From the Guidelines
Impaired Renal Function Diagnosis and Treatment: The diagnosis of impaired renal function, also known as chronic kidney disease (CKD), is based on the patient's history, physical examination, and laboratory evaluation, including serum creatinine and urine analysis 1.
Diagnosis
- Stages of CKD: The disease is classified into five stages based on the estimated glomerular filtration rate (GFR), with stage 1 being the least severe and stage 5 being kidney failure 1.
- Laboratory Evaluation: Laboratory tests, such as serum creatinine, blood urea nitrogen, and urine microscopy, are used to evaluate kidney function and detect any abnormalities 1.
- Imaging Studies: Imaging studies, such as ultrasound, may be used to evaluate kidney structure and detect any abnormalities 1.
Treatment
- Treatment of Comorbid Conditions: Treatment of comorbid conditions, such as hypertension and diabetes, is essential to slow the progression of kidney disease 1.
- Medications: Medications, such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), may be used to control blood pressure and slow the progression of kidney disease 1.
- Lifestyle Modifications: Lifestyle modifications, such as a low-protein diet and regular exercise, may be recommended to slow the progression of kidney disease 1.
- Referral to a Specialist: Patients with CKD should be referred to a specialist, such as a nephrologist, for consultation and comanagement if their primary care physician cannot adequately evaluate and treat them 1.
Clinical Action Plan
- Stage 1 and 2: Treatment of comorbid conditions, interventions to slow progression of kidney disease, and measures to reduce the risk for cardiovascular disease (CVD) should begin during stage 1 and stage 2 1.
- Stage 3: Evaluation and treatment of other complications of decreased GFR, such as anemia, malnutrition, bone disease, neuropathy, and decreased quality of life, should be undertaken during stage 3 1.
- Stage 4 and 5: Preparation for kidney replacement therapy should begin during stage 4, and initiation of dialysis and transplantation is triggered by the onset of uremic symptoms 1. The clinical action plan for each stage should include actions begun in preceding stages 1.
From the Research
Diagnosis of Impaired Renal Function
- Impaired renal function, also known as chronic kidney disease (CKD), is defined by persistent urine abnormalities, structural abnormalities, or impaired excretory renal function suggestive of a loss of functional nephrons 2.
- The diagnosis is usually made on the basis of an abnormal glomerular filtration rate (GFR < 60 mL/min/1.73 m2) and/or the presence of proteinuria (urine albumin to creatinine ratio > 30 mg/g or >3 mg/mmol) 3.
- GFR is usually estimated from serum creatinine concentration using a variety of validated equations, but serum creatinine may not be an accurate marker of GFR in people with high or low muscle mass 3.
- Cystatin C is an alternative endogenous marker of GFR that is increasingly being used, but also has limitations 3.
Treatment of Impaired Renal Function
- The management of patients with CKD is focused on early detection or prevention, treatment of the underlying cause (if possible) to curb progression, and attention to secondary processes that contribute to ongoing nephron loss 2.
- Blood pressure control, inhibition of the renin-angiotensin system, and disease-specific interventions are the cornerstones of therapy 2.
- 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 4.
- In patients with type 1 hepatorenal syndrome (HRS), liver transplantation is the ideal treatment, and systemic vasoconstrictor therapy with terlipressin, noradrenaline, or midodrine may improve renal function while waiting for liver transplantation 5.
- Synbiotic supplementations may reduce blood urea nitrogen in patients with CKD, but have no effect on other markers of kidney function 6.