Clinical Scenario:
A 12-year-old boy with stage 5 chronic kidney disease presents with worsening bone pain and difficulty walking. Examination reveals short stature and bony tenderness over the lower limbs. Laboratory investigations show:
- Serum calcium: 7.6 mg/dL
- Serum phosphate: 7.2 mg/dL
- Serum alkaline phosphatase: 680 IU/L
- Parathyroid hormone (PTH): Markedly elevated
What is the most likely cause of his bone disease?
A. Hyperparathyroidism
B. Osteogenesis imperfecta
C. Vitamin C deficiency
D. Vitamin D intoxication
E. Wilson disease
Correct answer & Explanation:
Correct Answer: A. Hyperparathyroidism
Explanation
Children with advanced CKD develop CKD-mineral and bone disorder (CKD-MBD) due to phosphate retention, reduced activation of vitamin D, hypocalcemia, and secondary hyperparathyroidism. Elevated PTH causes increased bone turnover, leading to renal osteodystrophy, bone pain, fractures, and growth failure.
Learning Point:
Secondary hyperparathyroidism is a common complication of advanced CKD and is managed with dietary phosphate restriction, phosphate binders, active vitamin D (calcitriol), and optimization of dialysis when indicated.
