8 - renal biochemistry Flashcards
Give some roles of the kidney
Regulates extra cellular fluid volume and electrode balance
Excretion of waste products
Selective reabsorption
Secondary endocrine function (production of erythropoietin and renin)
What does erythropoietin do?
stimulates RBC production
What does renin do?
It is involved in the renin angiotensin aldersterone system which balances sodium, potassium and water levels in the blood stream.
How does hypovaleamia impact electrolyte levels?
It causes low sodium and potassium (hyponatremia and hypokaleamia)
What is the role of aldosterone?
It causes reabsorption of sodium (and therefore water) in the nephron
What does ADH (vasopressin) do?
Increases reabsorption of water in the collecting ducts if the kidney
What are some causes of hypernatraemia?
Water depletion, excessive sodium intake and renal failure
How would you treat hypernatraemia?
Oral water or IV with 5% dextrose
What are clinical signs of hypernatraemia?
Decreased urine output, dry mucus membranes and low blood pressure (or high of salt gain
What is a cause of oedematous hyponatraemia?
Heart failure
How would you treat oedematous hyponatraemia?
Diuretic, restrict fluid and treat the underlying condition
What is a cause of non-oedematous hyponatraemia?
An increase in release of ADH secretion (Syndrome of inappropriate antidiuresis) which can be caused by an infection or malignancy
What are some causes of hyponatraemia via sodium loss?
Vomiting and diarrhoea, lack of sodium intake and lack of aldersterone
What are some clinical signs of hyponatraemia via sodium loss?
Tachycardia and hypotension
How would you treat hyponatraemia via sodium loss?
Oral correction of sodium loss or aldersterone therapy if it is caused by lack of aldersterone
What can hyperkalemia cause?
cardiac arrest
What can hypokalemia lead to?
Weak, cardiac arrhythmias
What are some causes of hyperkalaemia?
Renal failure, adrenal failure and release of potassium from damaged cells
How would you treat hyperkalaemia?
Calcium glauconate to protect the heart and insulin and glucose and dialysis to reduce potassium levels
What are some causes of hypokalaemia?
Vomiting, diarrhoea and diuretics
How do you treat hypokalaemia?
Oral or IV potassium (slowly with ECG monitoring)
What are some biochemical findings of acute renal failure?
Concentrated urine, increased serum urea and creatinine and hyperkalaemia
What are some causes of acute renal failure?
Pre-renal - damage to kidney’s blood supply
Renal - damage time kidney tissue
Post-renal - obstruction blocks urinary drainage
How do you treat acute kidney failure?
Treat the underlying causes and use dialysis if necessary
What are some biochemical findings of chronic renal failure?
Hyperkalaemia and high serum urea and creatinine
What is the management of chronic renal failure?
Sodium restriction Dietary protein restriction Diuretics Oral exchange resin (to reduce potassium) Dialysis and transplant in the long term
