Hypo & Hypercalcaemia Flashcards
What range of calcium suggests hypercalcaemia?
Serum > 2.6 mmol/l
Commonest causes of hypercalcaemia.
Primary hyperparathyroidism
Malignancy
How can one distinguish between primary hyperparathyroidism and malignancy?
Primary hyperparathyroidism is associated with normal or high PTH
Malignancy will be associated with a low PTH
What is hypercalcaemia with suppressed PTH until proven otherwise?
Malignancy
Which malignancy is usually the cause of hypercalcaemia?
Squamous cell epithelial tumours of the lung due to the secretion of PTH-rP
However rarely lymphoma can also cause hypercalcaemia.
In what stages of malignancy does hypercalcaemia usually present?
In large or advanced tumours.
Bony metastases are not always present.
When other than in malignancy might hypercalcaemia with a low PTH present?
Benign granulomatous disease such as TB or sarcoidosis
What is hypercalcaemia with non-suppressed PTH until proven otherwise?
Primary hyperparathyroidism
What is primary hyperPTH usually caused by?
A single parathyroid adenoma
What does parathyroid hyperplasia in more than one gland suggest?
Genetic cause such as multiple endocrine neoplasia.
It can also be present in CKD due to secondary hyperPTH, however calcium levels will be low in this case.
What might a very high serum calcium > 3.5 mmol/l with a large parathyroid tumour indicate?
Parathyroid cancer.
This is very rare
What might parathyroid cancer rarely occur in association with?
Jaw tumours
This is called Hyperparathyroidism-jaw tumour syndrome.
Most common clinical presentation of primary hyperPTH.
Often asymptomatic and discovered incidentally during routine blood tests.
Give examples of non-specific symptoms of hypercalcaemia.
Tiredness
Generalised aches and pains.
Specific symptoms of hypercalcaemia.
Polyuria
Polydipsia
Nephrogenic DI
Other symptoms of hypercalcaemia.
Abdominal pain
Constipation
Psychiatric symptoms
Kidney stones
Remember Bones, Groans, Stones and Moans.
What can severe metabolic parathyroid bone disease cause?
Classical cystic appearance on X-ray.
What is the classical cystic appearance on X-ray associated with severe metabolic parathyroid bone disease?
Brown Tumours
Osteitis fibrosa cystica
Subperiosteal erosions
Cysts
Acro-osteolysis
Pepper-pot skull
Investigations of primary hyperPTH.
Bloods
Imaging
Blood findings in primary hyperPTH.
High or non-suppressed PTH
Hypercalcaemia
Low phosphate
High ALP
Why might ALP be high in primary hyperPTH?
Co-exisiting vitamin D deficiency can lead to increased bone turnover.
Imaging findings of primary hyperPTH.
X-ray showing reduced bone density, sub-periosteal erosion of the phalanges.
Renal ultrasound can show nephrocalcinosis.
You might get chondrocalcinosis in joints that looks like pseudogout.
What is nephrocalcinosis?
Calcium depositions in the kidneys.
Associated with nephrolithiasis.
What is familial hypocalciuric hypercalcaemia (FHH)?
A genetic defect in the calcium sensing receptor.
FHH and primary hyperPTH can show similar levels of PTH and calcium.
How can the two be distinguished?
FHH shows a low urine calcium/creatinine ratio
Usually a family history of mild hypercalcaemia.
Why is it important to exclude FHH?
So you don’t send the patient to have an unnecessary neck exploration.
If it is deemed necessary to do parathyroid surgery, what is important to do?
Localise the adenoma.
How is a parathyroid adenoma localised?
Experienced hands might be able to do it by parathyroid ultrasound. It is however very operator-dependent.
SETAMIBI isotope scanning alongside of ultrasound is commonly performed.
SPECT CT / MRI and 4-D CT can also be used.
When should surgery be performed in hyperparathyroidism?
Surgery should be considered if serum calcium > 2.85 mmol/l or if symptoms are severe.
Young patients and severe acute hypercalcaemia.
What treatment can be considered if the patient is ineligible for surgery?
Drugs such as calcimimetics which are effective at lowering calcium in primary hyperPTH.
What are the dangers of acute severe hypercalcaemia?
Medical emergency characterised by profound dehydration and renal impairment.
Treatment of acute severe hypercalcaemia.
First off stabilise hydration by giving IV saline.
Give IV bisphosponates such as zoledronic acid to counter the calcium levels.
When everything is stabilised you can consider glucocorticoids, calcitonin, calcimimetics or parathyroidectomy.
When might glucocorticoids be given in hypercalcaemia?
In lymphoma or granulomatous disease.
When does symptomatics hypocalcaemia occur?
When serum calcium is < 1.9 mmol/l or at higher values if there is a rapid drop in calcium.
Most common cause of hypocalcaemia.
Post-surgical hypoPTH following thyroidectomy.
