MRI FINDINGS IN THE DIAGNOSIS OF RASMUSSEN’S

ENCEPHALITIS

A ACHOUR, S JERBI OMEZZINE, S YOUNES1, S BOUABID, MH SFAR1, HA HAMZA.

Department of Medical Imaging, Tahar Sfar University Hospital Center, Mahdia, Tunisia 1Department of Internal Medicine, Tahar Sfar University Hospital Center, Mahdia

NR16

INTRODUCTION :

Rasmussen encephalitis (RE) is a chronic inflamatory

disease wich affects mainly children , but also young adults.

RE is characterised by unilateral hemespheric progressive

atrophy, consecutive neurologic deficits and severe focal

epilepsy.

Pharmacoresistance against anti epileptic drugs is noted

early in the course of the disease.

Diagnosis is based on features from the electroencephalogram

(EEG) , MRI and clinical and/or histological characteristics.

Magnetic resonance (MR) findings, associated with clinical data

and electroencephalogram (EEG), may indicate the diagnosis and

could be an indicative of prognosis

Current approaches of immuno-modulatory and surgical techniques

are discussed.

Only surgery is able to provide complete seizure control.

We present the case of RE and neuroradiological findings.

Materials and methods

We report the longitudinal history of a 18-year-old women with RE who presented with seizures. Neurological symptoms included recurrent partial seizures with secondary generalized convulsions.

There was no concept of neonatal distress and psychomotor development was normal. 

She presented partial seizures to clonic seizures  type of predominantly straight-brachial cheiro with secondary generalization. Changes in several AEDs in combination was negative and there was an increase in seizure frequency that became multiple daily requiring hospitalization for 3 days in intensive care unit. 

- The electroencephalogram (EEG) objectified slower background

activity with a clear asymmetry of the plot. In fact, there was the left

side of paroxysmal abnormalities in type of slow waves.

- The brain MRI in T2 and flair showed atrophy of the right

hemisphere with dilatation of the lateral ventricle ipsilateral cortical

atrophy and a hyperintense white matter of the centrum ovale left.

Results

brain MRI in T2 and flair showed atrophy of the right hemisphere with dilatation of the lateral ventricle ipsilateral cortical atrophy and a hyperintense white matter of the centrum ovale left.

- The patient was treated with 3 antiepileptics in combination but no reduction in seizure frequency was observed.

- Immunomodulatory therapy was then tried, it was based on corticosteroid  associatedwith immunoglobulins by intravenous

 - The evolution was marked by a disappearance of transitional seizure.

Clinical featrues : Rasmussen’s encephalitis (RE) is an infrequent

progressive and inflamatory disease of the brain affecting one hemesphere .

Rasmussen’s encephalitis is typically associated with intractable focal epilepsy , cognitive decline and hemiparesis.

The age at onset is in childehood , between 6 and 8 years (range 1-13 years).

RE affects children who were previousely healthy. Both sexes are equally affected.

DISCUSSION

-The disease starts with focal seizures.-RE is charactirazed by polymorphus seizures therefore including somatosensory , motor , visual, or psychomotor seizures wich became rapidly resistant to antiepileptic treatment .-The pathology is usually not lethal but leads to cognitive , motor and visual defects . -The relation ship between the seizures’ frequency and the neurological deterioration is complex and not linear.-The course of the disease is divided into 3 stages.-During this stage the seizures frequency and intensity progressively increase .

Histology :

The aetiology and pathogenesis of RE still remain unkown Three hypotheses have been forwarded: a direct viral insult , an autoimmune process trigerred through a viral agent , a primary autoimmune process .

Diagnosis :

Is based on features from the electroencephalogram (EEG) , MRI and clinical and / or histological characteristics .The EEG shows slowing and multiple epileptogenic anomalies, always in the same hemisphere.

Radiology :

-In the MRI , hyperintense signals in the white matter of the affected hemisphere and cortical swelling are seen , followed by cortical atrophy .-Repetitive MRIs in the begining of the disease are necessary to visualise the progression of and consolidate the diagnosis.-The patient may also benefit from a gadolinuim-MRI, MRI-angiography or angiography to exclude deffirential diagnosis of vascularitis , wich occasionally presents on only one hemisphere .-Other brain imaging techniques including positron emission tomography (PET) or single photon emission computed tomography (SPECT) wich also shouws changes confined to only one hemisphere.MR-spectroscopy usually shows decreased N-acetyl aspartate a marker of neuronal integrity .

Treatment

-RE is highly pharmacoresistant in more than 80% of cases .

-Antiepileptic drugs reduced the risk of generalised seizures .

-Immunomodulatory treatment includes steroids , immunoglobulins (IG) , plasmapherisis (PE) and immunosupressive therapy .

-Up to now, only surgery allows seizure control and remains the most efficient treatment .

Conclusion

-Rasmussen’s encephalitis is a devastating syndrome of multifocal brain dysfunction and focal seizures.

- Magnetic resonance (MR) findings, associated with clinical data and electroencephalogram (EEG), may indicate the diagnosis and could be an indicative of prognosis .