Osteomalacia/Rickets
Overview
Plain-Language Overview
Osteomalacia and rickets are conditions that affect the bones, causing them to become soft and weak. These disorders occur when the body does not have enough vitamin D, calcium, or phosphate, which are essential for healthy bone formation. In children, this leads to rickets, characterized by bone deformities and growth problems, while in adults, osteomalacia causes bone pain and increased risk of fractures. The main problem is that the bones do not mineralize properly, making them fragile. This affects the skeletal system and can cause difficulty walking or standing. Both conditions result from problems with bone metabolism and mineralization.
Clinical Definition
Osteomalacia and rickets are metabolic bone diseases characterized by defective bone mineralization due to inadequate availability or metabolism of vitamin D, calcium, or phosphate. Rickets refers to this process in growing children, leading to defective mineralization of the growth plate cartilage, whereas osteomalacia occurs in adults with defective mineralization of the bone matrix. The most common cause is vitamin D deficiency, which impairs intestinal calcium absorption, resulting in secondary hyperparathyroidism and hypophosphatemia. Clinically, these conditions present with bone pain, muscle weakness, and skeletal deformities in rickets such as bowed legs or rachitic rosary. Biochemically, they show low serum calcium or phosphate, elevated alkaline phosphatase, and low 25-hydroxyvitamin D levels. The pathophysiology involves impaired hydroxyapatite crystal formation, leading to soft, poorly mineralized bones prone to fractures and deformities.