Variability in Radiographic Appearance of Skeletal Fluorosis

Osteosclerosis (dense bone) is the bone change typically associated with skeletal fluorosis, particularly in the axial skeleton (spine, pelvis, and ribs). Research shows, however, that skeletal fluorosis produces a spectrum of bone changes, including osteomalacia, osteoporosis, exostoses, changes resulting from secondary hyperparathyroidism, and combinations thereof. Although the reason for this radiographic variability is not yet fully understood, it is believed to relate to the dose of fluoride consumed, the individual’s nutritional status, exposure to aluminum, genetic susceptibility, presence of kidney disease, and area of the skeleton examined.

X-Ray Diagnosis of Skeletal Fluorosis

In 1937, Kaj Roholm published his seminal study Fluorine Intoxication in which he described three phases of bone changes that occur in skeletal fluorosis. (See below). These three phases, which are detectable by x-ray, have been widely used as a diagnostic guide for detecting the disease. They describe an osteosclerotic bone disease that develops first in the axial skeleton (the spine, pelvis, and ribs), and ultimately results in extensive calcification of ligaments and cartilage, as well as bony outgrowths such as osteophytes and exostoses. Subsequent research has found, however, that x-rays provide a very crude measure for diagnosing fluorosis since the disease can cause symptoms and effects (e.g., osteoarthritis) before, and in the absence of, radiologicaly detectable osteosclerosis in the spine.