AKI Flashcards
(119 cards)
1
Q
What is oliguria?
A
Low urine output (<400mL/day)
2
Q
What is anuria?
A
Failure of kidneys to produce urine (<100mL/day)
3
Q
What is Azotemia?
A
Buildup of nitrogen waste products in blood (Elevated BUN/Cr)
4
Q
What is Uremia?
A
Buildup of urea waste products in blood (clinical syndrome w/ worsening renal function)
5
Q
What is Creatinine?
A
Waste product produced by muscles from breakdown of creatine (filtered by kidneys –> urine)
6
Q
What is Glomerular filtration rate (GFR)?
A
Amount of blood filtered by glomeruli/min
“estimated GFR”
7
Q
How does GFR reflect how well kidneys are functioning?
A
Uses serum Cr levels in formula to calculate a #
8
Q
GFR will generally ______ with increased creatinine
A
Decrease
9
Q
What is Blood Urea Nitrogen (BUN)?
A
Measure of amount of urea & nitrogen in blood
10
Q
What is Creatinine Clearance (CrCl)?
A
Amount of creatinine excreted in urine
11
Q
CrCl is another way to measure what?
A
GFR
12
Q
What does CrCl compare?
A
Serum and urine creatinine levels in 24 hrs
13
Q
What is Fractional Excretion of Sodium (FENA)?
A
Measures % of filtered sodium excreted in urine
14
Q
What is acute kidney injury (AKI) characterized by?
A
Abrupt decrease in kidney function
15
Q
What does decreased kidney function result in?
A
Waste excretion dysfunction, inability to maintain acid-base balance, fluid/electrolyte imbalance
16
Q
Evidence of AKI?
A
Change in lab values
17
Q
Definition of AKI?
A
Absolute increase in serum creatinine by 0.3 mg/dL or more in 48hrs or relative increase of >1.5x baseline, known or presumed to have occurred in 7 days
18
Q
What are the three categories of AKI?
A
Prerenal, Intrarenal/Intrinsic, Postrenal
19
Q
AKI accounts for what % of hospital admissions?
A
5%
20
Q
AKI accounts for what % of hospital admissions?
A
30%
21
Q
AKI will develop in what % of hospitalized patients?
A
25%
22
Q
Increased mortality in what type of AKI?
A
Any type
23
Q
What does the RIFLE classification stand for?
A
Risk, Injury, Failure, Loss of kidney function, End-stage kidney disease
24
Q
What does the AKIN classification stand for?
A
Acute Kidney Injury Network
25
What does the KDIGO classification stand for?
Kidney Disease: Improving Global Outcomes
*most recent/preferred tool
26
According to KDIGO, AKI is the presence of what?
-Inc. in serum creatinine by >/=0.3 mg/dL w/in 48hrs
-Inc. in serum creatinine to >/= 1.5x baseline (w/in prior 7 days)
-Urine volume <0.5 mL/kg/hr for at least 6 hrs
27
KDIGO stage 1?
Inc. in serum creatinine to 1.5-1.9x baseline
OR
Inc. in serum creatinine by >/= 0.3 mg/dL
OR
Reduction in urine output to <0.5 mL/kg/hr for 6-12 hrs
28
KDIGO stage 2?
Inc. in serum creatinine to 2.0-2.9x baseline
OR
Reduction in urine output to <0.5 mL/kg/hr for >/= 12 hrs
29
KDIGO stage 3?
Inc. in serum creatinine to 3x baseline
OR
Inc. in serum creatinine to >/= 4.0 mg/dL
OR
Reduction in urine output to <0.3 mL/kg/hr for >/= 24 hrs
OR
Anuria for >/= 12 hrs
OR
Initiation of renal replacement therapy
OR Patients <18 yrs, dec. in eGFR to <35 mL/min/1.73M2
30
Prerenal AKI occurs in response to what?
Severe volume depletion w/ nephrons structurally intact (acute drop in BP/shock, interruption of b/f from severe injury/illness)
31
What occurs in prerenal AKI?
GFR decreased (compromised perfusion), Tubular/glomerular function normal
32
Intrinsic AKI occurs in response to what?
Toxins, ischemia, inflammatory insults to kidney w/ structural & functional damage
(drugs, prolonged hypotension, infection, etc.)
***Ischemic injury MC
33
Intrinsic AKI predominantly affects what part of the kidney?
Glomerulus or tubule
34
Postrenal AKI occurs in response to what?
Obstruction to passage of urine (enlarged prostate, kidney stones, tumor, injury)
35
What occurs in Postrenal AKI?
Obstruction causes increased tubular pressure - decreasing filtration force
36
MC type of AKI overall?
Prerenal
37
Prerenal AKI is characterized by what?
