Immobilization and burns: Other conditions associated with osteoporosis

Immobilization osteoporosis occurs in several conditions that represent a spectrum of inactivity ranging from mild gait disturbances to absolute bed rest. The most severe form of immobilization-related bone deterioration occurs after motor-complete spinal cord injury (SCI). The risk of fracture in stroke survivors is usually reported to be two to four times higher than that of an age-and gender-matched healthy population. Efforts to mobilize stroke victims early after paresis appear to improve bone mass of the lower extremities. Bone loss over time in persons with Parkinson disease (PD) is greater than in healthy controls. The etiology of bone loss in individuals with PD is likely reduced and/or impaired ambulation caused by neuromuscular dysfunction, malnutrition, vitamin D deficiency, and anti-PD medications, specifically L-dopa. Moreover, children with severe burns develop acute sustained hypocalcemia and hypoparathyroidism with urinary calcium wasting suggesting cytokine-mediated upregulation of the parathyroid calcium-sensing receptor (CaR).