Made Ridiculously Simple Flashcards
- filtration of blood
- regulation of blood volume and BP
- activation of vitamin D
- production of erythropoietin
4 major roles of the kidneys
- removes waste
- maintains appropriate concentrations of electrolytes
- maintains acid/base balance
Kidney functions (filtration of the blood)
this can cause… an increase in wastes in the circulation, disequilibrium of fluids and electrolytes, decreased activation of vitamin D (which can result in decreased calcium absorption and subsequent hypocalcemia), and/or decrease erythropoietin (which can lead to anemia)
Kidney failure
the kidneys get blood from the…
renal arteries
if the cause of renal failure is a decreased in blood supply to the kidneys (renal perfusion), this is called…
prerenal failure
if the cause of renal failure is a problem within the kidneys, this is…
intrinsic renal failure
if the renal failure is due to a problem in the collecting system (ureters/bladder/ urethra)
ie..obstruction by stones or tumor
postrenal failure
in preener failure, the kidneys do not get an adequate blood supply and thus cannot…
adequately filter the blood
any circumstance that can cause decreased blood volume (hypovolemia) can lead to..
decreased renal flow
ie..hemorrhage, dehydration
atherosclerotic disease of the renal arteries can decrease…
flow to one or both kidneys
effective volume depletion can cause…
prerenal failure
this is when the kidneys are not adequately perfused despite the fact that the blood volume is NOT actually depleted
ie…CHF, cirrhosis
Effective volume depletion
in CHF, the heart does not pump adequately, leading to decreased…
renal perfusion
cirrhosis is scarring of the liver that can impede blood flow through the hepatic portal system, causing….
portal hypertension
During cirrhosis, blood pools in the gut’s venous system causing the effective blood volume that reaches the kidneys to…
decrease
this decreased renal perfusion can result in PRERENAL failure… hepato-renal syndrome
the kidney(s) will try to reabsorb sodium and water in attempt to replenish intravascular volume in response to….
low blood volume
is Na and water reabsorption beneficial in hypovolemia? in effective volume depletion?
hypovolemia= this is beneficial
effective volume depletion= this is detrimental
the functional unit of the kidneys
nephron
tufts of capillaries and filtration surface for filtering blood
glomerulus
for reabsorption and secretion of various ions and molecules; parts include: proximal portion, loop of Henle, distal portion
tubule
used for further reabsorption/ secretion and delivery of urine to the ureters for delivery to the bladder
collecting duct
the one million or so nephrons of each kidney are surrounded by an _______ containing blood vessels and connective tissue.
interstitium
- diseases of the glomeruli (glomerulopathies)
- diseases of tubules (tubulointerstitial dz)
can cause…
intrinsic renal failure
one lab finding that distinguishes acute prerenal from acute intrinsic renal failure is the…
BUN to creatinine ratio in the BLOOD*
elevated serum creatinine signifies…
renal failure (of any kind!)
in prerenal kidney failure, they kidneys realize they are not getting enough fluid so they reabsorb Na and water in attempt to increase intravascular volume, causing an increase in…
BUN
The BUN to creatinine ratio in prerenal kidney failure is…
greater than 20:1
A “reabsorbing spree” in attempt to restore intravascular volume causes a rise in BUN out of proportion to the rise in creatinine is seen in….
prerenal failure
in INTRINSIC renal failure, the creatinine rises but since there is no hypovolemia, the kidney does NOT respond by reabsorbing. Thus, the BUN/Creatinine ratio will be…..
less than 20:1
dilute urine but an increased excretion of sodium (greater than 40 meq/L) is seen in…
intrinsic renal failure
concentrated urine but a low concentration of sodium (less than 20 me/L) is seen in…
prerenal failure
dilute urine with high Na concentration
intrinsic renal failure
concentrated urine with low Na concentration
prerenal failure
renal stones into the ureters or a tumor in the GU system or adjacent system can cause…
postrenal failure
- drugs (i.e. abx, chemo agents)
- endogenous toxins (i.e. light chains in multiple myeloma)
- ischemia
- immune processes
- infection (ie pylonephritis)
can all cause…
tubulointerstitial disease
edema
proteinuria (cause foamy urine)
hypoproteinemia
hyperlipidemia
signs of….
nephROTIC syndrome
hypertension
hematuria
proteinuria
signs of..
nephRITIC syndrome
*nephritic has “iti(s)” in it, meaning inflammation. the inflammation is either due to systemic inflammatory/immune complex disease (i.e. vasculitis, lupus) or infection.
