AKI overview Flashcards
1
Q
Definition of AKI
A
- Decline in renal function over hrs to days, mostly by rise in serum Cr and BUN (drop in GFR)
- May or may not be associated w/ drop in urine output (oliguira= <100ml per day)
- May or may not be associated w/ uremic Sx: anorexia, nausea, vomiting, cramps, restless legs, sleep d/o, mental status change, seizures, fluid/electrolyte disturbances, anemia, platelet dysfxn and pericarditis
- Etiologies are pre renal (functional AKI), renal (structural AKI), or postrenal (obstructive AKI)
2
Q
Requirements of AKI
A
- Increase in Cr from baseline of at least .3
- 50% increase of Cr
- Urine output <80 for Cr to rise much
- AKI can be stage 1, 2, or 3 depending on severity
3
Q
Manifestations of AKI
A
- Azotemia (high nitrogen): increased BUN and Cr are markers
- Hyperkalemia
- Metabolic acidosis
- Volume overload
- Hyperphosphatemia
- AKI is reversible but CKD is irreversible
4
Q
3 etiologies of AKI
A
- Prerenal: sudden and severe drop in BP or interruption of RBF
- Intrarenal: direct damage to kidneys from inflammation, toxins, drugs, infection, reduced blood supply
- Post renal: sudden obstruction of urine flow due to enlarged prostate, kidney stones, tumor, or injury
5
Q
Causes of pre renal AKI
A
- Intravascular depletion: diarrhea, vomiting, diuretics, hemorrhage, dehydration
- Decreased effective intravascular volume: HF, cirrhosis, sepsis
- Renal hypoperfusion: renovascular disease, NSAIDs, ACEIs, hepatorenal syndrome
6
Q
Kidneys response to pre renal AKI
A
- Kidneys perceive decreased RBF as depletion of ECFV, thus respond by the following
- RAAS/SNS stimulation leading to Na reabsorption and ADH release leading to concentrated urine that is low Na (Una 20)
- Usually have oliguria
- May show normal urinalysis if caught quick enough (no epithelial cell sluffed off to form casts, just hyaline casts)
- Normalization of renal function upon correction of the hypo fusion
7
Q
Clinical presentation of pre renal AKI
A
- Orthostatic Sx/hypovolemia signs
- Tachycardia
- Fat neck veins
- Volume loss Hx (diarrhea, vomiting, diuretics, hemorrhage)
- HF
- Liver disease
- Hypervolemia signs (edema, JVP, ascites)
- Thirst
8
Q
Rx of pre renal AKI
A
- Volume repletion
- Discontinue the problem (NSAIDs, diuretics, etc)
- Cardiac support from inotropes
9
Q
Post renal AKI etiologies
A
- Upper tract obstruction (ureter): intrinsic or extrinsic
- Intrinsic: kidney stone, transitional cell CA
- Extrinsic: retroperitoneal adenopathy, AAA
- Lower tract obstruction (bladder neck): BPH (!!! most common), prostate CA, urethral stricture, neurogenic bladder
10
Q
Clinical presentation and Dx of post-renal AKI
A
- Hx: flank pain, hematuria, pelvic malignancy, Sx of bladder outlet obstruction (nocturia, urgency, frequency, decreased stream, incomplete voiding)
- PE: distended bladder, enlarged prostate, ab/pelvic mass
- Diagnostic studies: ultrasound, CT scan (hydronephrosis from back-up of urine)
11
Q
Post renal AKI Rx
A
- Relief of obstruction
- Recovery of renal function is dependent on the duration of the obstruction
12
Q
Intra renal etiologies of AKI
A
- Vascular: atheroembolic (will have systemic emboli w/ petechiae or purpura), malignant HTN
- Glomerular: glomerulonephritis (GN)
- Tubular: acute tubular injury (ATI)
- Interstitial: acute interstitial nephritis (AIN)
13
Q
Glomerulonephritis (nephritic syndrome)
A
- Etiologies: post-strep GN, lupus nephritis, membranoproliferative GN, antiGBM/goodpasture’s disease
- Presentation: nephritic syndrome
- Nephritic syndrome consists of: hematuria (dysmorphic RBCs in urine), RBC casts, proteinura
- Dx requires biopsy
14
Q
Acute tubular necrosis
A
- Presentation of ATN: nephrotoxic meds (antibios, IV contrast, NSAIDs), muscle trauma (rhabdo), episodes of hypotension, cardiac arrest, cardiac bypass, sepsis
- Urinalysis: Una>40, FeNa >1%, +/- oliguria
- Urine sediment shows granular casts (muddy brown granular casts) and tubular epithelial cells
- Rx: discontinue drug, supportive Rx
15
Q
Acute interstitial nephritis
A
- Triad of: fever, rash, eosinophilia
- Urinary findings: pyuria, WBC casts, eosinophiluria, hematuria
- Rx: discontinue offending drug, possible steroids
