From the Guidelines
Impaired Renal Function is typically diagnosed and treated based on the underlying cause, which can be Acute Kidney Injury (AKI) or Chronic Kidney Disease (CKD).
Diagnosis
- The diagnosis of AKI is based on an increase in serum creatinine by 0.3 mg/dL within 48 hours or an increase in serum creatinine to 1.5 times baseline (within prior 7 days) or urine volume 0.5 mL/kg/hr for 6 hours 1.
- CKD is defined as an abnormality of kidney structure or function, present for >3 months, with health consequences, and is typically diagnosed using estimated GFR (eGFR) calculated using serum creatinine and standard equations 1.
Treatment
- Treatment of AKI depends on the underlying cause, and may involve fluid management, electrolyte management, and renal replacement therapy (dialysis or hemofiltration) in severe cases 1.
- Treatment of CKD typically involves lifestyle modifications, such as dietary changes and exercise, as well as medications to control hypertension and diabetes, which are common risk factors for CKD 1.
Monitoring
- Regular monitoring of renal function is crucial in patients with heart failure, as it can help identify Worsening Renal Function (WRF), a state of pre-AKI that can be prevented or ameliorated with early intervention 1.
- Monitoring should include serum creatinine, eGFR, and urine output, as well as biomarkers such as albuminuria and urinary sediment 1.
- Renal biopsy may be indicated in certain cases to differentiate between nephritic and nephrotic syndromes 1.
From the Research
Diagnosis of Impaired Renal Function
- Impaired renal function can be diagnosed by evaluating blood parameters and kidney function, including the determination of glomerular filtration rate 2
- Chronic kidney disease (CKD) is defined by persistent urine abnormalities, structural abnormalities or impaired excretory renal function suggestive of a loss of functional nephrons 3
- Risk factors for the development and progression of CKD include low nephron number at birth, nephron loss due to increasing age and acute or chronic kidney injuries caused by toxic exposures or diseases 3
Treatment of Impaired Renal Function
- Treatment of impaired renal function depends on the underlying cause, and may include fluid replacement, blood pressure control, inhibition of the renin-angiotensin system and disease-specific interventions 3
- In patients with CKD, synbiotic supplementations may reduce blood urea nitrogen levels, but have no effect on other markers of kidney function 4
- In patients with cirrhosis and acute renal failure, treatment targets the cause of hypoperfusion, and fluid replacement is used to treat 'non-HRS' prerenal failure, while liver transplantation is the ideal treatment for type 1 hepatorenal syndrome (HRS) 5
- In patients with acute myocardial infarction and impaired renal function, prompt recognition of the degree of renal function impairment and institution of appropriate preventive and therapeutic measures, such as the use of iso-osmotic contrast agents and appropriate hydration, are necessary to reduce the risk of contrast-induced nephropathy 2
- In patients with heart failure and impaired renal function, reduction of angiotensin II levels with angiotensin-converting enzyme (ACE) inhibitors may prevent glomerular hyperfiltration and ultimately preserve renal function, but should be initiated when the patient is volume replete 6