A 56-year-old male presented to emergency department with nausea and vomiting. He has fatigue, poor appetite, polyuria, polydipsia and constipation. Blood work showed hypercalcemia with the following laboratory results: PTH: 5 pg/ml (Normal 10- 55), creatinine: 1.9 mg/dL (Normal: 0.7-1.3), 25- hydroxyvitamin D 50 ng/mL (Normal: 20-60), 1,25-dihydroxyvitamin D: 17 pg/mL (Normal: 15-65 pg/mL). Which of the following is the most likely cause for hypercalcemia?
سؤال مجاني 5 من 10 اليوم · اشترك وكمّل بدون حد
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الإجابة والشرح
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الإجابة: B. Hypercalcemia of malignancy
Suppressed PTH means the hypercalcaemia is not parathyroid-mediated. With normal 25-OH D and low-normal 1,25-(OH)2 D, sarcoidosis (which raises 1,25-D) is unlikely, which leaves hypercalcaemia of malignancy (PTHrP). Primary HPT would have high PTH, and CKD alone causes hypocalcaemia.
ليش كل خيار صح أو غلط
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A
ليش غلط
CKD usually causes hypocalcemia and secondary hyperparathyroidism (raised PTH); this patient has suppressed PTH (5).
✓ Step Up To Medicine 6th, 2024 (CKD).pdf · p. 3 -
B
ليش صح
With low PTH, the approach chart goes to PTHrP (high → work-up for malignancy) and vitamin D metabolites (high → lymphoma/granulomatous disease); his vitamin D levels are normal, so among the options malignancy fits.
✓ Calcium and Parathyroid.pdf · p. 49 -
C
ليش غلط
Primary hyperparathyroidism needs a PTH that is elevated or inappropriately normal; this patient's PTH is suppressed (5).
✓ Step Up To Medicine 6th Edition 2024(Parthyroid).pdf · p. 4 -
D
ليش غلط
Sarcoidosis causes hypercalcemia through raised 1,25-dihydroxyvitamin D (macrophage 1-alpha-hydroxylase); this patient's 1,25-D is normal (17 pg/mL).
✓ Calcium and Parathyroid.pdf · p. 6
- المصدر
- Calcium and Parathyroid.pdf · p. 49
- المحاضرة
- Parathyroid & Calcium Disorders · Endocrinology · Module B
- ظهر في
- Endo bank