenil
Epidemiology of epilepsy
Increases in people >70 y/o
Most common neurological disorder in children
70% of patients can be seizure free with appropriate therapy
Pathophysiology of seizures involves what?
Origination from the gray matter of any cortical area (neurons fire abnormally)
Due to excessive excitation or disordered inhibition of neurons (normal membrane function breakdown, excess excitability)
What are the physiologic consequences of a seizure?
Increased consumption of oxygen & glucose
Increased production of lactate and CO2
Increased cerebral blood flow is generally sufficient to compensate for changes
Brief seizures rarely cause long-term seqeulae
Why don’t you want a seizure to occur over a long period of time?
Seizures cost a lot and take a lot out of a person depriving the brain of oxygen and glucose after a long period of time
What are the physiological consequences of a seizure?
Sympathetic discharge results in tachycardia, HTN, and hyperglycemia
Difficulty maintaining the airway
What results when an airway is not maintained during a seizure?
Hypoxia, hypercarbia, and respiratory acidosis
What results from a prolonged seizure?
Lactic acidosis, rhabdomyolosis, hyperkalemia, hyperthermia, and hypoglycemia.
Diagnosis can be made based on:
Patient hx
PE- neurological findings, cranial nerves, motor function, cerebellar function, and sensory function
Lab- metabolic causes- glucose, electrolytes, calcium, and renal function, also drugs/ETOH screen
EEG
MRI
What is an EEG and what is its significance?
An EEG confirms the presence of electrical activity, classifies the seizure type, and indicates the location of focus.
These are performed w/in 48 hrs of a seizure
More than 1/2 of epileptics initially have normal EEGs
What defines a primary seizure?
No specific anatomic cause and involves chronic treatment
How is secondary epilepsy caused?
Tumors, head injury, hypoglycemia, meningitis, or rapid withdrawal from ETOH. Drugs are used for tx until primary cause is corrected
What is the difference between a focal (partial) and generalized seizure?
The location of the cerebrum where the seizure originates
What is the difference between a simple and complex seizure?
Impairment of consciousness (whether the patient looses consciousness or not.
A seizure that begins in one hemisphere of the brain, has symptoms classified as motor, autonomic, or sensory, has ASYMMETRIC MANIFESTATIONS, and accounts for 80% of all adult epilepsies is what type of seizure?
Focal Seizure
A seizure that begins in BOTH hemispheres of the brain and has BILATERAL MANIFESTATIONS is what type of seizure?
Generalized Seizure
A seizure that does not result in loss of consciousness is a?
Simple focal seizure
A seizure that results in a loss or alteration of consciousness is what type of seizure?
Complex focal seizure
A focal onset evolving to generalized tonic-clonic seizures is what type of seizure?
Secondary generalized focal seizure
Tonic seizure is defined as?
A generalized seizure that consists of continuos muscle contraction
Clonic seizure is defined as?
A generalized seizure that consists of rhythmic muscle contractions
Tonic-clonic seizure is defined as?
A generalized seizure that involves an alteration b/w tonic and clonic
Myoclonic seizure is defined as?
A generalized seizure involving sudden, brief muscle spasm
Atonic seizure is defined as?
A generalized seizure consisting of a sudden brief loss of muscle tone
Absence seizure is defined as?
A generalized seizure that involves Impaired awareness or interaction
What is the clinical presentation of a focal seizure?
Asymmetrical manifestation
Symptoms of the motor (any part of the body), autonomic (pallor, flushing, vomiting, sweating, vertigo, or tachycardia), and sensory (visual, auditory, or olfactory)
What is the clinical presentation of a complex seizure?
Prodrome, aura, and automatisms
What is an awareness of an impending seizure such as HA, insomnia, irritability, feeling of impeding doom?
Prodrome
What is a simple focal seizure consisting of autonomic or sensory symptoms?
Aura
What is lip smacking, chewing, swallowing, abnormal tongue movements, thrashing, fumbling or snapping of fingers?
Automatisms
What is the clinical presentation of a generalized seizure?
Bilateral motor manifestations
Tonic-clonic (Grand Mal)- sometimes w/ aura, LOC, sudden tonic contractions followed by rigidity and clonic movements, cries or moans, loss of sphincter control, and unconsciousness followed by a deep sleep.
What type of seizure involves sometimes w/ aura, LOC, sudden tonic contractions followed by rigidity and clonic movements, cries or moans, loss of sphincter control, and unconsciousness followed by a deep sleep.
Tonic-Clonic (Grand Mal)
What is the clinical presentation of a absence (petit mal) seizure?
Sudden onset, interruption of activity
What is the clinical presentation of a complex seizure?
Prodrome, aura, and automatisms
What is an awareness of an impending seizure such as HA, insomnia, irritability, feeling of impeding doom?
Prodrome
What is a simple focal seizure consisting of autonomic or sensory symptoms?
Aura
What is lip smacking, chewing, swallowing, abnormal tongue movements, thrashing, fumbling or snapping of fingers?
Automatisms
What is the clinical presentation of a generalized seizure?
Bilateral motor manifestations
Tonic-clonic (Grand Mal)- sometimes w/ aura, LOC, sudden tonic contractions followed by rigidity and clonic movements, cries or moans, loss of sphincter control, and unconsciousness followed by a deep sleep.
What type of seizure involves sometimes w/ aura, LOC, sudden tonic contractions followed by rigidity and clonic movements, cries or moans, loss of sphincter control, and unconsciousness followed by a deep sleep.
Tonic-Clonic (Grand Mal)
What is the clinical presentation of a ansence (petit mal) seizure?
Sudden onset, interruption of activity
What is the clinical presentation of myoclonic seizure?
Brief shock-like contraction of face, trunk, and upper extremities.
What is the clinical presentation of an atonic seizure?
Head dropping, slumping to the ground
What is the clinical presentation of a febrile seizure?
Generalized seizure
Illness accompanied with a high fever
3 mo. to 5 y/o
Benign; rarely required medication
What are the goals of treatment for seizures?
Accurate diagnosis
Suppress seizure activity
Minimize adverse drug reactions
Optimize QOL
GABA Neurotransmitter
Major inhibitory amino acid
Alters the conductance of ion-selective channels -> K+ efflux or Cl- influx results in membrane hyperpolarization
Drugs- BZDP and barbituates
Glutamate Neurotransmitter
Primary excitatory amino acid
Influx of Na+ ions or reduced outflow of K+ ions depolarize membrane
Drugs- mostly experimental
Drugs that modulate GABA receptors affect what?
Arousal and attention Memory formation Anxiety Sleep Muscle tone
What is GABAs metabolism?
Glutamate synthesis and metabolism intertwined with GABA synthesis and metabolism.
Synthesis: decarboxylation of glutamate -> GABA.
Packaged into vesicles and in response to the action potential exocytosis of the vesicle with the release of GABA into the synaptic cleft occurs.
Termination of GABA action is via uptake by neurons and glia cells (GABA transporters), GABA-transminase converts GABA to succinic semiadehyde which is oxidized to succinic acid and then via the krebs cycle to a-ketoglutarate, GABA-transaminase regenerated glutamate from a-ketoglutarate. Then it is diffused out of the synaptic cleft.
What are the two types of GABA receptors?
Ionotropic and metabotropic