LECTURE 5 - finished Flashcards
What is alkaline phosphatase (ALP)?
A group of isozymes produced by cells found in the liver and the bone tissue. When these cells are damaged of destroyed, serum levels of ALP increase. Due to the increased turnover of bone tissue in growing children, increased ALP levels in kids are normal.
Where are ALP’s found in the body?
Liver
Bone tissue
Placenta
Intestinal mucosal cells
Renal cells
** diseases affecting intestinal mucosal cells and renal cells do not lead to increase serum ALP levels.
What 3 areas produce the most ALP?
Biliary epithelial cells (line biliary ducts)
Osteoblasts
Placental cells
What conditions cause elevated ALP levels?
Alcoholics Only Drink Hard Booze Or Hard Petrol
Healing fractures
Bone cancers (increased bone destruction and formation)
Osteomalacia/Rickets
Hyperparathyroidism (increased bone turnover)
Pagets (increased bone turnover)
How do we tell the difference between ALP from the bone or from the liver?
Osteoblasts and biliary epithelial cells synthesise different forms (isozymes) of ALP that can be distinguished by specific blood tests.
Another easier way to do it is to also tests for other liver enzymes in the serum. Raised liver enzymes + high ALP indicates a liver rather than a bone condition
What enzyme tests can be done to determine a hepatic cause for elevated ALP?
5’ nucleotidase (5’N)
Leucine aminopeptidase (LAP)
Gamma-glutamyl transpeptidase (Y-gtp)
Biological functions of calcium
Cell signalling Neural transmission Muscle function Blood coagulation Enzymatic co-factor Secretion Bone mineralisation
What is the role of PTH?
INCREASE serum calcium via effects on the kidneys and bone.
In the presence of decreased calcium, the parathyroid gland releases PTH:
PTH in the kidneys to INCREASE serum calcium:
- decreased phosphate resorption which causes increased urinary phosphate excretion. This decreases serum phosphate levels
- increases calcium reabsorption and decreased urinary excretion of calcium
- increases plasma vitamin D levels which in turns increases calcium absorption in the intestine
PTH in the bone to increase serum calcium:
- Increases release of calcium from the bones into the plasma
What is the role of calcitonin?
DECREASE serum calcium by affecting bones and kidneys
Increased serum calcium is detected by the thyroid gland, which releases calcitonin. Calcitonin then travels through the blood to the kidneys and bones:
Calcitonin in the kidneys:
- decreased renal calcium reabsorption
- decreased renal phosphate reabsorption
Calcitonin in the bones:
- temporarily decreases osteoclastic activity, leading to a decreased in calcium and phosphate release from bone
What is the most common cause for hypercalcaemia?
Hyperparathyroidism
What are some less common causes of hypercalcaemia?
KIMS HEM
Kidney failure Immobilisation Malignancy (mets, multiple myeloma) Sarcoidosis Hyperthyroidism Excessive dietary vit D or calcium Medications
What are the main causes of hypocalcaemia?
Hypoparathyroidism Kidney failure Liver disease (decreased albumin synthesis) Magnesium deficiencies Malabsorption Vit D deficiency Pancreatitis
When are serum calcium tests indicated?
The serum calcium test is usually ordered in patients who have a suspected or known disorder affecting: • Kidneys • Bones • Thyroid • Parathyroid • Nervous system
The serum calcium test may also be ordered in patients:
• exhibiting clinical manifestations of hypo or hypercalcemia
• to evaluate the effectiveness of treatment (e.g. hyperparathyroidism)
What are the symptoms of hypomagnesaemia?
- Loss of appetite
- Nausea/Vomiting
- Fatigue
- Weakness
- Vertigo
- Dysphagia
- Parasthesias
What are the signs of hypomagnesaemia?
Seizures Cramps Tetany Chvostek's sign Vertical nystagmus Arrhythmias
