Secondary Hyperparathyroid and Renal Osteodystrophy Question

[Southpaw]

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Hey all,

Ran into a question that has me stumped. Describes a patient in end-stage renal disease and asked what metabolic changes would be predicted? The answer was oseitis fibrosa cystica, and it claimed that increased serum phosphate would bind Ca2+, causing hypocalcemia, and this would be accentuated by decreased levels of 1,25 OH2 Vit D. Makes sense so far....

However first aid says that Osteitis fibrosa cystica would be characterized by high serum Ca2+, low serum phosphorus, and high alk phosph. This is pretty much the exact opposite of what the question said. What gives? Thanks for the help....

 

[beastmaster]

OFC (as used in first aid) is primary... ESRD is secondary... hence the reverse findings for calcium/phosph

 

[blz]

Hey all,

Ran into a question that has me stumped. Describes a patient in end-stage renal disease and asked what metabolic changes would be predicted? The answer was oseitis fibrosa cystica, and it claimed that increased serum phosphate would bind Ca2+, causing hypocalcemia, and this would be accentuated by decreased levels of 1,25 OH2 Vit D. Makes sense so far....

However first aid says that Osteitis fibrosa cystica would be characterized by high serum Ca2+, low serum phosphorus, and high alk phosph. This is pretty much the exact opposite of what the question said. What gives? Thanks for the help....

CRF by itself will lead to hypocalcemia, hyperphosphatemia (decreased renal excretion) ---> increase PTH ---> increased osteoclast acitivity (osteitis fibrosa cystica). the osteitis fibrosa cystica in this case is a result of a compensatory pathway to attempt to raise calcium levels. FA is describing PRIMARY OFC in which it just a primary increase in osteoclast activity with the expected metabolic changes.