Absorptive Bone Changes in Leprosy

Abstract

With few exceptions, the disease leprosy respects no human tissue. The skin may be involved by lesions of various types which can assume the characteristics of syphilis (1), tuberculosis (2), Besnier-Boeck sarcoid (3), and Raynaud's disease (4). Nerve structures are particularly susceptible to attack by the bacillus of leprosy, often with resultant local destruction of the nerve fibers and loss of function of the part. In some cases, osteoid changes occur in the nerve (5). The walls of the blood vessels may be invaded through the vasa vasorum (6), with subsequent inoculation of the parts distal to the diseased vessel wall and alteration of the blood flow through the vessel. Tajiri (7) reported finding small leprous foci in the lungs. The bone may be the seat of local leprosy involving the periosteum (8) or the nutrient artery and nerve (9). The periosteum and cortex may be completely destroyed by pressure (Fig. 1), direct extension of contiguous soft tissue leprosy (Fig. 2), or by local disease of the nutrient artery and nerve (Figs. 3 and 4). It is the purpose of this paper to present and discuss the phenomenon of complete bone absorption which occurs in the small bones of the hands and feet in lepers. Absorptive bone changes occur in the phalanges of the hands and in the metatarsal bones of the feet in leprosy. Such changes were described by Murdock and Hutter (9) as minute nicks, slices, frayings, collar buttoning, and grossly prominent nutrient foramina which are demonstrable by roentgen examination and are considered of diagnostic significance. The generalized bone absorption which follows results in a complete loss or lysis of bone structure (Figs. 5 and 6) and is associated with loss of sensation and muscle power in the hands and the feet due to sensory and motor nerve lesions. Neurocirculatory changes take place so that ulceration occurs at the points where usage causes pressure. While osteomyelitis, osteitis, and absorption of the phalanges of the hands always occurs before the involvement of the metacarpal bones, beginning at the distal end of the distal phalanx. It is felt that this is due to the fact that in the feet it is the heads of the metatarsal bones and in the hands the tips of the carpal phaarthritis may occur, they are merely coexistent and are not characteristic of leprosy. Our study of roentgenograms of the hands and feet of lepers demonstrates a point not hitherto mentioned in the literature. The phalanges in the feet are often preserved intact even when there is marked destruction of the metatarsal and tarsal bones (Figs. 5 and 6). In contrast, the langes that are subject to the maximum trauma and pressure in ordinary function and use. Several factors account for the phenomenon of complete bone absorption: altered circulation, anesthesia, and pressure. Roentgenograms of the extremities of lepers clearly show generalized increased density in the areas where bone absorption has not been completed.