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Regulatory: Acute Kidney Injury - Prerenal - Coggle Diagram
Regulatory: Acute Kidney Injury - Prerenal
Pathophysiology
Oliguric Phase
Azotemia occurs as kidneys don't clear nitrogenous wastes fast enough. F/E imbalances occur as kidney output drops.
Local mediators cause intrarenal vasoconstriction, neutrophil adherence in capillaries can cause an intrarenal injury - Cellular injury and necrosis (which may cause acute tubular necrosis)
Urine output below 400mL/day for 8-14 days
Diuretic Phase
over 102 weeks UO slowly increases, F/E balance move towards correction, and GFR improves
As the cause of the injury is corrected, kidneys begin to reperfuse
Onset Phase
Triggering event like a burn or an injury leading to a sudden blood or fluid loss - crushing injury, HF, vasodilation, V/D, hypovolemia... (
Prerenal)
Rapid systemic hypoperfusion affects the kidneys (which receive about 25% of CO)
Decrease in filtration causes urine output decreases below 0.5 mL/kg/hr and GFR to decrease
Recovery Phase
over 3 to 12 months after the AKI kidneys continue to return to normal or near normal, F/E balances, edema reduces
Postrenal
A mechanical structure beyond the kidney (BPH, bladder tumor, fecal impaction, kidney stones...) reduce urine output after it leaves the kidneys, eventually "backing up" the system: increasing tubular pressure and reducing filtration.
Intrarenal
Structural damage in the kidneys from toxins (drugs, infection), inflammation, injury like acute tubular necrosis, or ischemia cause the kidney to become hypoperfused
Symptoms
HTN or hypotension
Bibasilar crackle
tachycardia
AMD and decrease LOC
Oliguria / anuria
Arrythmias
Azotemia
Uremic breath odor
Pruritus
Dry mucous membranes and and/or skin
F/E imbalance -> HyperK+
Risk Factors
Surgery
Obesity
Hypotension
Chronic infection
Age
Nephrotic agents - aminoglycosides and ACEI
Comorbidities: HF, HTN, CAD, Diabetes, Liver disease...
Hemorrhage
Sepsis
Diagnostics and Labs
Urinalysis
Ultrasound
BUN
CT
Renal angiogram
CMP
Creatnine level in serum and creatinine clearance
CBC
Complications
Pulm. Edema
HF
Meta Acidosis
Fluid overload
Electrolyte imbalance (HyperK+, Hypocalcemia, Hyperphosphatemia)
GI bleed
Infection and sepsis
Uremia
Arrhythmia
Cognitive deficits
Death
Treatment
Sodium bicarbonate for acidosis
Diuretics - furosemide
Fluid restriction
N-acetylcysteine for contrast nephropathy
High cal, low K+ and NA+ diet
Dialysis
CRRT
Transplant