Jan8 M2-Edema and Diuretics Flashcards
2 components to edema pathophysiology
- alteration in capillary hemodynamics favoring Na and water mvmt to interstitium
- renal retention of dietary Na and water with ECF expansion
2 components to edema pathophysiology
- alteration in capillary hemodynamics favoring Na and water mvmt to interstitium
- renal retention of dietary Na and water with ECF expansion
example of cause of edema
low oncotic pressure (ex. loss of albumin in nephrotic syndrome)
example of cause of edema related to lymphatics drainage
lymph node infection, blockage, breast cancer surgery
example of cause of edema related to high capillary hydrostatic pressure
rise in venous pressure
urine protein and urine Na in nephrotic syndrome and why
above 3g protein/day
less than 15 meq/L U Na (holding on to Na)
hormones activated in nephrotic syndrome and why
- RAAS because low IV volume so low renal perfusion (renin activated)
- ADH (low IV volume)
condition where Na retention, edema and RAAS and ADH always active and why
CHF. low CO = sensed hypovolemia, state of volume contraction
what hormones act on the kidney in CHF
- NE and AT2 for proximal Na reabso
- ADH distally
- aldo distally
example of cause of edema
low oncotic pressure (ex. loss of albumin in nephrotic syndrome)
example of cause of edema related to lymphatics drainage
lymph node infection, blockage, breast cancer surgery
example of cause of edema related to high capillary hydrostatic pressure
rise in venous pressure
urine protein and urine Na in nephrotic syndrome and why
above 3g protein/day
less than 15 meq/L U Na (holding on to Na)
hormones activated in nephrotic syndrome and why
- RAAS because low IV volume so low renal perfusion (renin activated)
- ADH (low IV volume)
condition where Na retention, edema and RAAS and ADH always active and why
CHF. low CO = sensed hypovolemia, state of volume contraction
what hormones act on the kidney in CHF
- NE and AT2 for proximal Na reabso
- ADH distally
- aldo distally
SV as fct ov LVEDP curves: how does it change in heart failure and how kidney can change it
curve drops. lower SV for a same LVEDP. kidney retains water and sodium so increases it and moves the curve up
why K sparing diuretics called like that
because don’t cause hypoK
ascites in what disease and why
fibrotic liver so blood coming from splanchnic circulation is turned away and liver loses serous fluid in peritoneal cavity
where to look for edema
feet, hands, face, around the eyes, pulmonary, abdomen
normal urine output (per 8 hour shift)
300-400 cc
if notice edema, next step in physical exam
weigh the patient
limiting factors in thiazides (2)
- they have unknown mechanisms to lower BP
- low Na reabso there
thiazide used for what condition
BP control
K sparing diuretics 2 modes of action
block (nuclear) aldoR (a TF) so no enac channels made. (spironolactone)
-block ENac channels (triamterine, amiloride)
how diuretics get to the tubular lumen usually
are secreted
why must increase diuretic dose if low GFR
to get more blood to peritubular capillaries and the vasa recta
why is there an upper limit to the dose of diuretic that should be given
maximum dose where transporter is completely inhibited exists. beyond that, no benefit and only side effects
limiting factor in loop diuretics
more Na is delivered (and therefore reabsorbed) distally
limiting factors in thiazides (2)
- they have unknown mechanisms to lower BP
- low Na reabso there
how to follow GFR in patients on diuretics
urea and Cr concentrations
big side effect of diuretics
renal failure
consequence of giving too much diuretics too fast
loss of IV volume is too big to be compensated: AKI (rise in urea and Cr), less tissue perfusion, drop in CO, etc.
rate of fluid removal in pulm edema, ascites and peripheral edema
all slow except pulm edema if hypoxic
why diuretics can cause hypokalemia
more Na flow to the distal nephron (CT and CD) so more entry in ENac channels and consequent secretion of K from K channels
why diuretics can cause hyperuricemia
nephron compensates to reabso Na so more Na reabso in PCT and urea reabso linked to Na in PCT
