In CRF, main cause of Vit D deficiency is the failure of:
a. Vit D absorption in intestines
b. 25 alpha hydroxylation of Vit D
c. Excess Vit D loss in urine
d. 1 alpha hydroxylation of Vit D
e. Availability of Vit D precursors
answer: D
Vitamin D Deficiency
• deficient uptake or absorption
nutritional deficiency
malabsorption: post-gastrectomy, small bowel disease (e.g. Celiac sprue), pancreatic insufficiency
• defective 25-hydroxylation
liver disease
anticonvulsant therapy
• loss of vitamin D binding protein
nephrotic syndrome
• defective 1-α-25 hydroxylation
hypoparathyroidism
renal failure
• pathophysiology of vit d deficiency :
leads to secondary hyperparathyroidism and hypophosphatemia