Hypercalcaemia

Question 1

What is Malignant Hypercalcaemia?

Answer 1

Serum Ca of 2.6+, secondary to cancer

Question 2

What are the most common cancers associated with Hypercalcaemia? (4 things)

Answer 2

1. Breast cancer
2. Lung cancer (squamous cell carcinoma)
3. Multiple myeloma
4. Lymphoma

Question 3

What are the main mechanisms of Hypercalcaemia? (3 things)

Answer 3

1. Osteolytic metastasis
2. PTH-related prot secretion
3. Increased 1,25-dihydroxyvitamin D prod

Question 4

What is the cancer that Osteolytic metastasis is most assoc w?

Answer 4

Breast cancer

Question 5

How does Osteolytic metastasis cause Hypercalcaemia? (4 steps)

Answer 5

1. Tumour cells deposited within bone
2. Local prod of inflamm cytokines
3. Stimulates cytokines
4. Bone resorption

Question 6

What is PTHrP? (2 points)

Answer 6

1. Protein secreted by tumour cells
2. Similar to PTH

Question 7

How does PTHrP cause Hypercalcaemia? (3 things)

Answer 7

Similar to PTH, it leads to:
1. Increased bone resorption
1. Distal renal tubular calcium absorption
1. Inhibition of proximal phosphate transport

Question 8

How is PTHrP different to PTH?

Answer 8

Doesn’t lead to vit D activation

Question 9

What cancers is PTH-related prot secretion commonly assoc with? (2 things)

Answer 9

1. Breast cancer
2. Non-Hodgkins lymphoma

Question 10

How does Increased 1,25-dihydroxyvitamin D prod cause Hypercalcaemia?

Answer 10

Causes increased absorption of Ca from GI enterocytes

Question 11

What cancer is Increased 1,25-dihydroxyvitamin D prod commonly assoc with?

Answer 11

Hodgkins Lymphoma

Question 12

What are the CF of MILD hypercalcaemia? (5 things)

Answer 12

1. Asymptomatic (common)
2. Polyuria
3. Polydipsia
4. Mild cog imp
5. Dyspepsia

Question 13

What are the CF of MODERATE hypercalcaemia? (5 things)

Answer 13

1. All mild CF
2. Nausea
3. Dehydration
4. Weakness
5. Constipation

Question 14

What are the CF of SEVERE hypercalcaemia? (6 things)

Answer 14

1. All mild + moderate CF
2. Coma
3. Vomiting
4. Cardiac dysrhythmias
5. Pancreatitis
6. Abd pain

Question 15

What is the Dx of Malignant hypercalcaemia based on? (2 things)

Answer 15

1. Serum calcium level 2.6+
2. Identifying underlying cancer

Question 16

What is the difference in the Hypercalcaemia of Cancer vs Benign causes?

Answer 16

• Cancer = RAPID increase in Ca levels
• Benign = Slower + more asymptomatic

Question 17

How do you differentiate between Malignant Hypercalcaemia vs Primary Hyperparathyroidism?

Answer 17

Malignant hypercalcaemia = PTH suppressed

Question 18

What are the Mx options for Malignant hypercalcaemia? (3 things)

Answer 18

1. IV fluids (most important)
2. Calcitonin
3. Bisphosphonates

Question 19

How does Calcitonin work in Mx of Malignant hypercalcaemia? (2 things)

Answer 19

1. Promotes urinary calcium excretion
2. Inhibits bone resorption

Question 20

How do Bisphosphonates work in Mx of Malignant hypercalcaemia? (2 steps)

Answer 20

1. They are absorbed onto surface of bony network
2. Inhibit osteoclast activity