Chemical Pathology: Calcium Flashcards
Calcium:
What are normal blood calcium levels?
What form does it take in the blood?
Calcium:
What are the two main hormones involved in Calcium Metabolism and what do they do?
-
PTH:
- Stimulates 1-alpha hydroxylase to convert 25-hydroxycholecalciferol into 1,25-dihydroxycalciferol/Calcitriol/ (Acitvated Vitamin D)
-
Clacitriol is also called:
- 1,25-dihydroxycalciferol
Calcium:
Outline the overall Calcium feedback loop
Calcium:
Outline the Primary Defect, Calcium Level, Phosphate level, Alk Phos level and Vitamin D levels for Primary Hyperparathyroidism
- A disorder of the Parathyroids where excessive PTH is produced
Calcium:
Outline the Primary Defect, Calcium Level, Phosphate level, Alk Phos level and Vitamin D levels for Secondary Hyperparathyroidism
- Secondary Hyperparathyroidism is high PTH levels in response to Hypocalcaemia
Calcium:
Outline the Primary Defect, Calcium Level, Phosphate level, Alk Phos level and Vitamin D levels for Tertiary Hyperparathyroidism
- Tertiary hyperparathyroidism is a state of excessive secretion of PTH after a long period of secondary hyperparathyroidism and resulting in a high blood calcium level. It reflects development of autonomous/unregulated parathyroid function following a period of persistent parathyroid stimulation.
Calcium:
Outline the Primary Defect, Calcium Level, Phosphate level, Alk Phos level and Vitamin D levels for Hypoparathyroidism
Calcium:
Outline the Primary Defect, Calcium Level, Phosphate level, Alk Phos level and Vitamin D levels for Rickets/Osteomalacia
Calcium:
Outline the Primary Defect, Calcium Level, Phosphate level, Alk Phos level and Vitamin D levels for Paget’s disease
Calcium:
Outline the Primary Defect, Calcium Level, Phosphate level, Alk level and Vitamin D levels for Osteoporosis
Calcium:
What are the causes of Hypocalcaemia?
Calcium:
What is/are the symptoms and treatment of Hypocalcaemia?
Calcium:
What are the causes of Hypercalcaemia?
Calcium:
What is/are the symptoms and treatment of Hypercalcaemia?
Calcium:
What are the risk factors for Renal stones?
Calcium:
What is/are the signs, causes and preventative management of Calcium Stones?
Hyperoxaluria: excessive urinary excretion of oxalate
Calcium:
What is/are the % frequency and X-ray appearance of:
- Mixed Calcium stones
- Calcium oxalate
- Calcium phosphate
- Triple phosphate“Struvite”
- Uric acid
- Cysteine
- Others eg xanthine
Calcium:
What are the investigations for recurrent stones?
MCS = Microscopy Culture Sensitivities
Calcium:
Outline Vitmain D Synthesis
Vitamin D3 is made in the skin as cholecalciferol, which is converted into 25-hydroxycholecalciferol by 25 hydroxylase from the Liver. This is then converted into 1,25-dihydroxycholecalciferol 25-(OH)2 D3 by 1 aphla hydroxylase from the kidney.
Calcium
What are the roles of Vitamin D?
1,25-dihydroxycholecalciferol, Vitamin D roles:
- Intestinal Calcium absorption
- Intestinal Phosphate absorption
- Bone formation
- Cells have important Vit D receptors to control genes, cell proliferation, immune system and such
Caclcium
What is corrected Calcium?
How is it calculated?
Why is it needed?
- Total serum Calcium is between 2.2 - 2.6 mmol/L.
- Because calcium binds to albumin and only the unbound (free or ionized) calcium is biologically active, the serum level must be adjusted for abnormal albumin levels.
-
Corrected calcium can be given, which is serum Calcium + 0.02 x (40-serum albumin in g/L).
- Ionised calcium can also be given but not from a lab since the blood clots.
- With a low albumin, the bound calcium will show as low but the free will be normal. The corrected calcium refers to this.
Calcium
What is Pseudohypoparathyroidism?
- Pseudohypoparathyroidism is a condition associated primarily with resistance to PTH
- Those with the condition have a low serum calcium and high phosphate, but the parathyroid hormone level (PTH) is appropriately high (due to the low level of calcium in the blood).
