Week 3 Flashcards
What does hypochloremia lead to?
more HCO3- reabsorption to balance the loss of serum chloride
Why is it hard to correct prox. renal tubular acidosis with bicarb?
you won’t reabsorb much of the bicarb given
most of it will spill out into the urine
How is ammonia formed?
ammonia is formed by breaking down glutamine
What are 2 products of glutamine breakdown?
ammonia (secreted into lumen)
a-ketoglutamate
What does break down of a-ketoglutamate create as byproducts?
Breakdown requires 2 H+ so this leads to 2 HCO3- being produced
2 HCO3- can be absorbed into blood
What does a low pH do to amminogenesis ?
increases
we want more buffer since we have an acidic intracellular environment
Hypokalemia and amminogenesis
more K+ is being reabsorbed into blood and more H+ being pulled into cell
more H+ intracellularly leads to increased amminogenesis
What scenario should you use urine anion gap?
normal AG acidosis
Urine anion gap formula
UNa + Uk - UCl
What does a negative urine anion gap tell you?
the kidneys are working normally
excreting H+ as ammonium which is combining with Cl
What does a positive urine anion gap tell you?
the kidneys are not working normally
ammonium is not present and you probably have a RTA
Where is carbonic anhydrase found? (2)
proximal tubule
collecting duct
What type of urine pH is associated with distal RTA?
there is a problem secreted H+
this leads to a high urine pH (alkaline)
What potassium balance is associated with distal RTA?
hypokalemia
more K+ is secreted into lumen in attempt to replace the absent H+
What type of RTA can hypoaldosteronism cause?
little secretion of K+
this leads to hyperkalemia RTA (type 4)
How do catecholamines and insulin increase intracellular K+?
increase Na/K ATPase
What effects do carbonic anhydrase inhibitors have on potassium balance?
less reabsorption of bicarb leads to more bicarb at collecting duct
secrete more K+ to try to balance
this leads to hypokalemia
What hormone increases the concentration gradient of urea?
ADH
this leads to more water retention
How do ANA + dopamine work?
both counteract RAAS when there is increased volume
they decrease Na/K ATPase
What drives Ca and Mg reabsorption in the thick ascending limb?
this reabsorption is driven by K+ backflow
this K+ backflow into lumen causes increased lumen positivity
lumen positivity pushes Ca, Na and Mg into cell
What is normal GFR?
above 60
What defines CKD?
GFR < 60 for longer than 3 months
Is CKD reversible?
no
the damage to nephrons is irreversible
When do you define someone with ESRD?
GFR < 15
(also look for high phosphate and low bicarb)
How does CKD lead to osteoporosis?
hyperphosphemia sucks up the free Ca2+ which leads to hypocalecmia
PTH then recruits calcium from bones to try to raise serum calcium levels
this results in osteoporosis
How does renal failure cause hyperphosphatemia ?
decreased renal excretion of phosphate
Do you treat a UTI if there are no symptoms?
No!
What do granular casts indicate?
tubular injury
How do you treat RPGN?
IV glucocorticoid
What 3 supplements need to be given with IV glucocorticoids? Why?
Calcium / vitamin D (can cause osteoporosis)
Proton pump inhibitor (can cause acidosis in stomach)
Bactrim (can cause fungal infection, Candida)