Renal Flashcards
About how much is GFR
120 ml/min/1.73m2
What is creatinine?
Chemical waste product from muscle metabolism
What can cause a misleadign creatinine level ?
Extreme muscle mass e.g. cachexia/body builder = misleading
Why is creatinine clearance > GfR
Secreted as well as filtered
[Therefore inhibitors of secretion will make Cr rise and function look worse e.g. trimethoprim]
3 hormones in Na excretion and therefore volume control
Aldosterone (adrenal) -> decreased excretion
Angiotensin II -> decreased excretion
ANP - released by heart in response to high pressure -> increases excretion
In kidney which hormone dilates afferent arteriole? constricts?
Prostaglandin
Angiotensin II
[angi is a bit constrictive - the bitch]
Name 2 SEs od ACEi
May impair renal function: decrease GFR (avoid NSAIDs), hyperkalaemia (avoid K+ spare diuretics)
Postural hypotension
Bradykinin mediated dry cough
Fatigue
Name an ARB and 2 SEs
Losartan
Renal impairment
Postural hypotension
Hyperkalaemia
Name 1 med causing hypo K and 1 causing hyper K
Hypokalaemia meds
Loop diuretics, thiazide diuretics
Hyperkalaemia meds
Spironolactone, amiloride, ACEI, ARB
Key transporter in loop of henle
NKCC2:
Na K Cl Cotransporter (energy dependent)
Where do ADH and aldosterone take effect on?
Distal convoluted tubule and collecting duct
Barter’s syndrome .. same as?
When?
2 features
Effect of loop diuretics
Children
Metabolic alkalosis
Low Mg
High urinary Ca
[C’s - Children, [loop=Circle], high Ca]
Gitelmans syndrom same as?
age?
2 features?
same effect as Thiazide diuretic (Distal convoluted tubule)
Late childhood
Mg decreased, urine calcium normal/low,
Metabolic alkalosis
What does renal tubular acidosis result in?
Hyperchloraemic metabolic acidosis
+ hypobicarbonataemia + decreased arterial pH
+ normal anion gap
2 Most common cause of renal tubular acidosis
fanconi syndrome
drug induced
What happens in fanconi syndrome
Generalised dysfunction of renal proximal tubule ->
urinary loss of bicarb, [glucose, aa, phosphate, peptides, organic acids. ]
Leads to salt wasting and volume depletion
Name 2 Rfs for RTA
Childhood, urinary tract obstruction, DM, [stones, adrenal insufficiency]
Name 3 ways RTA could present?
Growth retardation/failure to thrive (children)
Muscle weakness (Fanconi)
Hypoglycaemia after fructose
Rickets (Fanconi and Type 2 proximal have persistent phosphate loss)
Kussmaul breathing if severe
2 key findings from Ix in RTA? name another one
Low serum bicarbonate
serum anion gap normal (12-18)
[high serum chloride, variable potassium, arterial pH low, ]
Mx of RTA
if Hyperkalaemia + mineralocorticoid deficiency?
Sodium alkali
Fludrocortisone + dietary restriction of potassium
Mx of Hyperkalaemia + mineralocorticoid deficiency
in RTA
Fludrocortisone + dietary restriction of potassium
Name 2 comps of RTA
volume depetion (due to loss of Na)
Nephrocalcinosis - due to bone buffering of acidosis
Osteoperosis - due to bone buffering of acidosis
Grow retardation - acidosis -> muscle catabolism
Renal rickets - in fanconi
2 Causes of end stage renal failure
Glomerulonephritis
Pyelonephritis
Diabetes
PKD
Usual cause and bugs for pyelonephritis
Escherichia coli, UPEC
[diabetes/HIV/malignancy/transplant - think candida/klebsiella]
ascending from lower urinary tract or spread hematogenously to kidney