Seizures

Question 1

Explain the mechanisms of patho of seizures

Answer 1

1. Ion channels

-Seizures involve dysfunction of ion channels such as sodium, potassium, calcium and chloride channels which causes abnormal depolarisation or hyperpolarisation of neurons.

2. Excitatory vs inhibition
   - Increased glutamate activity (the primary excitatory neurotransmitter) enhances the excitatory post-synaptic potentials.

• Decrease GABA activity reduces inhibition through hyperpolarization of the neuronal membrane making it harder for the threshold for firing an action potential.
• The balance between excitation and inhibition maintains normal brain function.

Question 2

Definition

Answer 2

Episodes of abnormal, excessive and synchronous neuronal activity in the brain which manifests as changes in behaviour, movement, sensation and awareness depending on affected area. Pathophysiology involves complex mechanisms, neuronal excitability, neurontransmitter imablance and network connectivity.

Question 3

Two types of seizures

Answer 3

Generalised
Focal

Question 4

What are generalised seizures

Answer 4

Widespread, bilateral activity across both hemispheres.
Typically LOC and altered awareness level

Question 5

Give examples and descriptions of Generalised seizures

Answer 5

• Tonic-Clonic Seizures:
  ‘ tonic’ stage: muscle stiffering with icital cry as air is forced out of the lungs.
  ‘clonic’: rhythmic jerking movement of limbs and face. postictal stage: confusion, headache, muscle stiffness and fatigue

Absence seizures
- Brief lapse in awareness
- Day dreaming, staring, blinking, no muscle contraction
- Non postictal stage

Tonic seizures
- sudden onset of muscle stiffening
- increased tone
- cyanosis
- associated with falls

Clonic seizures
- repeated rhymical jerking movement of the muscle
- Symmetrical

Question 6

What are focal seizures

Answer 6

Originate in a specific localised area of the brain

Question 7

State and describe different focal seizures

Answer 7

1. Focal aware seizures: consciousness is preserved, and symptoms reflect the area that is affected.
   - Motor: jerk/twitch
   - sensory: tingling, visual and auditory disturbances
   - autonomic: flushed, sweating, nausea
   - psychic: deja vu, fear or hallucination
2. Focal impaired awareness seizures
   - LOC impaired
   - Blank stare or unresponsive
   - May inbolve automatisms e.g. lip smacking and repetitive movements
3. Focal to Bilateral Tonic-Clonic
   - original focal but spread to generalised and both hemispheres.

Question 8

What are two main causes for seizures

Answer 8

Unprovoked or Provoked

Question 9

Name some provoked causes for seizures

Answer 9

These are identifiable and reversible

1. Metabolic e.g. hypoglycaemia, hypernatremia, hypocalcemia, uremia
2. Toxins e.g alcohol and drug withdrawal, toxins such as lead and carbon monoxide posioning
3. Infections e.g. CNS infections such as menigitis or fever in children
4. Trauma e.g. head injury, subdural hematomas
5. Structural brain lesions e.g Strokes, brain tumors

Question 10

Explain some unprovoked causes

Answer 10

1. epilepsy
2. genetic disorders: mutations affecting ion channels or synaptic proteins
3. Neurodegenerative disease: Alzheimers disease increase risk due to neuronal loss
4. Autoimmune disorders
5. idiopathic seizures

Question 11

What are some differential diagnosis

Answer 11

Convulsive syncope
Movement disorder
Sleep related events
Psychogeneic- non- epilpetic spell: no abnormal electrical activity instead associated with stress and trauma