Rickets

Background

• Rickets is a bone disorder characterized by soft, weak, and deformed bones
• Origin of the word 'rickets' is from the word 'wrickken', to twist
• The predominant cause is a Vitamin D deficiency, but also inadequate calcium and impaired metabolism of vitamin D may also lead to rickets
• Rickets is one of the most frequent childhood disease in many developing countries
  • Severe malnutrition from famine or starvation in early childhood
• Vitamin D is important because it helps in the absorption of calcium and phosphate, minerals responsible for the strength and hardness of bones
• This disease occurs in children (term used for adults is Osteomalacia
• Risk factors for Vitamin D deficiency in infants include:
  • Exclusive breastfed infants without vitamin D supplementation
  • Dark skin pigmentation
  • Maternal Vitamin D deficiency
    • In utero, 25-hydroxyvitamin D passes through the placenta to the infant

Types of Rickets

• Hereditary rickets is an inherited form of the disease
  • Kidneys are unable to retain phosphate
• Nutritional rickets
• Vitamin D Resistant Rickets
• Vitamin D Dependant Rickets
• Congenital Rickets

Clinical Features

• Peak incidence between 3 and 18 months of age
• Enlarged and soft skull (Craniotabes)
• Enlarged joints of long bones
• Enlarged joints of the rib cage (aka "rickety rosary"
• Double malleoli sign due to metaphyseal hyperplasia
• Widening of wrist due to metaphyseal cartilage hyperplasia
• Curvature of the spine and femurs
  • Bowed legs in toddlers (Genu varum)
  • Knock-knees in older children (Genu valgum)
• Generalized muscle weakness
• Bony pain or tenderness
• Dental problems
• Growth disturbance
• Hypocalcemia
  • Tetany

Management

• Prevention key:
  • For healthy infants, children, and adolescents recommend a vitamin D intake of at least 400 IU/day