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Rasmussen’s encephalitis
This very rare epilepsy usually begins with focal motor seizures, often very localised at least
initially. Episodes of focal motor status (epilepsy partialis continuans) is common. Other
seizure types, including GTCS, may occur. Over a period which can be only a matter of weeks
or else years, a progressive hemiplegia develops along with cognitive decline. Untreated the
disease eventually remits but usually leaving a dense motor deficit and severe learning
difficulties. Pathologically there are focal perivascular infiltrates characteristic of a viral or
autoimmune process: the cause, however, remains unknown. Early structural scans may be
normal or may show focal signal abnormalities. Later hemiatrophy develops. Some reports
suggest that bihemispheric involvement may occur but this is controversial. Some response
to conventional AEDs may occur, but nearly always this is temporary. Immunological
treatments, such as steroids and intravenous immunoglobulin are usually used, sometimes
with apparent success. However, most patients eventually require hemispherectomy.
Children should be reviewed in a specialised epilepsy surgery unit as timing of surgery will
be key.

Abnormalities of cortical development
Cortical dysplasias vary greatly in their epileptogenicity. This is perhaps best illustrated by
tuberous sclerosis. Many subjects with this live normal lives, others have mild epilepsies and
are of normal or near normal intelligence. However, many children with tuberous sclerosis
present very early on in life with severe epilepsy, particularly West syndrome, and are
devastated by the disorder.

Hemimegalencephaly is a particularly severe and complex dysplasia affecting one
hemisphere (although less severe abnormalities of the ‘uninvolved’ hemisphere may be
present). It often presents with refractory focal seizures in early life. Early hemispherectomy
maximises developmental potential.

Dysembryoplastic neuroepithelial tumours
These are indolent cortical brain tumours which include both neural and glial elements. Most
are temporal in origin but any cortical region can be involved. They may be congenital. They
commonly present in childhood or early adult life with focal epilepsy, which has a tendency
to be refractory to medical treatment. There is evidence that the early surgical resection not
only controls seizures but improves neurodevelopmental outcome in those children who
present at an early age with intractable seizures.

Sturge-Weber syndrome
This neurocutaneous disorder features a facial port wine stain with an ipsilateral pial angioma.
The clinical consequences are highly variable. However, a minority of infants with it develop:
refractory focal seizures, including episodes of potentially devastating status epilepticus;
progressive hemiplegia; and progressive cognitive decline. The last two of these appear to be
caused by a vascular steal phenomenon related to the pial angioma causing atrophy of the
underlying cortex. Surgical treatment with lobar, multilobar or hemispheric resection may
halt this progression.

Figures used here have been modified with permission from: A Clinical Guide to Epileptic Syndromes
and their Treatment, second edition. Springer, London (courtesy of CP Panayiotopoulos)