Chronic kidney disease Flashcards
What processes of the kidney can we measure to assess kidney disease?
Filtration (excretory) function - the ability of the kidneys to remove
Filtration (barrier) function - the ability to retain
Anatomy - abnormalities
How d you measure excretory renal function?
GFR estimating equations
- GFR estimated based off serum creatinine
Other measurements:
- Inulin clearance
- Isotope GFR
- 24 hour urine collection + blood test
How bad does kidney function need to be before creatinine levels are raised?
Creatinine will not be raised above the normal range until 60% of total kidney function is lost
Which ethnicity will have a higher serum creatinine level at any level of creatinine clearance?
Why?
African Americans - as they have higher muscle mass
What is the effect of muscle loss seen with cachexia or liver failure on creatinine levels?
Creatinine is generated from the breakdown of muscle - thus these groups would have higher serum creatinine
Creatinine levels depend on lots of things - age, sex etc
What formulae are used to estimate GFR based from serum creatinine?
MDRD 4 variable equation:
- 175 x [SCr/88.4]-1.154 x [age]-0.203 x (0.742 if female) x (1.212 if black)
Cockcroft Gault:
- ([140-age] x weight x 1.23) / SCr x (0.85 if female)
CKD-EPI equation
The international CKD classification system assigns stages to kidney dysfunction
What GFR readings are at either end of the scale?
Stage 1 - Which is Kidney damage with normal or high GFR - is characterised by GFR > 90
Stage 5 - which is advanced renal failure or with the patient on dialysis - is characterised by GFR < 15
So in summary - what is the best approach to measuring Filtration (excrete out) function?
use estimates of GFR (eGFR) from creatinine blood test
At the Glomerulus - what molecules:
a) Cross the GBM
b) Cross the GBM but are reabsorbed in proximal tubule
c) Does not cross GBM
a) Cross GBM:
- Water
- Urea
- Electrolytes
- Creatinine
b) Crosses GBM but reabsorbed in p. tubule:
- Glucose
- Low molecular weight proteins
c) Does not cross GBM:
- Cells
- Large proteins (albumin, immunoglobulins)
What urine tests exist to assess the kidney filtering function?
Urinalysis (dipstick):
- Identifies blood and proteins
Protein quantification ratio:
- Protein creatinine ratio (PCR)
What is the 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
fill in the values
What are the causes of Chronic Kidney disease?
Diabetes
Glomerulonephritis
Hypertension
Polycystic kidney disease
Renovascular disease
Describe the clinical approach to treating chronic kidney disease
Identify and treat underlying aetiology
Slow the rate of renal decline
Assessment of complications
Preparation for renal replacement therapy
what are the symptoms associated with CKD?
Urinary symptoms - polyuria, haematuria, proteinuria etc
Shortness of breath
Nausea and vomiting, GI symptoms
Cognitive changes
Itching
Cramps
What signs are associated with CKD?
Pallor (due to anaemia)
Hypertension
Peripheral oedema
Palpable kidneys
Uraemic odour
