Chronic Kidney disease Flashcards
Which 3 things do we assess for kidney disease?
Filtration (excretory) function – remove excess toxins + fluid
Filtration (barrier) function
Anatomy – abnormalities ie polycystic kidney
When will Creatinine increase above normal range?
When more than 60% of total kidney function is lost
Which isotope is used to measure renal function? How is it measured?
Chromium EDTA
Take a blood sample after giving patient isotope - test to see how the patient is clearing the isotope.
Which renal function test is pretty much impossible in the elderly population?
24 hour urine collection plus blood test - trying to get samples over 24hrs from a frail, elderly patient is not easy
What is most commonly used to measure excretory renal function?
GFR estimating equations
What does Creatinine rely on?
Creatinine is dependent on muscle mass - this varies a lot between different patients
Also depends on: Age Ethnicity - African Americans have higher serum creatinine Weight Gender Other issues e.g liver disease
What is the most commonly used formulae to estimate GFR?
MDRD 4 variable equation
Why are the current formulae not very reliable?
They cannot give an accurate value for the GFR if it’s higher than 60
Stages of chronic kidney disease
Stage 1 Kidney damage/normal or high GFR Stage 2 Stage 3a - moderate Stage 3b - moderate Stage 4 - severely impaired Stage 5 - advanced or on dialysis
How do we assess the kidney filtering function?
Urine dipstick - shouldn’t be any blood or protein if filtering properly
Send away for protein quantification - protein creatinine ration (PCR) - to see how much the kidneys are leaking
Current definition of chronic kidney disease
Chronic kidney disease (CKD) is defined by either the presence of kidney damage (abnormal blood, urine or x-ray findings) or GFR<60 ml/min/1.73m2 that is present for ≥3 months
Aetiologies of CKD
Diabetes Glomerulonephritis Hypertension Renovascular disease - narrowing of one or both arteries leading to the kidneys Polycystic kidney disease
What are 2 common causes of CKD in the younger populations
Glomerulonephritis or polycystic kidney (genetic)
Is CKD symptomatic?
More often than not CKD is asymptomatic with no signs until things are very advanced
CKD is often picked up incidentally
Which 4 investigations are often done for CKD
Blood tests
Urine test
Radiology - USS
Biopsy - reserved for difficult cases where clinicians are unsure of what is going on
Which blood tests are commonly done for CKD detection
U&Es
FBC
Which types of urine tests are done for CKD detection
Urine dipstick
Urine PCR or ACR (protein or albumin creatinine ratio) - tend to do PCR in pregnant women
24 hour collection
Why are blood tests done for CKD
Myeloma (bone cancer) can present with deteriorating kidney function – want to look for this in blood tests
Also want to check for anaemia
What is ACR
Albumin creatinine ratio
What are the only signs renal disease may show
Abnormal BP
Abnormal Urinalysis
What management is in place to slow the rate of renal decline
BP control - v important
Control proteinuria
Treat underlying cause
What classes of drugs are often used to control proteinuria
ACE inhibitors or ARBs
Complications associated with a reduced GFR
Acidosis Anaemia Bone disease CV risk Death & Dialysis Electrolytes Fluid overload Gout Hypertension Iatrogenic issues
As kidney function drops below about 30 these complications become more prevalent
Management of anaemia related to reduced GFR
Epoetin alfa - injectable drug
Iron
What is the most important complication to try and prevent in order to help kidney function
Cardiovascular risk - BP, aspirin, cholesterol, exercise, weight, smoking cessation
How do doctors prepare a patient for end stage renal disease and renal replacement therapy?
Education & information
Selection of modality
- HD / PD? transplant ?conservative care?
Planning access – fistula (needs to be in place for 6 weeks before it can be used)
Deciding when to start renal replacement therapy
MDT approach
How does Chronic Kidney Injury cause Anaemia?
The kidneys make an important hormone called erythropoietin (this travels to the bone marrow, where it works to stimulate stem cells to become RBC’s)
Injury to the kidneys results in low EPO levels and as a result your RBC count drops
