Clinical Manifestations of Stage 5 Chronic Kidney Disease
All of these manifestations may be seen in stage 5 CKD, including GFR ≤ 15 mL/min, elevated BUN, elevated creatinine, and hyperkalemia.
Defining Stage 5 CKD
Stage 5 CKD is defined by a GFR <15 mL/min/1.73 m² and represents kidney failure requiring replacement therapy. 1 This stage indicates loss of more than 85% of kidney function and necessitates dialysis or transplantation. 2
Laboratory Abnormalities in Stage 5 CKD
Glomerular Filtration Rate
- GFR ≤ 15 mL/min/1.73 m² is the defining criterion for stage 5 CKD according to KDIGO guidelines 1
- This threshold represents the most advanced stage of chronic kidney disease 1
Elevated Blood Urea Nitrogen (BUN)
- Increased BUN levels occur due to accumulation of uremic toxins as kidney function declines 1
- Elevated BUN is responsible for high salivary pH and buffering capacity in CKD patients 1
- BUN elevation contributes to uremic symptoms including ammonia taste and breath 1
Elevated Creatinine
- Serum creatinine rises progressively as GFR declines 1
- Creatinine levels are used in validated equations (MDRD, CKD-EPI) to estimate GFR 1
- Elevated creatinine reflects decreased renal clearance capacity 1
Electrolyte Disturbances Including Hyperkalemia
- Electrolyte and acid-base disturbances are characteristic clinical manifestations of renal failure 1
- Hyperkalemia occurs due to impaired potassium excretion by failing kidneys 3
- Patients require monitoring for hyperkalemia, metabolic acidosis, and hyperphosphatemia 3
Additional Clinical Manifestations
Uremic Syndrome
As kidney function decreases, toxins accumulate in the blood affecting multiple organ systems, collectively termed uremia. 1 This includes:
- Uremic frost, renal osteodystrophy, and asterixis 1
- Coagulation defects and congestive heart failure 1
- Ammonia taste and breath 1
- Growth delays in children and hypertension 1
Cardiovascular Complications
- CKD stage 5 patients have extremely high cardiovascular mortality risk with 3-year and 5-year survival rates of only 55% and 40% respectively on dialysis 2
- Cardiovascular complications are the most common causes of death in patients with kidney failure 4
Symptom Burden
- Patients with stage 5 CKD experience considerable symptom burden including lack of energy (76%), pruritus (74%), drowsiness (65%), dyspnea (61%), and pain (53%) 5
- Many patients remain asymptomatic in early CKD stages, with symptoms appearing only in later stages 1
Clinical Pitfall
A common error is relying solely on serum creatinine rather than estimated GFR for staging CKD. 1 GFR should be estimated using validated equations (MDRD or CKD-EPI) that account for age, sex, race, and body size, not simply by measuring serum creatinine and urea nitrogen alone. 1