Pathophysiology of Primary Hyperparathyroidism (PHPT)

  • In primary hyperparathyroidism due to adenomas:
    • The normal feedback on parathyroid hormone production by extracellular calcium seems to be lost:
      • Resulting in a change in the set point
  • In primary hyperparathyroidism from parathyroid hyperplasia:
    • An increase in the cell numbers is probably the cause of the change in the set point
  • The chronic excessive resorption of calcium from bone caused by excessive parathyroid hormone can result in:
    • Osteopenia
    • In severe cases, this may result in osteitis fibrosa cystica:
      • Which is characterized by subperiosteal resorption of the distal phalanges, tapering of the distal clavicles, salt-and-pepper appearance of the skull, and brown tumors of the long bones
        • This is not commonly seen now
  • In addition, the chronically increased excretion of calcium in the urine:
    • Can predispose to the formation of renal stones
  • The other symptoms of hyperparathyroidism:
    • Are due to the hypercalcemia itself:
      • And are not specific to hyperparathyroidism
    • These can include:
      • Muscle weakness
      • Fatigue
      • Volume depletion
      • Nausea and vomiting
      • In severe cases, coma and death
    • Neuropsychiatric manifestations are particularly common and may include:
      • Depression
      • Confusion
      • Subtle deficits that are often characterized poorly and may not be noted by the patient (or may be attributed to aging)
    • Increased calcium can increase gastric acid secretion, and persons with hyperparathyroidism:
      • May have a higher prevalence of peptic ulcer disease
    • Rare cases of pancreatitis have also been attributed to hypercalcemia
  • A prospective cohort study by Ejlsmark-Svensson et al:
    • Reported that in patients with primary hyperparathyroidism, quality-of-life questionnaire scores were significantly lower:
      • In association with moderate-severe hypercalcemia:
        • Than in relation to mild hypercalcemia:
          • However, quality of life did not seem to be related to the presence of organ-related manifestations of primary hyperparathyroidism, such as osteoporosis, renal calcifications, and renal function impairment
          • This suggests that hypercalcemia is the primary driver of an impaired quality of life

#Arrangoiz #PrimaryHyperparathyroidism #Hyperparathyroidism #Hypercalcemia #ParathyroidSurgeon #ParathyroidExpert #HeadandNeckSurgeon #EndocrineSurgery #MSMC #MountSinaiMedicalCenter #Mexico #Miami

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