Hyper/hypocalcaemia Flashcards
What are 13 causes of hypercalcaemia? (first 5 are key)
- Primary hyperparathyroidism
- Tertiary hyperparathyroidism
- Malignancy
- Osteolytic bone lesions
- Humoural hypecalcaemia (tumour derived PTHrP)
- Granulomatous disease (sarcoid, TB)
- Vitamin D
- Vitamin A
- Lithium
- Thiazides
- Thyrotoxicosis
- Milk-Alkali syndrome
- Familial hypocalcuric hypercalcaemia
What are 5 investigations that should be performed in the hypercalcaemic patient?
- ECG
- LFTs
- U+Es
- Bone profile (calcium, phosphate, albumin, total protein, ALP)
- PTH (parathyroid hormone) measurement
What are 5 things that form part of a bone profile?
- Calcium Calcium
- Phosphate
- Albumin
- Total protein
- ALP
What are 5 additional investigations to perform in suspected myeloma?
- Urinary Bence-Jones proteins
- Plasma electrophoresis
- FBC
- Chest x-ray
- Bone scan/PET scan
What is an important additional investigation to perform in suspected familial hypocalciuric hypercalcaemia?
24-hour urinary calcium
What further imaging would you perform in hypercalcaemia if you suspect primary hyperparathyroidism as the cause?
USS neck
What are 3 aspects of the immediate management of acute hypercalcaemia?
- Aggressive IV fluids - normal saline, 3-4L/day
- Bisphosphonates
- Management to prevent recurrent depending on cause, e.g. chemo, resection, radiotherapy, steroids, calcitonin, furosemide
Why are IV fluids given in hypercalcaemia?
corrects dehydration, protects the kidneys and increases calcium excretion
What IV fluid therapy is given in hypercalcaemia?
3-4L per day of normal saline
What is the mechanism of action of bisphosphonates to treat hypercalcaemia?
inhibit osteoclast activity, reducing calcium release from bones
How long do bisphosphonates typically take to work to lower calcium and when is the maximal effect?
- take 2-3 days to work
- maximal effect being seen at 7 days
What is an alternative drug to bisphosphonates which may be used instead of them and why?
calcitonin - quicker effect than bisphosphonates
What is the management when sarcoidosis is the cause of hypercalcaemia?
steroids
When are loop diuretics such as furosemide used in hypercalcaemia?
patients who cannot tolerate aggressive fluid rehydration
Why should loop diuretics be used with caution in hypercalcaemia?
may worsen electrolyte derangement and volume depletion
What is the commonest cause of primary hyperparathyroidism in non-hospitalised patients?
primary hyperparathyroidism
What is the commonest cause of hypercalcaemia in hospitalised patients?
malignancy
What are 3 examples of processes in malignancy that can cause hypercalcaemia?
- Bone metastases
- Myeloma
- PTHrP from squamous cell lung cancer
What are the 4 key features of hypercalcaemia?
- bone pain
- urinary tract stones
- abdominal pain
- psychiatric problems e.g. confusion
bones, stones, groans and moans
What is the key ECG features of hypercalcaemia?
shortened QT interval
What is the effect of hypercalcaemia on blood pressure?
causes hypertension
What is the definition of hypocalcaemia?
state of electrolyte imbalance in which the circulating serum calcium level is <2.1 mmol/L
What are 6 causes of hypocalcaemia?
- Vitamin D deficiency
- Hypoparathyroidism
- Hyperphosphataemia
- Acute pancreatitis
- Hypomagnesaemia
- Acute alkalosis
What are 3 causes of vitamin D deficiency?
- Malnutrition (i.e. osteomalacia)
- Malabsorption (e.g. gastrectomy, short bowel syndrome, Coeliac disease, chronic pancreatitis)
- CKD
What are 3 causes of hypoparathyroidism?
- Post-parathyroidectomy
- Inherited
- Pseudohypoparathyroidism
What are 3 causes of hyperphosphataemia (that can cause hypocalcaemia)?
- Tumour lysis syndrome
- Rhabdomyolysis
- Phosphate administration
What is the mnemonic to remember the clinical features of hypocalcaemia?
SPASMODIC
- S: spasm (Trousseau’s sign)
- P: perioral paraesthesia
- A: anxiety/irritability
- S: seizures
- M: muscle tone increase (colic, dysphagia)
- O: orientation impairment (i.e. confusion)
- D: dermatitis
- I: impetigo herpetiformis
- C: Chvostek’s sign
What is the Trousseau’s sign?
inflate BP cuff, occlude arterial flow to hand for 3-5 min
carpopedal spasm: flexion at wrists, MCP joints, extension of IP joints, adduction of thumbs/fingers
What is Chvostek’s sign?
contraction of ipsilateral facial muscles elicited by tapping facial nerve anterior to ear
positive response = twitching of lip to spasm all of facial muscles
What are 7 investigations to perform in hypocalcaemia?
- ECG - arrhythmia
- Bone profile (calcium, phosphate, albumin, total protein, ALP)
- PTH
- Magnesium
- Vitamin D
- Amylase (if suspected pancreatitis)
- X-rays (if suspected osteomalacia)
What are the 2 key signs (not that frequently used) of hypocalcaemia?
- Trousseau’s sign
- Chvostek’s sign
What is the key ECG sign of hypocalcaemia?
prolonged QT interval
What are 2 signs of chronic hypocalcaemia?
- Depression
- Cataracts
What can give falsely low calcium levels?
contamination of blood samples with EDTA
What is the acute management of severe hypocalcaemia?
IV replacement - preferred method is IV calcium gluconate, 10ml of 10% solution over 10 minutes
What monitoring is recommended in hypocalcaemia?
ECG - due to prolonged QT interval
What is the management of mild hypocalcaemia?
oral calcium supplementation
What constitutes severe hypocalcaemia (needing IV calcium gluconate)?
spasms or ECG changes
What are 5 aspects of long-term management of hypocalcaemia?
- Treat cause
- Encourage good dietary calcim and vitamin D intake
- Calcium and vitamin D supplementation
- Alphacalciferol if CKD
- Magnesium supplements if concurrent hypomagnesaemia
