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Yr3 Medicine- Endocrinology > Calcium > Flashcards

Calcium Flashcards

1
Q

Above what value is classed as hypercalcaemia?

A

>2.6mmol/L

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2
Q

State the two commonest causes of hypercalcaemia

A
  • Primary hyperparathyroidism
  • Malignancy
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3
Q

State some potential causes of hypercalcaemia

A
  • Primary hyperparathyroidism
  • Hypercalcaemia of malignancy
  • Pagets disease
  • Drugs e.g. thiazides & lithium
  • Excess calcium intake
  • Familial hypocalciuric hypercalcaemia (FHH)
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4
Q

We have said that the two most common causes of hypercalcaemia are primary hyperparathyroidism and malignancy; discuss how you could distinguish between the two

A
  • Primary hyperparathryroidism: normal or high PTH
  • Malignancy: low PTH
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5
Q

Hypercalcaemia with low PTH is ___ until proven otherwise

A

Malignancy

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6
Q

Explain why hypercalcaemia of malignancy occurs

A

Malignant tumours, oftten squamous cell epihtelial tumours, secrete PTH-related peptide.

PTH-rp acts like PTH; the only thing it doesn’t do (that PTH does) is increase renal C-1 hydroxylase activity and hence it deosn’t increase calcitriol like PTH

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7
Q

Although hypercalcaemia with low PTH is malignancy until proven otherwise, state some other potential causes of hypercalcaemia with low PTH

A

Granulomatous disease e.g. TB or sarcoidosis

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8
Q

Hypercalcaemia with normal or high PTH is usually caused by primary hyperparathyroidism. Hyperparathyroidism is commonly due to a single parathyroid adenoma. If parathyroid hyperplasia is found in >1 gland what might this suggest?

A

A genetic cause e.g. MEN syndrome

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9
Q

Very high serum calcium >3.5mmol/L with a large parathyroid tumour may indicate parathyroid cancer but this is exceptionally rare; true or false?

A

True

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10
Q

Explain what primary hyperparathyroidism is and how it leads to hypercalcaemia

A
  • Tumour of parathyroid gland
  • Produces excess PTH
  • PTH:
    • Increases osteoclast activity in bones
    • Increeases vit D activation
    • Vit D increases calcium absorption from gut
    • Decreases renal excretion of calcium
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11
Q

State the symptoms of hypercalcaemia

*THINK stones, moans, bones and groans

A
  • Renal stones
  • Painful bones
  • Abdominal groans: constipation, nausea & vomiting
  • Psychiatric moans: fatigue, depression, psychosis
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12
Q

What investigations would we do for a pt with hypercalcaemia?

A
  • ​PTH: asses if primary hyperparathyroidism is the cause
  • Bone imaging: if pt presents with bone pain. Bone density may be reduced
  • Parathyroid ultrasound: localise adenoma
  • SETAMIBI isotope scanning often used alongside ultraound
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13
Q

Discuss the treatment of actue severe hypercalcaemia

A
  • IV fluids (+/- loop diuretics dependent on if can tolerate fluid/risk of fluid overload)
  • Then bisphosphonates
  • Can also calcitonin (quicker effect than bisphosphonates) or steroids in sarcoidosis
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14
Q

Discuss the management of hypercalcaemia due to hyperparathyroidism

A
  • Definitive management is parathyroidectomy
  • May consider conservative management with calcimimetics (e.g. cinacalcet)- if:
    • Calcium level is less than 0.25 mmol/L above the upper limit of normal
    • AND the patient is > 50 years
    • AND there is no evidence of end-organ damage
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15
Q

Acute severe hypercalcaemia is a medical emergency; describe how it may present

A
  • Dehydration
  • Renal impairment
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16
Q

Explain what secondary hyperparathyroidism is, include what causes it and why PTH is high

How do we treat secondary hyperparathyroidism?

