Table 10.3

Differentiation of primarily versus secondarily GTCS

Primarily GTCS Secondarily GTCS
GTCS with other clinically evident seizures About 90%About 90%
 Typical absencesAbout 40%None
 Myoclonic jerksAbout 60%None
 Focal seizuresNoneAbout 90%
GTCS without other clinically evident seizures About 10%**About 10%**
 Precipitating factors> 60%< 10%
 Consistently on awakeningCommonUncommon
 Family history of similar epilepsiesCommonUncommon
EEG in untreated patients
 Generalised dischargesAbout 80%Exceptional
 Focal abnormalities aloneAbout 10%About 60%
 Generalised discharges and focal abnormalitiesAbout 30%Exceptional
High resolution brain imaging
 Focal abnormalitiesExceptionalAbout 60%
 NormalBy definitionAbout 40%
**

It is these patients, who make up about 10% of each category, without clinically apparent other types of seizures that constitute the main problem in the differential diagnosis between primarily and secondarily GTCS. However, other features, such as precipitating factors, circadian distribution, EEG and brain imaging, are often of diagnostic significance.

From: Chapter 10, Idiopathic Generalised Epilepsies

Cover of The Epilepsies
The Epilepsies: Seizures, Syndromes and Management.
Panayiotopoulos CP.
Oxfordshire (UK): Bladon Medical Publishing; 2005.
Copyright © 2005, Bladon Medical Publishing, an imprint of Springer Science+Business Media.

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