💧Urology💧- CKD & Renal Failure Flashcards
What are the homeostatic functions of the kidneys?
Electrolyte balance
Acid-base balance
Volume homeostasis
What are the excretory functions of the kidneys?
Nitrogenous waste
Hormones
Peptides
Salt and water
What are the endocrine functions of the kidney?
Erythropoietin
1- alpha-hydroxylase - Vitamin D
What are the glucose metabolism functions of the kidney?
Gluconeogenesis
Insulin clearance
What homeostatic functions will be impaired in kidney failure?
What excretory functions will be impaired in kidney failure?
*Decreased insulin requirement due to decreased clearance
What endocrine functions will be impaired in kidney failure?
Increased PTH - secondary hyperparathyroidism
Increased PTH as no vitamin D means low calcium - PTH cant raise calcium by itself
What is the overall main health risk due to kidney failure?
Increased cardiovascular risk
How was acute kidney injury occurred according to this image?
Vesicoureteral reflux
Retrograde flow of bladder urine into the ureters - lack of competent valve system in ureters
Can lead to pyelonephritis and scarring
Tubulointerstitial disease - salt and water loss
Why might a patient with CKD be tachypnoeic?
Decreased bicarbonate excretion and H+ elimination in kidneys - metabolic acidosis
Increased resp rate to get rid of CO2 and lower pH - compensatory mechanism
Known as Kussmaul respiration
Describe the bloods in a patient with kidney failure
*haemoglobin will be normal in acute, and low in chronic
*sodium will also be low in this case
Describe the ABG of a patient with CKD
Raised O2 and lowered CO2 - ?due to respiratory compensation
What conditions caused by renal failure can complicate management/diagnosis?
Hyperkalaemia
Hyponatraemia
Metabolic acidosis
Anaemia
Outline the key takeaways in kidney failure as acute kidney injury
Metabolic acidosis due to less bicarbonate secretion and H+ elimination
Tachypnoeic compensatory response
Salt and water loss - hypovolemia and dehydration
What investigations would you do in suspected CKD?
Kidney ultrasound
What would be the consequences of CKD induced hyperkalaemia?
ECG changes
Arrhythmias
Can be fatal if ventricular
What are the ECG changes seen in hyperkalaemia?
Peaked T waves
P wave - broadens, reduced amplitude, can disappear
QRS widening
Heart block
Asystole
VT/VF
What levels would you expect to find in AKI?
Increased Urea
Increased creatinine
Sodium - ↓ if volume overload or dilutional hyponatremia (fluid retention) - normal or ↑ if hypovolemic (prerenal AKI)
Increased Potassium
Normal haemoglobin
Acidic pH
pCO2 lower (respiratory compensation)
Decreased Bicarbonate
What would an ultrasound show in AKI?
Normal sized kidneys with no obstruction
What does kidney failure tend to do to salt and water?
Reduce secretion of salt and water
Leads to hypertension, oedema, pulmonary oedema
When can salt and water loss be seen in kidney failure?
Salt and water loss may be seen in tubulointerstitial disorders – damage to concentrating mechanism
& hypovolemia may be the cause of AKI
What does metabolic acidosis lead to?
Anorexia
Muscle catabolism
What are the causes of hyperkalaemia in kidney failure?
Decreased distal tubule potassium
Acidosis
What are the symptoms of chronic hyperkalaemia?
Cardiac arrythmias
Neural and muscular activity decrease
Vomiting
How does acidosis cause hyperkalaemia?
H+ concentration high extracellularly
H+ moves into cell, exchanged for potassium
Mass influx of potassium from cells into blood
What effect does kidney failure have on blood oxygen?
Reduced erythropoietin - anaemia
What effect does kidney failure have on calcium regulation?
Reduced 1-alpha hydroxylas - less vitamin D
Hypocalcaemia
Hyperparathyroidism
What is the major outcome for patients with CKD?
CKD acts as major predictor for end stage renal failure
BUT
Major outcome is CVD
(i.e. a patient with CKD is more likely to die from cardiovascular disease than end stage renal failure)
What is the initial treatment for kidney failure?
What are the long term management options for kidney failure?
What does the Kidney failure risk equation use?
Age in years
Sex
CKD-EPI eGFR
Urine albumin creatinine ratio (ACR)
When should the kidney failure risk equation not be used?
In patient with rapidly changing eGFR
Why should transfusion be avoided in patients with transplantable kidney disease?
Transfusions lead to immune sensitisation
This can lead to transplant failure
What are the various ways of assessing GFR?
Urea
Creatinine
Radionuclide studies
Creatinine clearance
Inulin clearance
Outline using urea as a way of assessing GFR
Poor indicator
Confounded by diet, catabolic state, GI bleeding (bacterial breakdown of blood in gut), drugs, liver function etc.
Outline using creatinine as a way of assessing GFR
Affected by muscle mass, age, race, sex etc.
Need to look at the patient when interpreting the result. TREND helpful.
Outline using radionuclide studies as a way of assessing GFR
EDTA clearance etc
Reliable but expensive
Outline using creatinine clearance as a way of assessing GFR
Difficult for elderly patients to collect an accurate sample
Overestimates GFR at low GFR (as a small amount of creatinine is also secreted into urine)
Outline using inulin clearance as a way of assessing GFR
Laborious - used for research purposes only
What is estimated GFR effectively equal to?
Serum creatinine concentration
