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Seizure/symptom diagnosis

Accurately identifying the type(s) of seizures involved is the first, and not the final, step
towards medical diagnosis in a patient with genuine epileptic seizures:

‘An epileptic seizure is defined as an abnormal paroxysmal discharge of
cerebral neurones sufficient to cause clinically detectable events that are
apparent to the subject, an observer, or both’9.

This definition ranges from the dramatic event of a generalised tonic-clonic seizure to the
mild myoclonic flicker of the eyelids or a focal numbness of the thumb and mouth. The latter
are often overlooked although they are more important than generalised tonic-clonic seizures
in the diagnosis of epilepsy6. Patients may often suffer many minor seizures long before or
after their ‘first seizure’ or ‘last seizure’6.

Epileptic seizures are classified10 as:
 Generalised seizures (tonic, clonic or tonic-clonic, myoclonic, typical or atypical

absences)
 Partial seizures (with great variation in clinical expression and severity)
 Partial seizures with secondary generalisation (any partial seizure which progresses to

become generalised).

Such a classification is necessary because ‘an abnormal paroxysmal discharge of cerebral
neurones’ may be localised (partial seizures) or simultaneously affect the whole cerebral
cortex from onset to termination (generalised seizures). Secondary generalised seizures are
partial at onset but do not remain localised  they spread and trigger a generalised fit.
Generalised seizures vary considerably: mild or severe myoclonic jerks; inconspicuous or
severe typical and atypical absences; generalised clonic, tonic, tonic-clonic or clonic-tonic-
clonic convulsions.

Symptom/seizure diagnosis cannot provide guidance to the physician on important items such
as severity of the disease, prognosis, short and long-term therapeutic decisions, genetics
(research and counselling)  all factors which crucially affect family and social life, and the
education and career choices of patients. Precise syndromic diagnosis is necessary to ensure
optimal management and avoid morbidity2.

Syndrome/disease diagnosis

The diagnosis ‘epilepsy’ is no more precise than the term ‘seizure’ and similar arguments
weigh against its use6. The World Health Organization Dictionary of Epilepsy11 gives this
definition:

‘Epilepsy is a chronic brain disorder of various aetiologies characterised by
recurrent seizures due to excessive discharge of cerebral neurones (epileptic
seizures), associated with a variety of clinical and laboratory
manifestations). Single or occasional epileptic seizures (such as febrile
convulsions and the seizures of puerperal eclampsia) as well as those
occurring during an acute illness should not be classified as epilepsy’.

Others consider epilepsy as a ‘condition in which more than one non-febrile seizure of any
type has occurred at any time’9. The statement: ‘Epilepsy is two or more seizures’ epitomises
the current formal definition of the Commission on Classification and Terminology of the
International League Against Epilepsy2 and this does not even clarify what type of seizures.
Such broad operational definitions reveal the diagnostic inadequacy of the term ‘epilepsy’,
which includes any patient with ‘two undefined seizures’ ranging from a normal child with
two Rolandic seizures to the severely brain-damaged patient with daily multiform epileptic