Physiology and Pathophysiology
Which receptor on parathyroid cells senses calcium and regulates PTH secretion.
What is the calcium-sensing receptor (CaSR)?
The most common cause of primary hyperparathyroidism
What is adenoma
The most common cause of secondary hyperparathyroidism.
What is chronic kidney disease (CKD)?
Tertiary HPT most often occurs after this event.
What is renal transplantation?
The “Miami criterion” requires this drop in PTH level at 10 minutes.
What is a ≥50% drop from baseline?
PTH increases serum calcium by acting on these three organs.
What are bone, kidney, and intestine?
This hereditary syndrome includes parathyroid tumors, pancreatic tumors, and pituitary adenomas.
MEN1
Name one non-renal cause of SHPT.
What is vitamin D deficiency, bariatric surgery, malabsorption, or liver disease?
In tertiary HPT, both calcium and PTH levels are _____.
What is elevated?
During parathyroidectomy, injury to this nerve can cause temporary hoarseness in 5–10% and permanent injury in ~1% of patients.
What is the recurrent laryngeal nerve (RLN)?
PTH decreases reabsorption of this ion in the proximal tubule.
What is phosphate?
Name the classic 4-word mnemonic for PHPT symptoms
What are “bones, stones, groans, and psychiatric overtones
This bone disease in CKD results from overtreatment with vitamin D analogs or calcimimetics and is characterized by low bone turnover.
What is adynamic bone disease?
The definitive treatment for refractory tertiary HPT.
What is subtotal or total parathyroidectomy?
Intraoperative PTH monitoring is unreliable in this patient population due to altered clearance.
Who are patients with chronic kidney disease?
This peptide hormone, secreted by osteocytes, downregulates calcitriol production and contributes to secondary HPT in CKD.
What is FGF-23?
This skeletal complication of long-standing PHPT is rare today but characterized by subperiosteal bone resorption and “brown tumors.”
What is osteitis fibrosa cystica?
This rare complication of refractory SHPT presents with painful violaceous skin lesions and has a mortality of 30–80%.
What is calciphylaxis?
Explain why phosphate is typically low in tertiary HPT but high in secondary HPT.
What is restoration of renal clearance after transplant (tertiary), versus phosphate retention in CKD (secondary)?
This life-threatening complication of parathyroidectomy requires immediate bedside wound opening. What is the next step?
What is a neck hematoma and you want immediate OR
Name the three biochemical criteria in the “rule of 3’s” that should raise suspicion for parathyroid carcinoma. [HINT REDFLAG]
What is tumor size >3 cm, serum calcium >3 mmol/L (~12 mg/dL), and markedly elevated PTH?
In primary HPT, cortical bone is preferentially lost. Which DEXA site most clearly reflects this?
What is the distal one-third radius (forearm)
The two most common surgical approaches for refractory SHPT are subtotal parathyroidectomy and this alternative procedure.
What is total parathyroidectomy with autotransplant (often into the forearm)?
The definitive surgical management of tertiary HPT includes these two operative options.
What are subtotal PTX (leaving 30–50 mg) or total PTX with autotransplant (usually in forearm)?
During parathyroidectomy, the strap muscles are retracted laterally to expose the thyroid lobe. The parathyroid adenoma is typically found in this anatomic location adjacent to the thyroid and near this critical structure not visualized in the figure.
What is tracheoesopahgeal groove?