clinical calcium homeostasis Flashcards
dietary sources of calcium
milk, cheese other diary green leafy veg soya beans tofu nuts bread fish where u eat bones
functions of calcium
bone formation
cell division and growth
muscle contraction
neurotransmitter relase
normal range calcium (adjusted)
2.2-2.6mmol/l
how do we calculate free calcium
inc albumin decreases free calcium
dec albumin increases free calcium
adjust Ca2+ by 0.1mmol/l for each 5g/l in albumin from 40g/l
sources of vitamin d
sun oily fish eggs fortified fat spreads fortified breakfast cereals
how are changes in ECF calcium levels transmitted to parathyriod cells
via calcium-sensing receptor
hypocalcaemia
serum calcium <2.20
hypocalcaemia - acute features
tetany parasthesia muscle twitching Trousseau's sign Chovstek's sign seizures laryngospasm bronchospasm prolonged QT interval hypotension heart failure arrythmia
hypocalcaemia - chronic features
extrapyramidal signs parkinsonism dementia subcapsular cataracts abnormal dentition dry skin
when do symptoms of hypocalcaemia typically develop
serum calcium below 1.9
Trousseau’s sign
hand curls up when pump up BP cuff
Chovstek’s sign
twitching - spasm of facial muscles when tap facial nerve anterior to earlobe
causes of hypocalcaemia
disruption PT gland VitD def Mg2+ def cytotoxic drug induced hypocalcaemia pancreatitis
hypocalcaemia investigations
check PTH
if low (not right) check magnesium
if high (right) check urea and creatinine
treatment hypocalcaemia: mild (>1.9)
oral calcium tablets
VitD if deficient
if low Mg2+, stop any precipitating drug and replace Mg2+
treatment hypocalcaemia: severe <1.9
medical emergency
IV calcium gluconae
initial bolus (10-20ml 10% calcium gluconate in 50-00ml of 5% dextrose IV over 10min with ECG monitoring)
calcium gluconate infusion
treat underlying cause
hypercalcaemia <3
often asymptomatic
treatment hypercalcaemia: 3-3.5
may be well tolerated if risen slowly
prompt treatment usually indicated
treatment hypercalcaemia: >3.5
requires urgent correction due to risk of dysrythmia and coma
causes of hypercalcaemia
primary hyperparathyrpidism
malignancy
clinical features of hypercalcaemia
bones, stones, groans and pelvic moans
polyruia, polydipsia nephrolithiasis anorexia nausea constipation muscle weakness bone pain dec concentration short QT interval
hypercalcaemia managemnet
rehydration
IV bisphosphonates
