A seizure is a transient occurrence of signs or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Epilepsy is diagnosed when there is a risk of recurrent seizures due to a chronic, underlying process.
APPROACH TO THE PATIENT Seizure
Seizure classification: Essential for diagnosis, therapy, and prognosis (Table 184-1). Seizures are focal or generalized: focal seizures originate in networks limited to one cerebral hemisphere, and generalized seizures rapidly engage networks distributed across both hemispheres. Focal seizures are further divided based on presence or absence of cognitive impairment.
Generalized seizures may occur as a primary disorder or result from secondary generalization of a focal seizure. Tonic-clonic seizures (grand mal) cause sudden loss of consciousness, loss of postural control, and tonic muscular contraction producing teeth-clenching and rigidity in extension (tonic phase), followed by rhythmic muscular jerking (clonic phase). Tongue-biting and incontinence may occur during the seizure. Recovery of consciousness is typically gradual over many minutes to hours. Headache and confusion are common postictal phenomena. In absence seizures (petit mal) there is sudden, brief impairment of consciousness without loss of postural control. Events rarely last longer than 5–10 s but can recur many times per day. Minor motor symptoms are common, while complex automatisms and clonic activity are not. Other types of generalized seizures include tonic, atonic, and myoclonic seizures.
Etiology: Seizure type and age of pt provide important clues to etiology (Table 184-2).
TABLE 184-1Classification of Seizuresa |Favorite Table|Download (.pdf) TABLE 184-1 Classification of Seizuresa
(Can be further described as having intact or impaired awareness, motor or nonmotor onset, or evolve from focal to bilateral tonic clonic)
Other motor (e.g., atonic, myoclonic)
(Can be further described as motor or nonmotor, or unclassified)
TABLE 184-2Causes of Seizures |Favorite Table|Download (.pdf) TABLE 184-2 Causes of Seizures
|Neonates (<1 month) || |
Perinatal hypoxia and ischemia
Intracranial hemorrhage and trauma
Metabolic disturbances (hypoglycemia, hypocalcemia, hypomagnesemia, pyridoxine deficiency)
|Infants and children (>1 month and <12 years) || |
Genetic disorders (metabolic, degenerative, primary epilepsy syndromes)
|Adolescents (12–18 years) || |
Illicit drug use
|Young adults (18–35 years) || |
Illicit drug use
|Older adults (>35 years) || |
Metabolic disorders (uremia, hepatic failure, electrolyte abnormalities, hypoglycemia, hyperglycemia)
Alzheimer’s disease and other degenerative CNS diseases
Careful history is essential since diagnosis of seizures ...