Decreased renal perfusion
38
Causes of Prerenal AKI?
-Hypovolemia (bleed, GI loss, dehydration, burns)
-Dec. circulating volume (liver failure, CHF)
-Hypotension (shock, dehydration)
-Embolism, renal artery thrombosis
-NSAIDs, IV contrast (afferent arteriole vasoconstriction)
39
Prerenal AKI may lead to what if not corrected promptly?
Intrinsic injury (acute tubular nercrosis)
40
Prerenal AKT may rapidly respond to what?
Volume repletion
41
What type of AKT accounts for 50% of cases referred to nephrologists?
Intrinsic
42
Diagnosis of Intrinsic AKT is considered when what other conditions are excluded?
Pre/postrenal AKI
43
What are the three types of intrinsic AKI?
-Acute tubular necrosis (destruction/necrosis of tubules)
-Acute interstitial nephritis (inflammatory response)
-Acute Glomerulonephritis (immunologic inflammation of glomeruli)
44
Most common type of intrinsic AKI?
Acute tubular necrosis (destruction/necrosis of tubules)
45
What are the two main causes of Acute tubular necrosis?
Ischemia & nephrotoxin exposure
46
How can ischemia cause ATN?
Prolonged prerenal hypoperfusion,
Inadequate renal b/f leads to poor perfusion causing tubular damage/necrosis
47
Exogenous nephrotoxins that can cause ATN?
Contrast dye***, aminoglycosides, vancomycin, NSAIDs, cyclosporine
48
Endogenous nephrotoxins that can cause ATN?
Tumor lysis syndrome, Rhabdo, Lymphoma, Leukemia, Multiple myeloma
49
Urinalysis for ATN?
2+ granular (muddy brown) casts or renal tubular epithelial cells
*strongly predictive
50
How to manage ATN?
Remove offender, volume balance
51
Recovery time for ATN?
Slower (wks - months)
52
Mechanism of acute interstitial necrosis?
Inflammatory or allergic response in the interstitium
53
Most common cause of acute interstitial necrosis?
Drug hypersensitivity (70%)
-NSAIDs, PCNs, cephalosporins, sulfa drugs, diuretics, phenytoin
54
Other causes of acute interstitial necrosis?
-15% of cases caused by infection:
Strep, CMV, RMSP, histoplasmosis
-8% idiopathic
-6% autoimmune (SLE, sarcoidosis, sjorgen's)
55
Clinical features of acute interstitial necrosis?
Fever, eosinophilia, maculopapular rash, arthralgia
56
Urinalysis of acute interstitial necrosis?
WBC casts, eosinophilia
57
Postrenal AKI is also known as what?
Obstructive uropathy
58
Postrenal AKi is characterized by what?
Obstruction of urine output: BPH, Cancer (bladder, prostate), Renal calculi, trauma
59
What is the least common cause of AKI (5-10%)?
Postrenal AKI
60
Postrenal AKI symptoms?
Usually asx
May have change in urine output, HTN, rarely have pain
61
Management of postrenal AKI?
Removal of obstruction (often readily reversible if correctly quick)
62
Clinical manifestations of AKI may be related to what?
Azotemia or underlying cause/condition
63
Overall signs/sx of AKI?
May be asx/found incidentally or have sx of: dec. urine output, hematuria, CP/arrhythmias, platelet dysfunction, pericardial effusion, SOB, AMS, seizes/coma (severe cases), peripheral edema, fatigue, N/V, malaise
64
Physical exam for skin in AKI may reveal what?
Butterfly rash, digital ischemia, palpable purpura, track marks
65
Physical exam for eyes in AKI may reveal what?
Iritis, uveitis, icteric sclera, signs of: HTN, DM
66
Physical exam for ears in AKI may reveal what?
Hearing loss
67
Physical exam for cardiovascular in AKI may reveal what?
Pericardial friction rub, JVD, S3 sound, edema, irreg. rhythm
68
Physical exam for pulm in AKI may reveal what?
Rales
69
Physical exam for abdomen in AKI may reveal what?
Pain, CVA tenderness
70
Physical exam for GU in AKI may reveal what?
Pelvic/rectal mass, bladder distention, enlarged prostate
71
What may be included in H&P for AKI?
Fluid status, inpatient setting, Meds, prior labs, comorbidities, IV contrast exposure
72
CBC for AKI may reveal what?
Leukocytosis, anemia, platelet dysfunction
73
Electrolytes for AKI may reveal what?
hyperkalemia, hyperphosphatemia
74
Hallmarks of AKI in renal function tests (BMP, CMP)?
Increased serum Cr and BUN
*But do not distinguish AKI vs. CKD
*often incidental finding
75
BUN:CR ratio suggestive of prerenal AKI?
