Introduction : Historical Perspectives

Introduction

The role of the clinician in the diagnosis and treatment of a weak child is as important today as it was in the 19th century, when pediatric neuromuscular diseases were first being recognized by such luminaries as Meryon (1852), Duchenne (1861), Werdnig (1891), and Hoffmann (1893), and later by Batten (1903). The clinician needs to react to the concerns of the patient and their parents at the first encounter. A detailed medical history and carefully performed physical examination remain the fundamental tools and starting point for assessing various symptoms and signs. This initial clinical assessment has three possible immediate outcomes: (1) the concerns of the patient and family appear to be unfounded, and the clinician can be reassuring. A follow-up visit is advised to substantiate this outcome and to give the parents peace of mind that all, indeed, is well; (2) the clinician shares the concerns of the patient and family but decides to use time as the first test to determine the natural history of the process; or (3) the clinician recognizes the importance of the clinical symptoms and realizes the need to perform diagnostic procedures as soon as possible.

This clinical approach places great demands on the physician at the first and subsequent encounters. Here, the difference between the 19th-century clinician and the 21st-century clinician is enormous. This difference is a measure of the scholarly advances of the past century, particularly over the past three decades, since the advent of molecular neurogenetics. Examples of such advances include major discoveries in the genetic analysis of the muscular dystrophies, congenital myasthenic syndromes, spinal muscular atrophies, and hereditary neuropathies. These advances in molecular neurogenetics have led to new diagnostic tests, which may confirm the clinical diagnosis accurately and noninvasively. Traditional diagnostic tests such as nerve conduction studies, electromyography (EMG), and open muscle biopsy are less often required in the evaluation of neuromuscular disorders in infancy, childhood, and adolescence. Nevertheless, these traditional tests remain useful in certain situations: to evaluate patients in whom molecular genetic analyses fail to confirm the initial clinical impression, to facilitate the rapid electrophysiologic diagnosis of a neuropathy or spinal muscular atrophy, or to focus more precisely on molecular mechanisms before ordering relatively expensive molecular genetic tests. The dramatic advances in DNA diagnostics have added to the complexity of a challenging clinical field and have left physicians occasionally uncertain about the relative indications for traditional tests such as EMG and muscle biopsy. Clearly, all these diagnostic tests remain useful, and it is up to the modern clinician to make informed decisions, after the initial clinical evaluation, to facilitate an accurate biomolecular diagnosis as quickly and as economically as possible.