calcium metabolism and disorders Flashcards
what are the classic symptoms of hypercalcemia?
- bones (bony pain)
- stones (kidney stones)
- abdominal groans (abdominal pain)
- psychic moans
what are some acute symptoms of hypercalcemia?
- thirst
- dehydration
- confusion
- polyuria
classic ones:
- bones (bony pain)
- stones (kidney stones)
- abdominal groans (abdominal pain)
- psychic moans
what are some chronic symptoms of hypercalcemia?
- myopathy
- fractures
- osteopenia
- depression
- hypertension
- pancreatitis
- DU
- renal calculi
Classic:
- bones (bony pain)
- stones (kidney stones)
- abdominal groans (abdominal pain)
- psychic moans
what are most common causes of hypercalcemia?
- primary hyperparathyroidism
- malignancy
what are some rarer causes of hypercalcaemia?
- drugs (vit D, thiazides)
- Granulomatous diseases (sarcoidosis, TB)
- familial hypocalciuric hypercalcaemia
- high turnover (bedridden, thyrotoxic, Pagets)
- tertiary hyperparathyroidism
what is the treatment for acute hypercalcaemia?
- fluids to rehydrate
- consider loop diuretics once rehydrated (avoid thiazides)
- biphosphonates
- steroids sometimes used
if malignant chemo
what is primary hyperparathyroidism?
- primary overactivity of the parathyroid gland i.e. adenoma
- it means there is a problem with the parathyroid gland itself
what occurs to the calcium and PTH levels in primary hyperparathyroidism?
both calcium and PTH are raised
what is secondary hyperparathyroidism?
-this is when the thyroid produces too much PTH in response to hypocalcaemia
what are the calcium levels and PTH levels like in secondary hyperparathyroidism?
- calcium levels are low
- PTH levels raised
what is tertiary hyperparathyroidism?
- the parathyroid becomes autonomous after many years of activity e.g. renal failure
- it just stops responding to the negative feedback
what are the levels of calcium and PTH like in hyperparathyroidism?
-both calcium and PTH are raised
what genetic syndrome will always develop a parathyroid adenoma with hypercalcaemia at a very young age?
-MEN1 and MEN2
what is another genetic condition apart from MEN1/2 that causes an adenoma causing primary hyperparathyroidism?
-familial isolated hyperparathyroidism
what are some symptoms of hypocalcaemia?
- paraesthesia (tingling) around fingers, toes, lips
- muscle cramps
- muscle weakness
- fatigue
- bronchospasm or laryngospasm
- fits
- Chovsteks sign (firing of fascial nerve when you tap over it)
- Trousseau sign (carpopedal spasm)
- ECG has prolonged QT
what is the treatment for acute hypocalcaemia?
this is an emergency!!
-IV calcium gluconate 10ml, 10% over 10 mins (in 50ml for saline or dextrose)
-if sufficiently low give by infusion (10ml 10% in 100ml infusate, at 50ml/h)
what are some causes of hypoparathyroidism?
- congenital absence (DiGeorge syndrome)
- destruction (surgery, radiotherapy, malignancy)
- autoimmune
- hypomagnesemia
- idiopathic
why can hypomagnaesemia cause hypoparathyroism?
- calcium release from cells is dependant on magnesium
- -in magnesium deficiency intracellular calcium is high
- high calcium inhibits PTH release
- skeletal and muscle receptors then become less sensitive to PTH
what causes hypomagnaesamia?
- alcohol
- drugs (thiazides, PPI)
- GI illness
- pancreatitis
- malabsorption
what is pseudohypoparathyroidism?
-a genetic disorder in which the body fails to respond to parathyroid hormone
what gene is affected in pseudohypoparathyroidism?
Dysfunction of G protein (Gs alpha subunit)- gene
GNAS 1
what are the calcium and PTH levels like in pseudohypoparathyroidism?
-low calcium but PTH elevated due to PTH resistance
what are some complications of pseudohypoparathyroidism?
- bone abnormalities
- obesity
- subcutaneous calcification
- learning disability
- brachdactyly (4th metacarpal)
what causes rickets and osteomalacia?
-vitamin D deficiency
what can cause a vitamin D deficiency?
- Malabsorption (gastric surgery, coeliac disease, liver disease, pancreatic failure)
- chronic renal failure
- lack of sunlight
- drugs
what causes osteomalacia?
-low calcium
what does osteomalacia cause?
- muscle wasting
- dental defects
- bone tenderness, fracture, rib deformity, limb deformity
what can chronic renal failure cause?
- vitamin D deficiency
- secondary hyperparathyroidism
what is treatment for a chronic vitamin D deficiency?
-either vitamin D (initially vitamin D3 tablets then Calcitriol or alfacalcidol)
or a combination of calcium and vitamin D (e.g. Adcal D3)
