Acute kidney injury
Prerenal: reduced perfusion — hypovolemia, heart failure, sepsis. The most common and the most reversible. Intrinsic: damage to the kidney itself — contrast, aminoglycosides, NSAIDs, prolonged ischemia, rhabdomyolysis. Postrenal: obstruction — prostatic hypertrophy, stones, blocked catheter. Always check the catheter before anything else. Signs: urine output under 0.5 mL/kg/h, rising creatinine and urea, weight gain, edema, hyperkalemia, nausea, confusion. Review every nephrotoxic agent and hold what can be held.