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
