Bone pain and extremely low bone mineral density due to severe vitamin D deficiency in celiac disease

Case report A 29-year-old wheelchair-bound woman was presented to us by the gastroenterologist with suspected osteomalacia. She had lived in the Netherlands all her life and was born of Moroccan parents. Her medical history revealed iron deficiency, growth retardation, and celiac disease, for which she was put on a gluten-free diet. She had progressive bone pain since 2 years, difficulty with walking, and about 15 kg weight loss. She had a short stature, scoliosis, and pronounced kyphosis of the spine and poor condition of her teeth. Laboratory results showed hypocalcemia, an immeasurable serum25-hydroxyvitamin D level, and elevated parathyroid hormone and alkaline phosphatase levels. Spinal radiographs showed unsharp, low contrast vertebrae. Bone mineral density measurement at the lumbar spine and hip showed a T-score of -6.0 and -6.5, respectively. A bone scintigraphy showed multiple hotspots in ribs, sternum, mandible, and long bones. A duodenal biopsy revealed villous atrophy (Marsh 3C) and positive antibodies against endomysium, transglutaminase, and gliadin, compatible with active celiac disease. A bone biopsy showed severe osteomalacia but normal bone volume. She was treated with calcium intravenously and later orally. Furthermore, she was treated with high oral doses of vitamin D and a gluten-free diet. After a few weeks of treatment, her bone pain decreased, and her muscle strength improved. Discussion In this article, the pathophysiology and occurrence of osteomalacia as a complication of celiac disease are discussed. Low bone mineral density can point to osteomalacia as well as osteoporosis. © International Osteoporosis Foundation and National Osteoporosis Foundation 2011

Evolutionary game theory

Evolutionary Game Theory is an extension of classical Game Theory that sought to account for the properties of real-world populations of organisms and the ecosystems they inhabit, by describing the fitness-enhancing strategies maintained by the forces of evolution. Game Theory is the study and mathematical analysis of rational decision-making, typically under conditions where there are clearly defined constraints on the information one possesses and the range of available response options. The field of Game Theory is particularly concerned with modelling the possible strategies an agent may employ when engaged in games where individual success critically depends on the choices made by other players (von Neumann and Morgenstern 1944), either because other players represent opportunities for cooperation or because they are competitive rivals for some scarce resource. Since its formal, modern inception by mathematician and polymath John von Neumann 1928 (see Tucker and Luce 1959, for English translation), Game Theory has been employed in a wide range of disciplines, including computer science, moral philosophy, and extensively within behavioral science and economics (Newton 2018), owing to the insights that Game Theoretical models can offer into population-level trends that emerge spontaneously from innumerable individual agents each pursuing the most favorable outcomes they can secure for themselves. One of the earliest and most influential of these emergent phenomena is the Nash equilibrium (Nash 1951), a stable state a population reaches where no individual agent is capable of improving their outcomes by changing from their present strategy (see Gintis 2009, for a detailed overview)