Biochemistry Flashcards
List criteria that the ideal marker of GFR would fulfil
Appear at constant rate
Freely filtered at glomerulus
Not reabsorbed or secreted
Which substance fulfils all the criteria for being an accurate measure of GFR, but is not usually used due to impracticality?
Inulin
What is the most widely used marker for GFR?
Creatinine
Which 1 of the criteria for being an accurate measure of GFR does creatinine not satisfy?
It is secreted into the renal tubule, but this is a small amount
Creatinine is very sensitive to small reductions in GFR. True/False?
False Only sensitive (rises) when large reduction in GFR occurs
Give the equation for urinary creatinine clearance
[creatinine]urine x urine volume
/
[creatinine]serum x duration of collection
Which formula is now more regularly used to determine GFR?
MDRD eGFR formula
170 x [creatinine]serum^-0.99 x [age]^0.176 x [0.762 if female] x [1.180 if black]
Which disease is characteristically associated with overflow proteinuria?
Multiple myeloma
What happens in glomerular proteinuria?
Dysfunctional glomerulus allows protein to leak through, producing albuminuria and nephrotic syndrome
Microalbuminuria refers to a small amount of albumin in the urine. True/False?
FALSE
Refers to abnormal amounts of albumin in the urine that is below the level detected by urine dipstick
What is microalbuminuria an early expression/warning sign for?
Diabetic nephropathy
What quantity of protein per day can cause significant glomerular damage?
150mg/day
How would you differentiate clinically between pre-renal and renal causes of tubular dysfunction?
Urine/ serum osmolality different in pre-renal phase (tubules working) but the same in the renal phase (tubules not working)
What is recommended for initial fluid resuscitation in a patient? What should be avoided?
Balanced crystalloid e.g. Hartmanns (avoid saline as it can cause metabolic acidosis)
When should saline be used for initial fluid resuscitation?
Rhabdomyolysis
AKI
CKD
