Hypocalcemia

Question 1

What is the definition of hypocalcemia in terms of ionized calcium?

Answer 1

Decreased calcium level in blood below the normal level of 1 to 1.25 mmol/L.

Question 2

What are the clinical features of hypocalcemia?

Answer 2

1. Neuropsychiatric - anxiety, dementia, depression, psychosis, seizures, papilledema
2. Neuromuscular - tetany, muscle cramping, weakness, Chvostek sign, Trousseau sign
3. Respiratory - apnea, laryngeal spasm, bronchospasm
4. CV - arrhythmias, heart failure, hypotension
5. ECG changes - prolonged QT, wide QRS, flat T waves

Question 3

What ECG changes are associated with hypocalcemia?

Answer 3

prolonged QT interval
wide QRS
flat T waves

Question 4

What electrolyte abnormality can cause the following ECG changes: long QT, wide QRS, flat T waves?

Answer 4

Hypocalcemia

Question 5

What is Chvostek sign?

Answer 5

A sign of hypocalcemia in which tapping the facial nerve by the tragus of ear results in twitching.

Question 6

What is Trousseak sign?

Answer 6

A sign of hypocalcemia in which inflation of arm BP cuff results in carpal spasm

Question 7

What is the differential diagnosis of hypocalcemia?

Answer 7

1. PTH deficiency (primary or post surgery)
2. Vit D deficiency
3. Hyperphosphatemia
4. Hypomagnesemia
5. Citrate chelation (massive blood transfusion)
6. Alkalemia
7. Renal failure
8. Liver failure
9. Medications (PPIs decrease calcium absorption)
10. Acute pancreatitis, rhabdomyolysis, sepsis

Question 8

What class of medications can cause hypocalcemia?

Answer 8

PPIs can cause hypocalcemia by decreasing calcium absorption.

Question 9

What is the management of hypocalcemia?

Answer 9

Assess for underlying cause
If symptomatic:
- assess need for intubation or CPR
- maintain ventilation/hemodynamics
- seizures do not respond to typical antiseizure medications until calcium is restored
- 10% calcium gluconate 10cc IV over 10 minutes
3. Calcium replacement:
- use caution with PIV due to risk of tissue necrosis
- central line preferred
4. Follow lab values

Question 10

Why might successful administration of typical antiseizure medications fail to resolve seizures in a patient liver failure?

Answer 10

Liver failure can cause hypocalcemia and if the patient is having seizures because of hypocalcemia, these medications may not work until calcium is restored.

Question 11

What are the CV effects of clinically significant hypocalcemia?

Answer 11

arrhythmias, heart failure, hypotension, ECG changes (long QT, flat T waves, wide QRS)

Question 12

What are the respiratory effects of clinically significant hypocalcemia?

Answer 12

apnea
laryngeal spasm
bronchospasm

Question 13

What are the CNS effects of hypocalcemia?

Answer 13

anxiety
dementia
depression
psychosis
seizures
papilledema

Question 14

What are the neuromuscular effects of clinically significant hypocalcemia?

Answer 14

tetany
muscle cramps
weakness
Chvostek sign (facial nerve tapping = twitches)
Trousseau’s sign (inflating BP cuff = carpal spasm)