QuestionSBA
QuestionChoice
This patient has developed secondary hyperparathyroidism as a consequence of his chronic kidney disease. Vitamin D is synthesized in the kidneys and is vital in maintaining calcium homeostasis. When renal function is impaired, the body cannot adequately synthesize vitamin D and the body struggles to absorb sufficient calcium as a result. Furthermore, the dysfunctional kidney cannot excrete sufficient phosphate, which ionizes with calcium in the blood and reduces the amount of free calcium available. These two mechanisms result in low serum calcium, which leads to excess parathyroid hormone production. Secondary hyperparathyroidism is now established. Elevated PTH causes excess mobilization of calcium from bones and subsequent mineral bone disease.
10000401
a
Elevated PTH, Low Ca2+, Elevated phosphate, Low vitamin D
QuestionChoice
This blood profile is characteristic of primary hypoparathyroidism. Deficient PTH secretion results in reduced calcium mobilization as well as reduced excretion of phosphate, which ionizes with calcium in the blood and further reduces the availability of free calcium. Primary hypoparathyroidism occurs due to impaired function of the parathyroid gland, for example as a result of iatrogenic causes such as thyroid surgery.
10000404
d
Low PTH, Low Ca2+, Elevated phosphate, Normal vitamin D
QuestionChoice
This profile of blood test results suggests inappropriately elevated calcium in absence of a parathyroid cause. Further investigation is required to rule out important diagnoses such as hypercalcaemia of malignancy.
10000403
c
Low PTH, Elevated CA2+, Low phosphate, Normal vitamin D
QuestionChoice
This combination of results is unlikely to occur in a patient suffering from CKD. Elevated PTH concurrent with elevated Ca2+ indicates primary hyperparathyroidism whilst elevated phosphate indicates renal dysfunction. An elevated vitamin D, however, is unlikely to occur in renal dysfunction as the kidney is responsible for synthesizing the vitamin. Therefore this combination of results would not occur in a stage 5 CKD patient.
10000405
e
Elevated PTH, Elevated Ca2+, Elevated phosphate, Elevated vitamin D
QuestionChoice
This profile suggests primary hyperparathyroidism, which most commonly occurs due to parathyroid adenoma rather than CKD. Primary hyperparathyroidism is characterised by inappropriately elevated PTH - i.e. in the presence of low calcium. This usually occurs due to the presence of an adenoma or carcinoma which uncontrollably excretes PTH.
10000402
b
Elevated PTH, Elevated Ca2+, Low phosphate, Normal vitamin D
Concept
Chapter
2693
3753
Chronic kidney disease
Topic
142
Nephrology
12627
A 67-year-old patient with stage 5 chronic kidney disease presents to the clinic for a scheduled check-up on his condition. He does not report any symptoms but his blood test results reveal that he has developed a complication of CKD and is at risk of developing renal osteodystrophy as a result. His previous check-up one year ago was normal.

Which of the following sets of results most accurately reflect this patient's condition?
a