1B CKD and renal failure Flashcards
What homeostatic functions do the kidneys have?
- Electrolyte balance
- Acid-base balance
- Volume homeostasis
What happens to homeostatic function in kidney disease?
- Potassium increases
- Phosphate increases
- Bicarbonate decreases
- pH decreases (metabolic acidosis)
- Salt and water imbalance
What excretory functions do the kidneys have?
- Nitrogenous waste
- Hormones
- Peptides
- ‘Middle sized molecules’
- Salt and water
What happens to excretory function in kidney disease?
- Increase in urea
- Increase in creatinine
- Decrease in insulin requirement (due to low insulin clearance so more stays in system)
What endocrine functions do the kidneys have?
- Erythropoietin
- 1-alpha hydroxylase for vitamin D
What happens to endocrine functions in kidney disease?
- Decrease in calcium
- Anaemia
- Increase in parathyroid hormone (to compensate for low calcium)
What glucose metabolism functions do the kidneys have?
- Gluconeogenesis
- Insulin clearance
In kidney disease, what is there an increased overall risk of?
Increase in cardiovascular risk
How does rate of deterioration affect clinical presentation?
- If rate of deterioration is slow, body is very good at adapting
- e.g. some patients present with urea of 50 (which for a normal person is really bad) but their body is used to it since it’s developed over years so they don’t feel unwell
- Acute renal failure presents quicker because body hasn’t adapted
What acid-base problems can be seen in CKD?
- pH lower
- pCO2 lower
- pO2 higher
- HCO3- lower
Mild metabolic acidosis with respiratory compensation
How would end stage renal failure patients typically present?
- Extreme lethargy
- Weakness
- Anorexia
- Itching because of hyperphosphatemia
What are complications of CKD?
- Elevated plasma urea and creatinine (renal failure)
- Hyperkalaemia
- Hyponatraemia
- Metabolic acidosis
- Anaemia
- Shrunken kidneys
What are urea, creatinine, salts and Hb complications of AKI?
- Urea higher
- Creatinine higher
- Sodium could be either- it’s normal here
- Potassium higher
- Haemoglobin normal (because it’s acute renal failure so there’s still some EPO around)
What are acid-base complications in AKI?
- pH lower
- pCO2 lower
- pO2 higher
- HCO3- lower
Mild metabolic acidosis with respiratory compensation
How does kidney failure affect salt and water balance?
- Kidney failure tends to reduce secretion of salt and water leading to:
- Hypertension
- Oedema
- Pulmonary oedema
In what kind of circumstances can salt and water loss be seen in kidney failure?
- In tubulointerstitial disorders- damage to concentrating mechanism of urine
- Seen right after kidney transplant- there’s a bit of damage to tubules and they pee out a lot of water
- Seen also after kidney obstruction is relieved, kidney can’t concentrate urine and you get kidney failure
What may be a cause of AKI?
Hypovolemia
What does hyponatremia mean and what does it not mean?
- It does not mean reduced total body sodium
- It’s to do with how much free water you have- you’ll have more in hyponatremia
What has free water got to do with treatment of hyponatremia?
You may not want to give them salt but instead remove the excess free water
Describe how acidosis happens in renal failure
- Reduced secretion of H+ ions which means you become acidotic
- Cells take up this H+
What does acidosis do to K+?
The cells taking up the H+ also forces K+ out of the cells leading to hyperkalaemia