From the Guidelines
Aki signs refer to the clinical signs associated with acute kidney injury (AKI), which include decreased urine output, fluid overload, electrolyte imbalances, and elevated blood urea nitrogen and creatinine levels, as defined by the KDIGO classification 1. These signs develop as the kidneys lose their ability to filter waste products, regulate electrolytes, and maintain fluid balance. According to the most recent study in 2022, AKI should be diagnosed when the serum creatinine increases by ≥0.3 mg/dL within 48 hours or is ≥50% from baseline or when the urine output is reduced below 0.5 mL/kg/h for >6 hours 1.
Key Signs of AKI
- Decreased urine output (oliguria or anuria)
- Fluid overload leading to edema
- Hypertension
- Electrolyte imbalances such as hyperkalemia, metabolic acidosis
- Elevated blood urea nitrogen (BUN) and creatinine levels
- Nausea, vomiting, fatigue, and confusion as uremic toxins accumulate
- Physical examination signs like pulmonary crackles, peripheral edema, and jugular venous distention
Importance of Early Recognition
Early recognition of these signs is crucial for prompt intervention, which typically includes addressing the underlying cause, managing fluid and electrolyte imbalances, and sometimes initiating renal replacement therapy if severe, as recommended by the American College of Radiology in 2021 1.
Variability in Presentation
The severity and presentation of Aki signs vary depending on the cause, extent of kidney damage, and whether the injury is acute or superimposed on chronic kidney disease.
Diagnosis and Classification
The diagnosis and classification of AKI are based on the KDIGO definition, which includes oliguria for > 6 h, rise in SCr level by > 0.3 mg/dl in 2 d or by > 50% in 1 wk 1.
Management
Management of AKI involves addressing the underlying cause, managing fluid and electrolyte imbalances, and sometimes initiating renal replacement therapy if severe.
Prognosis
The prognosis of AKI depends on the underlying cause, severity of kidney damage, and promptness of intervention.
From the Research
Definition and Causes of Acute Kidney Injury
- Acute kidney injury (AKI) is defined as an increase in serum creatinine or a decrease in urine output over hours to days 2.
- The etiology of AKI is conceptually classified into three general categories: prerenal, intrarenal, and postrenal 2, 3.
- AKI can be caused by various medical conditions, including acute tubular necrosis, ischemia, and nephrotoxicity 3.
Diagnosis and Management of Acute Kidney Injury
- A thorough history and physical examination can help categorize the underlying cause of AKI 2.
- Initial evaluation and management of AKI includes laboratory work-up, medication adjustment, identification and reversal of underlying cause, and referral to appropriate specialty care 2.
- Furosemide, a potent loop diuretic, is frequently used in different stages of AKI, but its clinical roles remain uncertain 4.
- The use of furosemide in AKI management is associated with reduced in-hospital mortality and improved recovery of renal function in critically ill patients 5.
Complications and Outcomes of Acute Kidney Injury
- Even one episode of AKI increases the risk of cardiovascular disease, chronic kidney disease, and death 2.
- AKI is associated with substantial morbidity and mortality, as well as increased risk of chronic kidney disease (CKD) 3.
- The timely and accurate identification of AKI and a better understanding of the pathophysiological mechanisms that cause kidney dysfunction are essential 3.
- Post-AKI risk of long-term sequelae includes incident or progression of chronic kidney disease, cardiovascular events, and mortality 6.