A plasma ascorbate concentration of <0.2 mg/dL usually is considered deficient. Gelatinous transformation of bone marrow, on aspiration, has been reported in children with suspected malignancy.īiochemical tests are not very useful in the diagnosis of scurvy, because they do not reflect the tissue status. MRI can demonstrate acute as well as healing subperiosteal hematomas along with periostitis, metaphyseal changes, and heterogeneous bone marrow signal intensity, even in absence of changes in plain radiographs. 63.5), sometimes giving a dumbbell or club shape to the affected bone. However, during healing the elevated periosteum becomes calcified and radiopaque ( Fig. Subperiosteal hemorrhages are not visible using plain radiographs during the active phase of scurvy. Epiphyseal separation can occur along the line of destruction, with either linear displacement or compression of the epiphysis against the shaft ( Fig. A Pelkan spur is a lateral prolongation of the white line and may be present at cortical ends. This zone of rarefaction (Trümmerfeld zone), a linear break in the bone that is proximal and parallel to the white line, represents area of debris of broken-down bone trabeculae and connective tissue. The more specific but late radiologic feature of scurvy is a zone of rarefaction under the white line at the metaphysis. The epiphyseal centers of ossification also have a ground-glass appearance and are surrounded by a sclerotic ring ( Fig. The white line of Fränkel, an irregular but thickened white line at the metaphysis, represents the zone of well-calcified cartilage. The cortex is thin and dense, giving the appearance of pencil outlining of the diaphysis and epiphysis. The shafts of the long bones have a ground-glass appearance because of trabecular atrophy. The typical radiographic changes occur at the distal ends of the long bones and are particularly common at the knees. A high index of suspicion is required in children on restrictive diets, particularly those with autism and other developmental disorders, and they should be evaluated for scurvy whenever they present with difficulty in walking or bone pains.
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The diagnosis of vitamin C deficiency is usually based on the characteristic clinical picture, the radiographic appearance of the long bones, and a history of poor vitamin C intake. Kliegman MD, in Nelson Textbook of Pediatrics, 2020 Laboratory Findings and Diagnosis