COLLAPSE OF THE LUNG. 103 structure of the lung, mucus cannot be expelled. In coughing to expel the mucus, the lung must be filled with air to the utmost; the contained air is then prevented from escaping by closure of the glottis, and at the same time, pressure is brought to bear upon the lungs by the muscles of expiration. The glottis is then suddenly opened, and the air is driven out, carrying with it the mucus which obstructed the tubes. The forced respiration seen in persons suffering from bronchitis, is merely the effort made to draw in the air past the obstructing mucus. A second impediment to the entrance of air into the lung is found also in the healthy child. It arises from the natural flexibility of the lower part of the thoracic parietes which yield to a certain extent in inspiration before the pressure of the external air. In advanced rickets, however, this natural flexibility is greatly increased by the abnormal softening of the ribs, so that even when the lungs are healthy each inspiration is only effected by a distinct laborious effort. Now add bronchitis to this condition, and the impediment is extreme. Air cannot enter deeply into the lungs ; mucus cannot be expelled; the air, however, in the lungs can be, and is expelled; there is, consequently, collapse, and the child dies—not properly speaking from the collapse, but from that which caused the collapse, viz., the inability of the inspired air to pass the obstructing mucus. The extent to which the ribs are softened, and the amount of their recession in inspiration, are therefore of extreme importance as regards the prognosis of bronchitis when it occurs in rickety children. Diarrhea.-Rickety children are especially liable to attacks of purging. This may be accounted for partly by their extreme sensitiveness to changes of temperature, and partly by the unhealthy condition of the alimentary canal, which always precedes and accompanies the disease, and which a very slight additional irritation would easily aggravate into diarrhoea. These attacks are exceedingly dan gerous. We know that even healthy children, seized with profuse purging, rapidly lose flesh, and soon become exhausted. A few hours are sufficient, if the drain is severe, to cause a marked change in their appearance; their features quickly lose the roundness of youth, and assume instead the pinched, drawn characters of age. Rickety children, already enfeebled, are still less able to withstand the depressing effects of the disorder, and fall victims to it all the more readily in proportion to the degree to which their strength has been previously reduced. Laryngismus stridulus and convulsions are very common complications of rickets. The first especially is almost always associated with rickets as its cause. Sir W. Jenner * has only known two cases of laryngismus to occur in children not the subjects of that disease. Whether it is, as Dr. Gee suggests, that the convulsive tendency and the rickety state are both due to the same condition of general malnutrition, or that the convulsions are a secondary result of the rickety constitution, the fact remains that in rickets the special and the general convulsive attacks are exceedingly frequent, and are often combined. Out of fifty cases of laryngismus noted by Dr. Gee, forty-eight were rickety, and of these nineteen had general convulsions. Out of one hundred and two children in whom general convulsions occurred, forty-six were rickety. This connection is exceedingly important, as regards the treatment of these attacks. Most of the children in whom this convulsive tendency is marked have carpo-pedal contractions. As dentition is backward in all these cases, the laryngismus and the convulsions are frequently attributed to teething. The teeth, however, are quite innocent of any share in the production of these complications. They are backward as a consequence of the arrest of growth of bone which * Medical Times and Gazette, May 12, 1860, p. 465. See an elaborate paper by Dr. Gee in St. Bartholomew's Hospital Reports, vol. iii. 1867. CHRONIC HYDROCEPHALUS. 105 is one of the characteristics of the disease. When the teeth do appear they are often cut with remarkable ease, and whereas the child had been formerly subject to convulsions, with or without apparent cause, the commencement of dentition is accompanied by no such phenomena; the removal of the rickety condition, as shown by the evolution of the teeth, being coincident with the disappearance of the spasmodic tendency. Chronic Hydrocephalus occasionally complicates the disease, and is most common, according to Dr. Merei,* between the ages of eight and eighteen months. The fluid may be in the lateral ventricles, in the arachnoid sac, or in both. It often appears to be a merely mechanical effusion, the serosity being thrown out to fill up the space left when the cranial cavity becomes enlarged without any corresponding increase