A
  • Pathophysiology
    • Insufficient vit D or chronic renal failure leads to low absorption of Ca2+ from intestines kidneys and bones causing hypocalcaemia
    • Parathyroid glands react by increasing PTH secretion
    • Over time, hyperplasia of parathyroid gland occurs to meet the increased demand for PTH
    • Serum calcium will be low or normal but PTH will be high
  • Treat by correcting underlying cause: vit D deficiency or CKD
17
Q

Explain what tertiary hyperparathyroidism is

How do you treat it?

A
  • Happens when secondary hyperparathyroidism continues for long time leading to hyperplasia of glands. In tertiary hyperparathyroidism, unlike in secondary hyperparathyroidism, when you treat the underlying cause of the secondary hyperparathyroidism the level of parathyroid hormone remains elevated.
  • Must treat it surgically by removing part of the parathyroid tissue
18
Q

Symptomatic hypocalcaemia occurs when Ca2+ less than ___?

A

<1.9mmol/L or at higher values if rapid drop in Ca2+

19
Q

State some potential causes of hypocalcaemia- highlighting the most common

A
  • Post thyroidectomy (secondary hypoparathyroidism)
  • Vit D deficiency
  • Hypomagnesaemia (causes functional hypoparathyroidism with normal or low PTH levels. Causes of low magnesium= GI loss, alcohol, drugs e.g. PPIs)
  • CKD
  • Acute pancreatitis
  • Massive blood transfusion
  • Acute stages rhabdomyolysis
  • Primary hypoparathyroidism
  • Pseudohypoparathyroidism
20
Q

What are the symptoms & signs of hypocalcaemia?

A

Those in image and….

  • Peri-oral and peripheral parasthesia
  • Positive Chvostek’s sign (facial spasm when cheek is tapped with finger)
  • Trousseau’s sign (carpo-pedal spasm induced after inflation of sphygmomanomenter)
21
Q

What is Chvostek’s sign?

What is Trousseau’s sign?

A
22
Q

Acute hypocalcaemia is a medical emergency; describe how it may present

A
  • Laryngospasm
  • Prolonged QT interval
  • Seizures
23
Q

Discuss the treatment:

  • Acute hypocalcaemia
  • Hypocalcaemia caused by vit D deficiency
  • Hypocalcaemia caused by hypoparathyroidism
  • Hypocalcaemia caused by magnesium deficiency
A
  • Acute hypocalcaemia:
    • 10ml of 10% IV calcium gluconate over 10 mins (ECG MONITORING RECOMMENDED)
    • *NOTE: severe hypocalcaemia classified by tetany, spasm, prolonged QT or seizures
  • Hypocalcaemia caused by vit D deficiency
    • Loading dose cholecalciferol (vit D3)
  • Hypocalcaemia caused by hypoparathyroidism
    • Oralcalcium supplements e.g. Adcal D3 & sandocal
    • 1-alfacalcidol or calcitriol
  • Hypocalcaemia caused by magnesium deficiency
    • Intravenous magnesium
    • Stop precipitating drugs
24
Q

What is primary hypoparathyroidism?

A
  • Parathyroid gland failure leading to decreased PTH. Causes can be autoimmune or congenital e.g. Di Geroge syndrome
25
Q

What is pseudohypoparathyroidism, include:

  • What it is
  • Characteristic biochemistry
  • Appearance of individuals
A
  • Mutation in G protein coupled ot PTH receptor
  • Leads to PTH resistance
  • Charcterised by:
    • Hypocalcaemia
    • Hyperphosphataemia
    • High PTH
    • Normal vit D
  • Appearance: short stature, round face short 4th & 5th metacarpals
26
Q

How do you distinguish between hyperparathyroidism and familial hypocalciuric hypercalcaemia?

A
  • FHH is defect in calcium sensing receptor in PTH glands and kidneys; hence PTH gland secreted PTH and kidneys reabsorb lots of calcium leading to low calcium/creatinine ratio
  • Hyperparathryoidism does not show low calcium/creatinine ratio
27
Q

What ECG changes will you see in hypercalcaemia?

A

Shortened QT (<400-440ms)

28
Q

What ECG changes will you see in hypocalcaemia?

A

Lengthened QT (>400-440ms)

Yr3 Medicine- Endocrinology (9 decks)

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