Bone disorders II Flashcards
What do we see with rickets on X ray?
metaphyseal flaring with cup-shaped deformity
genetic causes of vitamin D deficiency
type I: 1 alpha hydroxylase deficiency
type II: vitamin D receptor deficiency
Most common cause of osteomalacia in adults
intestinal malabsorption
lab results in osteomalacia and rickets
decr. calcium, decr. phosphate, incr. alk phos, decre 25 oh vitamin D, incr PTH
phosphate is important- if it is high, think of renal osteodystrophy instead
Why should I think about bone in CKD?
much more likely to have fracture
stage 3 or higher need vit D supplementation
what is renal osteodystrophy
combo of hyperparathyroidism and osteomalacia
high phosphate low 1a hydroxyalse = low calcium
may be from aluminum toxicity
What are some manifestations of renal osteodytrophy
4 gland hyperplasia of parathyroid with chronic low calcium
skeletal resistance to PTH
may see amyloid formation in the skeleton and soft tissue/organs
Labs with renal osteodystrophy
low Ca
high PTH
high PO4
low GFR
treatment of renal osteodystrophy
manage mineral metabolism treat w vitamin D manage acidosis if parathyroidism is severe, consider parathyroidectomy treat fractures
What is osteopetrosis?
normal new bone formation but deficiency of bone and cartilage resorption
decr. or absent osteoclasts
large numbers of defective osteoclasts
phenotypes of osteopetrosis
adult form:
congenital
intermediate
carbonic anhydrase II gene mutation
adult osteopetrosis. symptoms and inheritance
most common form, normal lifespan, mild anemia
autosomal dominant
congenital osteopetrosis
autosomal recessive
causes death in childhood
anemia, thrombocytopenia, hepatosplenomegaly, immune system compromise, cranial and optic palsies
carbonic anhydrase II gene mutation
associated with renal tubular acidosis, cerebral calcifications, and intellectual disability
treatment of osteopetrosis
IFN-gamma is FDA approved
maybe bone marrow transplant
some success with massive doses of 1,25 vitamin D
