Abnormalities of Growth and Development Abnormalities of Growth and Development

The conditions of dwarfism and infantilism can be considered together, for although dwarfism is not infrequently found without infantilism the two are more frequently combined. Both represent disturbances in the growth sphere, but whilst in dwarfism the defect is skeletal and limited to the skeleton, in infantilism the retardation of development is general. The term dwarfism implies a defect in stature below the normal standards but does not necessarily signify a pathological state, for dwarfism under certain conditions may occur without any evidence of disease. In simple dwarfism the skeleton is of small size, but the bodily characters and functions-especially in the sex sphereare appropriate to the age of the individual. The skeleton may be proportioned or disproportioned. If disproportioned the defect may be either in the trunk or the limbs -an abnormality of the spine or the long bones. In either cast the underlying cause may be developmental or acquired. The term infantilism is more difficult to define, and is often used ambiguously. Strictly speaking, it should be reserved for more or less permanent conditions in which the physical and psychological attributes of childhood persist into adult life-smallness of stature, underdevelopment of the musculature, a head large in proportion to the body, comparatively short limbs, lack of function of the genitalia, and certain qualities in the mental sphere. This strict interpretation of the term, however, is not generally adhered to, and there is a tendency to include conditions of temporary delay in development in which the stage reached is less than that appropriate to the age of the individual. This is perhaps justifiable if the wide sense in which the term is used is clearly understood. The term infantilism, however, should not include pathological states such as eunuchoidism, in which retardation or arrest of development in one sphere -in this instance the sex sphere-without any general disturbance of growth and development is found. It -is obvious from our consideration of the many factors which influence the growth process that there must be a number of different causes of dwarfism and infantilism. Physiological and pathological varieties both occur. Dwarfism may be a separate entity in simple hereditary dwarfism and in achondroplasia and allied conditions. -The various forms of rickets are also accompanied by growth defects, and in the coeliac and renal formss, where there is a pronounced interference with general metabolism, infantilism results too. The different forms of infantilism are difficult to classify, but there are two main groups. In the first, due to endocrine deficiency, the underlying cause may be hypopituitarism, hypothyroidism, or hypogenitalism. If the underlying condition is untreated the physical and psychological attributes of childhood persist into adult life. To the second group the term cachectic has been applied, and it includes those in which retardation or arrest of development has resulted from malnutrition, metabolic 'disturbance, or chronic infective disease. A convenient classification of the different varieties of dwarfism is as follows: