Acute kidney injury: a problem of definition

Abstract

Individuals with acute kidney impairment can have defects in the excretion of water, salts, and metabolic products, including creatinine. Classical nephrology taught that defective kidney excretion should be described on the basis of aetiology and anatomy. We learned to approach the patient with a pathophysiological focus: was the cause of defective excretion due to extrarenal volume deficiency, impaired blood perfusion, intrinsic kidney causes, or post-renal causes? If intrinsic damage was found, was the cause primarily related to sepsis, ischaemia, drugs or toxins, interstitial or glomerular causes, or a combination of the above? These categories were useful because they provided prospective insights into the clinical course and suggested appropriate therapeutic interventions. Hence, excretory defects, which can result from various challenges to the kidney, must be understood in their pathophysiological context. The definition of acute kidney injury – Authors' replyWe thank John A Kellum and Norbert Lameire for their letter in response to our Comment.1 An acute increase in serum creatinine (sCr) is caused by direct injury to kidney cells (ie, pathophysiological processes resulting from ischaemia, sepsis, medications, metals, or enzymes) or a compromise in cardiovascular homoeostasis (ie, substantial volume depletion,2 congestive heart failure,3 or portal hypertension4). Hence, we appreciate that an acute rise in sCr can indicate several pathophysiological processes with worsened patient population outcomes. Full-Text PDF The definition of acute kidney injuryWe read with interest the Comment in The Lancet by Jon Barasch and colleagues (Feb 25, 2017, p 779)1 with its controversial title “Acute kidney injury: a problem of definition”. We appreciate the opportunity to clarify what is written in the Kidney Disease Improving Global Outcomes (KDIGO) clinical practice guideline on acute kidney injury (AKI),2 in the hope that clinicians will read beyond the headlines. The guideline clearly states that AKI is a clinical diagnosis and stresses the importance of clinical judgment: “While the definitions and classification system discussed in Chapter 2.1 provide a framework for the clinical diagnosis of AKI, they should not be interpreted to replace or to exclude clinical judgment”. Full-Text PDF