AKI - Exam 2 Flashcards
what is AKI?
Abrupt decline in renal function manifesting as reversible acute increase in nitrogenous wastes over hours to weeks
AKI is a precursor to what?
renal failure
BUN, Cr, and GFR in AKI?
BUN and Cr increase
GFR decreases
what is the RIFLE criteria?
” Classification system for the degree of insult to the kidney
are acute renal failure (ARF) and AKI the same?
NO!!!
3 graded levels of injury in RIFLE Criteria
risk, injury, failure
2 outcome measures of RIFLE Criteria
Loss of function
-total loss of kidney function (GFR < 15 for >4weeks) -> need dialysis for >4 weeks
End stage renal disease
-GFR < 15 for >3 months -> need dialysis for >3 months
RIFLE Criteria based on what?
Based on either degree of serum creatinine elevation or decrease in urine output
what conditions are at a higher risk for developing AKI?
HTN, DM (2 M/C)
CHF (chronic low flow to the kidneys = greater risk for AKI)
MM (have underlying kidney injury at baseline)
Chronic infection
Myeloproliferative disorder
3 etiologies of AKI?
pre-renal causes, intrinsic causes, post-renal causes
what are pre-renal causes of AKI?
low flow problem into kidney
what are intrinsic causes of AKI?
problem with kidney itself
-Problem with glomerulus, interstitial nephritis, tubules
-tubular problems are the M/C
what is the most common cause of intrinsic causes to the kidney? what is it due to?
tubular problems
-d/t vascular problems, ischemic problems, toxic problems, obstructive problems
what are post-renal causes of AKI?
anything that blocks off both ureters
ex: large bladder cancer, clot in bladder if someone on Coumadin and starts bleeding, problems with prostate
MAP and AKI
MAP < 80mmHg causes AKI to occur quickly
pre-renal cause of AKI
can occur in septic pts, cariogenic shock pts
examples of pre-renal causes of AKI?
pre-renal azotemia (increase in BUN/Cr w/out sx’s associated with it)
MAP <80mmHg then steep decline in GFR
most common cause of ARF?
renal blood flow problems (pre-renal causes)
intrinsic renal diseases affect what?
affecting small vessels, interstitial, glomeruli, or tubules
-most common is obstructive (acute tubular necrosis)
most common cause of tubular problems for AKI?
acute tubular necrosis - causes obstruction
post-renal processes of AKI
Obstruction or urine flow in ureters, bladder, or urethra
REVERSIBLE
how do NSAIDs affect the kidney?
NSAIDs are bad for kidneys (not toxic to kidney itself), but b/c they prevent the afferent arteriole from dilating to increase flow to kidney -> thus decreases flow to kidney -> increases likelihood of developing AKI
what is TTP-HUS-DIC?
all are coagulopathy disorders which can cause clots in the vessels and blockage of the vessels -> causing an ischemic kidney
pre-renal AKI etiology
Hypovolemia, decreased cardiac output, decreased effective circulating volume (CHF, liver failure/hepatorenal syndrome, sepsis, pancreatitis, nephrotic syndrome) -> all cause low flow through glomerulus
what is the most common cause of renal failure?
pre-renal injury
how is pre-renal injury reversed?
with restoration of renal perfusion/glomerular pressure (ex: with IVF, blood, vasopressors -> all improve volume thru kidneys)
BUN/Cr ratio for pre-renal injury
> 20:1 (dehydration ratio)
what do you see a decrease of in pre-renal injury?
fractional excretion of sodium (FeNa)
-activating RAAS -> holding onto fluid and sodium, so see decrease in FeNa
what does urinalysis for pre-renal injury reveal?
hyaline casts
FeNa <1% is suggestive of what?
pre-renal azotemia
-Kidney is working well, it’s trying to hold onto sodium with aldosterone and also water, so have less Na being secreted, so < 1% FeNa
FeNa >1% is suggestive of what?
intrinsic renal failure
-kidney is losing Na, it can’t hold onto it
FeNa >4% is suggestive of what?
post-renal failure
-Early on the FeNa will be lower than 4%, but later on it will rise b/c later on you don’t make as much urine, so have a lot of Na just sitting around in the little bit of urine that you do make (urine is super concentrated with Na)
when is FeNa not accurate?
when pt is on diuretics - can’t do FeNa if have taken diuretics w/in past 24hrs
can have increase in FeNa and be pre-renal if ___
on diuretics, have CKD and baseline FeNa is already baseline high
what is an alternative to FeNa?
FeUrea or FeUA
FeUrea/FeUA is not influenced by what?
not influenced by diuretics like FeNa is
FeUrea < 35% or an FeUA < 9-10% suggests?
a prerenal etiology of ARF
FeUrea > 50% or an FeUA > 10-12% suggests?
ATN (intrinsic cause) - acute tubular necrosis
pre-renal labs
elevated H/H, albumin, Ca (b/c pts are dry)
elevated Na, BUN, Cr
Decreased CO/effective arterial volume -> have edema
Urine output - oliguria (<500ml/day) or anuria (<100ml/day); low urine Na (<20 mEq/L)
what is the urine output like in pre-renal AKI?
