[A new framework for cerebral palsy]. / Un nouveau cadre conceptuel pour l'infirmité motrice cérébrale.

Cerebral palsy was recently redefined as a group of disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain. The motor disorders of cerebral palsy are often accompanied by disturbances of sensation, perception, cognition, communication or behaviour, by epilepsy or by secondary musculoskeletal problems (Bax et al. 2005). It has an estimated incidence of 0.2 %, i.e., 200 new cases per year in Belgium and a total of about 18,000 patients (in a population of 10 millions). Over the last few years, interest has risen in issues pertaining to learning, social participation, services, some assessment modalities (including gait analysis), some therapeutic modalities (including orthotics and antispastic treatment). The Department of Neurology of the H6pital Universitaire des Enfants Reine Fabiola has taken an active part in several aspects of these developments, including research on pathophysiology, neurophysiology, motor control and management (including intrathecal baclofen) as well as setting up the Interuniversity Reference Centre for Cerebral Palsy ULB-VUB-ULg. The 20th anniversary of the hospital offers an opportunity to review this important topic.

[Imaging in paediatric epilepsy]. / Imagerie de l'épilepsie chez l'enfant.

Epilepsy is a chronic disease, often with an onset during childhood and characterized by spontaneous and recurrent seizures. It concerns 0.5-1% of children under 16 years of age. A classification proposed by the International League Against Epilepsy (ILEA) in 2001 takes into account recent genetic factors involved in epilepsy and attenuates the sharp demarcation between generalized and partial seizures. This classification tends to define whether imaging is indicated or not. Imaging is useless in simple cases of fits associated with hyperthermia and in benign idiopathic epilepsy. It is debated if it is a first episode of epilepsy without a particular context and no neurological signs. In all other cases of epilepsy in children, imaging is indicated. In descending order of frequency the possible causes include malformations (as abnormal gyral development and phakomatoses), hypoxic-ischemic lesions, non-accidental injuries, infections, metabolic diseases and tumors. Being much more sensitive than computed tomography (CT), magnetic resonance imaging (MRI) is the technique of choice to identify an underlying cause in symptomatic epilepsy. Clinical data are mandatory in order to direct a proper MRI investigation. The recently developed diffusion-weighted sequence is particularly useful in the acute phase of certain events such as hypoxia-ischemia, trauma and metabolic disease. CT scan is used in emergency situations and also as a complement to MRI for example to identify calcified lesions. In this way, imaging contributes to establish the nature and define the extension of epileptogenic lesions, thereby guiding therapeutic management. MRI also allows follow-up of the consequences of repeated seizures (such as mesial temporal sclerosis and selective neuronal necrosis) on the cerebral parenchyma and plays a role in the establishment of a prognosis.

[Headache in childhood: which diagnostic imaging strategies?]. / Céphalées chez l'enfant: quand et quelle imagerie?

There are various causes of headaches in children. The majority of cases are considered as primary and include migraine and tension headaches. Headaches secondary to an underlying pathology are much less frequent. The aim of imaging will be to depict lesions that can benefit from specific therapy and hence improve life quality and expectancy of the affected child. In case of secondary headaches, imaging will have to precise the diagnosis, which is based mainly upon history of the disease and clinical findings. These findings are important to the radiologist as they will help to choose the more adequate technique between CT scan and MRI. This choice is based upon the presumed diagnoses, degree of emergency and availability of the technique. Knowledge of the differential diagnoses influences the way to perform the examination itself (choice of slice thickness, plane of imaging, MR sequences, need for an MR angiogram or injection of contrast medium...). In our opinion, dedicated MR imaging is the technique of choice to investigate secondary headaches in children given its superior sensitivity in depicting certain tumors (glioma of the pons, posterior fossa tumors...), intracranial hypotension, Chiari I malformation, lesions of the hypothalamo-hypophyseal axis etc...

Oral ketamine in paediatric non-convulsive status epilepticus.

In children, non-convulsive status epilepticus (NCSE) is rare and difficult to treat. Response to steroids and GABAergic medication is variable and often decreases with increasing duration of NCSE. We present our experience with oral ketamine, an NMDA-receptor antagonist, administered to five children with severe epilepsy (Lennox-Gastaut Syndrome, myoclonic-astatic epilepsy, progressive myoclonic epilepsy and Pseudo-Lennox Syndrome) during an episode of NCSE. Resolution of NCSE was documented in all cases clinically and electroencephalographically within 24-48 hours of starting ketamine. No significant side effects were noted.

[Diagnostic imaging in non-accidental brain injuries]. / Pictorial essay. Imagerie dans les traumatismes craniens non-accidentels.

Diagnosis of nonaccidental injury (child abuse) may be difficult because most infants present with non-specific clinical findings and without external signs of trauma. Brain lesions severely disproportionate to the history of trauma, retinal hemorrhages and characteristic fractures or fractures of varying age are key indicators to child abuse when encountered in an infant. It is therefore incumbent upon the radiologist to recognize the radiologic findings of the various forms of nonaccidental injury and to correlate them with the physical findings in order to render a more accurate opinion. Craniocerebral injuries are not uncommon in infants who are physically abused and have a worse long-term outcome than accidental injuries. The particularities of the infant's skull and its content and the pathophysiology of cerebral nonaccidental injuries are remembered. The imaging findings in infants with blunt impact, shaken- and whiplash shaken-injuries are emphasized. The combination of edema, malignant hyperaemic cerebral swelling, hypoxic-ischemic brain injury, diffuse axonal injuries, and bilateral and/or interhemispheric subdural hematomas is almost typical of a shaken infant. MRI, with its multiplanar capability and its sensitivity to cytotoxic edema and to degraded hemoglobin, is the modality of choice for detecting cerebral lesions in nonaccidental injury.

[Chronic subdural hematoma and extramedullary erythropoiesis in an infant]. / Cellules érythropoïétiques et hématome sous-dural chronique chez un nourrisson.

We report the case of a six-month old child with bilateral chronic subdural hematoma of unknown origin containing erythroblasts, metamyelocytes and blast-like cells. No such cells were found in venous blood. No primary neoplastic disorder was found. Throughout a 19-month follow-up period, general and neurodevelopmental examination remained normal with complete resolution of the subdural haematoma in the presence of macrocephaly. We discuss the origin and role of these cells.

[Postinfectious hemicerebellitis]. / Hémicerebellite post-infectieuse.

The clinical signs of cerebellitis are usually bilateral and symmetrical. We report the case of a 9-year-old girl who presented with acute hemiataxia and flaccid hemiparesis associated with a lesion in the ipsilateral cerebellar cortex two weeks after a viral upper respiratory tract infection. The clinical outcome was good without treatment. Imaging follow-up showed hemiatrophy of the cerebellar cortex.

MRI spectrum of cortical malformations in tuberous sclerosis complex.

The diagnostic and prognostic value of magnetic resonance imaging in the tuberous sclerosis complex has increasingly been recognized. In this paper, we review the presumed pathogenesis of the cerebral dysgenesis seen in this condition in the light of magnetic resonance imaging features of selected patients. In addition to typical findings related to tubers, we show and discuss varied cortical malformations (from simple localized cortical dysplasia to transmantle dysplasia and schizencephaly) similar to those seen in sporadic cerebral dysgenesis. These cases support the hypothesis that the tuberous sclerosis complex focally affects the radial glial-neuronal complex as a basic unit for brain development. Abnormal stem cells would create dysplastic glia and neurons that fail to differentiate, proliferate, migrate and form a normally organized cortex.