Rachitis is found in city and country, less on mountains than in valleys. Still, it is met with at elevations of two thousand feet. In the tropical regions it is almost unknown. Why it should have been considered quite a new disease in England but a few centuries ago, or whether it did not exist before that time, it is difficult to say. It is certain, however, that deformities have been described in antiquity which we are accustomed to attribute to rachitis.
As the disease is one that occurs during the period of rapid growth, and is a developmental disease, everything that interferes with normal growth and development is apt to change physiological functions into pathological conditions and to produce rachitis. In the pregnant mother her ill-nutrition and the defective cell-material used in the building up of the embryo and foetus, or a defective placenta, may come in for the explanation of foetal and congenital rachitis, although the case of Klein's, who reports twins, of which one was normal and one rachitic, is rather difficult to explain on that basis only. Even rachitis of early infancy is not easily accounted for otherwise, for its first symptoms show themselves at a very early period; thus constipation, adiposity, and afterward craniotabes and thoracic grooving.
The common form, and that which is the usual subject of the text-books and monographs, has, however, in most cases a well-marked preparatory stage in the shape of diseases or ailments reducing sanguification and nutrition. Some cases are ushered in by, or follow the course of, acute exanthems or acute gastric disorders or the presence of entozoa. A larger number appear to result from insufficient oxygenation resulting from lung diseases, with a long chronic ailment following the acute stage. Even acute pneumonia, with its direct influence on general nutrition, stands often for the proximate cause of rachitis. Bad air alone, even swamp air, does not appear to be a sufficient cause. When it seems so, it is complicated with the main cause of rachitis; that is, bad, insufficient, improper food, with its immediate result—viz. intestinal catarrh. Cow's milk, particularly when acid, starchy food administered too early or in too large quantity or too exclusively, early weaning followed by improper artificial food, insufficient mother's milk or such as is either too thin or too caseinous, lactation protracted beyond the normal limit,—may all alike be causes of intestinal disturbances and rachitis.
Is rachitis hereditary? A number of women who were rachitical themselves have been known to have rachitical children. But it has been said that the process runs its full course during infancy, and that therefore a direct inheritance of rachitis from mother to child is an impossibility. Still, we must not forget that the consecutive conditions of the parents may, or will, influence the general condition of the infant and result in similar disturbances. No rule, however, exists. Dyscrasic parents may have healthy children, and healthy parents sickly or dyscrasic ones. But the probability is greater that diseased children should come from dyscrasic parents than from healthy ones. Tuberculosis in the parents has frequently been accused of being the cause of rachitis in the infant—not directly, but in consequence of general impairment of the tissues. Gout has also been accused of being the cause of rachitis, but it is a peculiar fact that the poor have but little gout and a great deal of rachitis. In all of these cases it is better to look upon rachitis as only one of the forms of general mal-nutrition, and to speak of inheritance of the disposition rather than of the disease. Thus it was that about the end of the eighteenth century Portal spoke of scrofulous, syphilitic, scorbutic, rheumatic, arthritic, and exanthematic rachitis. Particularly has syphilis been accused of being the main cause of rachitis by some, and even the only cause by others. Thus it was looked upon by Boerhaave. In modern times Parrot maintained, from 1872 up to the time of his death, which occurred recently, that every case of rachitis is of syphilitic origin. As his proof he relied mainly on the condition of the teeth and the bones. But those appearances in the teeth, the thin and ragged edges, the friability and the grooving, either horizontal or vertical, which have been considered characteristic of syphilis by Hutchinson and others, have no such dignity, and moreover they are not observed in the temporary teeth at all, but in the permanent only; the rachitical softening of the bones also is not found in syphilis at all. Particularly are there no curvatures in syphilis and no infractions. It is true that marasmus is found in both rachitis and syphilis, but it is met with in all sorts of diseases. The changes in the bones of syphilis are found at birth; in rachitis they usually develop in later months. When a baby is syphilitic and rachitic at the same time, the syphilis may last very much longer than the rachitis, which meanwhile has healed. The internal organs in rachitis do not exhibit any such changes as are known to occur in very many cases of syphilis. No gummata are ever found in rachitis, and the interstitial inflammation of the internal organs in syphilis is not met with to the same degree in rachitis. What Parrot claimed as a desquamative syphilide of the tongue—that is, red insulated spots, denuded of their epithelium, small in the beginning, later extending backward and increasing in size—is by no means always syphilitic, but is found in a great many cases where there is no suspicion of syphilis. It is mainly Kassowitz and Bouchut who have taken the stand against Parrot. The former, taking rachitis for a peculiar inflammatory process, admits that syphilis can be one of the causes. The latter directs attention mainly to the fact that by changing food in certain ways rachitis may be produced in dogs, but that they cannot be made syphilitic. There is no doubt, however, that syphilis may give rise to rachitis by its general influence on nutrition, and in this fact lies the key to the connection of great nutritive disorders with each other. Syphilis will undoubtedly change nutrition to such an extent as to result in rachitis. Rachitis will affect the glands; the caseous and suppurative degeneration of the glands will lead to metastatic processes, to acute tuberculosis, and so on.
