Disorders of calcium Flashcards
What are the three calcium disorders?
Hypercalcaemia
Hypocalcaemia
Osteomalacia
Which calcium disorder is more common?
Hypercalcaemia
What are the main causes of hypercalcaemia?
Primary hyperparathyroidism
Malignancy
What are the main causes of hypocalcaemia?
Hypoparathyroidism
What can the symptoms of hypercalcaemia be categorised into?
Groans
Bones
Moans
Stones
Cardiovascular
What ‘groan’ symptoms are there of hypercalcaemia?
What ‘bones’ symptoms are there of hypercalcaemia?
What ‘moans’ symptoms are there of hypercalcaemia?
What ‘stones’ symptoms are there of hypercalcaemia?
What are the cardiovascular symptoms of hypercalcaemia?
Which bloods would be checked when suspecting hypercalcaemia?
Calcium
U+E’s
Phosphate
Mg+
PTH
Vitamin D
ACE (Indirect indicator of sarcoidosis)
Why should an ECG be done in hypercalcaemia?
It can cause shortened QTc interval
What would be a normal 24hour urine calcium level?
<7.5mmol/day
What would a high and low calcium level on a 24hour urine collection mean?
High - primary hyperparathyroidism
Low - Familial Hypocalciuric Hypocalcaemia
What happens to PTH levels in primary hyperparathyroidism?
They remain high and don’t decrease with high calcium.
What is over secreted in hyperparathyroidism?
Parathyroid hormone
What are the three types of hyperparathyroidism?
Primary - autonomous, too much PTH produced
Secondary - Chronic stimulus causing PTH secretion
Tertiary - autonomous, too much PTH secretion
What are some causes of high PTH?
What are some causes of suppressed PTH?
Why do patients get low in vitamin D in hyperparathyroidism?
Low Vitamin D levels in patients with a high calcium and a high parathyroid hormone level occurs as a protective mechanism for the body. Because the blood serum doesn’t require any additional calcium the production and conversion of vitamin D is down-regulated as a protective mechanism for the body.
What is the main cause of primary hyperparathyroidism?
Adenoma of the thyroid gland
What is the main cause of secondary hyperparathyroidism?
Chronic renal failure
Vitamin D deficiency
What is the main cause of tertiary hyperparathyroidism?
End stage renal failure
What happens to the calcium, phosphate and PTH levels in primary hyperparathyroidism?
Calcium high
Phosphate low
PTH high
What is the typical age of someone diagnosed with hyperparathyroidism?
50-60years
Which familial syndromes have been associated with hyperparathyroidism?
Multiple endocrine neoplasia syndromes (MEN-1, MEN-2A, MEN-4)
Hyperparathyroidism-jaw tumour syndrome (HPT-JT)
Why would a renal scan be done in primary hyperparathyroidism?
To look for nephrocalcinosis and nephrolithiasis
Why would a DEXA scan be done in primary hyperparathyroidism?
To look for osteoporosis
What is the first bony site to be affected in primary hyperparathyroidism?
Distal third of the forearm as it’s enriched in cortical bone + PTH preferentially affects cortical bone.
Which bone condition is causes by primary hyperparathyroidism and is typically seen on imaging?
Osteitis Fibrosa Cystica
What are the symptoms of Osteitis Fibrosa Cystica?
Bone pain
Pathological fractures
Proximal muscle weakness with hyperreflexia
What is the first line treatment for primary hyperparathyroidism?
Surgery if <50 + there are secondary complications (Osteoporosis, renal involvement) + Calcium >3
Which medication can be used for primary hyperparathyroidism?
Cinacalcet
What is benign familial hypocalciuric hypercalcaemia (FHH)?
Benign disease causing high calcium, hypocalciuria and high PTH.
What causes benign familial hypocalciuric hypercalcaemia?
Loss of function mutation in the calcium sending receptor gene (CASR).
Autosomal dominant.
What percentage of patients with cancer will experience high calcium?
20-30%
Why does high calcium occur in malignancy?
Multifactorial;
PTHrP secretion
Local osteolytic hypercalcaemia
Bony mets
Ectopic PTH secretion
What is the first treatment for hypercalcaemia?
Hydration
Aim 200ml per hour
After hydration, what is the next treatment for hypercalcaemia?
Biphosphonates;
-Pamidronate (inhibits osteoblasts) or Zolendronic acid
Peaks in 48-72 hours
Which medication would be used in resistant hypercalcaemia?
Calcitonin
What is the main cause of hypoparathyroidism?
Post thyroid or parathyroid surgery
Rare.
What other causes (not surgery) of hypoparathyroidism are there?
Autoimmune/autoantibody destruction of PT glands (metastasis)
Genetic mutations;
- CATCH-22 syndrome
- HypoPT-deafness-renal dysplasia syndrome
- Mutation in autoimmune regulator (AIRE) gene
Low magnesium
What happens to calcium and PTH in hypoparathyroidism?
Calcium low
PTH low/normal
What is the treatment for hypoparathyroidism?
Calcium
Vitamin D
Magnesium if low
Treatment aims to abolish symptoms, not to normalise calcium.
What is osteomalacia?
Metabolic bone disease characterised by incomplete mineralisation of the underlying mature organic bone matrix (osteoid) following growth plate closure in adults.
What is the main cause of osteomalacia?
Vitamin D deficiency
What are the symptoms of osteomalacia?
Diffuse bony pain
Proximal muscle weakness
Spinal tenderness to percussion
Pseudofractures
Skeletal deformities
What is rickets?
Metabolic bone disease characterised by defective mineralisation of the epiphyseal growth plate cartilage in children, resulting in skeletal deformities and growth retardation.
Can also lead to bowing of bones during growth.
What is the normal Vitamin D level?
> 50nmol/L
How much vitamin D to adults need daily?
400-600 units
What happens to calcium, phosphate and PTH in tertiary hyperparathyroidism?
Calcium high
Phosphate high
PTH very high
Vitamin D low
