Case 103: Hypercalcaemia
A 48 year old woman is referred from her GP with a serum corrected calcium of 3.05 mmol/L. She is otherwise fit and well. Her parathyroid hormone (PTH) is inappropriately elevated but renal function is normal.
1. How would you classify hyperparathyroidism?
Pimary, secondary and tertiary forms are recognised. Primary hyperparthyroidism typically occurs as a result of an autonoumous functional parathyroid adenoma. Hyperplasia of all four glands occurs less commonly.
Secondary hyperparathyroidism occurs in the setting of chronic renal failure is due to complex abnormalities of calcium-phosphate metabolism and homeaostasis.
Tertiary hyperparathyroidism occurs when the an autonoumous gland develops as a result of chronic hyperstimulation in chronic renal failure. It typically manifests itself after cessation of the stimulus following successful renal transplant.
2. What imaging has been performed and what other options are there?
A parathyroid nuclear medicine scan. The isotope (Tc-99m Sestamibi) is taken up equally by the thyroid and parathyroid glands. The thyroid excretes the isotope while the parathyroid retains it for significantly longer. This results in delayed images showing the parathyroids. In this case a single adenoma is identified on the left and the other glands are suppressed (click on image for assistance).
Some experienced parathyoid surgeons do not use any localisation studies for the first exploration of the neck in primary hyperparathyroidism. They will routinely identify all four glands with a high level of success.
3. How can operative identification of the parathyroids be facilitated?
Intravenous methylene blue infusion pre-operatively will stain the parathyroids blue-brown as they preferentially take up the dye.
eMedicine --- Hyperparathyroidism ---