An estimated 1 in 5 hospital admissions in the UK is associated with acute kidney injury¹, providing a clear illustration of the need for novel, rapid detection methods. Our latest whitepaper looks at this common condition and the links between Acute Kidney Injury and Antimicrobial Stewardship. For more details on the things discussed in this article, you can download the full whitepaper below.

Acute Kidney Injury

Acute Kidney Injury is defined as a sudden loss of kidney function. This causes a disruption in the kidneys’ ability to filter waste out of your blood resulting in an accumulation of waste products as well as other imbalances.

The loss of kidney function is the result of a sudden reduction in glomerular filtration rate (GFR), the process through which waste is extracted from the blood and is often reversible².

Aetiology of Acute Kidney Injury

The differential pressure existing between the glomerulus and Bowman’s is the driving mechanism for glomerular filtration². This pressure contrast is influenced by the combined resistances of the afferent (leading to the glomerulus) and efferent (leading away from the glomerulus) vascular pathways in the kidney. Under normal kidney function, these resistances are in equilibrium, facilitating the proper functioning of the GFR. For example, an increase in efferent resistance restricts the blood flow out of the kidney, elevating pressure inside the kidney and reducing GFR, and vice versa². However, in AKI, the decline in renal blood flow and GFR has a pathological origin. The pathophysiology of AKI can be classified as prerenal, intrinsic renal, or postrenal.

Pre-renal Acute Kidney Injury

Pre-renal AKI is caused by reduced afferent blood flow or, in other words, increased afferent resistance. While tubular and glomerular functions generally remain intact, pre-renal AKI may be caused by systemic hypoperfusion (decreased blood flow) or selective hypoperfusion to the kidney, caused by renal artery stenosis or aortic dissection³.

Intrinsic Renal Acute Kidney Injury

Renal AKI describes the conditions which affect the glomerulus or tubule, for example, acute tubular necrosis and acute interstitial nephritis. This collection of conditions is associated with vasoconstrictor expression in renal afferent pathways².

Post-renal Acute Kidney Injury

Post-renal AKI usually results from an obstruction in the filtration system. Causes of obstruction include kidney stones, tumours, or blood clots, commonly in the bladder outlet. Obstruction affecting one side might not invariably lead to acute kidney injury, especially when the impediment develops slowly, such as with tumour growth. This is because the unaffected kidney might be able to adjust and make up for the compromised functionality³

Symptoms & Treatment

AKI often manifests with decreased urine output as its primary symptom. However, additional symptoms, when present, can encompass fatigue, nausea, vomiting, or confusion⁴. To achieve an accurate diagnosis, a comprehensive review of the patient’s medical history and a physical examination are essential to identify the underlying cause of the condition.

The treatment and management of AKI are contingent upon the root cause of the condition. In milder cases, measures are implemented to maintain appropriate levels of fluid, electrolytes, and blood pressure. Nutritional support may also be administered when necessary. In the most severe instances of AKI, dialysis may be warranted to compensate for the diminished kidney function⁵.

Creatinine serves as a valuable diagnostic tool for evaluating renal conditions, including kidney health, GFR, and muscular dystrophy. However, abnormal serum creatinine (SCr) levels only become evident when a significant portion of the renal mass is compromised. The kidneys possess an impressive capacity to adapt to reduced function, which means that a considerable loss of function or GFR is necessary to influence SCr levels. This poses a challenge when it comes to early detection of AKI⁶.

Novel biomarkers, KIM-1, NGAL, Clusterin, and Cystatin C, are associated with AKI² and can be analysed through molecular testing. These new methods can provide a fast and accurate assessment of an individual’s kidney health, at a much earlier stage than SCr quantification².

Antimicrobial Stewardship

Antimicrobial Stewardship (AMS) programs are specifically crafted to enhance the efficiency of antimicrobial utilization, curtail the emergence of Antimicrobiasl Resistance (AMR), and enhance patient outcomes⁷. These programs encompass a variety of approaches, such as educational initiatives, training, the establishment of guidelines and protocols, ongoing monitoring and feedback regarding antimicrobial usage, and the management of antimicrobial formularies. Through the promotion of prudent antibiotic utilization, AMS programs contribute to the safeguarding of the efficacy of currently available antimicrobial agents and the deceleration of AMR development⁷.

Antibiotics and Acute Kidney Injury

Various antibiotics are associated with the progression of AKI due to their nephrotoxicity which can cause severe damage to the kidneys. These antibiotics include polymyxins, aminoglycosides and the commonly used, vancomycin⁸.

Randox Renal Injury Detection

Using the patented Biochip Technology, the Randox Acute Kidney Injury (AKI) array, available on the Evidence Investigator, simultaneously tests for four novel biomarkers (KIM-1, NGAL, Clusterin, Cystatin C) delivering an early diagnosis and monitoring of treatment efficacy. Multiplex testing better captures reduced renal function, as each biomarker reflects different mechanisms that result in similar injury outputs, allowing for a more accurate picture of the underlying cause of AKI. Along with being able to identify AKI at a much earlier stage, this array provides an accurate and sensitive solution for the diagnosis and monitoring of AKI.

If you’d like some more information on the Randox Acute Kidney Injury Array or would like to add this technology to your laboratory, take a look at our website at https://www.randox.com/acute-kidney-injury/ or get in touch today at marketing@randox.com.