Parathyroid / Hypercalcaemia Flashcards

1
Q

hyperparathyroidism

A

high level of PTH (parathyroid hormone)

three types
primary
secondary
tertiary

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2
Q

physiology of the PTH

A

four glands in four corners of the parathyroid gland

chief cells produce PTH in response to low blood ca2+ concentration.

PTH raises blood ca2+ by the following mechanisms:

1) increase the absorption of ca2+ from intestine
2) increase reabsorption in the kidneys (less is secreted in the urine)
3) increase osteoclast activity in the bones (more is broken down so ca2+ is released into the blood)

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3
Q

vitamin D and PTH

A

body creates in response to sunlight. can be obtained through food / supplementation

PTH acts on vitamin D to convert it into its active forms

Vitamin D works by acting on all processes to increase absorption of ca2+from kidneys, intestines and bones = raise blood ca2+ level

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4
Q

primary hyperparathyroidism

A

uncontrolled PTH being produced by a tumor of the parathyroid gland.
increased absorption of ca2+ leading to hypercalcaemia.

(too much PTH so it’s causing too much of GI absorption / renal reabsorption and bone break down which leads to excessive ca2+ in the blood)

tx: surgical removal of tumor

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5
Q

secondary hyperparathyroidism

A

causes:
insufficient vitamin D
chronic renal failure

= reduced absorption, resorption and osteoclast of calcium which leads to hypocalcaemia.

as a result, the PTH react to the low level of ca2+ by excreting more PTH to try and compensate.

overtime the total number of cells in the parathyroid gland increase (hyperplasia)

serum ca2+ low/normal
PTH hormone high

treat: correct underlying cause (vitamin D, renal transplant)

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6
Q

tertiary hyperparathyroidism

A

this occurs when 2’ hyperparathyroidism continues for a long time which leads to hyperplasia of the glands. the baseline amount of PTH increases dramatically.

when you treat the 2’ hyperparathyroidism, the levels remain HIGH

serum ca2+ high
PTH high

treatment: surgical removal of bulky glands leaving just enough tissue to get PTH

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7
Q

summary of hyperparathyroidism

A

1’ tumor causing high PTH which leads to high Ca2= surgical tx

2’ deficiency in vit d/ chronic kidney disease. high PTH, serum ca2+ low or normal. tx vit D deficiency or renal transplant

3’ hyperplasia of parathyroid glands after secondary. high PTH, high ca2+. tx: surgical

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8
Q

causes of hyperpcalcaemia

A

CHAMPS

calcium supplementation
cancers myeloma/bone mets
hyperparathyroidism (1')
Addison's/acromealy
ilk alkali syndrome
pagets 
sarcoidosis
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9
Q

corrected calcium equation

A

corrected calcium = serum calcium + 0.02 (40-albumin)

give IV saline and re-check ca2+.

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10
Q

management of hypercalcaemia

A

> 3 mmol/l

adequate rehydration 3-4L saline/day

IV bisphosphonate (pamidronate)

identify cause.

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