Rickets is a disease of the children and adolescent caused mainly by vitamin D deficiency which helps in the mineralization of the bone by regulating the blood calcium and phosphorous level thus leading to softening, weakening of the bones and hypotonia due to low serum calcium.

Vitamin D is synthesized in the skin when exposed to sunlight and modified into its active form 1, 25-dihydroxycholecalciferol (vitamin D3) in 2 steps in the liver and than in kidney. It maintains the level of calcium in the blood so that mineralization of the bone occurs normally.

Vitamin D3 is also assisted by the parathyroid hormone in calcium and phosphorous regulation in the body. 

In adults it is called Osteomalacia.

Rickets is also caused by hyperparathyroidism, hypocalcemia, x-linked hypophosphatemia (familial rickets), lack of exposure to sunlight, fat Malabsorption syndromes, in vegetarian due to phytates which binds to calcium and phosphorus, end stage renal disease.

Signs and symptoms of Rickets

Rickets affects those children who are not exposed to sunlight and in familial rickets and low calcium and phosphorous diet like breast milk.

• Delayed growth in height and limbs
• Delayed teeth formation and enamel
• Delayed closure of anterior fontenella
• Muscle weakness
• Dull aching Bone pains
• Bowing of legs and knock knee appearance  when the child starts to walk
• Rachitic rosary – knobbing of the chest bones
• Sometimes associated with spine deformity
• X-ray shows cupping and flaring of the bones metaphyses. 

Diagnosis

• Physical examination and the history will give the clue
• Blood tests for calcidiol levels and serum ionized calcium and phosphorous levels are low
• Alkaline phosphatase level is high
• Calcitriol level may be normal with elevated parathyroid hormone level.
• X-ray of the knee joint shows low mineralization and cupping and flaring of the bones at the joints.

Treatment

The treatment of the Rickets is mainly by supplementing the Vitamin D3 in pediatric age group is

Single-day dose method: 15,000 mcg (600,000 U) PO divided in 4-6 doses for 1 d

Gradual method: 125-250 mcg (5000-10,000 U) for 2-3 months

• Vitamin D3 fortified milk and food is given to the child
• Calcium and phosphorous supplement
• And the deformities when severe appropriate orthopedic corrections are made after healing.