03 - Renal System and Diuretics Flashcards
Edema is the passage of fluid from vasculature to
Interstitial space
Fluid overload can occur
Throughout the body or in just one compartment
You can treat or prevent fluid overload with fluid restriction but you may need
Diuresis
Blood flows into the glomerulus via the afferent arteriole where it is
Filtrated into the renal tubule
Na is mostly reabsorbed
ISOTONICALLY
Throughout the renal tubule
What is the normal fractional excretion of Na (FENa)?
<1%
Where in the kidneys do diuretics work? What happens if diuretic cannot get to this area?
Renal tubule
If diuretic cannot get into the tubule, (renal failure) it can’t work.
Normally in the kidneys, H+ is ____ and bicarbonate is
Pumped into urine (Na/H pump)
Filtered into urine
Hydrogen ions and bicarbonate form carbonic acid which is broken down by ______ into water and carbon dioxide and reabsorbed by the body.
Carbonic anhydrase
Acetazolamide works in the proximal tubule by inhibiting ______. How does this act as a diuretic?
Carbonic anhydrase
Inhibition reverses the Na/H pump so that Na reabsorption is inhibited. Water will follow the Na that is in urine. There will also be excess bicarbonate
In summary, the effects of acetazolamide are
Alkaline urine
Hyperchloremic metabolic acidosis
If somebody has a sulfa allergy, what will they have cross sensitivity to?
Acetazolamide
Maybe mannitol
Mannitol is an osmotic diuretic that is _____ filtered and ____ reabsorbed
Freely
Poorly
How does mannitol limit passive water reabsorption?
It increases renal tubular osmolarity
How can mannitol cause fluid overload, pulmonary edema, or hypernatremia from hyponatremia?
It draws water from cells into plasma, which increases renal blood flow
Does mannitol show evidence for renal protection?
Maybe in acute injury in renal transplant but otherwise, no
Extravasation of mannitol can cause
Tissue injury
Compartment syndrome
Which diuretic would you use to decreases ICP or IOP?
Mannitol
