Seizures

Question 1

What is a seizure?

Answer 1

When there is uncontrolled neuronal discharge causing altered behaviour, movements and sensations.

Question 2

What is epilepsy?

Answer 2

A condition where the individual has recurrent seizures.

Question 3

What causes provoked seizures?

Answer 3

Provoked seizures have a genetic component and are acquired, they have an underlying cause:

• CNS insult (infection, physical trauma)
• fever (called a febrile seizure, common in kids)
• metabolic related (membrane potential is changed from hypoglycemia, hypoxia, electrolyte imbalance)

Question 4

What are the two types of seizures?

Answer 4

provoked and unprovoked

Question 5

What causes unprovoked seizures?

Answer 5

Unprovoked seizures are idiopathic. They may have a genetic component.

Question 6

Seizures can also be classified by where they originate, what are the two classes?

Answer 6

1) generalized seizure - originates in both hemispheres
2) partial seizure - originates in one hemisphere
a) simple partial - no loss of consciousness
b) complex partial - loss of consciousness

Question 7

What is the pathophysiology of seizures?

Answer 7

• epileptogenic focus (small group of hyper-responsive nuerons) in cerebral cortex and hippocampus triggered
• neurons fire excessively/ discharge with increased amplitude and frequency, spreads to other areas
• normal neuronal inhibition is blocked
• causes abnormal muscle action and loss of consciousness, there is intermittent contraction-relaxation phase
• inhibitory neurons ultimately control discharge and end he seizure
• epileptogenic cells completely inhibited
• CNS depressed (postictal phase)

Question 8

Why is there a potential for brain damage from a seizure?

Answer 8

The increased brain activity and consequent increase in muscle activity increases ATP use and increases the demand for oxygen and glucose. If perfusion isn’t adequate there can be hypoxia, and if muscles need to make energy anaerobically there is a potential for lactic acidosis. Potential for damage will depend on duration of the seizure.

Question 9

How are seizures diagnosed?

Answer 9

• history
• witnessed (unlikely in clinical setting)
• neurologic exam
• labs to rule out other stuff
• scans, EEG

try to determine underlying cause and avoid

Question 10

How are seizures treated?

Answer 10

• During a seizure = protect from injury.
• After a seizure = preserve brain function/life preservation.
• Later… try to find and avoid the cause.
• Anticonvulsant drugs.
• May be surgically corrected, but only if drugs don’t work.