Acute Kidney Injury Flashcards
What is acute kidney injury?
Sudden loss of renal function with subsequent rise in creatinine and BUN
What is the most frequent cause of acute kidney injury?
Decreased renal perfusion (prerenal)
What is the aetiology?
Pre renal acute kidney injury - hypovolemia, hypotension, decreased circulating volume, renal artery stenosis, drugs
Intrinsic acute kidney injury - acute tubular necrosis, acute interstitial nephritis, vascular diseases, glomerulonephritis
Postrenal acute kidney injury - acquired obstruction, neurogenic bladder, congenital malformations
What are the clinical features of acute kidney injury?
May be asymptomatic.
Oliguria or anuria
Signs of volume depletion (in prerenal AKI caused by volume loss)
Orthostatic or frank hypotension and tachycardia
Reduced skin turgor
Signs of fluid overload (from Na+ and H2O retention)
Peripheral and pulmonary edema
Hypertension
Heart failure
Shortness of breath
Signs of uremia
Anorexia, nausea
Encephalopathy, asterixis
Pericarditis
Platelet dysfunction
Signs of renal obstruction (in postrenal AKI)
Distended bladder
Incomplete voiding
Pain over the bladder or flanks
Fatigue, confusion, and lethargy
In severe cases: seizures or coma
Affected individuals have a higher risk of secondary infection throughout all phases (most common reason for fatalities)
What is the diagnosis for acute kidney injury?
Based on acute increase in serum creatinine and or decrease in urine output
What is the diagnostics criteria of acute kidney injury?
Acute kidney injury is defined as the presence of any of the following criteria: [7]
Increase in serum creatinine by ≥ 0.3 mg/dL (26.5 μmol/L) within 48 hours.
Increase in serum creatinine to ≥ 1.5 times baseline level within 7 days.
Decrease in urine output to < 0.5 mL/kg/hour for ≥ 6 hours.
Which staging is used for acute kidney injury?
KDIGO mainly (kidney disease improving global outcomes) based off serum creatinine level and urine output
What is the staging criteria for acute kidney injury with serum creatinine and urine output
AKI stage 1 - serum creatinine - increase of 0.3mg/dL or 1.5-1.9 times baseline. Urine output - less than .5mL/kg/hour for 6-12 hours
AKI stage 2 - serum creatinine - 2-2.9 times baseline. Urine output - less than .5mL/kg/hour for more than 12 hours
AKI stage 3 - serum creatinine - more than 3 times baseline or increase to >4mg/dL or renal replacement therapy initiated or in patients <18, decrease in eGFR to <35ml,min,1.73M^3. Urine output - <.3ml/kg/hour for >24 hours or anuria for >12 hours
What are the additional evaluations for acute kidney injury?
Imaging -
ultrasound - obtain urgently for hydronephrosis for patients with risk factors for urinary tract obstruction
Non contrast CT - get if ultrasound shows hydronephrosis
What is the management for acute kidney injury?
Initiate treatment for the underlying cause of AKI based on the presumed mechanism.
Prerenal: Correct adverse hemodynamic factors and replace the depleted volume as needed.
Postrenal: Relieve the urinary tract obstruction.
Intrinsic: Consider a trial of IV fluids; identify and treat underlying causes that require specific interventions.
Consider indications for acute dialysis and early nephrology consultation.
Provide supportive care to all patients.
Hold potentially nephrotoxic substances, ACE-Is, ARBs, NSAIDs, and nonessential medications.
Adjust the dosing of essential renally cleared medications.
Manage volume status and blood pressure to optimize kidney perfusion.
Identify and manage complications (e.g., electrolyte disturbances, acidosis, fluid overload).
Renal replacement therapy - Indications; consider urgently for:
Complications refractory to medical management
Refractory fluid overload
Electrolyte imbalances
Acid-base disturbances
Acute poisoning (e.g., by ethylene glycol); see “Approach to the poisoned patient.”
Uremic symptoms
Modalities include: [7][9]
Hemodialysis and/or hemofiltration (i.e., by CRRT or intermittent hemodialysis)
Peritoneal dialysis [7]
