Podcast
Questions and Answers
What does a family history of hypercalcaemia raise the possibility of?
What does a family history of hypercalcaemia raise the possibility of?
- Secondary hyperparathyroidism
- Primary hyperparathyroidism
- Milk-alkali syndrome
- Familial hypocalciuric hypercalcemia (correct)
What do high plasma phosphate and alkaline phosphatase levels accompanied by renal impairment suggest?
What do high plasma phosphate and alkaline phosphatase levels accompanied by renal impairment suggest?
- Familial hypocalciuric hypercalcemia
- Primary hyperparathyroidism
- Secondary hyperparathyroidism
- Tertiary hyperparathyroidism (correct)
What can hypercalcaemia cause that may result in hyperuricaemia and hyperchloraemia?
What can hypercalcaemia cause that may result in hyperuricaemia and hyperchloraemia?
- Nephrocalcinosis (correct)
- Renal tubular impairment
- Hyperparathyroidism
- Renal calculi
What is the net effect of prolonged exposure of bone to high levels of PTH?
What is the net effect of prolonged exposure of bone to high levels of PTH?
What is the effect of pulsatile release of PTH on bone?
What is the effect of pulsatile release of PTH on bone?
What is the most common cause of hypercalcaemia?
What is the most common cause of hypercalcaemia?
What are the classic symptoms associated with primary hyperparathyroidism?
What are the classic symptoms associated with primary hyperparathyroidism?
What is the role of parathyroid hormone (PTH) in regulating calcium and phosphate homeostasis?
What is the role of parathyroid hormone (PTH) in regulating calcium and phosphate homeostasis?
How do the parathyroid chief cells respond to changes in calcium concentrations?
How do the parathyroid chief cells respond to changes in calcium concentrations?
What happens to PTH secretion when serum ionized calcium levels fall?
What happens to PTH secretion when serum ionized calcium levels fall?
What is the main function of PTH on the skeleton?
What is the main function of PTH on the skeleton?
What is the most likely diagnosis if PTH levels are detectable or elevated in the presence of hypercalcaemia?
What is the most likely diagnosis if PTH levels are detectable or elevated in the presence of hypercalcaemia?
What does a biochemical presentation similar to primary hyperparathyroidism with low urinary calcium excretion indicate?
What does a biochemical presentation similar to primary hyperparathyroidism with low urinary calcium excretion indicate?
What condition is suggested by high plasma phosphate and alkaline phosphatase levels accompanied by renal impairment?
What condition is suggested by high plasma phosphate and alkaline phosphatase levels accompanied by renal impairment?
What is the recommended initial medical management for severe hypercalcaemia?
What is the recommended initial medical management for severe hypercalcaemia?
What is the duration of action of calcitonin in the treatment of hypercalcaemia?
What is the duration of action of calcitonin in the treatment of hypercalcaemia?
In the medical management of severe hypercalcaemia, what is the alternative option for patients with refractory hypercalcaemia if zoledronic acid is not effective?
In the medical management of severe hypercalcaemia, what is the alternative option for patients with refractory hypercalcaemia if zoledronic acid is not effective?
What is the most common cause of hypocalcaemia?
What is the most common cause of hypocalcaemia?
How does magnesium depletion cause hypocalcaemia?
How does magnesium depletion cause hypocalcaemia?
What is the effect of hypomagnesaemia on serum phosphate levels?
What is the effect of hypomagnesaemia on serum phosphate levels?
How should calcium be adjusted in the presence of hypoalbuminaemia?
How should calcium be adjusted in the presence of hypoalbuminaemia?
What is the characteristic phenotype associated with pseudohypoparathyroidism?
What is the characteristic phenotype associated with pseudohypoparathyroidism?
What is the characteristic triad of symptoms seen in children with tetany?
What is the characteristic triad of symptoms seen in children with tetany?
What is the latent tetany detected by eliciting Trousseau’s sign?
What is the latent tetany detected by eliciting Trousseau’s sign?
What may prolonged hypocalcaemia and hyperphosphataemia cause in association with hypoparathyroidism?
What may prolonged hypocalcaemia and hyperphosphataemia cause in association with hypoparathyroidism?
What is the recommended initial management for severe hypocalcaemia?
What is the recommended initial management for severe hypocalcaemia?
What may hypocalcaemia associated with hypophosphataemia cause in children and adults?
What may hypocalcaemia associated with hypophosphataemia cause in children and adults?
Study Notes
Overview of Hypercalcaemia in Cancer
- Hypercalcaemia is the most prevalent metabolic disorder in cancer patients, affecting up to 20%.
- Highest incidence occurs in myeloma and breast cancer, reaching approximately 40%.
- Intermediate incidence found in non-small cell lung cancer; uncommon in colon, prostate, and small cell lung cancers.
Mechanisms of Hypercalcaemia
- Overproduction of PTHrP (Parathyroid Hormone-related Peptide) accounts for around 80% of cases.
- PTHrP binds to the PTH receptor, leading to increased serum calcium through:
- Stimulating osteoclastic bone resorption.
- Enhancing renal tubular reabsorption of calcium.
- Direct invasion of bone metastases contributes to about 20% of hypercalcaemia cases.
- Ectopic secretion of PTH is rare.
Clinical Features
- Symptoms are often non-specific and can resemble those of the underlying cancer.
- Common symptoms include:
- Drowsiness and delirium.
- Nausea and vomiting.
- Constipation.
- Increased urination (polyuria) and thirst (polydipsia).
- Dehydration.
Diagnosis and Management
- Diagnosis involves measuring serum total calcium, adjusting for albumin levels.
- Correcting for hypoalbuminaemia is crucial as it is common in cancer, affecting ionised calcium calculations.
- Initial treatment includes:
- Administration of intravenous 0.9% saline for renal function improvement and increased urinary calcium excretion.
- Often leads to clinical improvement.
- Concurrently, intravenous bisphosphonates are used to inhibit bone resorption.
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Description
Explore the role of parathyroid hormone (PTH) in regulating calcium and phosphate levels, as well as its impact on vitamin D metabolism. Learn about the consequences of altered PTH function in gut and renal disease, metabolic bone diseases, disorders of the parathyroid glands, hypercalcemia, and hypocalcemia.