inflammation in the glomerulus leads to bleeding into the urine (hematuria) as well as renal vascular changes that produce HTN
nephRITIC syndrome
sodium, potassium, hydrogen ion, magnesium, ammonia and phosphate concentrations in the blood all increase and calcium concentrations decrease
advanced chronic renal failure
normally, the kidneys activate vitamin D. in renal failure, vitamin D activation decreases. Without vitamin D, ______ cannot be absorbed from the diet
calcium
*the amount of calcium in the serum decreases, thus…calcium concentration decreases in chronic renal failure
adding 1-OH to make 1,25 dihydroxy-vitaminD
the way the kidneys activate vitamin D
because of decreased calcium concentration in chronic renal failure, _____ hormone is secreted in attempt to increase blood calcium level
PTH
PTH increases blood calcium by releasing it from bone. thus, bone is constantly being broken down leading to….
renal osteodystrophy
the kidneys produce erythropoietin. in renal failure, erythropoietin decreases which can result in…
anemia
inflammation of the urethra, bladder and kidney
can be caused by UTIs
urethra= urethritis bladder= cystitis kidneys= pylonephritis
urethritis is most commonly caused by sexual transmission of….
N. gonorrhoeae
Chlaymydia trachomatis
dysuria
pain with urination
typically caused by gm negative organisms (i.e. E.Coli, Proteus, Klebsiella, enterobacteria and less commonly staph)
cystitis
flank pain, fever, malaise, increased urinary frequency, urgency, dysuria
Pyelonephritis
cells in the urine may signify…
lower urinary tract disease
conglomerates of protein and cells
*ALWAYS signify glomerular or tubular disease
casts
leukocyte esterase and nitrate tests used to test for…
UTIs
pediatric kidney tumor that often presents as an abdominal mass
abdominal pain, hematuria, HTN and/or fever
Wilm’s tumor
What is the main extracellular cation?
Sodium
the body’s goal is to maintain a constant concentration of..
sodium
*does this by altering the amount of water present, either by excreting or retaining water
when we say “hypernatremia” we are referring to the sodium concentration, not..
the ABSOLUTE amount of sodium
this IV solution increased sodium concentration in the blood
HYPERtonic saline
if a pt needs resuscitation or he/she cannot drink and needs maintenance fluid, one generally uses ________ saline
isotonic
in extreme cases of hypovolemia (i.e. shock), a ______ saline solution can be used
hypertonic
a ________ solution will stay in the intravascular space and pull more fluid into the intravascular space to try to dilute
hypertonic
electrolyte/fluid imbalances must be corrected…
SLOWLY
If electrolyte/fluid imbalances are corrected too rapidly with IV fluids, the brain does not have time to re-equilibrate. This can cause..
central pontine myelinolyiss (aka osmotic demyelination syndrome)
*due to dramatic fluid shifts that take place between the cells in the brain and the surrounding fluid
aldosterone causes reabsorption of….
sodium (and secretion of potassium)
*alsodteRoNe causes Reabsorption of Na and secretion of potassium
ADH causes….
water reabsorption
the main EXTRAcellular cation (higher in the serum than in the cells)
sodium
the main INTRAcellular cation (higher in the cells than in the serum)
potassium
Euvolemic
normal volume status
“volemias” refer to what is perceived on…
clinical exam
in increased in volume AND sodium
- most commonly from administration of sodium bicarb solutions or dialysis solutions
- can also be caused by primary hyperaldosteronism
Hypervolemic hypernatremia
if the amount of water loss is greater than the amount of sodium loss (and lots of water loss)
Hypovolemic hypernatremia
renal diseases or diuretics that waste water and or sodium
renal losses
extrarenal losses of water and/or sodium can occur through…
sweat, stool or fluid shifts from the intravascular space to the extravascular space
(i.e. major burns, surgery)
if water/sodium losses occur extra-renally (i.e. sweating, diarrhea, burns, etc), the kidneys will attempt to hold onto sodium, thus…
decreasing sodium concentration in the urine
if the cause of hypovolemic hypernatremia is RENAL (rather than extra-renal), there will be a ______ concentration of sodium in the urine
HIGHER
*higher sodium concentration in renal rather than extra-renal hypovolemic hypernatremia
urine sodium greater than 20 meq/L
renal sodium losses
urine sodium less than 20 meq/L
extra-renal sodium losses
hypodipsia
decreased water intake
*can lead to euvolemic hypernatremia
hypodipsia
diabetes insipidus
causes of euvolemic hypernatremia
loss of either ADH secretion or loss of ADH action
diabetes insipidus
increased ADH increases water reabsorption, resulting in a more ________ urine and a more _____ serum
- more CONCENTRATED urine
* more DILUTED serum
decreased ADH decreased water reabsorption, resulting in an _________ and ______ urine output, and a more concentrated serum
INCREASED and DILUTE urine output*
occurs with a decreased in ADH
Two extrinsic things that happen when BP decreases
- Baroreceptor reflex..afferent arterioles constrict to increase renal pressure
- RAA..renin is released to increase pressure
