Flashcards in Lecture 17 - Renal failure Deck (40):
What are the functions of the kidneys?
1. Elimination of waste products.
2. Control of fluid balance.
3. Regulate acid/base balance.
4. Produce hormones.
5. Regulation of electrolytes.
What is GFR?
Glomerular filtration rate - the rate at which the blood is cleared of waste products. Normal rate is >120ml/min.
How is GFR measured?
1. Inulin clearance - inject a person with inulin (completely untouched by the kidneys - not absorbed) and measure their urine and compare it to their blood.
2. eGFR - measure a persons creatinine as creatinine is completely cleared by the kidneys.
Acute Kidney Injury - rapid decline of GFR (hours to days) and is potentially reversible.
Chronic Kidney Disease - gradual decline of GFR (>3months) and is progressive and irreversible.
How do we asses an AKI?
1. Serum creatinine.
2. Urine output.
What is stage 1 of an AKI
1. 1.5-1.9 x baseline of serum creatinine OR >26micromol/L.
2. Urine output <0.5ml/kg/hr for 6-12 hours.
What is stage 2 of an AKI?
1. 2.0-2.9 x baseline of serum creatinine.
2. Urine output <0.5ml/kg/hr for >12 hours.
What is stage 3 of an AKI?
1. 3 x baseline of serum creatinine OR >354 micromol/L.
2. Urine output <0.3ml/kg/hr for >24 hours OR anuria >12 hours.
Describe a pre-renal AKI?
It is anything before the kidneys that is causing there to be decreased perfusion to them.
What can cause a pre-renal AKI?
1. Intra-renal vasoconstriction - there is something which is causing there to be less blood in the kidneys e.g. meds (NSAIDs, ACEi, Diuretics).
2. Systemic vasodilation - the vessel size has increased so BP has decreased/less blood to the kidneys. It can be due to sepsis or neurogenic shock.
3. Volume depletion - there is less blood going to the kidneys, could be due to: diuretic overdose; osmotic diuresis (DKA).
Describe an intra-renal AKI?
This is injury to the inside of the kidney:
What can cause an intra-renal AKI?
Describe a post-renal AKI?
This is an extra-renal obstruction.
What can cause a post-renal AKI?
1. Prostate hypertrophy.
2. Neurogenic bladder.
3. Retroperitoneal fibrosis.
4. Bladder, prostate and cervical cancer.
What are the risk factors for an AKI?
2. Past history of AKI.
4. Diabetes mellitus.
5. Congestive heart failure.
6. Liver failure.
10. High EWS.
What is stage 1 of a CKD?
What is stage 2 of a CKD?
GFR = 60-89ml/min.
What is stage 3 of a CKD?
GFR = 30-59ml/min.
What is stage 4 of a CKD?
GFR = 15-29ml/min.
What is stage 5 of a CKD?
GFR = <15ml/min.
What else can you do to measure the stages of CKD?
You can measure albuminuria. It is a marker of renal disease and prognosis. Essentially is means that the kidney is not working properly as albumin (protein - big molecule) is able to pass through the membrane filters and be filtered out of the body. There should not be any albumin/proteins in the urine.
What is stage A1 of CKD?
A1 = <30mg/mmol of albumin in the urine.
What is stage A2 of CKD?
A2 = 30-300mg/mmol of albumin in the urine.
What is stage A3 of CKD?
A3 = >300mg/mmol of albumin in the urine.
What are the causes of CKD?
1. Diabetic nephropathy.
3. Hypertensive nephrosclerosis.
4. Polycystic kidney disease.
What can contribute to the progression of CKD?
2. Intra-glomerular hypertension.
3. Glomerular hypertrophy.
4. Calcium and phosphate abnormalities.
7. Tubulo-interstitial fibrosis.
8. Toxicity or iron/ammonia/middle molecules.
What is proteinuria?
Presence of excess proteins in the urine - can make the urine foamy. Basically the kidneys aren't working properly so proteins are able to cross the function membrane when normally they wouldn't be allowed.
How do you try and modify proteinuria (improve it)?
1. Weight loss.
3. Aldosterone antagonists (spironolactone).
5. BP control.
What happens to calcium and phosphate in the kidneys?
There is a decrease in calcium in the kidneys so there is an increase in PTH and phosphate.
How do you improve increasing phosphate levels in the body?
2. Drugs - give phosphate binders e.g. calcium carboante, aluminium hydroxide, sevelemar, lanthrunum.
What is uraemia?
This occurs in end-stage renal failure. There are too many metabolic products in the blood - basically we cannot pee out the bad toxins our organs are producing. This is because the amount of blood entering the kidneys is minimal (not enough blood to be filtered out) so there are excess toxins in the blood.
What are the neurological effects of uraemia?
1. Lethargy and fatigue.
2. Sleep disturbances.
6. Peripheral neuropathy.
What are the haematological effects of uraemia?
2. Bleeding tendency.
3. Platelet dysfunction.
What are the cardiovascular effects of uraemia?
3. Heart failure.
4. Ischaemic Heart Disease.
6. Cerebrovascular Accident (e.g. stroke).
7. Peripheral Vascular Disease.
What are the pulmonary effects of uraemia?
2. Uraemic lung.
What are the GI effects of uraemia?
4. GI bleed.
What are the metabolic effects of uraemia?
2. Glucose intolerance.
5. Sexual dysfunction.
What are the skin effects of uraemia?
2. Easy bruising.
3. Uraemic frost.