>20:1
76
GFR in AKI is ______?
Decreased
77
CrCl in AKI is _______?
Decreased
78
GFR and CrCl both rely on what to measure kidney function?
Serum creatinine levels
79
eGFR uses factors such as _____, ______, _____ to help estimate GFR?
Age, gender, race
80
Formulas available to calculate estimated CrCl?
Cockcroft-Gault, Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)
81
Serology for AKI may reveal what?
Autoimmune etiologies if present
82
ABG for AKI may reveal what?
Metabolic acidosis
83
What does fractional excretion of sodium (FENA) measure?
% of Na filtered by the kidney that is excreted in urine
*has limitations
84
Preferred test to help distinguish between prerenal vs ATN AKI?
FENA
in Prerenal: <1%
in ATN: >2%
85
FENA calculation?
(Urine Sodium/Serum Sodium) divided by
(Urine Creatinine/Serum Creatinine) x100
86
What is visual urinalysis?
Gross inspection of color (cloudy, concentrated, red, clear, etc)
87
Dipstick urine analysis for provides a rapid assessment of what?
Urine characteristics using: pH, spec. gravity, protein, hemoglobin, glucose, ketones, bilirubin, nitrites, leukocyte esterase
88
What does microscopic urinalysis of urine sediment allow?
Confirmation/clarification of dipstick results and identifies structures that dipsticks cannot
89
What are urinary casts?
Tube-shaped structures from accumulation of proteins w/in renal tubule
*characteristic findings of casts strongly suggestive of certain diagnoses
90
What favors urinary cast formation?
Decreased: urine flow, urin pH
Increased: urine salt concentration
91
What type of casts in CRF?
Waxy or broad
92
What type of casts in pre-renal AKI?
Hyaline
93
What type of casts in Acute tubular necrosis (intrinsic AKI)?
Muddy brown
94
What type of casts in Allergic interstitial nephritis (intrinsic AKI)?
Urine eosinophils
95
What type of casts in Glomerulonephritis (Nephritic)(intrinsic AKI)?
RBC
96
What type of casts in Glomerulonephritis (Nephrotic)(intrinsic AKI)?
Fat oval bodies
97
What type of casts in post-renal AKI?
Normal or red/white cells, crystals
98
EKG in AKI may reveal what?
Peaked T-waves, PR prolongation, QRS widening in hyperkalemia
99
Initial imaging test for signs of obstruction/hydronephrosis in AKI?
renal US
100
What scan can be used if renal/ureteral calculi are suspected?
Non-contrast CT
101
Is renal biopsy routine for AKI?
No
May be used if results will change the tx, if noninvasive strategies unable to diagnose
102
Treatment for AKI is mostly _________
Supportive
103
Goals of AKI treatment?
Hemodynamic stability, fluid/electrolyte balance, d/c nephrotoxic agents, adjust meds if needed
104
Treatment regimen for prerenal AKI?
Optimize renal perfusion & cardiac function: Volume repletion (rapid response)
-Packed RBCs if blood loss
-IV fluids for dehydration
-Avoid fluid overload & hyperkalemia
105
Treatment regimen for intrinsic AKI?
Tx underlying cause
-remove offending agents
-immunosuppressive agents
-plasmapheresis (removing plasma from blood via centrifuge and re-infusion for autoimmune dz)
106
Treatment regimen for postrenal AKI?
Identify/remove cause of obstruction:
-catheterization
-nephrostomy tube
-ureteral stent/lithotripsy
107
Dialysis is also known as what?
Renal replacement therapy (RRT)
108
How many modalities for dialysis?
many
109
Hemodialysis is most commonly used where?
the U.S.
110
What does dialysis entail?
Filtering waste from blood when kidneys cannot
-Machine connected to large vein --> filters blood --> returns blood to large artery
111
What are the "AEIOU" indications for dialysis?
Acidosis (severe metabolic)
Electrolyte abnormalities (uncontrolled hyperkalemia)
Intoxications/ingestions (overdose of meds)
Overload (severe fluid overload)
Uremia s/sx (pericarditis, encephalopathy, unexplained decline in MS)
112
AKI prognosis is variable depending on what?
duration, degree of recovery, recurrence
113
AKI carries a risk of progression to what?
CKD/ESRD
114
Which types of AKI carry better prognosis?
Prerenal and postrenal AKI
115
Does AKI increase mortality?
Yes
116
Which population has a 40-50% mortality rate with AKI?
Hospitalized pts w/ AKI
117
Which population has a >50% mortality rate with AKI?
ICU pts w/ AKI
118
What can improve outcomes in AKI?
Nephrology referral
119
Post-AKI requires what surveillance?
Nephrology surveillance
