Hypocalcaemia

Question 1

What is the normal serum calcium concentration?

Answer 1

2.2mmol/L - 2.6mmol/L

Question 2

What is hypocalcaemia?

Answer 2

It is defined as a serum calcium concentration less than 2.2mmol/L

Question 3

What are the two classifications of hypocalcaemia?

Answer 3

Mild Hypocalcaemia

Severe Hypocalcaemia

Question 4

What is mild hypocalcaemia?

Answer 4

It is defined as a serum calcium level > 1.9mmol/L, in which individuals are asymptomatic

Question 5

What is severe hypocalcaemia?

Answer 5

It is defined as a serum calcium level < 1.9mmol/L, in which patients are symptomatic

Question 6

What are the eight risk factors associated with hypocalcaemia?

Answer 6

Hypoparathyroidism

Pseudohypoparathyroidism

Parathyroid Surgery

Acute Pancreatitis

Chronic Kidney Disease

Rhabdomyolysis

Vitamin D Deficiency

Magnesium Deficiency

Question 7

What are the seven clincial features associated with hypocalcaemia?

Answer 7

Muscle Spasms

Muscle Cramping

Perioral Paraesthesia

Chvostek’s Sign

Trousseau’s Sign

Seizures

Hypertension

Question 8

How do we test for Chvostek’s sign?

Answer 8

It involves tapping the patient’s parotid, over the facial nerve

Question 9

What is a positive Chvostek’s sign?

Answer 9

It is indicated by facial muscle twitching

Question 10

How do we test for Trousseau’s sign?

Answer 10

It involves applying a blood pressure cuff on the patient’s arm and inflating it above their systolic level

Question 11

What is a positive Trousseau’s sign?

Answer 11

It is indicated by carpal spasm, in which there is wrist and finger flexion

Question 12

What are the three investigations used to diagnose hypocalcaemia?

Answer 12

Blood Tests

Arterial Blood Gas (ABG)

ECG Scan

Question 13

What are the six blood test results of hypocalcaemia?

Answer 13

Decreased Calcium Levels

Normal/Decreased PTH Levels

Normal/Increased Phosphate Levels

Normal ALP Levels

Decreased Magnesium Levels

Decreased Vitamin D Levels

Question 14

What is the first line investigation used to determine the cause of hypocalcaemia?

Answer 14

Parathyroid hormone blood test

Question 15

What ABG feature indicates hypocalcaemia?

Answer 15

Respiratory alkalosis - in the presence of normal phosphate levels

Question 16

What ECG feature indicates hypocalcaemia?

Answer 16

Prolonged QT interval > 460ms

Question 17

What is the normal QTc interval?

Answer 17

350ms - 460ms

Question 18

What is the conservative management option of hypocalcaemia?

Answer 18

It involves detection and treatment of the underlying cause of hypocalcaemia

Question 19

What is the pharmacological management option of hypocalcaemia?

Answer 19

IV Calcium Gluconate

Question 20

When is IV calcium gluconate used to manage hypocalcaemia?

Answer 20

It is the first line management option used to manage severe hypocalcaemia

Question 21

What dose of IV calcium gluconate is administered to manage hypocalcaemia?

Answer 21

10ml of 10% solution for a period of 10 minutes

The initial bolus can be repeated until the patient is asymptomatic and/or calcium levels have significantly increased

Question 22

What monitoring should be conducted during IV calcium gluconate administration?

Answer 22

ECG scan