C H A P T E R 2 3
Antiseizure agents
355
grouping them into two main categories: generalised or
partial seizures. Each of these categories can be further
subdivided (see Figure 23.1).
Generalised seizures
Generalised seizures
begin in one area of the brain and
rapidly spread throughout both hemispheres. People
who have a generalised seizure usually experience a loss
of consciousness resulting from this massive electrical
activity throughout the brain.
Generalised seizures are further classified into the
following seven types:
1.
Tonic–clonic seizures
involve dramatic tonic–clonic
muscle contractions (involuntary muscle contraction
followed by relaxation appearing as an aggressive
spasm), loss of consciousness and a recovery period
characterised by confusion and exhaustion.
2.
Absence seizures
involve abrupt, brief (3- to
5-second) periods of loss of consciousness. Absence
seizures occur commonly in children, starting at
about 3 years of age, and frequently disappear by
puberty. Absence seizures do not usually involve
muscle contractions.
3. Myoclonic seizures involve short, sporadic periods
of muscle contractions that last for several minutes.
They are relatively rare and are often secondary
seizures.
4. Febrile seizures are related to very high fevers and
usually involve tonic–clonic seizures. Febrile seizures
most frequently occur in children; they are usually
self-limited and do not reappear.
5. Jacksonian seizures are seizures that begin in one
area of the brain and involve one part of the body,
and then progressively spread to other parts of the
body; they can develop into generalised tonic–clonic
seizures.
6. Psychomotor seizures are complex seizures that
involve sensory, motor and psychic components.
They usually begin with a loss of consciousness and
people have no memory of the event. People may
exhibit automatic movements, emotional outbursts,
and motor or psychological disturbances.
7.
Status epilepticus
, potentially the most dangerous of
seizure conditions, is a state in which seizures rapidly
recur again and again with no recovery between
seizures.
Partial seizures
Partial seizures
, or focal seizures, are so called because
they involve one area of the brain, usually originating
from one site or focus and do not spread throughout
the entire organ. The presenting symptoms depend on
exactly where in the brain the excessive electrical dis
charge is occurring. Partial seizures can be further
classified as follows:
• Simple partial seizures, which occur in a single area of
the brain and may involve a single muscle movement
or sensory alteration.
• Complex partial seizures, which involve a series of
reactions or emotional changes and complex sensory
changes such as hallucinations, mental distortion,
changes in personality, loss of consciousness and loss
of social inhibitions. Motor changes may include
involuntary urination, chewing motions, diarrhoea
and so on. The onset of complex partial seizures
usually occurs by the late teens.
■■
Epilepsy is characterised by seizures that result from
sudden discharge of excessive electrical energy from
nerve cells in the brain.
■■
There are two major categories of seizures:
generalised and partial seizures.
■■
Generalised seizures include the following
types: tonic–clonic, absence, myoclonic, febrile,
Jacksonian, psychomotor and rapid recurring
(status epilepticus).
■■
Partial seizures may be simple or complex.
KEY POINTS
Seizures
Tonic-
clonic
Absence
Atonic
Myoclonic
Status
epilepticus
Febrile
Simple
(consciousness
not impaired)
Complex
(consciousness
impaired)
Partial
(involves one
hemisphere)
Generalised
(involves both
hemispheres;
loss of
consciousness)
FIGURE 23.1
Classification of seizures. [From Aschenbrenner, D. S.
& Venable, S. J. (2008).
Drug Therapy in Nursing
(3rd edn).
Philadelphia: Lippincott Williams & Wilkins; p. 332, Figure 21.2.]
