Hypercalcaemia Flashcards
Differential Diagnosis
Primary Hyperparathyroidism
Multiple Myeloma
Bony Metastases
Sarcoidosis
Thyrotoxicosis (effect of thyroid hormone on bone metabolism)
Milk Alkali syndrome
What is primary hyperparathyroidism caused by?
Investigation findings
How is it treated/
Uncontrolled parathyroid hormone produced directly by a tumour of the parathyroid glands.
High PTH
Hypercalcaemia
Low Phosphate
This is treated by surgically removing the tumour.
Secondary Hyperparathyroidism
What causes it?
Investigation findings
insufficient vitamin D or chronic renal failure leads to low absorption of calcium from the intestines, kidneys and bones.
This causes hypocalcaemia: a low level of calcium in the blood.
The parathyroid glands reacts to hypocalcaemia by excreting more parathyroid hormone.
Over time the total number of cells in the parathyroid glands increase as they respond to the increased need to produce parathyroid hormone by hyperplasia
Investigation findings:
Hypocalcaemia
High PTH
High Phosphate
This is treated by correcting the vitamin D deficiency or performing a renal transplant / dialysis to treat renal failure.
Tertiary Hyperparathyroidism
What causes this?
This happen when secondary hyperparathyroidism continues for a long period of time. It leads to hyperplasia of the glands.
The baseline level of parathyroid hormone increases dramatically. Then when the cause of the secondary hyperparathyroidism is treated the parathyroid hormone level remains inappropriately high.
This high level of parathyroid hormone in the absence of the previous pathology leads to high absorption of calcium in the intestines, kidneys and bones and causes hypercalcaemia.
Tertiary Hyperparathyroidism
Investigation findings
High calcaemia
High PTH
Normal or decreased Phosphate
Tertiary Hyperparathyroidism
Treatment
Treated by surgically removing part of the parathyroid tissue to return the parathyroid hormone to an appropriate level.
