Seizures

Question 1

Seizures definition

Answer 1

• occur due to abnormal synchronous discharges of neurons in the cerebral cortex.
• classified as focal (partial) if they originate from a localized region of one cerebral hemisphere or generalized if they involve both hemispheres at onset.
• focal seizure can be subclassified as simple if consciousness is preserved
• complex if there is loss of consciousness.
• The manifestations of focal seizure depend on the brain region in which the seizure activity is occurring.
• This patient’s episodic right upper limb rhythmic jerking movements with preserved consciousness suggest a simple partial seizure originating in the contralateral motor cortex.

Question 2

Absence seizures

Answer 2

• classified as generalized seizures as they involve both hemispheres at onset.
• clinically present as brief (<10 seconds) staring spells during which the patient has absence of consciousness.

Question 3

Atonic seizure

Answer 3

• type of generalized seizure in which the patient completely loses postural tone and collapses, with associated loss of consciousness.

Question 4

Complex partial seizure

Answer 4

• focal seizure associated with loss of consciousness and behavioral automatisms (eg, lip smacking) followed by postictal confusion.
• often have a preceding aura (eg, epigastric rising sensation, déjà vu).

Question 5

Generalized tonic-clonic seizures

Answer 5

• characterized by loss of consciousness with diffuse, bilateral muscle contractions of the limbs followed by rhythmic jerking.
• Associated features may include tongue biting and urinary/bowel incontinence.

Question 6

Partial seizures

Answer 6

• originating from a localized brain region may become secondarily generalized to involve both cerebral hemispheres; however, this is usually associated with loss of consciousness and bilateral (versus unilateral) symptoms.
• patient’s initial right arm numbness/paresthesias were likely caused by a simple partial seizure originating in the left primary somatosensory cortex (postcentral gyrus)
• This brain region is responsible for processing all somatic sensory modalities (eg, touch, temperature/pain, vibration/proprioception) of the contralateral body.