Chronic Kidney Disease Flashcards
What are some functions of the kidneys?
Body fluid homeostasis
Endocrine function
Acid-base homeostasis
Electrolyte homeostasis
Excretory function
Regulation of vascular tone
How do we assess for kidney disease?
- Filtration (excretory) function
- Remove
- Tested by using estimates of GFR (eGFR) from creatinine blood test
- Filtration (barrier) function
- Retain
- Tested by checking presence of blood or protein in urine
- Anatomy
- Abnormality
- Tested by histology or imaging
What causes glomerular filtration?
Pressure differences
How do you measure excretory renal function?
- Insulin clearance
- Isotope GFR
- 24 hour urine collection plus blood test
-
GFR estimating equations (most commonly used in clinical practice)
- Creatinine
What is a problem with using creatinine to estimate GFR?
A problem with using creatinine is it is generated from the breakdown of muscle, and not everyone has the same muscle mass, it also depends on:
- Age
- Ethnicity
- Gender
- Weight
- Other issues such as liver disease
What are some different formulae used to estimate GFR from serum creatinine?
What is used to stage kidney disease?
International chronic kidney disease (CKD) classification
What does CKD stand for?
Chronic kidney disease
What % is GFR of normal in stage 1 chronic kidney disease?
>90%
What % is GFR of normal in stage 2 chronic kidney disease?
60-89%
What % is GFR of normal in stage 3a chronic kidney disease?
45-59%
What % is GFR of normal in stage 3b chronic kidney disease?
30-44%
What % is GFR of normal in stage 4 chronic kidney disease?
15-29%
What % is GFR of normal in stage 5 chronic kidney disease?
<15%
What does GBM stand for?
Glomerular basement membrane
Do all substances cross the GBM?
Not all substances cross the glomerular basement membrane (GBM):
- Crosses GBM
- Water
- Electrolytes
- Urea
- Creatinine
- Crosses GBM but reabsorbed in proximal tubule
- Glucose
- Low molecular weight proteins (a2-microglobulin)
- Does not cross GBM
- Cells (RBC, WBC)
- High molecular weight proteins (albumin, globulins)
What are examples of substances that cross the GBM?
- Water
- Electrolytes
- Urea
- Creatinine