Primary hyperparathyroidism
Primary hyperparathyroidism
Updated: 02/05/2024
© Jun Wang, MD, PhD
Definition
- Autonomous overproduction of parathyroid hormone
- More common in women; usually age 50+
- NO evidence of prior parathyroid stimulation by renal or intestinal disease
- Most common cause: Adenoma
- Other causes: parathyroid hyperplasia and carcinoma
Key
pathogenesis
- Autonomous overproduction of parathyroid hormone
- Subsequent activation of osteoclast
Clinical
presentations
- May be asymptomatic
- Incidental finding of hypercalcemia
- Associated with hypercalcemia and excessive calcium resorption
- Bones: Osteoporosis, osteitis fibrosa cystica (brown tumor)
- Stones: Renal calcium stones, nephrocalcinosis
- Abdominal groans: Nausea, peptic ulcers (associated with high serum gastrin caused by hypercalcemia), constipation, pancreatitis, gallstones
- Psychic moans: Depression, lethargy, seizures
- Others: Proximal myopathy, Weakness, fatigue, calcifications
Key laboratory findings
- Hypercalcemia, although may be normocalcemic
- Inappropriately elevated levels of PTH
- Low serum phosphorus, high serum alkaline phosphatase, high urine calcium and phosphorus
- If low urine calcium but hypercalcemia, consider familial hypocalciuric hypercalcemia
- Calcium sensing receptor mutation
- Reduced sensitivity to serum calcium
- Higher level of serum calcium to suppress PTH secretion
- Low excretion faction of calcium, causing low urine calcium
- Usually asymptomatic, but may present with non specific symptoms, including fatigue, polyuria, polydipsia, and abnormal renal function
Key
radiologic features
- Increased bone absorption
- Osteoporosis
Osteitis fibrosa cystica
- Solitary or multiple
- Large lytic lesion resembling bone tumor
- Usually starts from fingers, facial bones, ribs, and pelvis
- Well-defined radiolucent bone lesions
- Brown due to hemorrhage
- Microscopic: Increased osteoclasts with interstitial hemorrhage, hemosiderin, microfractures, ingrowth of vascularized fibrous tissue with fibroblasts
Treatment
- Surgery
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