Prognosis of post-surgical hypoparathyroidism.
Often temporary, usually there is recovery of the parathyroid.
However it can be permanent if there is damage or inadvertent removal of the parathyroid.
This means that long-term follow-up is needed to assess if there is recovery of the parathyroid.
What else can cause hypocalcaemia?
Vitamin D deficiency
Hypomagnesaemia
In which populations should vitamin D deficiency be considered?
High risk groups such neonates and elderly.
Northern africans
Populations which commonly covers themselves in clothes entirely.
Presentation of vitamin D deficiency in neonates.
Seizures
Tetany
This is due to hypocalcaemia.
How can you distinguish via bloods between hypoparathyroidism and vitamin D defiency?
Phosphate will be low in vitamin D deficiency due to elevated PTH levels.
In hypoparathyroidism phosphate will be high due to low PTH levels.
What does hypomagnesaemia cause?
Functional hypoparathyroidism with normal or low PTH levels due to inhibition of the parathyroid.
Common causes of hypomagnesaemia.
GI loss
Alcohol
Drugs such as PPis.
Clinical features of acute severe hypocalcaemia.
Laryngospasm
Prolonged QT interval
Seizures
How does hypocalcaemia usually present?
Muscle cramps
Carbo-pedal spasms
Peri-oral and peripheral paraesthesia
Neuro-psychiatric symptoms
Tests to assess hypocalcaemia.
Positive Chvosteks sign
Positive Trousseaus sign
Explain a +ve Cvhosteks sign.
Facial spasm when the cheek is gently tapped with a finger.
Explain a +ve Trousseaus sign.
Carpo-pedal spasms induced by the inflation of a sphygmomanometer (blood-pressure cuff)
Treatment of acute hypocalcaemia.
IV calcium
Treatment of severe vitamin D deficiency.
Loading dose of cholecalciferol
20000 IU per week given for 7 weeks.
Then a maintenance dose of 1-2000 IU per week.
Treatment of hypoparathyroidism.
1-alfacalcidol or calcitriol
Sandocal or Adcal D3 (oral calcium supplements) are given in combination with 1-alfacalcidol.
Dose regiment of 1-alfacalcidol in hypoparathyroidism.
Starting dose of 0.25 microgram/day
Aim of treatment of hypocalcaemia.
Symptom relief
Keep calcium levels at lower end of reference range.
Why is the treatment aim to keep the calcium levels at the lower reference range?
To reduce the risk of nephrocalcinosis.
Treatment of acute magnesium deficiency.
Any drugs that caused it should be stopped.
IV magnesium replacement started.
Usually given as MgS04 24 mmol/24 hours.
Treatment of magnesium deficiency if there is chronic GI loss or alcohol ingestion?
Appropriate specialist input.
What is pseudo-hypoparathyroidism?
A rare condition caused by a mutation in a G protein coupled to the PTH receptor leading to PTH resistance.
Parathyroid hallmarks of pseudo-hypoparathyroidism.
Hypocalcaemia
High phosphate
High PTH
Normal vitamin D
How can you distinguish between pseudo-hypoparathyroidism and hypoparathyroidism?
Low levels of calcium and high levels of phosphate usually suggest hypoparathyroidism. This is because of low levels of PTH.
Howevery the high levels of PTH alongside of hypocalcaemia and hyperphospataemia suggests PTH resistance rather than a deficiency.
Clinical presentation of pseudo-hypoparathyroidism.
Syndromic appearance with short stature, round face and short 4th and 5th metacarpals.
Pathway to determine cause of hypercalcaemia.
Treatment of acute hypercalcaemia.
If Ca2+ is >3.5 mmol/L and symptomatic:
1 - Correct dehydration with IV 0.9% saline
2 - Bisphosphonates to prevent bone resorption by inhibiting osteoclastic activity. E.g. Pamidronate, Zoledronic acid.
3 - Chemotherapy can help in malignancy, steroids are used in sarcoidosis.
Causes of hypocalcaemia with increased phosphate.
CKD
Hypoparathyroidism
Pseudohypoparathyroidism
Acute rhabdomyolysis
Hypomagnesaemia
Causes of hypocalcaemia with normal or decreased phosphate.
Vit D def
Osteomalacia
Acute pancreatitis
Over hydration
Respiratory alkalosis
Features of hypocalcaemia.
SPASMODIC
Spasms (Trousseau’s sign)
Perioral paraesthesiae
Anxious, irritable, irrational
Seizures
Muscle tone increased
Orientation impaired and confusion
Dermatitis
Impetigo herpetiformis
Chvostek’s sign, choreoathetosis, cataract, cardiomyopathy.
Treatment of hypocalcaemia.
Calcium 5 mmol/6h PO if mild
In CKD may require alfacalcidol PO
Severe => 10 ml of 10% calcium gluconate IV over 30 min
