Renal Bone Disease Flashcards
What other name is given to renal bone disease?
Renal bone disease is also known as chronic kidney disease-mineral and bone disorder (CKD-MBD).
What are the features of CKD-MBD?
- Osteomalacia (softening of bones)
- Osteoporosis (brittle bones)
- Osteosclerosis (hardening of bones)
What are the x-ray changes seen in CKD-MBD?
Spine xray shows sclerosis of both ends of the vertebra (denser white) and osteomalacia in the centre of the vertebra (less white). This is classically known as “rugger jersey” spine after the stripes found on a rugby shirt.
Why does high serum phosphate occur?
High serum phosphate occurs due to reduced phosphate excretion.
Why does low active vitamin D occur?
Low active vitamin D because the kidney is essential in metabolising vitamin D to its active form.
Active vitamin D is essential in calcium absorption from the intestines and kidneys. Vitamin D also regulates bone turnover.
Why does secondary hyperparathyroidism and increased osteoclast activity occur?
Secondary hyperparathyroidism occurs because the parathyroid glands react to the low serum calcium and high serum phosphate by excreting more parathyroid hormone. This leads to increased osteoclast activity. Osteoclast activity lead to the absorption of calcium from bone.
Why does osteomalacia occur?
Osteomalacia occurs due to increased turnover of bones without adequate calcium supply.
Why does osteosclerosis occur?
Osteosclerosis occurs when the osteoblasts respond by increasing their activity to match the osteoclasts by creating new tissue in the bone, however due to the low calcium level this new tissue is not properly mineralised.
Why does osteoporosis occur?
Osteoporosis can exist alongside the renal bone disease due to other risk factors such as age and use of steroids.
Briefly describe the management of RBD-MBD
- Active forms of vitamin D (alfacalcidol and calcitriol)
- Low phosphate diet
- Bisphosphonates can be used to treat osteoporosis
