Before closing the subject of the pathology of rickets a few words may be said with regard to the cases of so-called " congenital rickets." This term is applied to a condition in which the limbs of a new-born child are found to present peculiar characters. The shafts of the bones are short and thickened, and may be found bent or even broken. At the same time the epiphyses are swollen, soft, and quite cartilaginous. The condition, however, differs materially from true rickets, and has been compared by Eberth to that found in cretinous children. In all recorded cases where the appearances have been noted the shafts of the bones have been found much ossified and remarkably thick and stunted. This peculiarity gives, of course, a curious shortness to the limbs.' The dia physes, instead of being imperfectly ossified as in rickets, with great porosity of the medullary parts of the bone and thickness of the perios team, are excessively hard and compact. Fibrous tissue derived from the inferior layers of the periosteum intrudes between the epiphysis, and the shaft. The epiphyses, also, are enlarged generally and not only at the line of calcification, as in rickets ; and their microscopical characters present sensible differences. In a case recorded by Urtel the cartilage cells in the epiphyses were found lying confusedly together. As they approached the cliaphysis they were seen to become flatter, especially in the peripheral portions, and finally passed into the layer of connective tissue which sep arated the greater part of the epiphysis from the shaft of the bone. The resemblance between these cases and cretinism is displayed not only by the stunting and firm ossification of the cliaphyses. There is the same tendency to early union by ossification of the basi-occipital and post sphenoidal bones. Some specimens of " congenital rickets " preserved in the Museum of the Royal College of Surgeons exhibit this peculiarity, and in others, where the soft parts remain intact, many of the facial char acteristics of the cretin are also to be observed.
Symptoms.—As might be expected in a disease which arises as a direct consequence of faulty nutrition, the symptoms proper to rickets are usu ally preceded by others indicating a general interference with the nutritive processes. Digestive derangements are common, but these comparatively seldom consist in attacks of severe or repeated vomiting or diarrhoea. In most cases the derangement is limited to a lessening of digestive power, so that the motions, without being actually loose, are more frequent than natural. They are large, pasty-looking, and offensive from the quantity of farinaceous and curdy matters which are passing undigested out of the body. At this time the child is often irritable and fretful. His belly may be swollen from flatulent distention, and he frequently cries with pains in the abdomen. For this reason he may be often found asleep in his cot resting on his chest, or supported on his knees and elbows with his head buried in the pillow. The urine is often very acid and causes uneasiness in mic,turition. If the child perspires copiously the renal secretion may contain considerable quantities of uric acid sand.
Unless by judicious treatment and diet the alimentary canal be restored to a healthy state the child, although often still plump to the eye, becomes pale and flabby. Then, after an interval which varies in duration according to the natural strength of the patient and the more or less wholesomeness of his surroundings, the early symptoms are noticed. The onset of the disease is announced by three special symptoms. The child begins to sweat about the head and neck ; he throws off his coverings at night and lies naked in his cot ; and begins shortly afterwards to exhibit uneasiness if much danced about in his nurse's arms or handled without the utmost gentleness.
The sweating is profuse and occurs principally during sleep. At night beads of moisture may be seen standing on his brows, and the sweat trickles off his head on to the pillow, which is often saturated by the secre tion. If the child fall asleep in the day-time, or even if he exert himself much while awake, the same phenomenon may be noticed. The irritation of this perspiration often gives rise to a crop of miliaria about the neck, behind the ears, and on the forehead. The superficial veins of the temples are full, the jugular veins are unusually visible, and the carotid arteries may be felt to pulsate strongly.
The desire of the child to lie cool at night comes on almost at the same time with the preceding, and may be observed in the coldest weather. It is, indeed, a frequent cause of catarrh in these patients, and I have seen.
many cases in which continued looseness of the bowels was apparently maintained by repeated chills so contracted. For the same reason a fre quent cough from pulmonary catarrh is a common symptom.
General tenderness usually begins to be noticed at a certain interval after the two other symptoms which have been mentioned. It is shown by unusual sensitiveness to even slight pressure, and appears to be seated in the muscles as well as the bones. The child cries if lifted up at all abruptly or subjected to any jolt or jar, and prefers to lie quietly in his cot or .on the lap of his nurse. This symptom seldom occurs until the osseous changes are well marked. It is accompanied by uneasiness or pain about the head, which is indicated by a monotonous movement of the head from side to side upon the pillow. The hair covering the occiput is often worn away by this constant movement, and the bareness of the back of the scalp from this cause is a very characteristic symptom. Tenderness is not always noticed. It is usually confined to cases where the disease is severe. In the mild cases, which are merely by a slight enlarge ment of the wrists and ankles, without any apparent softening of the bones, the symptom is usually absent. • The bone changes consist in an enlargement of the epiphyseal ends of the long bones, in a thickening of the flat bones, and in a general softening of all. The enlargement of the ends of the bones occupies the point of junction of the shaft with the epiphysis. Both extremities of the bone may suffer, but the change is naturally most obvious in the part which is near est to the surface. The ribs at their sternal ends are usually the first to be affected ; then the bones of the wrists. As a rule, the epiphyseal swelling is more marked in the bones of the upper extremities than it is in those of the lower. The thickening of the flat bones is well seen in the bones of the cranium, and the softening of all the bones is one of the causes of the deformities of the trunk and limbs which are so common in early life. It must not, however, be supposed that every case of rickets ends in softening and distortion. All degrees of severity of the disease may be met with, and in mild cases softening and the consequent deformities of bone are entirely absent. Even in more severe cases we must not expect in every instance to find all the symptoms to be enumerated. In one child the epiphyseal swellings attract most attention ; in another the softening of the bones. In some the chest is excessively distorted and the bones of the limbs are comparatively straight. In others the limbs are greatly twisted while the thorax is but little altered from the normal shape. These differences are said by Baginsky to be determined by the part of the skeleton in which growth happens to be most active at the time of the attack.