OLIGURIA (< 500ml/day) or anuria (<100ml/day)
Low urine Na (<20 mEq/L)
if a male has anuria, what is the first thing to think about?
their prostate
if not making any urine, then what is usually the cause?
an obstruction of some kind
pre-renal tx
volume depletion
-NS and titrate
decreased CO/effective circulating volume
-diuretics (high dose IV), nitrates, dobutamine
all meds cleared by renal excretion should be avoided or doses adjusted
if pt volume depleted -> do not give diuretics
what meds are never given to a person that anuric?
diuretics
why give high dose IV diuretics for pre-renal tx?
to get the volume off, so give something nephrotoxic
treating like severe CHF pts with low volume
what is acute interstitial nephritis?
ALLERGIC reaction to medication (usually a new drug)
intrinsic renal cause
classic presentation of acute interstitial nephritis?
after recent new drug exposure
peripheral eosinophilia
***More commonly, pts are found incidentally to having rising serum creatinine after initiation of new med
most common meds associated with causing acute interstitial nephritis?
antibiotics
-Beta-lactams, sulfonamides, vancomycin, erythromycin, rifampin
what does urinalysis in acute interstitial nephritis show?
WBC casts (PATHOGNOMONIC)
treatment of acute interstitial nephritis?
D/C offending agent -> leads to reversal of renal injury
Glucocorticoids (can accelerate renal recovery) - 6wk taper prednisone or IV methylprednisolone x 3 days
can damage be permanent in acute interstitial nephritis?
yes, if long duration of exposure
is acute tubular necrosis reversible?
yes, unless severe/prolonged injury to tubular cells
causes of acute tubular necrosis?
- Ischemia (protracted pre-renal condition like AAA and have to clamp aorta -> causing low flow to both kidneys)
- Sepsis
- Toxins
(sepsis and toxins b/c of poor renal perfusion)
toxins that cause acute tubular necrosis
exogenous nephrotoxins (meds, poison)
endogenous nephrotoxins
what are some endogenous nephrotoxins that cause acute tubular necrosis?
myoglobinuria (rhabdo)
severe transfusion rx (get hemolysis) -> hemoglobinuria
uric acid (tumor lysis syndrome)
light chains (multiple myeloma)
exogenous nephrotoxins that cause acute tubular necrosis
NSAIDs, chemotherapeutic agents, ahminoglycosides (GN’s), amphotericin (anti-fungal), Vancomycin, radio contrast dye, poison (ethylene glycol -> alcoholics)
what is seen on urinalysis for acute tubular necrosis?
pigmented granular casts (muddle-brown casts) - PATHOGNOMONIC
what is the first thing to do when treating pt with acute tubular necrosis?
aggressive volume replacement (hydrate!!!) (esp if nephrotoxic agent, volume depletion)
what can you consider giving a pt with acute tubular necrosis?
high dose loop diuretics (100-200mg Lasix) to improve urine output if oliguria is present and extracellular-volume normalized
restrict what fr any pt with renal disease and for acute tubular necrosis?
Protein restriction
what examples of glomerular diseases?
Infectious Disease associated Syndromes
-Post-streptococcal glomerulonephritis - M/C (group strep A)
Nephrotic syndrome
-Minimal change disease (pediatric version of nephrotic syndrome)
Membranous glomerulonephritis
IgA nephropathy
Henoch-Schonlein Purpura
Goodpasture syndrome
Diabetic nephropathy
Hypertensive nephropathy
Progressive Glomerulonephritis
Polycystic kidney disease
which glomerular diseases are d/t chronic renal failure?
Goodpasture syndrome, Diabetic nephropathy, Hypertensive nephropathy, Progressive Glomerulonephritis, Polycystic kidney disease
what is post-strep glomerulonephritis?
immune-mediated disease
-Immune complex containing strep Ag deposited in affected glomeruli -> body keeps attacking the antigen and thus causes inflammation -> causes glomerular nephritis
post-strep glomerulonephritis caused by what and occurs when?
Caused by the infection, but occurs 7-12 days following the infection/sore throat/impetigo (usually untreated infection)
color of urine in post-strep glomerulonephritis?
cola colored urine (blood degraded/hematuria/RBC casts)
classic sign of post-strep glomerulonephritis?
HTN (salt and fluid retention) in the child
post-strep glomerulonephritis is the M/C of what? occurs where?
AKI in children globally
M/C in developing countries
post-strep glomerulonephritis highest risk at what age?
children 5-12 y/o
what does urinalysis show for post-strep glomerulonephritis?
RBC casts - PATHOGNOMONIC
-also have proteinuria, hematuria, pyuria (all b/c glomerulus is leaking everything)
if see a lot of sediment on urinalysis and maybe no infection, but child has HTN what should you think?
