From the Guidelines
Acute tubular necrosis (ATN) is the most common cause of acute kidney injury (AKI) in hospitalized patients, resulting from damage to the tubular epithelial cells of the kidneys, and its management focuses on identifying and treating the underlying cause, maintaining fluid and electrolyte balance, and providing supportive care while the kidneys recover. ATN typically occurs due to ischemic, nephrotoxic, or septic causes. Ischemic ATN results from reduced renal blood flow during hypotension, shock, or major surgery. Nephrotoxic ATN is caused by exposure to substances harmful to the kidneys, including medications (aminoglycosides, NSAIDs, contrast media), heavy metals, and myoglobin from rhabdomyolysis. Sepsis can cause ATN through both inflammatory mediators and reduced renal perfusion.
Causes of ATN
- Ischemic causes: reduced renal blood flow during hypotension, shock, or major surgery
- Nephrotoxic causes: exposure to substances harmful to the kidneys, including medications (aminoglycosides, NSAIDs, contrast media), heavy metals, and myoglobin from rhabdomyolysis
- Septic causes: inflammatory mediators and reduced renal perfusion
Management of ATN
- Discontinue any nephrotoxic medications and treat the primary condition causing ATN
- Ensure adequate hydration while avoiding volume overload, using intravenous fluids like normal saline or balanced crystalloids as needed
- Monitor electrolytes closely, particularly potassium, and treat hyperkalemia promptly if it develops using insulin with glucose, sodium bicarbonate, calcium gluconate, or potassium binders like sodium polystyrene sulfonate (15-30g orally or rectally) or patiromer (8.4-25.2g daily) 1
- Adjust medication dosages for reduced kidney function and maintain nutritional support with appropriate protein intake (0.8-1.0 g/kg/day)
- In severe cases with complications like volume overload, severe acidosis, hyperkalemia, or uremic symptoms, renal replacement therapy (dialysis) may be necessary 1
Approach to ATN
- Identify and treat the underlying cause of ATN
- Maintain fluid and electrolyte balance
- Provide supportive care while the kidneys recover
- Consider the use of biomarkers to predict the clinical course of AKI and identify patients who are more likely to respond to a specific intervention 1
Most patients with ATN recover kidney function within 1-3 weeks with appropriate management, though some may have residual kidney damage requiring long-term monitoring. It is essential to prioritize the management of ATN to prevent long-term kidney damage and improve patient outcomes.
From the Research
Cause of Acute Tubular Necrosis (ATN)
- The cause of ATN can be divided into nephrotoxic, ischemic, or mixed 2
- Nephrotoxic ATN is associated with a lower mortality rate (10% on day 21) compared to ischemic ATN (30% on day 21) 2
- Ischemic ATN is often associated with serious comorbidities such as cardiogenic shock, hypotension, sepsis, and respiratory failure 2
Approach to ATN
- The diagnosis and management of ATN depend on the clinical setting and the type of injury or exposure to nephrotoxic substances 3
- Alternative classifications of ATN are based on the clinical setting, and different types of therapies are used in management 3
Management of ATN
- Optimizing medical therapy is crucial in patients with chronic heart failure with a reduced ejection fraction (HFrEF) to prevent ATN associated with angiotensin receptor-neprilysin inhibitors 4
- Close monitoring of patients treated with sacubitril/valsartan, an angiotensin receptor-neprilysin inhibitor, is necessary to prevent hypotension, oliguria, progressive azotemia, and renal failure 4
- The management of ATN should take into account the underlying cause and the presence of comorbidities, as well as the clinical outcomes and prognosis 2, 3