Acute kidney injury after burn

- Acute kidney injury (AKI) is common after severe burn and carries a high mortality rate.
- Burn-related AKI has numerous etiologies and can be classified as early or late.
- Renal replacement therapy has reduced the mortality of burn patients with AKI.
- Biomarkers for the early diagnosis of AKI in burn patients are being investigated.
- Long-term effects of burn-related AKI are unknown and further investigation is needed.

Acute kidney injury (AKI) is a common and morbid complication after severe burn, with an incidence and mortality as high as 30% and 80%, respectively. AKI is a broad clinical condition with many etiologies, which makes definition and diagnosis challenging. The most recent Kidney Disease: Improving Global Outcomes (KDIGO) consensus guidelines defined stage and severity of AKI based on changes of serum creatinine and urine output (UOP) across time. Burn-related kidney injury is typically classified as early (0-3 days after injury) or late (4-14 days after injury). Early burn AKI is typically due to hypovolemia, poor renal perfusion, direct cardiac suppression from TNF-alpha, and precipitation of denatured proteins, while late AKI is often due to sepsis, multi-organ failure, and nephrotoxic drugs. Diagnosis can be difficult as UOP and biochemical markers can be relatively normal even with significant renal injury. A sensitive and specific biomarker for the early diagnosis of AKI is sorely needed, and multiple potential biomarkers are being investigated. For treatment, the reversal of the underlying cause is the first intervention. The advent of renal replacement therapy has significantly improved the mortality of burn patients with AKI and should be initiated early if injury progresses despite initial maneuvers. Unfortunately, no beneficial pharmacologic agents have been identified, despite multiple investigations. Of burn patients who survive AKI, the vast majority do not receive long-term hemodialysis and they are generally thought to have a good renal prognosis although this view is shifting. Preliminary data in the burn population suggest that AKI may confer an increased risk of end-stage renal disease and long-term all-cause mortality, but further research is needed.