Vitamin C (ascorbic acid) deficiency causes failure of collagen synthesis and osteoid formation. Results in osteoporosis which is most marked in infants in the juxta-epiphysial bone and may be associated with spontaneous bleeding
Clinically
- Infants are irritable and anaemic
- Gums may bleed spontaneously and haemorrhage near large joints may cause excruciating pain and tenderness
- Fractures or epiphyseal separation may occur
- Onset at 6 months – 2 years
- Rare in adults
X-Rays
- Generalised bone rarefaction
- Most marked in the long bone metaphyses, which may be deformed or fractured
- 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)
- Metaphyseal lucency (Trummerfeld Zone)
- Metaphyseal corner fractures through the weakened lucent metaphysis (Pelkan spurs), results in cupping of the metaphysis
- Zones of provisional calcification appear dense
- Subperiosteal haematomas show as soft tissue swellings or periosseous calcification
Pathology
- Failure to lay down bony matrix, associated with 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 and the 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
Treatment
Large doses of vitamin C bring prompt relief