Hypo- and Hypercalcaemia

Question 1

What are some aetiologies of hypocalcaemia?

Answer 1

Renal failure
PTH deficiency
Hypoparathyroidism
Post surgery
Congenital – DiGeorge’s
Insufficient vitamin D
Insufficient dietary calcium (rare)
Excess dietary magnesium (rare)

Question 2

How does hypocalcaemia present?

Answer 2

Asymptomatic, lab finding

Muscle pain
Bone pain - due to decreased turnover and high bone mineral density
Abdo pain

Paraesthesiae of face, fingers and toes
Facial twitching - Chvostek’s sign = tapping of facial nerve in front of the ear with the patient’s mouth slightly open causes twitching of facial muscles
Trousseaus sign
Inflation of sphyg. cuff above systolic pressure for 3 mins causes titanic spasm of fingers and wrist
Headaches
Memory impairment
Emotional lability, anxiety depression, confusion
Lethargy
Hyperreflexia
Convulsions

Dry skin
Brittle nails 
Painful menstruation 
Stridor 
Raised ICP 
Cataracts

Question 3

What are some complications of hypocalcaemia?

Answer 3

Laryngospasm - can cause stridor and airway obstruction

Neuromuscular irritability - cramps, tetany, seizures

QT changes - syncope, arrhythmias, death

Stunted growth, malformed teeth and mental impairment - if untreated in childhood

Over treatment: hypercalcaemia (+sequalae)

Question 4

How do you manage acute hypocalcaemia?

Answer 4

Present if severe symptoms are present e.g. tetany

Urgent IV Ca given

Question 5

How do you manage chronic hypocalcaemia?

Answer 5

Manage any specific underlying causes

Supplementation with oral Ca + Vit D e.g. AdCal

Question 6

What are some causes of hypercalcaemia?

Answer 6

Primary and tertiary hyperparathyroidism
Cancer - humoral factors secreted by tumours that upset normal organs involved in Ca 2+ homeostasis; bone metastases

Dehydration

Rare causes:
Sarcoidosis
Thyrotoxicosis
Myeloma
Vit D excess

Question 7

How does hypercalcaemia present?

Answer 7

Majority are asymptomatic

(Signs of hypercalcaemia: Bones, stones, abdo groans and psychic moans:)

Renal:

• Nephrolithiasis
• Dehydration, poluria/nocturia - impaired urine concentration that is refractory to exogenous vasopressin = a renal diabetes insipidus

Cardiovascular:
- Calcification of arteries or heart muscle leading to LVH and HTN

MSK:

• Bone, muscle and joint pain
• Pseudogout
• Granular decalcification of the skull = salt+pepper skull

GI:

• Lack of appetite - weight loss
• Nausea, constipation
• Gastric or duodenal ulcers
• Pancreatitis

Psych:

• Depression
• Anxiety
• Sleep disorders
• Fatigue

Question 8

How do you treat acute hypercalcaemia?

Answer 8

IV saline - rehydration - will improve renal perfusion and thus functioning, increasing renal excretion of Ca

Bisphosphonate therapy (pamidronate + zolendronic acid)

Can give calcitonin whilst waiting for bisphosphonates to work (opposes the action of PTH to keep calcium IN the bones)

Correct other electrolyte imbalances e.g. hypokalaemia, hypomagnesia

Manage any AKI

Treat underlying cause e.g. malignancy

Question 9

How does hypercalcaemia and hypocalcaemia present on ECG?

Answer 9

Hypercalcaemia:

• Shortening of the QT interval
• J waves = notching of the terminal QRS; best seen in V1; in severe

Hypocalcaemia:

• QT prolongation due to elongating the ST segment
• T wave morphology typically normal