PSGN
what will pts with post-strep glomerulonephritis have elevated?
elevated titers of antibodies to strep
ELEVATED anti-streptolysin (ASO)
post-strep glomerulonephritis tx
PCNs if there is infection
symptomatic tx if no infection (anti-HTNs, Na restriction, diuretics)
children usually recover, adults can progress to permanent kidney damage
what is IgA Nephropathy?
IgA deposition in glomerulus (like PSGN), but NOT INFECTIOUS
IgA nephropathy often following?
URI
color of urine in IgA nephropathy?
red or Coca Cola 1-2 days s/p onset
IgA nephropathy dx?
renal bx
IgA nephropathy tx?
ACEI/ARB
steroids
renal transplant (will need this eventually)
what is Henoch Schonlein Purpura?
small vessel vasculitis w/IgA complex deposition (related to IgA)
PEDIATRIC VERSION OF IgA Nephropathy
Same IgA complex deposited at glomerulus and in small vessels -> so causes vasculitis/inflammation of vessels -> causes ischemic state
who is affected in Henoch Schonlein Purpura?
children about 6 y/o
Classic presentation of Henoch Schonlein Purpura?
Rash - esp LE’s and buttocks
Severe abdominal pain/vomiting
(can also have arthralgia in knees, ankles)
Henoch Schonlein Purpura tx?
Mostly supportive (immunosuppressants and/or plasmapheresis for worsening disease)
Excellent prognosis
Recover spontaneously in weeks (if not then use immunosuppressants)
nephrotic syndrome can be problem with what?
primary (problem with kidney) or secondary
type of nephrotic syndrome?
minimal change disease (pets version of nephrotic syndrome)
what is seen in nephrotic syndrome?
***Heavy proteinuria (> 3.5g/24hrs) -> foamy urine
***Hypoalbuminemia (< 3 g/dL)
***Peripheral edema
Hypercoag state (DVT, PE may be first presentation)
Bland urinary sediments (not many cells or casts)
what is minimal change disease?
nephrotic syndrome in children
what is the characteristic histologic finding for minimal change disease?
diffuse effacement of the epithelial cell foot processes on electron microscopy
abrupt onset what for minimal change disease?
edema & nephrotic syndrome
Minimal change disease tx
all children treated with PREDNISONE (steroids) for 8-16 weeks (most have complete remission after 8 weeks of steroids)
PREDNISONE!!! (up to 16 weeks of therapy)
urine sediment in nephrotic syndrome?
heavy proteinuria
what is vascular AKI?
intrinsic use of AKI
d/t:
- renal artery obstruction from thrombus, embolus, dissection, vasculitis
- renal vein obstruction
- microangiopathy (TTP, HUS, DIC)
- scleroderma renal crisis
vascular AKI sx’s?
LE rash, lived reticularis, urine eosinophils
tx for vascular AKI?
no tx just BP control and symptomatic management
common cause of post-renal failure?
bladder outlet obstruction
-check with bedside U/S -> see no urine output
d/t:
-prostatic obstruction, bladder Ca, stone, clots
treatment for bladder outlet obstruction/post-renal failure (d/t obstruction)?
relief of obstruction -> bladder catheterization
what is polycystic kidney disease?
Multisystem and progressive genetic d/o w/cyst formation and enlargement of the kidney (and other organs i.e. Pancreas, liver, spleen)
where are cysts predominantly in polycystic kidney disease?
in the kidney (but can be in other organs like pancreas, liver, spleen)
pt with polycystic kidney disease may come in with what and at 2x the risk of what?
May come in with worst headache of their life
-at 2x the risk of intracranial aneurysm
polycystic kidney disease significant association with?
ESRD
polycystic kidney disease signs and sx’s?
Pain (M/C) - abd, flank, back d/t enlargement of cysts, bleeding of cysts, kidney stones, infections
Hypertension
need to image polycystic kidney disease pts for what?
for bleeding from the cysts
polycystic kidney disease are on a lot of what for their pain?
narcotics -> need chronic pain management
diagnostic for polycystic kidney disease?
U/S - see multiple cysts in the kidney
Urinalysis - hematuria (d/t bleeding cysts)
polycystic kidney disease tx
BP management (ACEI/ARB - slows progression of disease)
Pain control -> use narcotics
- AVOID NSAIDs b/c promote bleeding and suppress auto-regulation
- AVOID Tylenol b/c of liver cysts
- surgical cyst decompression (done by IR)
- Nephrectomy = LAST LINE
Hematuria
- hydrate and if a lot then transfuse
- can bleed a lot
when to dialyze?
Acidosis Electrolytes (can't fix them) -***hyperkalemia***, hyperphosphatemia, hypocalcemia
Ingestions: OD
Overload:
-severe volume overload, esp on many IVs + anuria (on diuretics, but not peeing -> dialysis)
Uremia
-many sx’s:
CNS (asterixis, seizures, coma), platelet dysfxn (gi bleed, diathesis, coagulopathies), infectious risk, pleuritis/pericarditis (friction rub), pericardial effusion
