Calcium Disorders COPY

Question 1

What are the common causes of hypercalcaemia?

Answer 1

90% are either:

• Primary Hyperparathyroidism
• Malignant Hypercalcaemia

OTher:

• Familial Hypocalciuric Hypercalcaemia (FHH)
• Drugs e.g. Thiazide diuretic or Lithium
• Sarcoid

Question 2

What causes Primary Hyperparathyroidism?

Answer 2

85% are adenomas
~15% are 4 gland hyperplasia

Very rarely:

• MEN 1 or 2A
• Parathyroid Carcinoma

Question 3

How does Hypercalcaemia present?

Answer 3

GI - Anorexia, Constipation & N&V

CV - Short QT, Hypertension & Bradycardia

Neuro - Loss of Conc. & confusion

Renal - Polyuria & Polydipsia + Nephrolithiasis

MSK - Muscle Weakness & bone pain

Question 4

How does Primary Hyperparathyroidism present?

Answer 4

Its generally asymptomatic but can cause symptoms of hypercalcaemia

Question 5

What is Familial Hypocalciuric Hypercalcaemia?

Answer 5

An autosomal dominant disorder causing Calcium-Sensing Receptor (CaSR) defects

Question 6

What tests are appropriate for Hypercalcaemia?

hint theres loads

Answer 6

• Serum Ca, PO4, PTH & Albumin
• Serum ACE (Sarcoid)
• 24 hour urine collection for calcium (low = FHH)
• U&Es
• ALKP
• Lymph node exam (malignancy)
• Myeloma screen (osteolytic metastases)
• ECG (short QT)
• FH
• Med History

Abdo US for kidney stones
Parathyroid US for adedomas etc.

Question 7

What are the initial tests for hypercalcaemia?

Answer 7

Serum Ca / PO4 / PTH / Albumin

FH & Med history

Question 8

What are the “levels” of hypercalcaemia?

Answer 8

<3mmol/l - Generally aymptomatic

3-3.5mmol/l -~symptomatic & prompt treatment needed

> 3.5mmol/l - Emergency. Risks Dysrhythmia & coma

Question 9

How do you treat hypercalcaemia first?

Answer 9

Rehydration & IV bisphosphonates (inhibit osteoclasts)

Question 10

What can you give hypercalcaemics when bisphosphonates fail/arn’t tolerated?

Answer 10

Calcitonin

Question 11

What treatments are there for lymphma or granulomatous disease causing hypercalcaemia?

Answer 11

Glucocorticoids e.g. Hydrocortisone

Question 12

How would we treat Primary Hyperparathyroidism Hypercalcaemia?

Answer 12

Parathyroidectomy

OR

Calcimetics e.g. Cinacalcet

Question 13

Summary of Hypercalcaemia treatments?

Answer 13

1st) Rehydrate and IV bisphosphonates

• Calcitonin
• Cinacalcet
• Parathyroidectomy
• Glucocorticoids

Question 14

How does PTH differentiate the cause of Hypercalcaemia?

Answer 14

In hypercalcaemia PTH should be low.
If it is then the cause is outside the Parathyroid e.g. malignancy or drugs

If its high then theres some reason PTH is overproduced e.g. FHH, renal failure or Primary hyperparathyroidism

Question 15

What are the main causes of Hypocalcaemia?

Answer 15

Low PTH aka hypoparathyroidism:

• Neck surgery e.g. thyroidectomy
• Autoimmune
• Magnesium Deficiency
• CaSR defect

High PTH (2nd* Hyperparathyroidism due to hypocalcaemia):

• Renal Disease
• Pseudohypoparathyroidism
• Pancreatitis
• Vit D deficiency

Inhibition of Bone resorption e.g. Bisphosphonates

Question 16

What is Pseudohypoparathyroidism?

Answer 16

A set of disorders in which target organs like kidneys & bone become unresponsive to PTH

Question 17

What causes pseudohypoparathyroidism?

Answer 17

• Agenesis e.g. Digeorge syndrome
• Destruction e.g. surgery
• Infiltration e.g. haemachromatosis or Wilson’s
• Hypomagnesaemia
• PTH resistance

Question 18

What special about pseudohypoparathyroidism presentation?

Answer 18

Albright’s Hereditary Osteodystrophy (AHO):

• Obesity
• Short Stature
• Short Metacarpals

Low Ca
High PO4 & PTH (hence pseudo)

Question 19

At what Serum Ca2+ level do symptoms of hypocalcaemia appear?

Answer 19

Around 1.9mmol/l

Question 20

How does hypocalcaemia present?

Answer 20

Lots of symptoms, main ones are:

• Paraesthesia
• Muscle twitchin
• Trosseaus sign
• Chovstek’s Sign

Prolonged QT
Hypotension
Papilloedema

Question 21

What are the named signs of hypocalcaemia?

Answer 21

Trosseau’s sign = Attach a tight BP cuff and watch the patients hand slowly form a claw

Chovstek’s Sign = Facial twitch when you tap on the parotid over the Facial nerve

Question 22

What tests are appropriate for Hypocalcaemia?

Answer 22

Serum Ca, albumin, PO4

PTH (High Pseudoparathyroidism vs low Hypoparathyroidism)

Mg (Mg deficiency)

U&Es (renal failure)

Vit D (Vit D deficiency)

ECG

Question 23

Explain how blood tests will appear for the 2 biggest causes of hypocalcaemia?

Answer 23

Vit D deficiency - Low Ca, low PO4 & high PTH

Hypoparathyroidism - Low Ca, High PO4 & low PTH

Also pseudoparathyroidism
- Low Ca, High PO4 and high PTH

Question 24

How do you treat mild Hypocalcaemia?

Answer 24

Mild meaning >1.9mmol/l and asymptomatic.

Put them on oral Ca2+ suppleents

Also Oral Vit D tablets and Mg replacement as appropriate

Question 25

How do you treat severe hypocalcaemia?

Answer 25

Severe meaning symptoms or <1.9mmol/l
Considered a medical emergency

IV Calcium Gluconate

Then treat cause

Question 26

why do you test albumin?

Answer 26

Some calcium is albumin bound, to find a true serum calcium do serum calcium and serum albumin.
Then add 0.1mmol/l for every 5g/l reduction in Albumin from 40g/l