1 / 16

RICKETS/OSTEOMALACIA

RICKETS/OSTEOMALACIA. The case of Sunset Sky. Sunset Sky Davis. 7 month old female Pomeranian Hx: Hypocalcemia, hyperphosphatemia Accession 86423 MRN 136554. Radiographic signs. Flared metaphyses Widened, lucent physes “Cupping” of physes. Diagnostic Testing.

maia
Download Presentation

RICKETS/OSTEOMALACIA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. RICKETS/OSTEOMALACIA The case of Sunset Sky

  2. Sunset Sky Davis 7 month old female Pomeranian Hx: Hypocalcemia, hyperphosphatemia Accession 86423 MRN 136554

  3. Radiographic signs • Flared metaphyses • Widened, lucent physes • “Cupping” of physes

  4. Diagnostic Testing • Increased PTH 90.7 (3-17) • Low ionized Calcium 0.94 (1.25-1.45) • Low vitamin D 43 (60-215) • These findings are consistent with nutritional sec. hyperPTH with decreased vitamin D intake/GI absorption. Strange, since other pups in household are unaffected.

  5. Metabolic Bone Disease Osteolysis (i.e.—hyperparathyroid states) Defective Bone Formation • Nutritional sec. • Renal sec. • Primary Defective osteoid production (aka Osteoporosis) Inadequate mineralization of osteoid (RICKETS) • HAC • Osteogenesis imperfecta • Renal sec. • Decr. Ca or P • VITAMIN D DEF. • Hepatic • anticonvulsant

  6. Osteolysis • Nutritional—too much P or too little Ca causes PTH secretionbone resorption • Renal secondary—inadequate P excretionhypocalcemiaPTH secretionbone resorption • Hypercalcemia of malignancy (PTHrp) • Primary hyperPTH

  7. Causes of Osteoporosis (decreased osteoid production) • Hyperadrenocorticism • Osteogenesis imperfecta • Other causes of decreased collagen or matrix production

  8. Causes of Inadequate Min. • USUALLY HYPOVITAMINOSIS D --inadequate intake --disorders of vitamin D metabolism --renal failure (decreased synth. Of 1, 25-(OH)2-vitD—the most active) • Decreased Calcium or phosphorus intake (e.g.—inappropriate feeding of renal diets)

  9. Dietary-Related Skeletal Changes in a Shetland Sheepdog Puppy • 10 wk old Sheltie • Suspected renal failure (azotemia, isosthenuria) • Placed on a commercial renal failure diet (low phosphorus/low protein/adequate vit D) • Presented with carpal varus and failure to grow • Radiographs—consistent with rickets J Am Anim Hosp Assoc 2006; 42:57-64

  10. Bottom line: Nutritional Rickets • Note: serum PTH was LOW due to low phosphorus intake (in nutritional sec. hyperPTH, the PTH goes UP in response to decreased Ca) • Hypophosphatemia/Normocalcemia • Treatment: commercial puppy food

  11. Interesting points • In this case, PTH was low because of decreased P, rather than decreased Ca. • Both nutritional sec. hyperPTH and vitamin D deficient rickets can present with HIGH PTH levels. • So, diagnosis can be complex—must carefully analyze diet • Ca:P is ideally 1:1, no higher than 1:2

  12. Vitamin D-Dependent Rickets Type II in a Cat • 4 month old male DSH • Presented for inappetence and decreased mobility • Radiographic signs of rickets • Fed adult food/chicken/white fish • Changed to a commercial kitten food • Signs continued to progress (devel. rachitic rosary) Journalof Small Animal Practice (2005); 46:440-444

  13. Unable to utilize vitamin D appropriately • PTH concentrations were HIGH • Calcium levels were slightly LOW • Phosphorus levels were normal • At 20 mos, plasma 1,25-(OH)2-vitD concentrations were VERY HIGH

  14. How to test vit D receptors?? • Skin biopsy • Obtain fibroblast cultures • Test for ability of radiolabelled 1,25-(OH)2-vit D to bind to nuclear extracts • This cat showed complete lack of binding

  15. Dietary Vitamin D Intake Liver converts to 25-OH-vit D Kidney—proximal tubules convert to 1,25-(OH)2-vit D, the most active form 1, 25-(OH)2-vit D tells GI to absorb more Calcium

  16. Over 30 diseases can decrease vitamin D absorption, metabolism, or actions! Dietary Renal failure Liver disease Pancreas/small intestinal dz Hypoparathyroidism

More Related