Diseases of the Nervous System in Childhood

Aicardi’s Diseases of the Nervous System in Childhood

 

Treating neurological disorders in childhood

Diseases of the nervous system in infancy and childhood have a profound impact on the life of patients and their families and are probably the most disruptive of all paediatric ailments. Around 20–30% of hospitalized paediatric patients have a neurological problem, either as a sole or as an associated complaint. However, many well-educated paediatricians not infrequently feel uncomfortable and hesitant about how to treat children and what to tell to parents of patients with neurological disorders.

 

The ‘philosophy’ of paediatric neurological examination

In this age of ubiquitous technology, collection of clinical data and their correct interpretation remain as essential as ever.

 

History taking

In the first place, the eminent importance of history taking needs to be re-emphasized, as the history of the disease – as well as that of the child from conception and that of his/her family–forms the initial and most important step of the diagnostic approach. For most conditions, the diagnosis is established by thorough clinical history even before, and much more frequently than by, examination. History taking is a difficult art requiring careful listening, patience, clinical acumen and understanding. It also necessitates a thorough knowledge of which information is worth looking for, and constant attention to possibly revealing words that may occasionally emerge out of a casual or even apparently irrelevant conversation.

 

Neurological examination

This emphasis on history taking does not in any way minimize the essentiality of neurological examination, which should be as thorough as possible and largely guided by historical data. However, in children, and especially in infants or neonates, it cannot be conducted systematically as in adults. Attempts at ‘adult-type’ examination will lead to crying and fussing. Much of the examination should not require that the child be lying, as the lying position will often frighten the child by reminding him/her of previous unpleasant experiences and prevent the gathering of more important information on central nervous system functioning. After all, the vertical posture has been a major evolutionary acquisition and, since the emergence of Homo erectus, most human activities take place in the standing position.

 

Observation

Indeed, a major part of examination, and one too often neglected, consists of watching the spontaneous activity of the child. While an early example of observation is of neonatal and early infantile general movements, which have been shown to have predictive value, later observation should be watching children’s spontaneous activity with special emphasis on how they relate to their surroundings and to other children or adults, the duration of their capacity of attention, and their verbal or preverbal communication. Playing or interacting with the child is the best manner of assessing CNS function and provides information not only on purely neurological function but also on behavioural problems, which is clearly essential for the diagnosis of the behavioural syndromes that are currently taking a major place in child pathology. Advantage can be taken as often as possible of video-recording for prolonged observation of children’s behaviour and is also particularly useful for the precise study of transient events such as seizures as it allows leisurely and repeated analysis of the ictal phenomena.

 

Behaviour

It cannot be overemphasized that the basic role of the nervous system is to produce not just reflexes but above all complex and adaptive behaviours that are much more informative on the status of the central nervous system than elementary responses to imposed stimuli. This is best achieved by prolonged observation of the qualitative aspects of the spontaneous activities of the children or infants. All too often, the child is examined but not looked at.

 

Medical  technologies

Spectacular advances  in  medical  technologies  made over the past decades have revolutionized and enormously increased our diagnostic possibilities, both pre- and postnatally (and recently even in pre-implantation diagnosis), and also improved follow-up surveillance far beyond what could be imagined 20 years ago. Neuroimaging, especially MRI, has become an almost routine investigation, and with continuing improvements and new developments such as diffusion-weighted MRI, tensor tractography, functional MRI and MR spectrography can now provide information not only on the anatomy but also on the function of some of the central nervous system structures.

 

Molecular genetics

Biochemical progress in the molecular structure of proteins and the advent of molecular genetics allow a precise diagnosis of many genetic disorders even in the absence of clinical manifestations, representing an entirely new field opening new perspectives in diagnosis and prevention. However, at the same time, the availability of these multiple techniques has made the task of choosing among the possibilities offered much more difficult.

 

Diagnostic hypotheses

Investigations should not be performed indiscriminately or systematically but only after formulation of one (or a limited number) of diagnostic hypotheses, arising mainly from history and clinical findings, with a view to validate or reject them on the basis of their confrontation by clinical and laboratory data. Clinical medicine is and must remain an intellectual process whereby all sources of information, whether clinical stricto sensu or arising from technical aids, are used to formulate a diagnosis that will lead to the best possible care of the patient. One’s last task is to communicate and discuss our, sometimes complex, findings with the patient and their family.

In this era of genomic medicine, understanding the phenotypic spectrum of the huge variety of disorders of the child’s nervous system remains of paramount importance. Family history-taking needs to be taught to all those who wish to practice child neurology. A thorough clinical and physical examination is the second indispensable step towards diagnosis.

The combination of these two steps represents the optimal road to the formulation of a diagnostic hypothesis, then followed by the selection of the most appropriate laboratory and/or imaging investigations and the correct interpretation of the impressive quantity of complex results provided by all types of screening.

 

Diagnosis

Physicians caring for children with rare or common neurodevelopmental, disorders must keep in mind that a ‘disease’ will always be defined as a disorder of structure or function typically manifested by distinguishing signs and symptoms, with aetiology probably being the most important factor influencing prognosis and outcome. Each diagnostic investigation, taken alone, no matter how sophisticated, provides only a hint towards diagnosis.

Child neurology is reaching a turning point. During its early adolescence the discipline focused on description of numerous disorders. Identifying and homogeneously classifying, as best as possible, these disorders led to a better understanding of underlying mechanisms and to the development of global care practices.

In the 21st century, the development of new technologies needs to be perceived not just as an easy road to diagnosis but as a tool for a better understanding of the causes and as a support for research in discovering novel treatments that will improve the clinical management of affected children.

 

* Excerpted from the book Aicardi’s Diseases of the Nervous System in Childhood, 4th Edition edited by Alexis Arzimanoglou with Anne O’Hare, Michael V Johnston and Robert Ouvrier.

 

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