Acute Kidney Injury I and II Flashcards
T/F usually there are a lot of symptoms of AKI
false. usually they first do not have symptoms. History is crucial but not sensitive or specific
Diagnosed through ____ ___
Investigate patients with diseases or symptoms that cause AKI
Diagnosed through laboratory measurements Investigate patients with diseases or symptoms that cause AKI
Diagnosing Definition of AKI
- less than 7 days; over hours to days.
- rise of creatinine of 26.5 umol/L OR
- rise of creatining to 1.5x baselines OR
- or less than 0.5ml/kg/hr for 6 hours
general causes of AKI
vomiting, CHF, infection, pr autoimmune conditions
T/F eGFR is beneficial in diagnosing AKI
false. It’s just an estimate that assumes that creatinine is stable. in AKI, creatinine may not be stable and eGFR calculations are wrong.
Fill out AKI staging table
Natural history of AKI:
10 – 15% chance of __
___ increases chance of surviving to 40-60%
Survivors are at risk of ___ and __
10 – 15% chance of dying
Dialysis increases chance to 40-60%
Survivors are at risk of CKD and hypertension
ultimate pre-renal cause of AKI
decreased perfusion of the kidneys
ultiamate renal cause of AKI
injury to the kidney parenchyma
ultimate post-renal cause of AKI
blockage of urine outflow
pre-renal cause of AKI (that lead to reduced blood flow to kidneys) can be due to: (3)
Any disease state that lowers blood flow to the kdineys can cause an injury, they are separated into different categories:
hypovolemia (GI bleed), distributive shock (septic shock), cardiogenic shock (CHF).
signs that can help lead you to diagnose PRE-renal AKI
- look for signs that indicate reduced blood flow or poor perfusion. The kidneys are holding onto salt to keep water.
- random urine sodium less than 20 mmol/L
- fractional excretion of sodium FeNa than 1%
FeNa equation and what it means
FeNa<1% indicates that kidneys are underperfused. The body is doing anything it can to hold onto sodium. Measure of the percentatge of sodium that the body is wasting, compared to the amount of creatinine being filtered.
Note that low urine sodium is not exclusing to pre-renal AKI. it can also be due to renal and post- renal causes due to low EABV. Rule out with urinalysis and microscopy, and ultrasound KUB
Note that low urine sodium is not exclusing to pre-renal AKI. it can also be due to renal and post- renal causes due to low __. Rule out with ___ and __, and ultrasound ___
Note that low urine sodium is not exclusing to pre-renal AKI. it can also be due to renal and post- renal causes due to low EABV. Rule out with urinalysis and microscopy, and ultrasound KUB
Post renal (blocked outflow to the kidneys). As more urine enters the urinary tract, the pressure builds due to the blockage. the pressure rises to the point where it rises to the kidenys. pressure leads to kidney damage. What are some diseases that can result in blockage of the urinary tract?
males: prostatic hypertropy, prostate cnacer
Both sexes; kidney stones, developmental anomalies, cancers, retroperitoneal fibrosis (where lining of the abdomen gets fibrotic and compresses the kidneys)
signs of prostatic hypertrophy
hesitancy, low flow, frequent urination, nocturia
signs of kideny stones
flank pain
signs of cancer causing AKI
constitutional symptoms, hematuria
ultrasound indications of blocked UT
- hydronephrosis (due to blocked ureteres)
- kidney stones (mechanical block)
- bladder masses
foley catheterization can used in diagnosing and treatment of urinary tract obstruction. how?
when you put the catheter in, a large amount of urine released may indicate an obstruction and treat the condition/symptoms of pressure
In renal, the injury is happening to the kidney parenchyma itself. there are four parts of the parenchyma:
- glomeruli
- tubules
- microvasculature
- interstitium
glomeruli renal injury; damaged filers causing AKI. What components of urine would indicate damaged glomeruli?
dysmorphic red blood cells,
red blood cell casts
proteinuria
MAID acroncym for causes of glomerular renal injury resulting in AKI
M: malignancy
A: Autoimmune
I: infection
D: drugs
Acute tubular necrosis (ATN)- the tuubles draining the glomeruli are damaged to the point that they die. This causes an acute kidney injury. there are two main causes of ATN:
- ischemic; tubules not getting enough blood and die from hypoxia
- toxins.
Diagnosing ATN via Lab findings and microscopy
when tuublar cells die, they fall into the lumen of the tubule. they get trapped and form a casting of the tubule cell. there are lots of granules in the tubular cells and thus their casts look granular. depending on the scope, they may have a muddy brown color.
- FeNa greater than 2%. Tubular cells are not working properly. thirsty kidneys do everything they can be reabsorbing salt then water. if they have a low EABV, urine Na is low. if tubular cells are low, they cannot reabsorb sodium. therefore if someone has a low EABV and their fractional excretion of sodium is greater than 2%, the tubular cells are not working.
interstitial nephritis – 4 big causes
inflammation of kidney interstitium. Caused by
- antibiotics
- NSAIDS
- Autoimmune conditions
- Infections; WBC flood into interstitium, causing damage.
classic lab clue that will indicate interstitial nephritis (renal cause of AKI)
WHITE BLOOD CELL CASTS are pathognmonic. some WBCs that cause the inflammation move throuhg the tubules and get trapped in the proteins, coming out as white cell casts.
in vascular cases of renal AKI, we refer to ___ vasculature of kidneys, not the renal arteries. caused by the same things that cause __ __ __ (__)
in vascular cases of renal AKI, we refer to microscopic vasculature of kidneys, not the renal arteries. Its caused by the same things that cause microangiopathic hemolytic anemia (MAHA)
- TTP and HUS (ecoli)
- microthrombi form in the small vasculature of the organs, causing ischemia that ultimately lead to AKI
biggest clues that can indicate a vascular cause of AKI (renal)
recall that vascular renal AKI is caused by similar things that cause MAHA (TTP/HUS).
-therefore, the clues are MAHA findings, like thrombocytopenia, hemolysis and schistocytes
summary;
