2.2.1 Acute Kidney Injury Flashcards
What are some of the various causes of pre-renal kidney injury?
Low CO
Renal artery stenosis
Decreased intravascular volume (blood loss, dehydration)
Decreased systemic vascular resistance (sepsis, cirrhosis)
Taking what type of medication can alter FeNa?
Diuretic medications
Determine the source of the AKI and how to treat it, doc
Renal US - distended bladder w/ bilateral hydronephrosis; Post-renal AKI secondary to bladder outlet obstruction from prostate cancer
Treat: Indwelling Foley
Determine the source of the AKI and how to treat it, doc
Pre-renal AKI secondary to intravascular fluid depletion (dehydration
IV fluids
What are the three main subclasses of intrinsic (interstitial) AKI?
Allergic, infectious, infiltrative
What are the four different types of intra-renal (intrinsic) AKI?
Large vessels, small vessels, tubules, interstitium
What are the three sites of kidney injury and their corresponding prevelance?
Pre-renal injury (55%)
Intra-renal (40%)
Post-renal (5%)
What term is synonymous with AKI?
Acute Renal Failure (ARF)
What is the most common intrinsic (tubular) AKI?
Acute tubular necrosis (ATN)
This microscopic finding is consistent with what type of disease?
Interstitial Disease
What are two different sources of intrinsic (small vessel) AKI?
Glomerulonephropathies - damage to GBM
Small vessel occlusion - HTN, coagulopathies, embolic dz
What is the most common cause of post-renal AKI?
Bladder neck obstruction
What are some symptoms that are consistent with AKI?
Generalized fatigue, nausea and anorexia, itching
Determine the source of the AKI and how to treat it, doc
ARN secondary to hypoxia and possibly iodinated contrast dye w/ cardiac catheterization
Treat: supportive care including oxygen, BP support, IVF
What are 4 major complications of AKI?
Fluid overload
Electrolyte disorders (Na, Phos, K, Ca)
Metabolic acidosis
Mental status change (seizures)
Describe the two renal US?
Left: Normal
Right: Hydronephrosis
Determine the source of the AKI and how to treat it, doc
Pre-renal AKI secondary to cardiac tamponade (low CO)
Treat: Pericardiocentesis
By definition, what is acute kidney injury (AKI)?
Sudden decrease in kidney function that can lead to: inability to maintain fluid balance, electrolyte disorders, inhibition of nitrogenous waste excretion
What are three different ways to classify AKIs?
Duration
Amount of Urine Output
Site of Kidney Injury
What are some systemic dz’s that can lead to glomerular injury?
Skin (purpura, petechiae)
GI (hematochezia, diarrhea)
Lung (pulmonary hemorrhage)
MSK (arthalgias, myalgias)
What are some physical exam findings that are consistent with AKI?
Cardiac rub
Neurological deficits (asterixis, confusion, tremor)
Signs of volume overload (cardiac gallop, JVD, pulm edema, peripheral edema)
Determine the source of the AKI and how to treat it, doc
Acute interstitial nephritis secondary to Cipro (key word: WBC casts)
Treat: Discontinue cipro
What are the two different classifications of amount of urine output?
Oliguria: <400 mL urine/day
Anuria: <50 mL urine/day
What are some of the indications for renal biopsy?
Proteinuria
Nephritic syndrome: Proteinuria, glomeular hematuria, progressive AKI, severe HTN, evidence of inflammation on urine microscopy
Unexplained AKI
What disease has these common urine findings?
Glomerular Dz’s
What are some the ways to resolve obstruction?
Foley catheter for bladder outlet obstruction
Ureteral stenting for ureteral obstructions
If obstruction unresolvable, percutaneous nephrostomhy tubes inserted
What are the two inciting events that can lead to ATN?
Nephrotoxic Agents (endogenous or exogenous)
Ischemic states
Which imaging study is most useful for evaluating AKI?
Abdominal US
What are some of the indications for hemodialysis in acute setting?
HyperK w/ EKG changes
Pulmonary edema
Severe metabolic acidosis
Mental status change
Certain drug intoxications
Progressive dz w/o reversibility of underlying cause
What are some common tests to assess kidney function?
Lab studies (BUN, CR, BUN:CR ratio)
Blood Test: Electrolyte abnormalities (hyperkalemia, hyperphosphatemia, metabolic acidosis)
Urine Studies (cellular elements)
This microscopic finding is consistent with what type of disease?
Tubular Dz (ATN)
What the two different sources of intrinsic (large vessel) AKI?
Arterial obstruction (plaque, hypertrophy of muscular layer, dissection)
Renal vein outflow obstruction (uncommon)
What are some characteristic urine findings w/ glomerular injury? (3)
RBC casts, dysmorphic RBCs, proteinuria
What is the equation for fractional excretion of sodium? Normal values?
FeNa = [(UNa/PNa) / (UCr/PCr)]
Normal value: 1-2 %
FeNa < 1% - suspect pre-renal AKI
FeNa > 3% - suspect intrinsic AKI with some degree of tubular damage
