Calcium Homeostasis and disorders of calcium metabolism 2

Question 1

What are some symptoms and signs of hypocalcaemia

Answer 1

Paraesthesia - fingers, toes , perioral
Muscle cramps 
Muscle weakness
Fatigue
Bronchospasm or laryngospasm
Fits
Chovsteks sign (tapping over facial nerve)
Trousseau sign (carpopedal spasm)
ECG: QT prolongation

Question 2

What are some of the causes of hypocalcaemia

Answer 2

Hypoparathyroidism
Vitamin D deficiency (osteomalacia, rickets
Chronic Renal Failure
Pancreatitis
Hyperventilation
Osteoblastic bone metastases 
Rhabdomylolysis

Question 3

What should be give in acute Hypocalcaemia

a) emergency
b) over time

Answer 3

IV calcium gluconate 10ml 10% over 10 mins

Infusion (10ml 10% in 100ml infusate)

Question 4

Hypoparathyroidism

Answer 4

Congenital absence 
Destruction 
Autoimmune 
Hypomagnesaemia 
Idiopathic

Question 5

What is the long term management for hypoparathyroidism

Answer 5

Calcium supplement (1-2g per day)
Vitamin D (tablets or depot injection monthly)

Question 6

Why is hypomagnesaemia important?

Answer 6

Calcium release from cells is dependent on magnesium

Question 7

What happens to the intracellular calcium in magnesium deficiency

Answer 7

It becomes high

Question 8

What happens to PTH in hypomagesaemia

Answer 8

Its release is inhibited

Skeletal and muscle receptors are less sensitive to PTH

Question 9

What is the treatment for hypomagnesaemia

Answer 9

Calcium and magnesium replacement

Question 10

What are the causes of hypomagnasaemia

Answer 10

Alcohol
Drugs (thiazide, PPI)
GI illness
Pancreatitis
Malabsorption

Question 11

What type of disease is pseudohypoparathyroidism

Answer 11

Genetic defect in GNAS1

Question 12

What are the biochemistry indications of pseudohypoparathyroidism

Answer 12

Low calcium

PTH concentration elevated

Question 13

Why are PTH concentrations elevated in pseudohypoparathyroidism

Answer 13

Due to PTH resistance

Question 14

What are some symptoms of pseudohypoparathyroidism

Answer 14

Obesity 
Bone abnormalities (McCune Albright)
Subcutaneous calcification
Learning Disability 
Brachdactyly (4th metacarpal)

Question 15

What is pseudo-pseudohypoparathyroidism

Answer 15

The same as pseudohypoparathyroidism but with normal calcium levels

Question 16

What are the names of two conditions in which there is a vitamin D deficiency

Answer 16

Rickets and Osteomalacia

Question 17

Why might a patient be vitamin D deficient

Answer 17

Dietary deficiency 
Malaborsption: gastric surgery, coeliac disease, liver disease, pancreatic failure 
Chronic liver failure 
Lack of sunlight
Drugs e.g. anticonvulsants

Question 18

What are the features of osteomalacia

Answer 18

Low calcium
Muscle wasting (proximal myopathy)
Dental defects (caries, enamel)
Bone tenderness, fractures, rib deformity, limb deformity
pseudofractures
UV exposure

Question 19

If a patient has had a lot of UV exposure and presents with bone tenderness, what should be high on your differential list

Answer 19

Osteomalacia

Question 20

What are some biochemical markers that would be present in osteomalacia

Answer 20

Low calcium
low phosphate
high alkaline phosphatase
Low vitamin D 
High PTH

Question 21

What are some of the long term consequences of Vitamin D deficiency

Answer 21

Demineralisation/ fractures
osteomalacia/ rickets 
malignancy (especially colon)
heart disease
diabetes