Y5 - Hypercalcaemia of malignancy Flashcards Preview

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Flashcards in Y5 - Hypercalcaemia of malignancy Deck (28):
1

what does hypercalcaemai of malignancy result from

1 secretion of parathyroid hormone related peptide by primary tumours
2 local release of factors which increase osteoclast proliferation/activity
3 production of calcitriol (1,25-dihydroxvitamin D) by lyphomas
4 production of PTH by primary tumours (rare)

2

what is most commonly used to treat hypercalcaemia of malignancy

IV biphosphonates

3

how common is malignancy associated with hypercalcaemia of malignancy

25% o cases

4

what four factors could lead to hypercalcaemia of malignancy

1 secretion of parathyroid hormone related peptide
2 release of factors including PTHrP to promote osteoclasts
3 calcitriol by lymphoma cells
4 ectopic hyperparathyroidism (PTH release from a primary tumour)

5

what is humoral hypercalcaemia (release of PTHrP) of malignancy associated with

renal cancer
ovarian cancer
breast cancer
endometrial cancer
squamous cell cancer

6

what is local osteolytic hypercalcaemia (promotion of osteoclasts) associated with

breast cancer
multiple myeloma

7

what is assoicated with calcitriol mediated hypercalcaemia

lymphoma
sarcoid
TB

8

how does humoral hypercalcaemia work

tumour secretion of PTHrP causes:
1 osteoclast bone resorption
2 suppression of osteoblast bone formation
causing an increase in calcium
also PTHrP reduces calcium clearance in the kidneys

9

what happens to phosphate levels in humoral hypercalcaemia

hyperphospaturia and hypophosphataemia

10

how does local osteolytic hypercalcaemia occur

cytokines (IL1/6), chemokines, and PTHrP cause increased osteoclast activity

11

how does calcitriol mediated hypercalcamia work

overexpression of 1-a hydroxylase (enzyme which converts 25-hydroxyvitamin D to calcitriol) by malignant cells which leads to autonomous production of bioactive vitamin D
vitamin D increases intestinal calcium absorption

12

epi

most common is humoral hypercalcaemia of malignancy

13

signs and symptoms

Hx of malignancy
often normal physical exam
sometimes signs of dehydration, fatigue, constipation, loss of appetite, polyuria, polydipsia

14

investigations

calcium studies
-raised total serum
-raised serum ionised
serum albumin levels
metabolic panel
-raised urea and creatinine in AKI
-raised bicarbonate in malignancy
raised PTH or PTHrP

15

what would be found on ECG

shortened QT interval

16

mneumonic for symptoms of hypercalcaemia

"painful bones, renal stones, abdominal groans, and psychic moans,"

17

approach to management

long-term maintenance of normocalcaemia requires eradication of malignancy

18

management

IV saline
IV biphosphonate
calcitonin

treat underlying malignancy

19

what medications should be avoided which can worsen hypercalcaemia

thiazide diuretics
calcitriol
lithium

20

what is the first line therapy for hypercalcaemia and why

IV saline to reverse dehydration secondary to hypercalcaemia induced nephrogenic diabetes
PLUS oral rehydration

21

what is the best treatment for reducing calcium levels

IV biphosphonates
-block osteoclastic bone resorption

22

what biphosphonates are used

pamidronate disodium
zoledronic acid

23

why might calcitonin be used to treat hypercalcaemia

interferes with osteoclast bone resorption

24

first line treatment for mild hypercalcaemia or asymptomatic

treat underlying malignancy

25

which works faster, biphosphonates or calcitonin

calcitonin (given while waiting for effects of biphosphonates)

26

management for severe hypercalcaemia with advanced kidney disease

renal dialysis

27

complications

biphosphonate induced flu like syndrome (aches, fever, chills)

28

prognosis

IV saline, biphosphonates can temporarily induce normocalcaemia
however eradication of malignancy is required for long term effects