Scurvy (vitamin C Deficiency) - Imaging

Scurvy (vitamin C Deficiency) - Imaging

Scurvy is a disease caused due to deficiency of Vitamin C. It is characterized by bleeding gums, pseudoparalysis, and bony changes.

Pathophysiological basis of a radiologic finding of scurvy

The pathophysiological changes seen in scurvy are the result of depression of normal cellular activity such that the ability to support tissue to produce & maintain intracellular substance is markedly impaired. There is the suppression of osteoblasts, however, resorption continues & osteoporosis results.

At the growth plate, though cartilage proliferation is decreased mineralization is unimpaired & hence zone of provisional calcification appears wide & dense. Such changes around the epiphyseal ossification center give the appearance of a thin ring of increased density. Vascular invasion in the zone of provisional calcification with suppression of osteoblastic activity results in decreased density in the zone of primary & secondary spongiosa. The zone of provisional calcification extends beyond the margins of metaphysis resulting in periosteal elevation & marginal spur formation. Periosteum might be elevated due to subperiosteal hemorrhage (due to increased capillary fragility). All these above changes are most pronounced in the region of active endochondral bone growth.

Radiological Signs Associated With Scurvy

White line of Frankl:

Wimberger's ring:

Trummerfeld zone of lucency:

Pelkan's spur:

Corner sign:

Figure 1: Scurvy

Which Bones Are Involved?

Changes of scurvy are best seen involving:

• The distal end of the femur (medial side).

• Proximal & distal ends of tibia & fibula

• The distal end of Radius & ulna

• The proximal end of the humerus

• Sternal ends of Ribs

Why Vitamin C Deficiency Causes Bone Changes?

Vitamin C deficiency leads to a defect in the formation of the bone matrix as it is necessary for the formation of hydroxyproline, which is vital for collagen. About 90% of the matrix of mature bone is collagen & hence a lack of collagen will have a severe effect on bone formation. In childhood, this gives rise to scurvy & the adult counterpart is osteoporosis.

Radiological Picture In Scurvy Following Treatment

With the onset of healing, the cortex becomes thicker & spongiosa is more clearly defined. The transverse band of diminished density in metaphysis regains its normal density & disappears as terminal spongiosa & cortex become completely mineralized. As growth proceeds, the thickened provisional zone of calcification is buried within the shaft as a "Transverse line". When a subperiosteal hematoma is present, raised periosteum begins to layer the periphery of the hematoma with a new shell of subperiosteal bone. Concurrent with resorption of hematoma, this new layer of bone thickens & shrinks down onto the shaft to become the new cortex. The residue of this cortical thickening may persist for years. The central inset of rarefaction may also persist for years in epiphyseal centers.

Co-existent Rickets & Scurvy

Multiple deficiencies may modify Roentgen's appearance of skeletal response. The difference in time of onset of individual deficiencies as well as periods of remission & relapse may also affect classical description. When scurvy & Rickets both are present, scurvy features predominate because of diminished osteoblastic activity. The consequent low alkaline phosphatase levels contrast with high levels in rickets that are associated with excessive osteoid production.

Other Diseases Causing Wimberger's Sign

In congenital syphilis, there are erosions involving upper medial surfaces of the tibia. This is also known as Wimberger's sign.

Scurvy Line

The Lucent transverse band between the sclerotic provisional zone & heavier spongiosa deeper in the shaft is called a scurvy line.