Introduction
- Scurvy is disease that results from vitamin C deficiency
- Vitamin C (ascorbic acid) deficiency causes failure of collagen synthesis and osteoid formation
- Results in osteoporosis and possibly spontaneous bleeding
Pathogenesis
- Normal collagen synthesis depends upon the hydroxylation of proline and lysine for which vitamin C acts as a cofactor
- Vitamin C deficiency prevents hydroxyproline and hydroxylysine formation
- Produced collagen contains only ‘non-hydroxylated’ proline and lysine
- The resulting collagen fibrils lack hydrogen bonding and lose mechanical stability
- Bony pathogenesis consists of two parts
- Failure to lay down bony matrix
- Persistence of an unabsorbed calcified cartilage lattice
- Cartilage cells of the epiphyseal plate multiply and orientate themselves normally
- Intervening matrix becomes calcified, but osteoblasts fail to lay down osteoid
- Calcified cartilaginous matrix is not completely resorbed
- Epiphyseal plate becomes widened and irregular
- Spicules of calcified cartilage fracture and a very irregular radiologically dense zone arises at the junction of epiphysis and shaft
- Failure of resorption of calcified cartilage also makes ring sign
Natural History
- Onset at 6 months – 2 years
- Rare in adults
Clinical Presentation
- Infants are irritable and anaemic
- Gums may bleed spontaneously
- Haemorrhage near large joints may cause excruciating pain and tenderness
- Fractures or epiphyseal separation may occur
Imaging and Diagnostic Studies
- Generalised bone rarefaction
- Most marked in metaphyses of the long bone which may be deformed or fractured
- Metaphyseal lucency (Trummerfeld Zone)
- Metaphyseal corner fractures through the weakened lucent parts (Pelkan spurs) results in cupping of the metaphysis
- Normal calcification in growing cartilage produces dense transverse bands :
- At juxta-epiphysial zones (Frankel white line)
- Around ossific centres of the epiphyses (Wimbergers ring sign)
- Zones of provisional calcification appear dense
- Subperiosteal haematomas appear as soft tissue swellings or peri-osseous calcification
Treatment
- Large doses of vitamin C bring prompt relief
