The terms chronic kidney disease (CKD) and chronic renal failure (CRF) are synonyms. It is the gradual decline in renal function that occurs over a period of months to years or the evidence of kidney damage that has been present for at least three months. In the early stages symptoms and signs are often not present. But they do tend to occur in the later stages. Since CKD stages tend to correlate with the symptoms, knowledge of them is important to patients as well as doctors.
There are five stages of chronic kidney disease. Each of the CKD stages except for stage 1 relates to a range of GFRs. Those ranges reflect how well the kidneys are working at a given stage. The various stages are as follows:
- Stage 1 CDK – Kidney damage with normal or high GFR (GFR greater than 90 ml/min)
- Stage 2 CKD – Mild (GFR = 60-89 ml/min)
- Stage 3A CKD – Moderate (GFR = 45-59 ml/min)
- Stage 3B CKD – Moderate (GFR = 30-40 ml/min)
- Stage 4 CKD – Severe (GFR = 15-29 ml/min)
- Stage 5 CKD – End-stage renal disease (ESRD) (GFR is less than 15 ml/min) requires dialysis.
Stage 1 denotes just kidney damage. Markers of kidney damage can be blood tests, urine tests, or imaging studies. Proteinuria is one of the markers most commonly used. Note that state 3 consists of two sub-stages.
Chronic Kidney Disease Symptoms and Signs
CKD symptoms and signs vary from one patient to the next and are frequently not present at all in stages 1-3 of the disease. Signs and symptoms usually appear during stages 4 and 5 when the GFR is between 20 to 35 percent of normal. They might range from a few to many, if not most, of the gamut of uremia. The number and the severity of the expressions of CKD often vary from one person to the next. One reason is how quickly the stages 4 and 5 develop. Another reason is the systems and organs affected; of which genetic factors appear to play a role.
Chronic kidney disease symptoms and signs are due to a number of disturbances. The most obvious is the lost ability to produce urine. Less obvious though are the absence of or decline in the ability to excrete end products of metabolism and the other kidney functions.
Urine output can be increased, decreased or normal in the setting of end-stage chronic renal failure because it is not determine only by GFR. Other factors such as renal tubular function, volume expansion due to retained sodium and osmotic diuresis from urea also play a role. Therefore, the amount of urine that one produces is not a good indicator of CKD. A change in the amount might be though. The new onset of nocturia might also be a clue.
There is a myriad of signs and symptoms of end-stage CKD; many are nonspecific. Therefore, it is not practical to commit them to rote. Instead, it is more insightful to acknowledge that uremia can affect almost every system of the body; then become aware of the secondary diseases that it can cause; then connect the dots in terms of the uremic symptoms and signs that they can give rise to. To begin that process click here.