By Michael Spinner
Acute kidney injury (AKI) is a common problem among hospitalized patients with numerous etiologies. Common causes include:
- Volume depletion or renal hypoperfusion (prerenal)
- ATN from ischemia or nephrotoxins (intrinsic), and
- Urinary obstruction (postrenal).
For all of these etiologies, the final common pathway is an acute decline in the GFR, resulting in elevation of serum BUN and creatinine and often a decline in urine output. In most cases, patients with AKI recover with treatment of the underlying cause (e.g. IV fluids for prerenal azotemia). In some cases, however, prompt treatment with dialysis is warranted. Use the mnemonic below to remember the indications for dialysis in patients with AKI:
A – Acidosis – metabolic acidosis with a pH <7.1
E – Electrolytes – refractory hyperkalemia with a serum potassium >6.5 mEq/L or rapidly rising potassium levels; see this post for a review of the causes and management of hyperkalemia
I – Intoxications – use the mnemonic SLIME to remember the drugs and toxins that can be removed with dialysis: salicylates, lithium, isopropanol, methanol, ethylene glycol
O – Overload – volume overload refractory to diuresis
U – Uremia – elevated BUN with signs or symptoms of uremia, including pericarditis, neuropathy, uremic bleeding, or an otherwise unexplained decline in mental status (uremic encephalopathy)
Of note, the likelihood of developing one or more of these complications of AKI is increased in patients with chronic kidney disease at baseline (most commonly hypertensive and/or diabetic nephropathy). Thus, particular care should be taken to monitor electrolytes, fluid balance, and acid-base status for these patients with acute or chronic renal failure. For these AEIOU indications, prompt treatment with dialysis can help prevent acute complications and preserve long-term renal function.
UpToDate – Renal replacement therapy (dialysis) in acute kidney injury (acute renal failure) in adults: Indications, timing, and dialysis dose