hyperparathyroidism Flashcards
what is it
hyperparathyroidism results when there is excessive secretion of parathyroid hormone (PTH)
what are the different types of HPPT
primary:
one parathyroid gland (or more) produces excess PTH, this may be asymptomatic or can lead to hypercalcaemia
secondary:
there is increase secretion of PTH in response to low calcium because of kidney, liver or bowel disease
tertiary:
there is autonomous secretion of PTH, usually because of chronic kidney disease
what are the causes of primary HPPT
parathyroid gland adenoma
hyperplasia of all four glands
two adenomas
parathyroid carcinoma
what are some signs of hypercalcaemia
Moans Stones Groans and psychiatriac Moans
-painful bones
-renal stones
-abdominal upset > nausea, vomiting, constipation and indigestion
-psychiatric moans > lethargy, fatigue, memory loss, psychosis and depression
causes of secondary HPPT
> vitamin D deficiency and chronic renal failure resulting in hypocalcaemia
also:
loss of extracellular calcium > pancreatitis , rhabdomyolysis , hungry bone syndrome
calcium malabsorption
abnormal parathyroid hormone activity > chronic kidney disease, pseudohypoparathyroidism
inadequate calcium intake
what are the biochemical findings in secondary HPPT
what are the causes of tertiary HPPT
usually occurs after prolonged secondary HPPT > the glands become autonomous, producing excessive PTH even after the cause of hypocalcaemia has been corrected
long standing kidney disease is the most common cause
management of tertiary HPPT
cinacalcet
total or subtotal parathyroidectomy
what cells in the parathyroid glands produce PTH and when
chief cells produce PTH in response to hypocalcaemia
how does PTH raise blood calcium levels
increasing osteoclast activity in bones (reabsorbing calcium from bones)
increasing calcium absorption from the gut
increasing calcium absorption from kidneys
increasing vitamin D activity > vit. D increases calcium absorption from the intestines
tx for primary HPPT
surgically removing the tumour
pathophys of secondary HPPT
insufficient Vit D or chronic renal failure leads to low absorption of calcium > hypocalcaemia
the parathyroid glands reacts to low serum calcium by excreting more PTH > overtime the cells in the glans increase in numbers due to the response > hyperplasia
the gland becomes bulky
*the serum calcium level will be low or normal but the PTH will be high
tx of secondary HPPT
treat underlying cause
ie renal transplant
pathophys of tertiary HPPT
when secondary HPPT continues for a long time, and then the underlying cause is treated, the hyperplasia is still there and so PTH levels remain inappropriately high > hypercalcaemia
tx for tertiary HPPT
surgical resection of the parathyroid tissue to return PTH to an appropriate level
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