AKI, CKD, and Dialysis Flashcards
How is AKI defined?
ACUTE reduction in function (GFR, UOP) and accumulation of nitrogenous wastes (BUN, creatinine)
According to the RIFLE criteria, changes in labs need to be within how many days to be classified as AKI?
7 days
What are the three distinct types of AKI?
Pre-renal (most common)
Intra-renal
Post-renal
What is the cause of pre-renal AKI?
Hypoperfusion due to: low volume, bad pump, vasodilation, or intra-renal vasoconstriction
What are the causes behind intra-renal AKI?
- 85% due to ATN (Ischemic or nephrotoxic)
- Glomerulonephritis
What is the cause of post-renal AKI?
Obstruction
What drug classes are considered to be nephrotoxic?
A LOT! Just to name a few…
ACE
ARBs
Antibiotics (aminoglycocides in particular)
Diuretics
Vancomycin
Contrast
Methotrexate
What is the number one cause of intra-renal AKI?
Acute tubular necrosis (ATN)
What are the typical causes of ATN?
- Ischemia
- Infection (sepsis)
- Nephrotoxins (direct cellular injury)
What are the response expectations in the three distinct types of AKI to fluids?
- Pre-renal: improve with fluids
- Intra-renal: no change with fluids
- Post-renal: no response to fluids
What type of AKI will have symptoms of volume depletion, CHF, and cirrhosis?
Pre-renal
What type of AKI will appear euvolemic?
Intra-renal and Post-renal
Because intra-renal and post-renal AKI will present similarly, what test should be ordered to differentiate the type of AKI?
Fractional excretion of sodium (FENa)
What does fractional excretion of sodium (FENa) help differentiate?
Helps differentiate between pre-renal and intra-renal AKI
Normal 1-2%
< 1% = pre-renal
> 2% = intra-renal
What type of AKI will there be abnormal casts?
Intra-renal
What type of AKI will there be no casts?
Post-renal
What type of AKI will have increased urine osmolality?
Pre-renal
What is the treatment for AKI?
Supportive
- Avoid additional injury: discontinue offending agents
- Maintain perfusion/volume (fluids)
- +/- renal replacement therapy
The rise in what element is used to define AKI?
Creatinine
*AKI is defined as an absolute increase in serum creatinine by 0.3 mg/dL or more over 48 hours, or a relative increase of 1.5 times baseline or more that is known or presumed to have occurred within 7 days.
Can there be neurologic changes with AKI?
Yes, prolonged bleeding time due to platelet dysfunction may occur with uremia. Progressive uremia may also cause neurologic signs such as asterixis, encephalopathy, and seizures
Most commonly associated with pre-renal AKI
What are the risk factors associated with chronic kidney disease?
- Hypertension
- DM
- Small birth weight
- Childhood obesity
- Increasing age
- Black race
- FH
How is the decline in kidney function measured in CKD?
GFR
A GRF greater than ______ is considered severe CKD
30
What is the presentation of stage 1 or 2 of (mild) CKD?
Asymptomatic, typically caught on routine labs
What symptoms are associated with moderate (stage 3 and 4) CKD?
- Hypertension
- Anemia
- Fatigue
- Decreased appetite
- Malnutrition
- Electrolyte and mineral abnormalities
What labs should be ordered in the work-up for CKD?
BMP/CMP
*Persistant reduced GFR (>3 months) is diagnostic of CKD
What is the mainstay of treatment for ESRD?
Renal replacement therapy
What is the definitive treatment of CKD?
Renal transplant
What is likely the complication leading to mortality in CKD?
CVD
*80% will die of CVD before reaching ESRD
What GFR value qualifies a patient for dialysis (RRT)?
GRF < 10 if no DM; GFR < 15 in DM
In pre-renal AKI there is decreased GFR, what are the downstream effects?
- Elevated creatinine, urea (BUN)
- Decreased Na+ in distal convoluted tubule which activates RAAS
Why does intrarenal AKI more associated with surgery, trauma or burns?
Due to the fluid shifts and third spacing –> kidney’s become dry from decreased blood flow
What is the pathophysiology of intrarenal AKI?
Decreased blood flow –> ischemia –> necrosis –> dead, sad nephrons
How do you differentiate prerenal vs. intrarenal AKI?
Fluid response
True or False: Typically, Post-renal AKI requires bilateral obstruction to occur
True
What type of casts will be present with kidney tubule injury?
Brown casts
What are the two most common causes of chronic kidney disease?
DM and HTN
What is Azotemia?
Increased urea, creatinine, nitrogenous compounds
Elevated BUN and creatinine in labs
What is uremia?
Azotemia with symptoms or signs of renal failure (uremic syndrome)
What systemic changes will be seen in CKD?
Hyperkalemia
Hypocalcemia
Hyper/onatremia
Hypoalbuminemia
What is a simple cyst?
Acquired, thin walled cyst (serous fluid) within the surface of the kidney
What type of genetic inheritance is polycystic kidney disease?
Autosomal dominant
What is the pathophysiology of polycystic kidney disease?
Ciliary defects will decrease the signaling between cells
Decreased intracellular signaling –> increased cellular division, increased apoptosis, decreased resorptive function