Malaria been claimed as the main cause of rachitis by Z. Oppenheimer,12 or, rather, rachitis is presumed by him to be the form in which malaria makes its appearance in young infants. After disposing of other alleged causes of rachitis, none of which is proved to give rise to every case, and referring to the anatomical belief that the peculiar hyperæmia and inflammation of rachitical bones is created by the embryonic condition of the growing osseous tissue, he points to the prodromi, amongst which he emphasizes chronic diarrhoea and the nocturnal crying. The latter, with its perspiration and subsequent sleep, he claims as evidence of malaria, and as a substitute for the intermittent neuralgia of adults, the more so as he believes he finds the spleen tumefied. The persistent diarrhoea of these infants is said to be paroxysmal—to take place in the morning, contrary to what is seen in the usual form of intestinal catarrh; the discharges are said to be serous, not tinged with bile; the appetite to be good through the rest of the day; the weight of the body not to be lessened, but anæmia to develop gradually, and fever to occur occasionally. In other cases infants have cold hands and feet and blue lips toward evening; the skin is pale, the spleen enlarged; otherwise there are perhaps no symptoms, but the infants try to get uncovered, and have an increase of temperature of from 1° to nearly 3° F., and a perspiring head in the morning. After a while the rachitical symptoms belonging to the bones and the general system become apparent. After all of the author's ingenious and emphatic assertions and deductions, it becomes evident that malaria—in the severe forms in which it has been found by Arnstein, Browicz, and Henck to cause bone diseases—may give rise to rachitis, but it is also clear that he tries to prove too much. The long series of attempts at proving that every form and case of rachitis depends upon a single and uniform cause have proved futile. The physiological hyperæmia of the bones and the rapid growth of all the infant tissues are shaped into the complex ailment which we call rachitis by more than a single disease or a single nutritive disturbance.
12 D. Arch. f. klin. Med., xxx., 1881.
SYMPTOMS.—Before entering upon a more accurate and elaborate enumeration of the symptoms of rachitis, I mean to dwell upon peculiar differences which take place according to the age in which the disease makes its appearance. Very young babies—that is, infants of a month or two—develop rachitis in such a manner that many cases are overlooked until it is too late to relieve them in time. This occurrence takes place when there are no prominent causes, such as diarrhoea or other nutritive disorders, nor any premonitory symptoms. Such infants appear to be perfectly well; they have the average weight, and even more; they have plenty of adipose tissue, and look well. The only anomaly appears to be an undue degree of paleness. Without pain or flatulency they are constipated. This constipation is not congenital, as it always is when the colon is unusually long even for an infant, and when the sigmoid flexure is of double or even treble length, but makes its first appearance about the end of the first or the beginning of the second month. It is relieved only when the increasing muscular power of the intestine results in more effective peristalsis. The second symptom is the thoracic groove, to which I shall allude later, and a gradual thickening of the costo-cartilaginous junctures, with or without periosteal pain on pressure. About the same time the cranial softening, craniotabes, with its hyperæmia and perspiration of the entire scalp, and baldness, and the first symptoms of maxillary rachitis, become perceptible. During all this time the epiphysial swellings and the diaphysial curvatures develop but very slowly; but at a very early time chronic bronchial catarrh, with a loose cough, begins to be troublesome. When rachitis begins at a late period—say, about the sixth or eighth month—the aspect of the case is different. The infant has suffered before either from bronchitis and broncho-pneumonia, or in most cases from indigestion and intestinal catarrh. There is some degree of emaciation; the skin does not fit the limbs, as it were—is loose, thin, flabby, and rather dry. The tendency to diarrhoea continues to prevail. The epiphyses, particularly of the lower extremities, are thickened at an early time, curvatures of the tibiæ become apparent, and all the rest of the bones participate in the process, with the exception, sometimes, of those of the head.
