The extremities begin to suffer at a later period than the ribs and cranium. The opinion of Guérin, that the rachitical process begins in the lower extremities and ascends gradually, is erroneous. It cannot even be stated that the lower extremities are affected sooner than the upper. There is no regularity at all; it is not even necessary that all the osseous tissue should fall sick. But this can be taken as a fact, that hands and feet, and particularly the phalanges, are the latest to undergo the rachitical change. First in the line of morbid alteration of the bones are the epiphyses, mainly of the tibia, fibula, radius, and ulna. Their integument appears to be thin; now and then the cutaneous veins are dilated. The periosteum of the diaphysis becomes thick, softened, and painful to the touch and pressure, its compact layer thin, the medullary space large, the whole bone flexible, at the same time that the ligamentous apparatus of the joint becomes softened and flabby. At this time babies are greatly admired and applauded for the facility with which they introduce their feet into their mouths. For at the same time the bones begin to curve under the influence of the flexor muscles, which are always stronger, as they do in later months under the weight of the body when the child begins to walk. The curvature is not always a mere arching, but sometimes the result of infraction (green-stick fracture), a complete fracture not being accomplished because both of the softness of the osseous tissue and the resistance on the part of the thickened and softened periosteum. Both the legs and forearm bend on the external side, the resulting concavity looking inward. The humerus bends in a direction opposite to that of the forearm; the thigh, usually outward and forward.
The attempts at locomotion are often the causes of quite preposterous anomalies; creeping, sliding, walking, turn the extremities in such unexpected directions that talipes valgus, genu valgum, and now and then double curvatures, are the results. These, however, may not always be very marked, but there is one change in the rachitical bone which is constant—viz. the impairment of longitudinal growth. In every case the diaphyses remain abnormally short, and the proportion of the several parts of the body are thereby disturbed. Chiari measured parts of the skeleton of a rachitical woman of twenty-six years who was nine years old before she could walk. Her height was 116 centimeters, the length of the lower extremities 42, femur 23, tibia 15, fibula 20, humerus 16, right radius 12.5, left radius 11, right ulna 15, left ulna 14 centimeters. In a second case the parts of the skeleton were measured after they had been extended with great care. The right arm from the acromion to the middle finger (incl.) was 39 centimeters, the left 38; the right lower extremity from the trochanter to large toe (incl.) 39, the left 41.
The skin participates in the general nutritive disorder. It is soft and flabby. In those infants who become rachitical gradually while proving their malnutrition by the accumulation of large quantities of fat, it exhibits a certain degree of consistency. When rachitis develops in the second half of the first year or later, with the general emaciation the skin appears very thin, flabby, unelastic. The veins are generally large. Complications with eczema and impetigo are very frequent; where they are found the glandular swellings of the neck and below are still more marked than in uncomplicated cases. Circumscribed alopecia is sometimes found (not to speak of the extensive baldness of the occiput). It is not attended with or depending on the microsporon Audouini, but the result of a tropho-neurosis. In the hair Rindfleisch found fat-globules between its inferior and central third. Then it would break, the axial evolution would cease, and the end become bulbous by the new formation of cells.
Acute Rachitis.
There is a form of rachitis which may be, and has been, called multiple epiphysitis or multiple periostitis of the articular ends of the long bones. The changes which in the usual form of rachitis require months to develop take place in a very short time. Not infrequently the children were quite well before they were taken with this peculiar affection. Cases have been known to occur between the fourth and twenty-fourth months of life, and to last from two to six weeks, or just as many months. They have been known to get well, or a few of them terminate fatally. They are accompanied with fever and rapid pulse, perspiration, now and then with diarrhoea, with eager or reduced appetites. At the same time the epiphyses swell very rapidly, and are painful. The same is true of the diaphyses and the flat bones of the head. Many authors do not recognize this form as an independent variety. Some call it an acute initial stage of certain cases of rachitis, as they are not infrequently found in infants which exhibit a very rapid growth. Some have taken it as an independent disease, developed on the basis of a constitutional disposition; some look upon it as a very intense acute form of rachitis; others, as an intense growth of the osseous tissue only. Others call it an inflammation of the bone. Some refer it to hereditary syphilis, and a few to the influence of malaria. That the disease is epiphysitis and periostitis there is no doubt. I do not hesitate to claim it as rachitis, for epiphysitis and periostitis of early age not of rachitical basis are not apt to run such a favorable course as this form frequently does. The cases complicated with subperiosteal hemorrhages are claimed as scurvy by Th. Barlow.
