Osteopetrosis

OSTEOPETROSIS, more commonly known as marble bones, was described originally in 1904 by Albers-Schönberg (1). The condition first appeared in the English literature in 1922, when G. G. Davis (2) collected seven cases from the foreign literature and added another one. Various names have been used in referring to the condition, i.e., Albers-Schönberg disease; marmorknochen, or marble bones; lime gout; osteosclerosis with anemia, and osteosclerosis fragilis generalisata. The name “osteopetrosis” was suggested and used by Karshner (3) in 1926. It is not entirely suitable, because literally it means “stone-like bone,” whereas, Pirie (4) showed the bones to be more like chalk in consistency. For the same reason, “marble bones” is a misleading term, despite the fact that the outstanding characteristic is a generalized increased radiopacity of the bones resembling marble. Another characteristic is the fragile nature of the bones. It might be better to use a term more descriptive of this chalk-like consistency, such as osteocretosis. The etiology of this condition is unknown. Observers agree on an abnormal calcium metabolism of the bones but cannot satisfactorily explain it. The rôle of the parathyroid secretion and vitamins has not been established. In many cases serum-calcium and phosphorus have been studied without indicating any definite variation from normal. Hereditary influence is considered a strong factor. Howard Pirie (4) reports a study of four cases in one family—the mother and her three children. In one child the condition was first suspected while it was a fetus in utero, due to the density of the vertebras as seen roentgenographically. After birth, examination revealed the early stages of marble bones. Pirie studied the increase in the condition as age advanced. He suggested that infection plays a more important rôle in the production of the condition than endocrine disturbances. The symptomatology varies, depending upon the stage to which the condition has advanced. The liver and spleen are frequently enlarged. Anemia is common, due to transformation of the medullary canal into compact bone. Imperfect dentition is usually present due to disturbance of the dental calcification as well as to a poor blood supply. Frequently, the mandible is necrotic because the main blood supply is cut off and there is no collateral circulation. The cranial nerves are often involved due to pressure on them because of bony changes in the canals. Poor eyesight and blindness are not uncommon. In a number of cases the condition was first discovered when spontaneous fracture of a bone occurred. The bone becomes chalky and fragile from the excess calcium.