Parathyroid Hormone and Hyperparathyroidism Flashcards
what nuclear medicine scan is used to image the parathyroid glands
sestamibi scan
what are the causes of primary hyperparathyroidism
80% due to solitary adenoma
20% due to hyperplasia of the glands
presentationof primary hyperparathyroidism
often asymptomatic with increased calcium on routine tests
signs related to increased calcium: stones, bones, groans and psychotic moans
bone resorption and PTH effects can cause pain, fractures and osteopenia/osteoperosis
increase in blood pressure
what is the association of primary hyperparathyroidism with MEN syndromes
95% of MEN 1 have parathyroid hyperplasia - most have increased calcium
80% of MEN 2a have also parathyroid hyperpalsia - but only 20% have increased calcium
what must be checked in everyone diagnosed with hypertension
calcium levels
management of primary hyperparathyroidism
surgery or nothing
diet and drugs have no proven effect
when is cinacalcet used in
in tertiary hyperparathyroidism and parathyroid carcinoma
cinacalcet
a calcimetic - increases the sensitivity of the parathyroid cells to calcium ion concentrations - resulting in a decrease in PTH secretion
what are the indications for a parathyroidectomy
high serum or urinary calcium (>2/85 mmol/L)
under age 50
eGFR < 60mL/min - decreased renal function
end organ damage
- bone disease
- osteoperosis
- gastric ulcers
- renal stones
Osteitis Fibosa Cystica
literally: ‘inflammation of bone with fibrosis and cysts’
chronic result: loss of bone mass, and weakening of the bones as their calcified support structures are replaced with fibrous tissue, and the formation of cyst like brown tumours
radiographs may be described as pepper pot skull
primary hyperparathyroidism biochemical analysis
PTH raised
calcium raised
secondary hyperparathyroidism
a physiological respones to decrease calcium levels
- high PTH, low Ca
what are some causes of secondary hyperparathyroidism
decreased vitamin D intake (malabsorption, dietary, sun etc) , chronic renal failure
tertiary hyperparathyroidism
parathyroid becomes autonomous after many years of secondary hyperparathyroidism as the glands have undergone hyperplastic or adenomatous change
this causes increased calcium secretion from increased secretion of PTH unlimited by feedback control
PTH very high, Ca raised
