Module 103 (3 case) ILOs By the end of the session the student should be able tor © Identify the function of vitamin D. ‘* Identify dietary sources of vitamin D ‘+ Recognize the manifestation of vitamin D deficiency = * Determine the vitamins responsible for normal bone formation © Recognize causes of rickets A mother for female child Mona came to pediatric clinic complaining of delayed dentition of her child, despite of Mona's cousin start dentition on 9 months. On taking a history from the mother she told that, Mona now has 18 mont hs old, her birth weight and length were of normal average. She was fully breastfed until age 12 months, since the baby was refusing any supplementary food, Growth and development milestones were normal until the age of six months, as the ability to sit, begin to crawl at seven months, but at the age of 10 months, growth and weight stagnated, and she lost the ability to crawl and stand. There was no history of seizures or recurrent diarrhea, no jaundice or edema. a On examination, the pediatrician noticed delayed eruption of teeth, delayed closure of ‘anterior fontanel, but he was unable to examine the limbs from multiple clothes Mona wear. Biochemical tests are, ionized calcium 1.08 mmol/L (1.20-1.35 mmol/L), serum phosphate 0.72 mmol/L (1.20-1.80 mmol/L). Serum alkaline phosphatase 14020U/L (55-SISU/L), PTH 57.0 pmol/L (1.1-6.9 pmol/L). ALT 12(7-56 wi), AST 15(10-40u/1), done on wrist and ankle, showed widening and Creatinine 0,6(0.5-1.1) x - ray which w irregular epiphyseal plate.Module 103 (3 case) 1- Comment on Mona’s biochemical test 3) The increased secretion of PTH maintains the serum calcium level within the ‘normal limits, early in the disease but later on it decreases. b) Low plasma phosphate level due to deficiency of vitamin D and increased secretion of PTH. ©) Increase in plasma level of alkal disease, 4) Normal liver and kidney functions 2-What is the diagnosis? Rickets 3+ What is the cause of this case? ‘Vitamin D deficiency 4- What are the risk factor for Mona to develop this case? - delayed weaning (Milk and its products are poor sources for vitamin D) ~ Inadequate exposure to sun (7- dehydrocholesterol present beneath skin is converted 10 tamin D3 on exposure to sunlight) 5- What do you expect that the physician could find on limb examination? Enlarged osteochondral junctions. The lower extremities show bow or knock knees. ‘6-mention other signs could be found in Mona's examination? ‘The classical features of rickets are bony deformities: a) The head is enlarged with delayed closure of the fontanels. b) The chest has protruded stemum (pigeon chest) and rosary beads due to enlargement of costochondral junctions. ©) The vertebral column appears with kyphosis or scoliosis. d) The pelvis is contracted. ‘e) The Jong bones have enlarged osteochondral junctions. The lower extremities show bow or knock knees. 7- Mention the sign in this image? 1e phosphatase, This is an early marker of theModule 103 (3 case) Box shaped skull, rosary beads, enlaged costochondral junction, knock knee 8 Concerning the function of the deficient vitamin, which of the following is rue? = Caleitriol increases the absorption of calcium by the intestine and it increases the phosphate absorption secondary to calcium. T Calcitriol enters the intestinal cell and binds to a cytosolic receptor. T = Itinereases loss of calcium by the kidney. F = Calcitriol helps normal calcification and mineralization of bone. T ~ Vitamin D supplementation increases pancreatic insulin release and reduces insulin resistance in people with impaired glucose tolerance and type 11 diabetes mellitus (see insulin).T 9 For calcium absorption, the ion enters the intestinal cells down its electrochemical gradient vi .. (channels! pump/ lipid bilayer) at the luminal border, and gets ‘out at the basal border against electrochemical gradient with the help of .2.~ (passive carrier/ channel/pump). Justify your choice. ‘Answer: L.channel (as calcium is small sized charged, lipid insoluble) 2.pump (against gradient so active transport is involved) 10- Enumerate other vitamins that play a role in healthy bone formation? Explain? ~ Vitamin A: has an important role in growth of bone and teeth as it induces synthesis of glycoproteins of the connective tissue matrix. Vitamin K: acts as coenzyme for Osteocalcin carboxylation , where y carboxylation helps its binding to hydroxyapatite crystals in bone. Due to this mechanism, vitamin K helps the bones to retain calcium = Vitamin C: It acts as a coenzyme in Prolyl and lysyl hydroxylases that hydroxylate proline and lysine residues of collagen into hydroxyproline and ydroxylysine respectively. Therefore, it is required for normal synthesis of ‘connective tissue, bone, cartilage and teeth. 11- The pediatrician advised the mother for diet rich in vitamin D, what type of diet could you expect? D deficiency? in obstructive jaundice and steatorthea. as in chronic liver and renal diseases. ase or calcitriol receptors.Module 103 (¥" case) jon in the picture: 13- Enumerate stages of endochondral calcific 2-Stage of proliferation — 3- Stage of Hypertophy 4-Stage of calcification '5-Stage of ossification (spongy bone formation). ‘14-Identify the character of epiphyseal plate in rickets (this case)? Answer: Widened epiphyseal plate with thickening in cartilage layer and delayed calcification 15- What is the cell responsible for bone formation and bone remodeling? Answer: Osteoblast is bone-forming cell, Osteoclast is bone-cating cell,