scurvy

definition

· hypovitaminosis C with impaired

· collagen formation

· osteoid synthesis

epidemiology

· seen in

1. artificially fed infants

· onset age 6 mths to 2 yrs

· because no vitamin C in heated milk

2. elderly

· rare

· due to restricted diet

pathogenesis

· vitamin C required for hydroxylation of proline and lysine residues in collagen synthesis

· result is defect in connective tissue

· esp. endothelium and osteoid

pathology

Defective bone formation

· subperiosteal haemorrhage

· leads to clot formation

· stimulates fibrous tissue formation and ossification

· metaphyseal heamorrhage

· interferes with osteogenesis at physis

· osteoclastic activity continues

· thin trabeculation

· ground glass appearance

· osteoporosis

· thin cortices

· enchondral ossification proceeds to zone of calcified cartilage

· causes dense zone of provisional calcification

· leads to sclerotic line (line of Frankel)

· adjacent metaphysis improperly ossified (zone of Trummerfield)

· weakened metaphysis can fracture

· corner fracture called Pelkan spur

· epiphyseal ossification affected

· zone of calcified cartilage around bony centrum

· Wimberger’s ring

Capillary fragility

· haemorrhages in areas of abundant capillaries

· gums

· intestine

· conjunctiva

· skin

· bladder

clinical

· irritable and restless

· spongy bleeding gums

· ecchymoses

· pain and tenderness near large joints

· muscle spasm

· fractures and epiphyseal separations

investigations

Radiology

· osteopania

· often only sign in adult

· thin cortices

· ground glass translucency

· epiphyseal separation

· periosteal reaction

· due to subperiosteal haematoma

· line of Frankel

· sclerosis of metaphysis

· Trummerfield zone

· zone of metaphyseal lucency

· Pelkan spur

· metaphyseal corner fracture

· usually lateral distal femoral

· Wimberger’s ring

· sclerotic line around epiphysis

Laboratory

· decreased serum ascorbic acid

· anaemia

differential diagnosis

· polio

· rickets

· osteomyelitis

· osteogenesis imperfecta

treatment

· vitamin C supplementation