Describe the vitamin C Deficiency of Scurvy.

Definition

• Scurvy is a disease caused by deficiency of vitamin C (ascorbic acid), which is essential for collagen synthesis (hydroxylation of proline & lysine).
• Defective collagen produces fragile capillaries and impaired bone & connective-tissue formation.

Etiology

• A diet lacking fresh fruits & vegetables; prolonged feeding with only boiled/processed milk (heat destroys vitamin C).
• Increased requirement (infection, prematurity); food fads.

Pathogenesis

• Vitamin C is a cofactor for prolyl & lysyl hydroxylase → without it, collagen cross-linking fails.
• Weak collagen → fragile capillaries (bleeding), poor osteoid formation at growth plates, and defective wound healing.
• It also aids iron absorption — hence associated anaemia.

Clinical Features

• Irritability and bone pain — tender limbs; the infant lies still in a 'frog-leg' (pithed-frog) position and resists handling (pseudoparalysis from painful subperiosteal haemorrhage).
• Bleeding tendency — spongy, bleeding gums (around erupted teeth), subperiosteal & skin haemorrhages, perifollicular petechiae.
• Scorbutic rosary at the costochondral junctions (sharper & more angular than the rachitic rosary).
• Poor wound healing; anaemia; and delayed bone growth.

Investigations (x-ray of Long Bones — Characteristic)

• White line of Frankel — a dense zone of provisional calcification.
• Wimberger's ring sign — a dense ring around the epiphysis.
• Pelkan spurs; a 'ground-glass' osteoporotic appearance with a pencil-thin cortex; subperiosteal haemorrhage.
• Low plasma / leucocyte ascorbic acid supports the diagnosis.

Management & Prevention

• Vitamin C 100–200 mg/day orally → a rapid, dramatic clinical response within days.
• Prevention — include citrus fruits, guava, amla, tomatoes and green vegetables; avoid over-boiling foods; supplement in at-risk infants.

Differential Diagnosis

• Rickets (widened wrists, ↑ALP), leukaemia/bone tumours (limb pain), septic arthritis/osteomyelitis, and other bleeding disorders — differentiated by X-ray and blood tests.

Prognosis

The response to vitamin C is rapid and complete; untreated severe scurvy can be fatal from haemorrhage or infection.

Pain from subperiosteal bleeding causes the pseudoparalysis.