CHAPTER 5 Nervous System^253
Seizures may be a symptom of another condition—such as a tumor or stroke
which has increased the intracranial pressure, a metabolic disorder, withdrawal
from alcohol or drugs—or may be due to a chronic seizure disorder such as
epilepsy. Prior to the seizure, the patient may experience an aura, a sensory alter-
ation involving sight, sound, or smell. After the seizure, the patient enters a
post-ictal stage where there may be confusion and the patient is often fatigued. The
patient may not recall any of the seizure or the time immediately surrounding
the seizure.
INTERPRETING TEST RESULTS
- EEG (electroencephalogram) to identify areas of abnormal electrical activity
within the brain. - CT scan of the brain to identify causes of increased intracranial pressure
(rule out tumor or bleed). - MRI to identify causes of increased intracranial pressure (rule out tumor or
bleed). - PET (positron emission tomography) or SPECT (single photon emission
computed tomography) to determine areas in the brain that are not ade-
quately perfused.
Generalized seizures
Tonic clonic Begins with tonic (stiffening/rigidity of muscles of limbs), loss of
consciousness, then clonic (rhythmic jerking)
Tonic Stiffening or rigidity of muscles; loss of consciousness
Clonic Rhythmic jerking of muscle contraction and relaxation
Absence Brief loss of conscious awareness and staring into space; appears to
be daydreaming
Myoclonic Brief stiffening or jerking of extremity, either single or in groups
Atonic Loss of muscle tone
Partial seizures
Simple partial Begins with aura; may have unilateral unusual sensation or move-
ment of extremity, autonomic (heart rate, flushing), or psychic
changes; no loss of consciousness
Complex partial Loss of consciousness; automatisms (lip smacking, picking, patting)