in the size of the brain. In these cases the convolutions are perfectly natural, and show no signs of pressure. On account of the altered shape of the skull, hydrocephalus is often suspected where it does not really exist. The differences between the ordinary rickety head, and the skull expanded by fluid in its cavity, have already been pointed out. (See page 90.) Besides the complications which have been mentioned, tubercular formation may occur in rickety children. This, however, is not a special complication of the disease, and is comparatively rare. When death results from the intensity of the general disease, without the occurrence of any of these complications, the child becomes weaker and weaker; he loses all power of supporting himself, and can hardly move. The difficulty of respiration, owing to the softened state of his ribs, absorbs all his attention. The face gets livid, or leaden-coloured; the perspirations are extreme; the tenderness is so great that he cannot bear to be touched; the *Disorders of Infantile Development and Rickets, 8vo, 1855, softening of the bones, and the consequent deformities, continue, although sometimes the bones seem to get brittle, and fractures may occur unless the child is moved with very great care. The appetite becomes completely lost; the body generally is much wasted, although the belly remains full and distended; and at last the child dies exhausted or asphyxiated. If the disease terminates favourably the symptoms gradually subside, and finally disappear. The tenderness becomes less marked; the bones cease to soften; the child appears more lively, and takes an interest in what passes around him. As the softening of the ribs diminishes his respiration grows less laborious, and he will then begin to amuse himself with his toys. The appetite improves, and gets less capricious; the bowels are more regular, and the stools healthier-looking. The wasting ceases; the child begins to gain flesh, while the belly decreases in size, and becomes less prominent. The head-sweats are less noticed, and his sleep at night is more tranquil, although for a long time he will continue to throw off the bed-clothes at night unless restrained. Dentition recommences, and goes on rapidly and easily. The deformities of the bones gradually diminish; the bones get very much straighter than would be expected from their former distortion, and become exceedingly thick and strong. The muscles also begin to be more developed, and increase rapidly in size. The increase in length of the bones, however, is not rapid, and the child remains more or less stunted, seldom when full grown reaching the average height. Pathology.-Rickets is a general disease, and affects very widely the tissues of the body. Its influence is, most manifest in the bones, which are always implicated, but we find in addition, changes in the brain, liver, lymphatic glands, spleen, muscles, and often of every organ in the body. Rickets affects the bones in three different ways. It interferes with their growth, not only temporarily, but permanently; for children who have been thus affected never, as Mr. Shaw has pointed out, grow into average sized adults. It interferes with their development, perverting the process of ossification, and rendering the calcareous deposit irregular and incomplete. Indeed, according to Sir W. Jenner, it is not true ossification at all, but rather petrifaction, such as we see occasionally taking place in enchondromata. But besides its influence over the growth and development of bone, rickets produces equally serious changes in bone already completely ossified. It softens and consumes the osseous tissue, so that the bones lose in density, in weight, and in firmness; they yield under the pressure of a finger, and can be cut "like carrots with a knife."† This softening is due to the removal of the lime salts, which enter the blood in a soluble form, and are excreted by the kidneys. Some pathologists have attempted to explain this absorption of lime by the excessive formation in the alimentary canal of an acid which has been variously stated as lactic, oxalic, phosphoric and hydrochloric. The acid, whatever it may be, enters the blood, and so assists in the abduction of lime from the bones. This, however, is mere hypothesis. Some change probably takes place besides the loss of the earthy matter of the bones, for in some of Lehman's and Marchand's experiments the bones yielded no gelatin on boiling. Anatomical characters.-The enlargement of the ends of the long bones is a real hypertrophy. "In rickets," says Sir W. Jenner, "there is an exaggeration of the conditions we find in the first stages of ossification in the healthy subject; the completion of the process only is stayed. There is great development of the spongy tissue of the head of the bone, and of the epiphysis, and also of that layer of * Medical Times and Gazette, March 17, 1860, p. 261. |