The Five Stages of Chronic Kidney Disease, Symptoms, Early Diagnosis, and the Importance of Prevention
Kidney dysfunction manifests through the five stages of chronic kidney disease (CKD), also known as chronic renal failure. The loss of kidney function is caused by underlying pathological conditions. A key feature of CKD is that it presents no symptoms during the first two stages. Therefore, CKD is difficult to diagnose in its early stages, making prevention and early diagnosis essential.
Key Data for Diagnosing Chronic Kidney Disease
To diagnose CKD early, it is necessary to monitor specific health values, starting with the Glomerular Filtration Rate (GFR).
This value, along with proteinuria (the presence of proteins in the urine), classifies the stage of kidney disease. Proteinuria can be assessed either over 24 hours or as the albumin-to-creatinine ratio (ACR). The normal GFR range in adults is 100–120 mL/min.
The Five Stages of Chronic Kidney Disease
Stage 1
The first stage is asymptomatic and features a normal or slightly increased GFR. However, this alone is not sufficient for a CKD diagnosis. If proteinuria is also present, it may serve as an early warning sign.
Stage 2
Stage 2 is also asymptomatic, but unlike stage 1, it involves a slight reduction in GFR. If significant proteinuria is detected, an immediate consultation with a nephrologist is recommended. This becomes especially important when GFR is significantly reduced and high albuminuria (excess albumin in the urine) is present.
Stage 3 – The Onset of Renal Insufficiency
Stage 3 of CKD is split into two subcategories. From this stage onward, the condition is considered chronic renal insufficiency, and a nephrologist consultation becomes essential. Stage 3 is marked by a GFR below 60 mL/min.
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Stage 3a may still show no symptoms, but action can be taken to slow disease progression.
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Stage 3b is often accompanied by symptoms like malnutrition, bone pain, nerve numbness, and concentration difficulties. Secondary hyperparathyroidism and anemia due to CKD are also common at this stage.
The nephrologist typically prescribes drug therapy and a specific dietary program to reduce disease progression and prevent metabolic imbalances.
Stage 4
Stage 4 involves a significant drop in GFR and is characterized by noticeable reductions in physical strength and endurance. The nephrologist recommends an even stricter diet with low-protein foods. Erythropoietin supplementation is also prescribed to treat anemia. Metabolic complications become more evident in this stage.
Stage 5
This is the final stage of kidney failure, defined by a GFR below 15 mL/min. At this point, the patient enters a predialysis phase under the nephrologist’s supervision. Several factors are assessed to determine whether dialysis should begin:
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Elevated blood urea nitrogen (BUN)
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Changes in urination frequency
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Presence of edema (swelling)
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Anemia
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High levels of parathyroid hormone (PTH) and phosphorus
Dialysis becomes necessary when these factors can no longer be managed through diet alone.
Prevention
As with other diseases, prevention is crucial for chronic kidney disease and kidney failure. In CKD, prevention is even more important, as early stages typically lack warning signs.
The first step in identifying potential kidney disease is to evaluate renal function through GFR testing, along with measurements of creatinine and albumin levels in the urine.
Blood tests—especially for creatinine, albumin, urea, sodium, potassium, calcium, PTH, and complete blood count—along with urinalysis, help monitor the disease’s progression toward advanced stages and are the primary tools for early detection.
At Nefrocenter’s Centers of Excellence, all laboratory tests needed for the prevention, diagnosis, and treatment of chronic kidney disease are available.