See also: Bone endocrine diseases

 

Sx
     Defective mineralization of the bone
     Softening of the bone
     Development of deformities, particularly in the weight-bearing bones of the lower extremities
     Rickets is characterized by defective mineralization of both bone and growth plate cartilage. It is also caused by vitamin D deficiency, but is seen only in children.
Classic radiologic features
     Symmetrical "looser zones"
     Pseudofractures
     Blurring of the spine
Labs
     25-OH Vitamin D     | Low
     PTH                       | High
     Ca2+                     | Low or Low-normal
     Phosphate             | Low
Pathophysiology
     May be caused by
          Calcium deficiency
          Parathyroidectomy
          Renal tubular acidosis
          Vitamin D deficiency
               Vitamin D deficiency leads to decreased inestinal calcium and phosphorus absorption, thereby resulting in hypocalcemia and hypophosphatemia. Hypocalcemia then stimulates the parathyroid glands. The resultant secondary hyperparathyroidism brings the serum calcium levels to normal or near-normal (especially in the early stages), and increases urinary phosphate excretion, thereby worsening the hypophosphatemia. Vitamin D deficiency thus causes more marked hypophosphatemia than hypocalcemia, especially in the early stages.
See also: Vitamin deficiencies, bone endocrine diseases

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The Compendium platform was created by David Kwinter, MD, CCFP(EM).