The head, however, is liable to exhibit symptoms of rachitis at a very early period of life. It is large, or appears to be so,13 mostly for the reason that the face is proportionately small. The forehead is large, the frontal protuberances very prominent, as are also those of the parietal bones. Thus, the head is more or less square. Dilated veins are visible in and through the pale skin; there is but little hair, on the occiput less than on the rest of the head. Sometimes the occiput is quite bald, the hair having been rubbed off on the pillow. The scalp feels warm, except during perspiration. The latter is very copious, particularly on the occiput—to such an extent, indeed, that the pillow is drenched—and will remain so for months. The sebaceous follicles are often still larger and more numerous than they normally are at that age, and seborrhoea is often, though not always, met with. The sutures are wide, sometimes one or two centimeters; the posterior fontanel remains open; the large anterior fontanel is very large, being sometimes several inches long and wide. The pulse is felt very distinctly through it. The systolic cerebral murmur, which was first found by Fisher of Boston in 1833, and considered to be a positive symptom of rachitis (which certainly it is not, as it is found in almost every healthy baby with a patent fontanel), is very audible. The fontanel and sutures remain open for a long period. Instead of closing, as they do normally at the fourteenth or fifteenth month, the former ossifies about the end of the second or third year, or later. Gerhardt reports a case in which it persisted to the ninth year. The cranial bones appear to be thin, and give way under the pressure of the finger. Ordinarily, it is true, the cranial bones of every baby, even if perfectly healthy, are movable under pressure, but they are so only along the sutures, where they may retain this mobility, in some instances, a long time. Indeed, it appears that sometimes about the middle of the first year the occipital bone becomes thinned out in apparently quite healthy children. Moreover, even in the skulls of infants who were taken to be in good health small defects in the bones were found (Friedleben), with no uncomfortable symptoms at all. Therefore it is rather difficult to draw the exact boundary-line between the healthy and the morbid condition; thus it is possible that some of those cases which exhibited apparently morbid local changes without morbid symptoms may not have been diseased after all. In those, however, in which rachitis is really developed in the cranium a peculiar condition is found. In the posterior half or third of the parietal bones, either the right or the left side being more marked, there are in the tissue of the bone distinct spots in which the osseous material is not only thinned out, but has entirely disappeared. In fact, the bone is perforated, the edges of the holes being rather steep, sometimes slightly thickened, and the scalp separated from the brain only by a thin, transparent membrane, the remnant of the periosteum. These holes can be easily found through the integument. The finger, though ever so gently pressing down upon it, moves the cranium, if any be left, before it; the bone feels like paper, and the sensation as if it could be easily broken through is quite distinct and embarrassing. Such perforations are usually quite numerous; from five to twenty or more can often be counted. They are surrounded by normally hard bone, and thereby can be recognized from the flexible part of the cranium extending along the sagittal and lambdoid sutures. Where these results of rachitical softening, craniotabes, are most prominent—that is, on the part on which the infant is mostly reclining—the bone is flattened, and may remain so for life, though in the majority of cases the asymmetry will disappear. The flattening and perforations result from the same causes—viz. softening of the bones and pressure upon the bone between the pillow outside and the brain inside. With it go, hand in hand, thick rachitical deposits under the hyperæmic periosteum of other portions of the skull. Where craniotabes is largely developed on the occipital portion, the frontal and the parietal bones (in their anterior halves) are usually thus thickened. A cross-section with a knife will reveal a diameter of the new osteoid material between the periosteum and bone of one-half to one centimeter in thickness. It is very hyperæmic—even more so than the bone itself, which, when cut into, exhibits an unusual amount of blood. Sometimes the deposits are still larger, and are apt to change the appearance and weight of the skull considerably after recovery has taken place and eburnation and sclerosis have taken the place of the normal osseous tissue.
13 Boötius (1649), quoted by Haller (Bibl. Med. pract., 1779): "Infantibus caput grandescit, reliquum corpus contabescit, ossa in articulis tument, dextrum hypochondrium tumore æquali prominet; hoc malum multis millibus infantum molestum est" ("The infant head grows large, the rest of the body emaciates, the articular bones swell, the right hypochondrium is raised by a uniform tumor; this malady is a sore affection in many thousands of infants").
Such a case of rachitical cranial sclerosis I have described in the Amer. Med. Monthly of 1861. It was, however, by no means a mate of the case related by E. Huschke. The latter skull was that of a girl of seventeen years, and weighed 4117 grammes instead of the normal weight of 600 grammes. The medullary (Havers') canaliculi were large and very numerous on the surface, narrow and very few in the interior of the sclerotic bones, and the osseous canaliculi were more spherical and irregular in site and shape. The chemical composition was also abnormal, phosphate of lime being 65.59, carbonate of lime 11.12, sulphate of magnesia 1.14, cartilage and fat (very little), etc. 22.15 per cent. No fluorate of lime was found. Most of the bones were exceedingly hard, but fragile when tried in small pieces; very white inside, yellowish on the surface, the latter color being the remnant of extravasated blood or other pigmentous matter. Another skull, in Huschke's possession, and moderately sclerotic, weighed (lower jaw excluded) 1075 grammes; a third, in the museum of the University of Jena, is that of a young baboon,14 in which all the bones covering the hemispheres had become sclerotic.