Albert C. Clairmont

Calcitriol and bone mass accumulation in females during puberty.

Abstract. Adolescence is characterized by rapid skeletal development and high demands for bone minerals. Though the stimulative effect of calcitriol on intestinal calcium and phosphorus absorption is well understood, its effect on bone development is not completely clear. It may be directly involved in the facilitation of calcium economy during this critical phase of skeletal development. Therefore, we evaluated the serum concentrations of calcitriol in relation to skeletal development in a cross-sectional study of 178 healthy Caucasian females during different pubertal stages, extending from childhood to young adulthood. In addition, a subsample of 57 younger girls was followed for a 1-year period to evaluate the association among serum calcitriol, nutrition parameters (dietary calcium, phosphorus, and vitamin D), bone mass accumulation, and biochemical markers of bone turnover. The serum calcitriol concentration in a cross-sectional sample was the highest during pubertal growth spurt (sexual maturity index 3–4, age 11–13 years) (ANOVA: F = 2.4945; P= 0.0329). This correlated to the peak skeletal calcium accretion (g/year) and bone mass accumulation in total body and forearm. In a longitudinal sample, there was a positive association between annual change in TBBMC (P= 0.0255); TBBMD (P= 0.0168); proximal radius (1/3 distance from styloid process) BMC (P= 0.0096); BMD (P= 0.0541), and baseline calcitriol level in forward stepwise regression analyses. The results of the forward stepwise regression analyses with serum calcitriol as a dependent variable and different serum, urinary, and dietary parameters measured at baseline (age 11 years, n = 114) and after 1 year (age 12 years, n = 57) showed that osteocalcin was positively associated with calcitriol in both years; more so in a second year (P= 0.0514, P < 0.0001, respectively). Dietary vitamin D and phosphorus showed negative association with serum calcitriol at age 11, and dietary Ca and P were selected at age 12. The results of this study show that calcitriol is a significant correlate of bone mass accumulation during pubertal growth, presumably in response to the high requirements for calcium during this critical phase of skeletal development.

Nutrition and bone health in children and adolescents

Bone accretion during childhood is proportional to the rate of growth. During this time, interval height velocity is relatively slow for both boys and girls. As a direct consequence of this, calcium retention in the body of an average child is lower than the calcium retention in an adolescent. Bone size, bone mass, and bone mineral areal density of the regional skeletal sites increase on average by about 4%/yr from childhood to late adolescence and young adulthood, when most of the bone mass is accumulated. Calcium needs are greater during adolescence (pubertal growth spurt) than in childhood or adulthood. According to calcium balance studies, the threshold in take for adolescents is about 1500 mg/d. Inadequate calcium intake during growth may increase the risk of childhood fractures and predispose certain individuals to a lower peak bone mass.

Reflex Sympathetic Dystrophy

Publisher Summary This chapter provides an overview of Reflex Sympathetic Dystrophy (RSD). It is a syndrome characterized by diffuse limb pain, swelling, vasomotor and sudomotor phenomena, hyperalgesia, allodynia, and trophic changes. The exact pathophysiology of RSD is still unclear. Fractures or ankle sprains frequently precede RSD. Several other events are associated with RSD includes stroke, myocardial infarction, cancer, surgery, and even the use of antituberculous medications. Transient regional osteoporosis is also a form of RSD. It is now grouped as a member of the Complex Regional Pain Syndromes (CRPS). The diagnosis is based on clinical signs and symptoms— such as trophic changes of skin, appendages of skin, subcutaneous tissues, and bone atrophy develop at a later stage. A number of clinical tests have to be done to help clinch the diagnosis: sympathetic blocks, skin surface temperature measurement, bone scans, radio graphs, and quantitative bone mineral analysis. A number of different pharmacologic approaches and pathophysiologic mechanisms for RSD are reported. Restoration of function using principles of physical medicine and rehabilitation is essential to a successful outcome. The mainstay of treatment is sympathetic blockade, use of pulse steroid therapy, physical and occupational therapy techniques and modalities, and ability to engage in functional therapeutic exercise.

Acute Spinal Cord Injury and Traumatic Brain Injury

Publisher Summary This chapter discusses the causes, preventions, epidemiology, diagnosis and treatment of acute Spinal Cord Injury (SCI) and Traumatic Brain Injury (TBI). Acute SCI is characterized by sustained damage to neural elements in the spinal canal, resulting in impairment or loss of motor and or sensory function. This is described as “tetraplegia” as the cervical segments are involved and paraplegia when thoracic, lumbar, or sacral segments are involved. The major causes of SCI are: motor vehicle accidents, falls, and acts of violence, sports, and several others. Four major complications along with their diagnosis and treatment that occur at the bone tissue level are: disuse osteoporosis, renal calculi, hypercalcemia, and heterotopic ossification. TBI is more likely to be present with head injury in children and elder people. The leading causes of TBI: motor vehicle accidents and violence-related injuries. The contusion caused by shearing forces applied to the brain and the most important complication related to bone tissue in persons who have sustained TBI is heterotopic bone formation and abnormal cerebral perfusion.