OSSIFYING MYOSITIS Localized bone formation in the muscles results from constant irritation of certain muscles o`rider's bone, Exerzierknochen"), more rarely from injuries to the muscle. This ossifying form of myositis has practically no significance in pediatrics.
On the other hand, progressive multiple ossifying myositis is a dis ease that is peculiar to childhood. Of 51 cases collected by Lorenz, 11 occurred in the first year of life, Ill between the ages of 1 and 5, 11 be tween 5 and 15, and only 7 among individuals more than 15 years of age.
This remarkable incidence must be taken into account in formulating theories about the pathogenesis of this form of myositis, and points strongly to some inherited or congenital injury as the cause of the disease. This, however, is not the case, since the disease is not so far as we know, either hereditary or family, but always develops gradually. Nor can it be denied that in many cases the exciting cause appears to be an injury, albeit one which otherwise would be disregarded in childhood. We are accordingly forced to assume a constitutional anomaly altinch meyer) that renders the muscular tissue abnormally sensitive to external irritation. The affection is therefore not an endogenous disease accord ing to the definition we have given, but represents a deviation from the normal in the tissues of the affected children. That these children are actually- abnormal from birth is shown from the frequent combination of ossifying myositis with smallness of the large toes and of the thumbs (Gerber).
Clinically we observe local signs of inflammation in certain muscles following injury accompanied by fever, pain, swelling, and cedema. These symptoms subside and are followed by the development of a doughy, muscular wheal, which may persist for years without change. Similar alterations develop again and again in various muscles in con nection Nvith external injuries. Sometimes the disease begins in a num ber of muscles without any known cause, and in such cases the nodular foci of inflammation may temporarily disappear. Gradually we are able to see or feel small bony kernels within these nodes, which increase in size and ultimately involve large portions of the muscular apparatus. Pain is usually slight, but the interference with movements steadily increases and is a great annoyance to the patients.
The muscles of the neck and back are usually attacked first, then the muscles of the extremities and finally the masseter and temporal muscles, greatly interfering both with locomotion and mastication. While at first no more than a certain awkwardness is noticed in the child's movements, and it can»ot stand erect, there gradually develops great interference with every kind of movement or even complete loss of mobility. The entire body is bent until finally the patients become entirely helpless and have to keep their beds.
The progress of the disease takes place by successive stages, inter rupted by long intervals during which tbe disease is arrested. Years elapse before the malady reaches its height, so that well-marked cases are more frequently seen in adults than in children.
Pathologically we recognize a stage of acute myositis followed by proliferation of intramuscular connective tissue (fibrous myositis), and true ossification in the muscles. Ossification starts partly from the bone. itself in the form of exostoses, hardening of the muscular attachments and bony unions between different bones, and partly within the intra muscular connective tissue or even within the muscle fibrils. The muscle elements atrophy and are replaced first by- proliferated connective tissue and later by bone substance. The ossification does not involve the muscles in their entire extent, but occurs rather in the form of dissemi nated nodules within the muscle tissue.
The prognosis is grave, not only as regards recovery but also, in severe cases, with regard to life on account of the interference with respiration and the difficulty of administering nourishment.
The diagonsis, which presents no difficulties in the terminal stage, is practically impossible at the beginning, and the disease is at first usually mistaken for some rheumatic affection.
The treatment is hopeless. At best, the progress of the disease may be slightly retarded by avoiding injuries, and by means of baths, and the iodides administered by inunction.
The above description applies only to the typical form of progressive ossifying myositis. The many deviations and unusual varieties which we are forced to ignore in the present discussion merely serve to accen tuate the enigmatical character of this interesting disease.