The differences of opinion would probably not have been so great if every author had seen all the cases of the other observers. It will not do to judge of unobserved cases by the light shed by a single case under one's own observation. I have seen cases of acute rachitis which were the initial stages of general rachitis, and have observed those of local or multiple epiphysitis, mainly after infectious fevers, which were diagnosticated as such. They are, however, very uncommon. But even without a preceding infectious fever, such as scarlatina or more frequently typhoid fever, there are unexplained cases of rachitis and deformity. Thus, R. Barwell had some before the Pathological Society of London,18 which are positive proofs that some forms of ostitis may occur and result in the most formidable deformities without being rachitical. A girl of seventeen years was perfectly well formed up to the age of two and a half or three years. After that time the deformities began to develop, and did not change after she was thirteen, at which time the author saw her the first time.
| Her | left humerus measured | 7¾ inches | from shoulder to elbow; | distance 6¼ |
| right humerus measured | 7½ inches | from shoulder to elbow; | distance 4¼ | |
| left tibia measured | 10 inches | from knee to ankle; | distance 7¼ | |
| right tibia measured | 9½ inches | from knee to ankle; | distance 4½ |
Her bones were always very brittle. When she was between nine and thirteen she broke her arms four times and her lower limbs on several occasions. A male patient of twenty-two years, who was born healthy and well formed, continued thus until five years of age, when he was attacked with a fever, after which his bones became soft and bent. Osteotomy was performed on him, and the femora were found to be mere thin shells of bones surrounding cavities containing great quantities of medulla, which flowed out of the wound as oil; five ounces were discharged at once. In both cases there appeared to be a hypertrophy of the medulla at the expense of the bone-substance—a condition which Barwell proposes to call eccentric atrophy. "While these subjects are still youthful very little bone-earth is deposited, or at least remains in the very thin layer of osseous tissue that subsists. The relationship between infantile ostitis and extreme development of the intraosseous fat, though well known, is still occult; neither should we lose sight of the possibility that the softening process of ostitis may be due to a fatty acid. Now, fatty ostitis usually occurs in epiphyses. In these cases the shafts were affected."
18 Trans., xxxiv., 1883, pp. 203-208.
PROGNOSIS.—The course and the prognosis of rachitis are, as a rule, favorable, but they change according to the degree and locality of the affection and the age of the patient. Generally there is neither fever nor rapid exhaustion. But the process lasts for months and even years. In favorable cases, when recovery takes place the teeth will grow faster, the bones become firmer, the epiphyses will diminish in relative size, the bowels become regular. But the length of the bones is, and remains, reduced, and the head remains large as compared with the length of the body. Not only are the bones of normal firmness, but the compact substance undergoes a process of hardening called eburnation by Guérin. The internal organs also become very active, perhaps because the total amount of blood has to supply only a body less extended in length. Nor does the brain suffer after complete recovery has taken place. On the contrary, it appears that the somewhat more than normal vascular dilatation, which under unfavorable circumstances leads to effusion, is frequently apt to nourish the organ of intellect up to a higher standard. In all cases of rachitis, however, the curvatures of the extremities will not disappear altogether, while mild ones, it is true, are hardly recognizable in advanced age. Curvature of the ribs and of the vertebral column, however, will remain, and interfere with the expansion and the normal functions of the lungs and heart. In regard to the lungs, it appears that in many cases they do not find sufficient space to expand. As far as the heart is concerned, it touches the flattened, no longer elliptic, chest-wall over a larger surface, and is very apt to give rise to the suspicion of enlargement in consequence of extended dulness on percussion. The rachitic pelvis is well known to the obstetrician for the difficulties it gives rise to during parturition.