True about scurvy is:
Correct Answer: Bowing of legs
Description: Bowing of legs [Ref: Robbins 7/e p458; Nelson 18/c p251; Grainger Radiology 4/e p1942/ Scurvy results from a long-term deficiency of vitamin C. Humans are unable to synthesize vitamin C, due to lack of the enzyme gulonolactone oxidase and therefore depend on dietary sources. Vitamin C is not stored in the body, but is taken up by all tissues; the highest levels are found in the pituitary and adrenal glands. This disorder occurs more frequently in children (paicularly infants) than in adults, and for the most pa, results from a diet of pasteurized or boiled milk. (This type of milk is deficient in vitamin C because the vitamin is inactivated by heat). For scurvy to develop, the deficiency must be present for a long time of approx. 4 to 6 months. Therefore it is unlikely that the disorder will be seen before the age of 4-6 months. The occurrence of scurvy in adults is rare, being seen mostly in patients suffering from chronic severe malnutrition. Vitamin C is essential for the hydroxylation of lysine and proline in collagen formation. The defect in collagen synthesis results in inadequate suppo of the walls of capillaries and venules leading to bleeding in the skin and in the gingival mucosa, haemahroses, and subperiosteal hemorrhages. The gums are swollen and bleed easily. Bleeding in the skin causes petechiae, eccyhmoses, perifollicular hemorrhages. Skeletal changes may also develop in infants and children. The pritnaly disturbance is in the formation of osteoid matrix, rather than in mineralization or calcification. (Rickets is characterized by the presence of excess osteoid and lack of calcification; whereas scurvy is associated with deficient osteoid and much calcified cailage). The potential for skeletal lesions diminish with increasing age. The skeletal changes are most pronounced in regions of active endochondral bone growth and therefore are best seen in the distal end of the long bones paicularly of the lower extremity. Changes at the sternal ends of the ribs cause scorbutic rosary formation. Key imaging features of scurvy or Vit. "C" Def Osteoporosis White line of Frank! (irregular but thickened white line at the growth plate, it represents the zone of well-calcified cailage). Pelkan's spur (the zone of calcification extends beyond the margins of the metaphyses, resulting in periosteal elevation and inetaphyseal spurs) Trummerfield zone or scurvy line (a transverse band of radioluscency subjacent to the white line of Frank!) Winiberger's sign (thin ring of increased density surrounding epiphyses) Periosteal elevation (due to subperiosteal hemorrhage) The weakened bones yield to the stresses of weight bearing and muscle tension, with bowing of the long bones of the lower legs and abnormal depression of the sternum. Wound and fracture healing is impaired due to derangement of collagen synthesis. Laboratory diagnosis of vitamin C deficiency is made on the basis of low plasma or leukocyte levels.
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Pediatrics
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